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Colossus.html
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<h2>Contents</h2>
<ul>
<li><a href="#What_is_Colossus_">What is "Colossus"?</a></li>
<li><a href="#Its_Always_Sunny_in_Outer_Space_">It's Always Sunny
in Outer Space</a></li>
<li><a href="#Known_Software_Versions">Known Software Versions</a></li>
<li><a href="#Source_Code_and_Binary">Source Code and Binary</a></li>
<li><a href="#Validity">Validation</a></li>
<ul>
<li><a href="#ValidityApollo9">Validity of the Colossus 249 Code
(Apollo 9)</a></li>
<ul>
<li><a href="#A_Tour_of_the_Source_Materials">A Tour of the
Source Materials</a></li>
<li><a href="#Proofing_in_the_Usual_Case">Proofing in the
Usual Case</a></li>
<li><a href="#Proofing_in_Extraordinary_Cases_">Proofing in
Extraordinary Cases</a></li>
<li><a href="#When_All_Else_Fails">When All Else Fails—Digital
Archaeology</a></li>
<li><a href="#Happy_Epilogue">Happy Epilogue!</a></li>
</ul>
<li><a href="#ValidityApollo11">Validity of the Comanche 055
Code (Apollo 11)</a></li>
<li><a href="#ValiditySource15">Validity of Artemis 072 Code
(Apollo 15-17)</a></li>
<li><a href="#ValidityApollo8">Validity of Colossus 237 (Apollo
8)</a></li>
<li><a href="#Validity_of_Solarium_055_Apollo_4">Validity of
Solarium 055 (Apollo 6)</a><br>
</li>
</ul>
</ul>
<h2><a name="What_is_Colossus_"></a><small><big>What is "Colossus"?</big><br>
</small></h2>
<span style="font-weight: bold;">Colossus</span> is the program
which was run on the Apollo Guidance Computer installed in the
Command Module (CM). In order to be loaded into the
AGC—actually, to be converted to the "core ropes" within the AGC—it
was necessary to "assemble" <span style="font-weight: bold;">Colossus</span>'s
source code into binary machine language, using a computer program
called <span style="font-weight: bold;">YUL</span>. In the
context of the Virtual AGC project, of course, the process is
somewhat different: <span style="font-weight: bold;">Colossus</span>
source code is assembled by the <span style="font-weight: bold;">yaYUL</span>
program, and then loaded into the <span style="font-weight: bold;">yaAGC</span>
simulation.<br>
<h2><a name="Its_Always_Sunny_in_Outer_Space_"></a>It's Always Sunny
in Outer Space<br>
</h2>
<a href="AGC-versions.jpg"><span style="font-weight: bold;"><img
alt="AGC software family tree" title="Click on the image to
enlarge." src="AGC-versions-thumb.jpg" style="border: 2px
solid ; width: 132px; height: 160px;" width="219" hspace="16"
height="360" border="0" align="left"></span></a><a
href="a042186-051.jpg"><span style="font-weight: bold;"><img
src="a042186-051-small.jpg" alt="" width="140" height="160"
border="2" align="right"></span></a><a href="a042186-033.jpg"><img
src="a042186-033-small.jpg" alt="" width="116" height="160"
border="2" align="right"></a><a href="R700-3-Table4-11.jpg"><img
alt="" title="Click to enlarge" src="R700-3-Table4-11-small.jpg"
width="171" hspace="16" height="160" border="2" align="right"></a>Programs
with names like <span style="font-weight: bold;">Sundisk</span>, <span
style="font-weight: bold;">Solarium</span>, and <span
style="font-weight: bold;">Sunspot</span> were pre-<span
style="font-weight: bold;">Colossus</span> versions of the Command
Module AGC's software. They were not forms of <span
style="font-weight: bold;">Colossus</span> as such, but provided
some code for <span style="font-weight: bold;">Colossus</span>.
If you click on the image to the left, you can see a simplified
family tree for <span style="font-weight: bold;">Colossus</span>,
drawn by me, while if you click on the tables to the right depicts
the various versions of the software from Apollo-era documents.<br>
<br>
The <span style="font-weight: bold;">Colossus</span> program
eventually had three major versions, not surprisingly known as <span
style="font-weight: bold;">Colossus</span> 1, <span
style="font-weight: bold;">Colossus</span> 2, and <span
style="font-weight: bold;">Colossus</span> 3. Additionally,
there were minor versions such as <span style="font-weight: bold;">Colossus</span>
1A, <span style="font-weight: bold;">Colossus</span> 2C, and so on.<br>
<br>
<span style="font-weight: bold;">Colossus</span> 2 was also referred
to by the separate name of <span style="font-weight: bold;">Comanche</span>.
I'm not fully aware of how the versioning within the "Colossus 2"
nomenclature was interrelated to versioning within the "Comanche"
nomenclature, but here are some relationships I'm sure of:<br>
<br>
<div style="text-align: center;">
<table summary="" style="width: 50%; text-align: left;
margin-left: auto; margin-right: auto;" cellspacing="2"
cellpadding="2" border="1">
<tbody>
<tr>
<th style="text-align: center; vertical-align: middle;">
Colossus<br>
</th>
<th style="vertical-align: top; text-align: center;">
Comanche<br>
</th>
</tr>
<tr>
<td style="vertical-align: top; text-align: center;"> 2<br>
</td>
<td style="vertical-align: top; text-align: center;">Rev. 44
and Rev. 45<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: center;"> 2A<br>
</td>
<td style="vertical-align: top; text-align: center;">Rev. 51
and Rev. 55<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: center;"> 2C<br>
</td>
<td style="vertical-align: top; text-align: center;">Rev. 67<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: center;"> 2D<br>
</td>
<td style="vertical-align: top; text-align: center;">Rev. 72<br>
</td>
</tr>
</tbody>
</table>
<div style="text-align: left;"> <br>
Additionally, <span style="font-weight: bold;">Colossus</span>
3 was referred to by the separate name of <span
style="font-weight: bold;">Artemis</span>. <span
style="font-weight: bold;"><br>
<br>
</span> Finally, <span style="font-weight: bold;">Skylark</span>
was post-<span style="font-weight: bold;">Colossus</span>
Command-Module software. I suspect that it was probably <span
style="font-weight: bold;">Colossus</span> with features added
or removed, but I have no real evidence for this suspicion.<span
style="font-weight: bold;"><br>
<br>
</span> Of course, the command-modules themselves are still in
existence, though that doesn't imply they still contain their
AGCs. Zach Greene has compiled the following partial list:<br>
<ul>
<li><font size="2"><span style="font-size: 10pt;">Apollo 7 is
located at the Frontiers of Flight Museum in Dallas,
Texas</span></font></li>
<li><font size="2"><span style="font-size: 10pt;">Apollo 9 is
located in the</span></font> <font size="2"><span
style="font-size: 10pt;">San Diego</span></font> <font
size="2"><span style="font-size: 10pt;">Aerospace</span></font>
<font size="2"><span style="font-size: 10pt;">Museum</span></font></li>
<li><font size="2"><span style="font-size: 10pt;">Apollo 10 is
located at the</span></font> <font size="2"><span
style="font-size: 10pt;">Science</span></font> <font
size="2"><span style="font-size: 10pt;">Museum</span></font>
<font size="2"><span style="font-size: 10pt;">in</span></font>
<font size="2"><span style="font-size: 10pt;">London</span></font></li>
<li><font size="2"><span style="font-size: 10pt;">Apollo 11 is
located at the National Air and</span></font> <font
size="2"><span style="font-size: 10pt;">Space</span></font>
<font size="2"><span style="font-size: 10pt;">Museum</span></font>
<font size="2"><span style="font-size: 10pt;">in</span></font>
<font size="2"><span style="font-size: 10pt;">Washington</span></font>
<font size="2"><span style="font-size: 10pt;">D.C.</span></font></li>
<li><font size="2"><span style="font-size: 10pt;">Apollo 12 is
located at the Virginia Air and</span></font> <font
size="2"><span style="font-size: 10pt;">Space</span></font>
<font size="2"><span style="font-size: 10pt;">Museum</span></font>
<font size="2"><span style="font-size: 10pt;">in</span></font>
<font size="2"><span style="font-size: 10pt;">Hampton</span></font><font
size="2"><span style="font-size: 10pt;">,</span></font> <font
size="2"><span style="font-size: 10pt;">Virginia</span></font></li>
<li><font size="2"><span style="font-size: 10pt;">Apollo 13 is
located at the Kansas Cosmosphere and</span></font> <font
size="2"><span style="font-size: 10pt;">Space</span></font>
<font size="2"><span style="font-size: 10pt;">Center</span></font><font
size="2"><span style="font-size: 10pt;">.</span></font></li>
<li><font size="2"><span style="font-size: 10pt;">Apollo 14 is
located at the Astronaut Hall of Fame in</span></font> <font
size="2"><span style="font-size: 10pt;">Titusville</span></font><font
size="2"><span style="font-size: 10pt;">,</span></font> <font
size="2"><span style="font-size: 10pt;">Florida</span></font></li>
<li><font size="2"><span style="font-size: 10pt;">The Apollo
Soyuz CM is located at</span></font> <font size="2"><span
style="font-size: 10pt;">California</span></font> <font
size="2"><span style="font-size: 10pt;">Space</span></font>
<font size="2"><span style="font-size: 10pt;">Center</span></font>
<font size="2"><span style="font-size: 10pt;">in</span></font>
<font size="2"><span style="font-size: 10pt;">Los Angeles</span></font><font
size="2"><span style="font-size: 10pt;">,</span></font> <font
size="2"><span style="font-size: 10pt;">California</span></font></li>
</ul>
</div>
</div>
<h2><a name="Known_Software_Versions"></a>Known Software Versions</h2>
<h3>Summary of the Versions Available Here at this Site<br>
</h3>
<ul>
<li>Sample Block I — <a href="listings/TRIVIUM/MAIN.agc.html">TRIVIUM</a>
and <a href="listings/TRIVIUM-repaired/MAIN.agc.html">TRIVIUM-repaired</a><br>
</li>
<li><a href="listings/Solarium055/MAIN.agc.html">Apollo 6
(unmanned mission) — Solarium, build 055</a></li>
<li><a href="listings/Colossus237/MAIN.agc.html">Apollo 8
—Colossus 1, build 237</a><br>
</li>
<li><a href="listings/Colossus249/MAIN.agc.html">Apollo 9 —
Colossus 1A, build 249</a><br>
</li>
<li><a href="listings/Comanche055/MAIN.agc.html">Apollo 11 —
Colossus 2A (Comanche), build 55</a><br>
</li>
<li><a href="listings/Artemis072/MAIN.agc.html">Apollo 15-17 (all
the same) — Colossus 3 (Artemis), build 72</a><br>
</li>
</ul>
<h3>Highlighted Versions, in Gory Detail, Whether We Have Them or
Not</h3>
Information in the following table was taken from online sources,
rather than from official software-configuration documentation, and
should not be regarded as authoritative.<br>
<table summary="" style="width: 95%; text-align: left; margin-left:
auto; margin-right: auto;" cellspacing="2" cellpadding="2"
border="1">
<tbody>
<tr>
<td style="font-weight: bold; text-align: center;"> Mission</td>
<td style="text-align: center;"><span style="font-weight:
bold;">CSM number</span><br>
</td>
<td style="font-weight: bold; text-align: center;">CM Program</td>
<td style="font-weight: bold; text-align: center;"> Version</td>
<td style="font-weight: bold; text-align: center;">Source Code<br>
</td>
<td style="text-align: center;"><span style="font-weight:
bold;">Mission-specific documentation</span><br>
</td>
<td style="font-weight: bold; text-align: center;"
valign="middle">Where is it now?</td>
</tr>
<tr>
<td valign="middle" align="center">n/a<br>
</td>
<td valign="middle" align="center">n/a<br>
</td>
<td valign="middle" align="center"><b>TRIVIUM</b><br>
</td>
<td valign="middle" align="center">12/1963<br>
</td>
<td valign="middle" align="center"><a
href="ScansForConversion/TRIVIUM">Scanned pages</a><br>
<br>
or <br>
<br>
<a href="listings/TRIVIUM/MAIN.agc.html">Colorized HTML</a><br>
</td>
<td valign="middle"><a href="Documents/agcis_13_yul.pdf">AGC
Information Series #13: YUL Programming System</a><br>
</td>
<td valign="middle"><a name="TRIVIUM"></a>This is an unusual
program, in that its sole purpose was to demonstrate usage
of the original AGC assembler, YUL. In fact, its very
short program listing (only one page of source code!) was
attached to a 1963 manual (hyperlinked at left) for
YUL. The document itself was obtained from the
personal papers of the late Russel Larson.<br>
<br>
The program is for a Block I AGC, and thus is not only one
of the very few Block I AGC programs that has survived, but
is probably the earliest such program that will ever be
found.<br>
<br>
The program itself contains a pedagogically deliberate error
— one of the variables it references is not defined within
the program — and thus YUL could not fully assemble
it. Besides that error, there are three
also-deliberate items in the program that are not aligned at
the proper punch-card columns: one program label, one
operator, and one operand. YUL was apparently fine
with those misalignments, though our modern assembler, <a
href="yaYUL.html">yaYUL</a>, is not, and it treats two of
them as errors. In spite of all that, however, yaYUL's
assembly of the code is remarkably like YUL's.<br>
<br>
Because TRIVIUM contained these deliberate errors and
oddities, we're actually providing it for you in two
forms: TRIVIUM (as hyperlinked at the left)
corresponds exactly to the original program, errors and all,
while <a href="listings/TRIVIUM-repaired/MAIN.agc.html">TRIVIUM-repaired</a>
fixes those errors, and thus assembles as a
syntactically-correct program.<br>
<br>
However ... you may notice that the program identifies
itself as being by "IMA NIT-PICKER". I surmised that
IMA may really have been Hugh Blair-Smith, and Hugh tells me
that that is indeed true. The name IMA NIT-PICKER is
actually a tongue-and-cheek reference to Richard Volpi, the
principal author of the AGC Information Series document
(hyperlinked at the left) in which the program
appears. Richard apparently tended to pay an enormous
amount of attention to detail, and hence (Hugh says) was the
<i>true</i> nit-picker. (See also the comments about
Volpi in Hugh's book, <a
href="https://www.amazon.com/Left-Brains-Right-Stuff-Computers/dp/0996434534">Left
Brains for the Right Stuff</a>.) <br>
<br>
Amusingly, though, in reviewing the program after all these
years (about 55 of them!), Hugh was surprised to notice that
even with the assembly-time error fixed, the program does
not actually work. Given that the program is less than
20 lines long altogether, that may hint at some of the
difficulties involved in writing AGC software. As to
exactly what's wrong with the program, I leave that as an
exercise for the reader!<br>
</td>
</tr>
<tr>
<td valign="middle" align="center">Apollo 3<br>
(AS-202)<br>
</td>
<td valign="middle" align="center">CSM-011<br>
</td>
<td valign="middle" align="center"><b>Corona</b><br>
</td>
<td valign="middle" align="center">261<br>
</td>
<td valign="middle" align="center"><br>
</td>
<td valign="middle"><span style="text-decoration: underline;">GSOP
(R-477)</span><br>
<ul>
<li><a href="Documents/R477-AS202-GSOP.pdf">Initial
version</a></li>
<li><a href="Documents/R477-AS202-GSOP-Rev1.pdf">Revision
1</a></li>
<li><a href="Documents/R477-AS202-GSOP-Rev2.pdf">Revision
2</a><br>
</li>
</ul>
"<a
href="Documents/ApolloExperienceReport-GuidanceAndControlSystems-MissionControlProgramerForUnmannedMissionsAS202Apollo4Apollo6.pdf">Apollo
Experience Report—Guidance and Control Systems: Mission
Control Programer for Unmanned Missions AS-202, Apollo 4,
and Apollo 6</a>"<br>
<br>
"<a
href="Documents/Programming%20Changes%20from%20AS-202%20to%20AS-501.pdf">Programming
Changes from AS-202 to AS-501</a>"<br>
<br>
"<a
href="Documents/E-1828%20G&N%20System%20Data%20for%20Mission%20AS-202,%20Development%20Engineering%20Inspection.pdf">G&N
System Data for Mission AS-202 Development Engineering
Inspection</a>"<br>
</td>
<td valign="middle"> Quoting from the wikipedia article:<br>
<blockquote> <small><b>"AS-202</b> (also referred to as <b>SA-202</b>)
was the second unmanned, suborbital test flight of a
production Block I <a
href="https://en.wikipedia.org/wiki/Apollo_Command/Service_Module"
title="Apollo Command/Service Module">Apollo
Command/Service Module</a> launched with the <a
href="https://en.wikipedia.org/wiki/Saturn_IB"
title="Saturn IB">Saturn IB</a> launch vehicle. It was
launched on August 25, 1966 and was the first flight
which included the spacecraft Guidance and Navigation
Control system and <a
href="https://en.wikipedia.org/wiki/Fuel_cell"
title="Fuel cell">fuel cells</a>. The success of this
flight enabled the Apollo program to judge the Block I
spacecraft and Saturn IB ready to carry men into orbit
on the next mission, <a
href="https://en.wikipedia.org/wiki/Apollo_1"
title="Apollo 1">AS-204</a>."</small><br>
</blockquote>
In case you're wondering about the designation "Apollo 3",
which is not mentioned specifically in the wikipedia
article, that is how the mission is referenced in the
Instrumentation Lab's report <a href="hrst/archive/967.pdf">R-700,
MIT's Role in Project Apollo</a>, from which a lot of the
software-versioning information here comes, and frankly,
it's just catchier than "AS-202".<br>
<br>
A fellow named Francois Rautenbach has <i>physically
extracted</i> the contents of the rope memory from this
specific AGC, which, he says, was "found on a rubbish dump"
some time after the mission. He has posted a YouTube
video of the extraction process which is interesting to
watch, and includes information about the mission itself
(including video) as well:<br>
<div align="center"> <iframe
src="https://www.youtube.com/embed/WquhaobDqLU?feature=player_detailpage"
allowfullscreen="" width="640" height="360"
frameborder="0">&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;br&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;</iframe><br>
<br>
<div align="left"> Right now, the data Francois extracted
is simply in the form of stored electrical waveforms,
and isn't even a machine-readable file of octal
data. But with some luck, perhaps we can convert
this waveform data into an octal dump of the rope, and
from that point, convert it back into Block 1 AGC source
code, to be presented here. Right now this is just
a plan rather than a reality, so stay tuned!<br>
<br>
It may not be immediately obvious to you what the
significance of the document "Programming Changes from
AS-202 to AS-501, hyperlinked at the left is. The
significance is that we <i>have</i> the source code for
AS-502 (Solarium 55, see below), which is almost
identical, or indeed perhaps even <i>exactly identical</i>
to AS-501 (Solarium 54). Thus if we knew the
changes between AS-202 and AS-501, it might help us
reconstruct the Corona source code from Solarium 55
source code, and those change are exactly what the
document gives us. The document was contributed by
AGC developer Jay Sampson, who actually coded the
changes!<br>
</div>
</div>
</td>
</tr>
<tr>
<td style="text-align: center;">Apollo 1<br>
(AS-204A)<br>
</td>
<td style="text-align: center;">CSM-012<br>
</td>
<td style="text-align: center;"><span style="font-weight:
bold;">Sunspot</span><br>
</td>
<td style="text-align: center;">≥247<br>
</td>
<td><br>
</td>
<td style="text-align: left;"><u>GSOP (R-507)</u><br>
<ul>
<li>Volume I</li>
<li><a href="Documents/R507-AS204A-205-GSOP-Volume-II.pdf">Volume
II</a></li>
</ul>
<a href="WebMirror/SM2A-03-SC012.pdf">Operations Handbook</a><br>
<br>
"<a
href="Documents/TRW-66-FMT-470%20Independent%20Flight%20Software%20Validation%20Test%20Results%20for%20Mission%20AS-204A.pdf">Independent
Flight Software Validation Test Results for Mission
AS-204A</a>"<br>
</td>
<td style="vertical-align: top;" valign="middle">Yes, Apollo 1
never flew, but it deserves a place of honor. I'd sure
like to know where this program can be found!<br>
<br>
This was a Block I spacecraft.<br>
<br>
The exact version of SUNSPOT that would have flown isn't
presently known to me, but SUNSPOT 247 is the version TRW
evaluated in the independent validation testing hyperlinked
at the left. Therefore, the version that would have
been in the AGC at mission time must be at least 247, but
probably higher.<br>
</td>
</tr>
<tr>
<td style="text-align: center;">Apollo 4<br>
(AS-501)<br>
</td>
<td style="text-align: center;">CSM-017<br>
</td>
<td style="text-align: center;"><span style="font-weight:
bold;">Solarium</span><br>
</td>
<td style="text-align: center;">54<br>
</td>
<td style="text-align: center;">See the comments at the far
right.<br>
<a href="ScansForConversion/Solarium055/"> </a></td>
<td style="text-align: left;">GSOP (R-537)<br>
<ul>
<li><a href="Documents/R537-AS501-GSOP-Volume-I.pdf">Volume
I</a><br>
</li>
<li><a href="Documents/R537-AS501-GSOP-Volume-II.pdf">Volume
II</a><br>
</li>
<li>Section 8<br>
</li>
</ul>
"<a
href="Documents/ApolloExperienceReport-GuidanceAndControlSystems-MissionControlProgramerForUnmannedMissionsAS202Apollo4Apollo6.pdf">Apollo
Experience Report—Guidance and Control Systems: Mission
Control Programer for Unmanned Missions AS-202, Apollo 4,
and Apollo 6</a>"<br>
<br>
"<a
href="Documents/Programming%20Changes%20from%20AS-202%20to%20AS-501.pdf">Programming
Changes from AS-202 to AS-501</a>"<br>
<br>
<a
href="Documents/Trip%20Report%20on%20AS-501%20Meeting%20at%20MIT-IL%20on%20July%206%201967.pdf">"Trip
Report on AS-501Meeting at MIT/IL on July 6, 1967"</a><br>
<br>
"<a
href="Documents/Apollo%20Mission%20SA%20501%20Preliminary%20Mission%20Profile.pdf">Apollo
Mission SA 501 Preliminary Mission Profile</a>"<br>
<br>
<a href="links.html#Miscellaneous_Mission_Documents">Various
documents specific to this mission</a><br>
</td>
<td style="vertical-align: top;" valign="middle"><a
name="Solarium54"></a>Apollo 4 was an unmanned mission,
but it did have a working CSM and a working AGC in the
CM. <br>
<br>
This was a Block I spacecraft.<br>
<br>
The "Programer"—yes, that's the real spelling, though some
sources do refer to it as the "programmer"—was the gadget
that was the stand-in for the crew.<br>
<br>
By the way, in the GSOP volumes linked to the left, Volumes
I and II are actually separated in time by a few months, and
sections 6-7 overlap between them, but with modifications.<br>
<br>
The "Programming Changes ..." and "Trip Report ..."
documents were contributed by AGC developer Jay Sampson, who
authored them and made the coding changes described in the
former.<br>
<br>
Regarding the software itself: Jay Sampson, who as I
mentioned above coded the changes from the Corona (AS-202)
code to derive Solarium (AS-501), is insistent that there
were no code changes between missions AS-501 (Apollo 4) and
AS-502 (Apollo 6). He does note that he had left MIT
between Apollo 4 and 6 rather than after Apollo 6, and thus
there is a tiny time window in which such changes could have
occurred without his knowledge. Still, he believes
that Solarium 54 is actually 100% identical to Solarium 55
(see below). Jay speculates that they simply rebuilt
the memory rope, without changing the source code, and gave
it a new number.<br>
<br>
Here's a timeline of events which, while odd, completely
support Jay's assertion:<br>
<ul>
<li>According to Instrumentation Lab document <a
href="hrst/967.pdf">R-700, "MIT's Involvement in
Project Apollo", Volume 1</a>, page 20, both Solarium
54 and 55 were released, for Apollo 4 and Apollo 6
respectively, in November of 1966. (And indeed,
there are other documents supported this same factoid.)<br>
</li>
<li>Our copy of Solarium 55 is dated December 4, 1966, and
thus should be from the released version. <a
href="ScansForConversion/Solarium055/0010-P1130128.jpg">For
example, page 10</a>.<br>
</li>
<li>Solarium 54 flew on November 9, 1967, nearly a year
after that.</li>
<li>Solarium 55 flew in April of 1968.<br>
</li>
</ul>
In summary, at this point in time, Jay's account is
reasonable and I have no evidence that would lead me to
believe that Jay is mistaken, thus I would maintain that the
Apollo 4 source code is indeed identical to the Apollo 6
source code described below.<br>
</td>
</tr>
<tr>
<td style="text-align: center;">Apollo 6<br>
</td>
<td style="text-align: center;">CM-020<br>
SM-014<br>
</td>
<td style="text-align: center;"><span style="font-weight:
bold;">Solarium</span><br>
</td>
<td style="text-align: center;">55<br>
</td>
<td><a href="listings/Solarium055/MAIN.agc.html">As colorized,<br>
hyperlinked,<br>
HTML</a><br>
<br>
<a href="ScansForConversion/Solarium055/"> As scanned page
images (<span style="font-style: italic;">very</span>
big!)</a></td>
<td style="text-align: left;"> "<a
href="Documents/ApolloExperienceReport-GuidanceAndControlSystems-MissionControlProgramerForUnmannedMissionsAS202Apollo4Apollo6.pdf">Apollo
Experience Report—Guidance and Control Systems: Mission
Control Programer for Unmanned Missions AS-202, Apollo 4,
and Apollo 6</a>"<br>
<br>
"<a
href="Documents/MSC-PA-R-68-8%20Apollo%206%20Mission%203-Day%20Report.pdf">Apollo
6 Mission 3-Day Report</a>"<br>
</td>
<td style="vertical-align: top;" valign="middle"> Apollo 6 was
an unmanned mission, but it did have a working CSM and a
working AGC in the CM. Eldon C. Hall's copy of this
program listing is in the American Computer Museum, which
has graciously allowed us to digitize the program listing
for use in Virtual AGC.<br>
<br>
<table summary="" style="text-align: left; margin-left:
auto; margin-right: auto;" cellspacing="2" cellpadding="2"
border="1">
<tbody>
<tr>
<td style="vertical-align: top;">
<div style="text-align: center;"> <span
style="font-weight: bold;"><span
style="text-decoration: underline;">Honor Roll</span><br>
</span>
<div style="text-align: left;"> <span
style="font-style: italic;"><br>
<span style="text-decoration: underline;">Organizational
honors</span></span><br>
</div>
</div>
<table summary="" style="text-align: left; width:
100%;" cellspacing="2" cellpadding="2" border="0">
<tbody>
<tr>
<td style="vertical-align: middle;
white-space: nowrap;"> <big><span
style="font-family: sans-serif;">American
Computer Museum</span><br
style="font-family: sans-serif;">
<span style="font-family: sans-serif;">Bozeman,
Montana</span><span style="font-family:
sans-serif;"><br>
<a href="http://www.compustory.com"><small>www.compustory.com</small></a><br>
</span></big></td>
<td style="text-align: center; vertical-align:
middle;"> <span style="text-decoration:
underline;"><a
href="http://www.compustory.com"><img
alt=""
src="AmericanComputerMuseumLogo.jpg"
style="border: 0px solid ; width:
171px; height: 59px;" width="342"
height="117" border="0"></a></span><br>
</td>
</tr>
</tbody>
</table>
<br>
<span style="font-style: italic; text-decoration:
underline;"> Individual honors</span><br>
<ul>
<li>Eldon C. Hall, for his foresight in
preservation, the leads he provided, and for his
overall approval.<br>
</li>
<li>George Keremedjiev, Curator of the American
Computer Museum, for making the listing
available.<br>
</li>
<li>Kim Scott, Archivist of Special Collections,
Renne Library, Montana State University, and
other MSU individuals whose names I do not know,
for helpful and responsible supervision of the
digitization effor.<br>
</li>
<li>Marilyn Chang, Librarian, Wings Over the
Rockies Air & Space Museum, for the
necessary research and contacts.<br>
</li>
<li>Fabrizio Bernardini, for bringing Marilyn into
the loop.</li>
<li>Henry Wesso, for constructing the special copy
stand used for the digitization.</li>
<li>Gil Guerrero, for providing advice and camera
equipment.</li>
<li>Jim Lawton, for single-handedly converting the
page scans to source-code files.<br>
</li>
</ul>
</td>
</tr>
</tbody>
</table>
<br>
This was a block I spacecraft.<br>
<br>
The "Programer"—yes, that's the real spelling, though some
other sources refer to it as the "programmer"—was the gadget
that was the stand-in for the crew. The same physical
programer, not merely the same <span style="font-style:
italic;">type</span> of programer, was used in both the
Apollo 4 and Apollo 6 missions<br>
<br>
The "3-Day Report" was contributed by AGC developer Jay
Sampson.<br>
</td>
</tr>
<tr align="center">
<td style="white-space: nowrap;">Apollo 7<br>
</td>
<td>CSM-101<br>
</td>
<td style="font-weight: bold; white-space: nowrap;"> Sundisk<br>
</td>
<td style="white-space: nowrap;">282<br>
</td>
<td style="text-align: center;"><br>
</td>
<td style="text-align: left;">E-2150, <a
href="Documents/HSI-208476.pdf">Guidance, Navigation, and
Control Block II Command and Service Module Functional
Description and Operation Using Flight Program SUNDISK
(Rev. 282)</a> </td>
<td style="text-align: left; vertical-align: middle;"
valign="middle"> Regarding document E-2150, linked to the
left, the preface reads: "The purpose of this document is
twofold. The first is to provide a functional
description (operationally oriented) of the CSM GNCS
hardware and software and the interfaces with other SC
systems. The level of detail is that required to
identify and define telemetry outputs. Also included are
functional flow diagrams of the Sundisk 282 programs and
routines together with lists of verbs, nouns, option codes,
and checklist codes for this flow. The second purpose is to
provide the operational procedures for this hardware and
software including malfunction procedures, and program
notes. The nominal airborne expanded and condensed
checklist for Sundisk appear in the Guidance System
Operation Plan, R547." </td>
</tr>
<tr align="center">
<td style="color: rgb(255, 0, 0); vertical-align: middle;
white-space: nowrap;"> Apollo 8<br>
</td>
<td>CSM-103<br>
</td>
<td style="font-weight: bold; color: rgb(255, 0, 0);
white-space: nowrap;"> Colossus 1<br>
</td>
<td style="white-space: nowrap;">237<br>
</td>
<td colspan="1" rowspan="1" style="text-align: center;"> <a
href="listings/Colossus237/MAIN.agc.html">As colorized,<br>
hyperlinked,<br>
HTML</a><br>
<br>
<a href="ScansForConversion/Colossus237/"> As scanned page
images (<span style="font-style: italic;">very</span>
big!)</a> <a href="ScansForConversion/Colossus249"> </a></td>
<td style="text-align: left;"> <span style="text-decoration:
underline;">GSOP (R-577)</span><br>
<ul>
<li><a href="NARA-SW/R-577-sec1-rev1.pdf"> Section 1</a><br>
</li>
<li><a href="NARA-SW/R-577-sec2-rev2.pdf"> Section 2</a></li>
<li><a href="NARA-SW/R-577-sec3-rev3.pdf"> Section 3</a></li>
<li>Section 4:</li>
<ul>
<li><a href="NARA-SW/R-577-sec4-rev6-intro.pdf">
Introduction</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-P00-P29.pdf">
P00-P27</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-P30-P39.pdf">
P30-P39</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-P40-P69.pdf">
P40-P67</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-P70-R32.pdf">
P70-R32</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-R33-V41.pdf">
R33-V41</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-V42-end.pdf"> V42-</a></li>
</ul>
<li>Section 5:</li>
<ul>
<li><a href="NARA-SW/R-577-sec5-rev4-start-5.2.pdf">
-5.2</a><br>
</li>
<li><a href="NARA-SW/R-577-sec5-rev4-5.3-5.5.pdf">
5.3-5.5</a><br>
</li>
<li><a href="NARA-SW/R-577-sec5-rev4-5.6-end.pdf"> 5.6-</a><br>
</li>
</ul>
<li><a href="NARA-SW/R-577-sec6-rev1.pdf"> Section 6</a></li>
</ul>
<span style="text-decoration: underline;">Flight Plan</span>
<ul>
<li><a
href="Documents/FlightPlanApollo8-Martin-sects1-2.pdf">
Sections 1-2</a><br>
</li>
<li><a
href="Documents/FlightPlanApollo8-Martin-sects3-5.pdf">
Sections 3-5</a><br>
</li>
</ul>
<span style="text-decoration: underline;">Digital Simulation<br>
</span>
<ul>
<li>Relatively-small PDF: <a
href="ScansForConversion/Colossus237DigitalSimulation-Anomaly45.pdf">Bailout
during Burn (Colossus Anomaly #45)</a></li>
<li>Large, full-resolution scan: <a
href="https://archive.org/details/Colossus237DigitalSimulationAnomaly45Images">Bailout
during Burn (Colossus Anomaly #45)</a></li>
</ul>
<span style="text-decoration: underline;"><a
href="links.html#Checklists">Checklists</a><br>
<br>
Technical Debriefing<br>
</span>
<ul>
<li><a
href="Documents/Apollo8-TechnicalDebriefing-Martin-1.pdf">
pp. 1-70</a></li>
<li><a
href="Documents/Apollo8-TechnicalDebriefing-Martin-2.pdf">
pp. 71-149</a><br>
</li>
</ul>
</td>
<td style="text-align: left; vertical-align: middle;"
rowspan="1" colspan="1" valign="middle"><a name="Apollo8"></a>I
presently have no definitive configuration-management data
from the original Apollo Program which I can call upon to
state conclusively which AGC software versions were used for
which missions. In particular, I couldn't prove in
court that either <span style="font-weight: bold;">Colossus</span>
1 (build 237, August 24, 1968) or <span style="font-weight:
bold;">Colossus</span> 1A (build 249, October 28, 1968)
actually flew. The GSOP linked at left is a combined
operations plan for both builds 237 and 249, and it refers
specifically to spacecraft AS-503 and CM-103 (used for
Apollo 8), and LM-3 (used for Apollo 9). From this I
infer that build 237 flew on Apollo 8 and build 249 flew on
Apollo 9, and will operate on this assumption until more
data is available. Long-time followers of this site
will perhaps recall that I used to identify build 249 as
being for Apollo 8, but I now think this was probably an
error.<br>
<br>
The <span style="font-weight: bold;">Colossus</span> 237
program listing was made available by original AGC developer
Fred Martin. (Thanks, Fred!) The listing cuts
off abruptly after page 1557—whereas you'd normally
anticipate that there are 1700+ pages—so some of the
assembler-generated tables at the end of the listing are
missing. Of particular inconvenience, because it
presents special problems for verifying the correctness of
the simulation, is the absence of the octal listing and of
the memory-bank checksums. However, all of the source
code is present, and that's enough to work with.<br>
<br>
The Apollo 8 Flight Plan and Technical Debriefing were also
provided by Fred.<br>
<br>
The digital simulation linked at the left is an Apollo-era
simulation, and not one produced by the Virtual AGC
Project. It is the only Colossus digital simulation
available so far, although there are a number of <a
href="Luminary.html">Luminary</a> digital simulations in
our library, and as such it has a unique value.
Specifically, it has pad-loads, though those pad-loads are
for March 1969 rather than for December 1968. <br>
</td>
</tr>
<tr align="center">
<td style="color: rgb(255, 0, 0); vertical-align: middle;
white-space: nowrap;"> Apollo 9<br>
</td>
<td>CSM-104<br>
</td>
<td style="font-weight: bold; color: rgb(255, 0, 0);
vertical-align: middle; white-space: nowrap;"> Colossus 1A<br>
</td>
<td style="vertical-align: middle; white-space: nowrap;"> 249<br>
</td>
<td><a href="listings/Colossus249/MAIN.agc.html">As colorized,
hyperlinked, HTML</a><br>
<br>
<a href="ScansForConversion/Colossus249-Martin/"> Scanned
image set #1 (<span style="font-style: italic;">very</span>
big!)</a><br>
<br>
<a href="ScansForConversion/Colossus249"> Scanned image set
#2 (<span style="font-style: italic;">very</span> big!)</a></td>
<td style="text-align: left;"> <span style="text-decoration:
underline;">GSOP (R-577)</span><br>
<ul>
<li><a href="NARA-SW/R-577-sec1-rev1.pdf"> Section 1</a><br>
</li>
<li><a href="NARA-SW/R-577-sec2-rev2.pdf"> Section 2</a></li>
<li><a href="NARA-SW/R-577-sec3-rev3.pdf"> Section 3</a></li>
<li>Section 4:</li>
<ul>
<li><a href="NARA-SW/R-577-sec4-rev6-intro.pdf">
Introduction</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-P00-P29.pdf">
P00-P27</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-P30-P39.pdf">
P30-P39</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-P40-P69.pdf">
P40-P67</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-P70-R32.pdf">
P70-R32</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-R33-V41.pdf">
R33-V41</a></li>
<li><a href="NARA-SW/R-577-sec4-rev6-V42-end.pdf"> V42-</a></li>
</ul>
<li>Section 5:</li>
<ul>
<li><a href="NARA-SW/R-577-sec5-rev4-start-5.2.pdf">
-5.2</a><br>
</li>
<li><a href="NARA-SW/R-577-sec5-rev4-5.3-5.5.pdf">
5.3-5.5</a><br>
</li>
<li><a href="NARA-SW/R-577-sec5-rev4-5.6-end.pdf"> 5.6-</a><br>
</li>
</ul>
<li><a href="NARA-SW/R-577-sec6-rev1.pdf"> Section 6</a></li>
</ul>
<a
href="ApolloProjectOnline/Documents/CSM%20104%20Systems%20Handbook%2019690124.pdf">Systems
Handbook</a><br>
<br>
<a href="Documents/Apollo9FlightPlan.pdf"> Flight Plan</a><br>
</td>
<td style="vertical-align: top; text-align: left;"
valign="middle">See the Apollo 8 notes above for the
rationale for believing that build 249 flew on Apollo 9.<br>
<br>
Two separate sets of scanned images of the Colossus 249
program listing are provided. They are from different
reproductions of the <i>same</i> original 1968 printout, as
owned by different AGC developers. Scanned image set
#1 is in far better condition than set #2 and is more
legible, but only the less-legible set #2 was actually
available to me when I originally implemented Colossus
249. Any hand-written notes on the listings are from
the original developers (as far as I know), and so those
notes differ on the two image sets.<br>
<br>
Scanned image set #1 is from a copy in the collection of
original AGC developer Fred Martin. (Thanks,
Fred!) Fred provided it to us temporarily for the
purpose of scanning it. As far as I know, this
reproduction is available only here.<br>
<br>
As for scanned image set #2, the marking on the front of the
document implies that it was original AGC developer Norm
Brodeur's copy. I originally obtained the scan from
MIT's Dibner Institute's now-discontinued website titled
"History of Recent Science and Technology." Here at
Virtual AGC, I choose to present the listing as a set of
individual page images instead of a giant PDF. This
listing has been improved by the replacement of 52 garbled
pages (supplied by Mr. Gary Neff), which I suppose are
probably available only here as well.<br>
<br>
I have been told that the assembly listings, originally,
could be printed either on "very noisy" line-printers with a
restricted character set that happened to correspond to the
character set allowed for the AGC programs themselves, or
else on a page-printer that had a 256-character set, but in
which the character set could be swapped out to allow
different characters to be printed from the same numerical
codes. All of the AGC printouts that are available to
us are from the line printers, <i>except</i> this Colossus
249 printout, which was made on the page printer.
Unfortunately, the wrong character-set was set up on the
printer when the printout was made, so that while all of the
upper-case alphanumeric characters were printed correctly,
many of the non-alphanumeric characters were systematically
printed as different characters, in a kind of substitution
cipher. The complete set of character-substitutions,
in so far as I have been able to discern them, is as
follows:<br>
<div align="center">
<table cellspacing="2" cellpadding="2" border="1">
<tbody>
<tr>
<th valign="top">Desired Character<br>
</th>
<th valign="top">Printed As<br>
</th>
</tr>
<tr>
<td valign="top" align="center"><<br>
</td>
<td valign="top" align="center">±</td>
</tr>
<tr>
<td valign="top" align="center">'<br>
</td>
<td valign="top" align="center">α</td>
</tr>
<tr>
<td valign="top" align="center">"<br>
</td>
<td valign="top" align="center">β</td>
</tr>
<tr>
<td valign="top" align="center">|<br>
</td>
<td valign="top" align="center">γ</td>
</tr>
<tr>
<td valign="top" align="center">><br>
</td>
<td valign="top" align="center">δ</td>
</tr>
<tr>
<td valign="top" align="center">?<br>
</td>
<td valign="top" align="center">π</td>
</tr>
<tr>
<td valign="top" align="center">%<br>
</td>
<td valign="top" align="center">Σ</td>
</tr>
<tr>
<td valign="top" align="center">&<br>
</td>
<td valign="top" align="center">d<br>
</td>
</tr>
<tr>
<td valign="top" align="center">#<br>
</td>
<td valign="top" align="center"><math
xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mo>∫</mo><annotation
encoding="TeX">∫</annotation></semantics></math><br>
</td>
</tr>
<tr>
<td valign="top" align="center">:<br>
</td>
<td valign="top" align="center">'<br>
</td>
</tr>
<tr>
<td valign="top" align="center">@<br>
</td>
<td valign="top" align="center">:<br>
</td>
</tr>
<tr>
<td valign="top" align="center">_<br>
</td>
<td valign="top" align="center"><i>discarded</i><br>
</td>
</tr>
</tbody>
</table>
<div align="left">Naturally, in transcribing the scanned
assembly-listing as source code, we have made these
substitutions already, so a '<' looks like a '<',
a '?' looks like a '?', etc. <br>
</div>
</div>
</td>
</tr>
<tr>
<td valign="middle" align="center">N/A<br>
</td>
<td valign="middle" align="center">N/A<br>
</td>
<td valign="middle" align="center"><b>Colossus 2<br>
(Comanche)</b><br>
</td>
<td valign="middle" align="center">44<br>
</td>
<td valign="middle" align="center">Perhaps some day ...<br>
</td>
<td valign="middle"><br>
</td>
<td valign="middle">We know that Margaret Hamilton has a copy
of this, and hope to get it from her some day. Alas!
today is not that day. While it is not a flown
version, it's pretty close to the flown version on Apollo 10
(only a two-month difference according to the table from
R-700 at the top of this page).<br>
</td>
</tr>
<tr align="center">
<td style="vertical-align: middle; white-space: nowrap;">
Apollo 10<br>
</td>
<td>CSM-106<br>
</td>
<td style="font-weight: bold; vertical-align: middle;
white-space: nowrap;"> Colossus 2<br>
(Manche)<br>
</td>
<td style="vertical-align: middle; white-space: nowrap;"> 45/2<br>
</td>
<td style="text-align: center;"><br>
</td>
<td style="text-align: left;"> <span style="text-decoration:
underline;">GSOP (R-577)</span><br>
<ul>
<li>Section 5:</li>
<ul>
<li><a href="Documents/R-577-Colossus2-Martin-5.1.pdf">
5.1</a></li>
<li><a href="Documents/R-577-Colossus2-Martin-5.2.pdf">
5.2</a></li>
<li><a href="Documents/R-577-Colossus2-Martin-5.3.pdf">
5.3</a></li>
<li><a href="Documents/R-577-Colossus2-Martin-5.4.pdf">
5.4</a></li>
<li><a href="Documents/R-577-Colossus2-Martin-5.5.pdf">
5.5</a></li>
<li><a
href="Documents/R-577-Colossus2-Martin-5.6789.pdf">
5.6,7,8,9</a><br>
</li>
</ul>
</ul>
</td>
<td style="text-align: left; vertical-align: middle;"
valign="middle"> Section 5 of the GSOP, presented here, was
provided by original AGC developer Fred Martin.<br>
</td>
</tr>
<tr align="center">
<td style="vertical-align: middle; white-space: nowrap; color:
rgb(255, 0, 0);"> Apollo 11<br>
</td>
<td style="color: rgb(255, 0, 0);">CSM-107<br>
</td>
<td style="font-weight: bold; vertical-align: middle;
white-space: nowrap; color: rgb(255, 0, 0);"> Colossus 2A<br>
(Comanche)<br>
</td>
<td style="vertical-align: middle; white-space: nowrap;"> 55<br>
</td>
<td style="text-align: center;"><a
href="listings/Comanche055/MAIN.agc.html">As colorized,
hyperlinked, HTML</a><br>
<br>
<a href="ScansForConversion/Comanche055"> As scanned page
images (<span style="font-style: italic;">very</span>
big!)</a><br>
</td>
<td style="text-align: left;"> <span style="text-decoration:
underline;">Operational Data Book</span><br>
<ul>
<li><a href="Documents/HSI-41539.pdf">Volume 1, Part 1</a><br>
<a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">
</a></li>
<li><a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">Volume
3</a></li>
</ul>
<span style="text-decoration: underline;">Crew Debriefing</span><br>
<ul>
<li><a
href="Documents/Apollo11TechnicalCrewDebriefing-Volume1.pdf">
Volume 1</a></li>
<li><a
href="Documents/Apollo11TechnicalCrewDebriefing-Volume2.pdf">
Volume 2</a></li>
</ul>
<a href="Documents/Apollo11FlightPlan.pdf">Flight Plan</a> </td>
<td style="text-align: left; vertical-align: middle;"
valign="middle"> Page images have been taken from a hardcopy
from the Charles Stark Draper Historical Collection, MIT
Museum, and then converted to source code by a team of
volunteers. <br>
<br>
<table summary="" style="text-align: left; margin-left:
auto; margin-right: auto;" cellspacing="2" cellpadding="2"
border="1">
<tbody>
<tr>
<td style="vertical-align: top;">
<div style="text-align: center;"> <span
style="font-weight: bold;"><span
style="text-decoration: underline;">Honor Roll</span><br>
</span>
<div style="text-align: left;"> <span
style="font-style: italic;"><br>
<span style="text-decoration: underline;">Organizational
honors</span></span><br>
</div>
</div>
<table summary="" style="text-align: left; width:
100%;" cellspacing="2" cellpadding="2" border="0">
<tbody>
<tr>
<td style="vertical-align: middle;"> <big><span
style="font-family: sans-serif;">Massachusetts
Institute of Technology / MIT Museum</span><br
style="font-family: sans-serif;">
<span style="font-family: sans-serif;">Building
N51, 265 Massachusetts Avenue</span><br
style="font-family: sans-serif;">
<span style="font-family: sans-serif;">Cambridge,
MA 02139<br>
<a href="http://web.mit.edu/museum/"><small>web.mit.edu/museum/</small></a><br>
</span></big></td>
<td style="text-align: center; vertical-align:
middle;"> <a
href="http://web.mit.edu/museum/"><img
alt="" title="Click to visit the MIT
Museum website"
src="MITMuseumLogo_red.gif"
style="border: 0px solid ; width: 107px;
height: 101px;" width="107" height="101"></a><br>
</td>
</tr>
</tbody>
</table>
<br>
<span style="font-style: italic; text-decoration:
underline;"> Individual honors</span><br>
<ul>
<li>Deborah Douglas, the Museum's Curator of
Science and Technology, who conceived the idea
of making this material available to us, and
without whom we had literally no chance of
obtaining it.</li>
<li>Paul Fjeld, for digitizing the hardcopy.</li>
<li>(In alphabetical order) Fabrizio Bernardini,
Hartmuth Gutshe, Onno Hommes, Jim Lawton, and
Sergio Navarro, for converting the page images
to source code.</li>
<li>... and those whose names I do not know at the
Charles Stark Draper Laboratory and NASA who
allowed us to do this.<br>
</li>
</ul>
</td>
</tr>
</tbody>
</table>
<br>
</td>
</tr>
<tr align="center">
<td style="vertical-align: middle; white-space: nowrap;">
Apollo 12<br>
</td>
<td>CSM-108<br>
</td>
<td style="font-weight: bold; vertical-align: middle;
white-space: nowrap;"> Colossus 2C<br>
(Comanche)<br>
</td>
<td style="vertical-align: middle; white-space: nowrap;">67<br>
</td>
<td style="text-align: center;"><br>
</td>
<td style="text-align: left;"> <span style="text-decoration:
underline;">Operational Data Book</span><br>
<ul>
<li><a href="Documents/HSI-41539.pdf">Volume 1, Part 1</a><br>
<a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">
</a></li>
<li><a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">Volume
3</a></li>
</ul>
<a href="Documents/Apollo12FlightPlan.pdf">Flight Plan</a><br>
<br>
<a
href="Documents/MSC%2069-FM-248%20Spacecraft%20Operational%20Trajectory%20for%20Apollo%2012%20Volum%20I.pdf">Spacecraft
Operational Trajectory</a><br>
<br>
E-2442, <a href="Documents/HSI-208615.pdf">Guidance,
Navigation, and Control Command Module Functional
Description and Operation Using Flight Program COLOSSUS 2C
(COMANCHE 67)</a><br>
</td>
<td style="text-align: left; vertical-align: middle;"
valign="middle"> Regarding document E-2442, linked to the
left, the preface reads: "The purpose of this document is
twofold. The first is to provide a functional
description (operationally oriented) of the CSM GNCS
hardware and software and the interfaces with other
spacecraft systems. The level of detail is that
required to identify and define telemetry outputs. Also
included are function flow diagrams of the COLOSSUS programs
and routines together with lists of verbs, nouns, option
codes, and checklist codes for this flow. The second purpose
is to provide the operational procedures for this hardware
and software including nominal airborne condensed
checklists, malfunction procedures, and program notes." </td>
</tr>
<tr align="center">
<td style="vertical-align: middle; white-space: nowrap;">
Apollo 13<br>
</td>
<td>CSM-109<br>
</td>
<td style="font-weight: bold; vertical-align: middle;
white-space: nowrap;"> Colossus 2D<br>
(Comanche)<br>
</td>
<td style="vertical-align: middle; white-space: nowrap;">72/3<br>
</td>
<td style="text-align: center;"><br>
</td>
<td style="text-align: left;"> <span style="text-decoration:
underline;">Operational Data Book</span><br>
<ul>
<li><a href="Documents/HSI-41539.pdf">Volume 1, Part 1</a><br>
<a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">
</a></li>
<li><a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">Volume
3</a></li>
</ul>
<p><a href="Documents/j2-80-E-2448-REV1_text.pdf">Users'
Guide to Apollo GN&CS Major Modes and Routines, Rev
1</a><br>
</p>
<ul>
</ul>
</td>
<td style="text-align: left; vertical-align: middle;"
valign="middle"> Regarding the Users' Guide hyperlinked at
the left, it is "a comprehensive, user-oriented description
of the APOLLO GN&C system ... revised as necessary to
remain current", but not targeted at specific
missions. However, given that it is dated July 1970,
it is probably pretty accurate for Apollo 13.<br>
</td>
</tr>
<tr align="center">
<td style="vertical-align: middle; white-space: nowrap;">
Apollo 14<br>
</td>
<td>CSM-110<br>
</td>
<td style="font-weight: bold; vertical-align: middle;
white-space: nowrap;"> Colossus 2E<br>
(Comanche)<br>
</td>
<td style="vertical-align: middle; white-space: nowrap;">108<br>
</td>
<td style="text-align: center;"><br>
</td>
<td style="text-align: left;"> <span style="text-decoration:
underline;">Operational Data Book</span><br>
<ul>
<li><a href="Documents/HSI-41539.pdf">Volume 1, Part 1</a><br>
<a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">
</a></li>
<li><a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">Volume
3</a></li>
</ul>
<p><a href="Documents/j2-80-E-2448-REV1_text.pdf">Users'
Guide to Apollo GN&CS Major Modes and Routines, Rev
1<br>
</a></p>
<ul>
</ul>
</td>
<td style="text-align: left; vertical-align: middle;"
valign="middle"> <a name="Apollo14"></a>Regarding the
Users' Guide hyperlinked at the left, it is "a
comprehensive, user-oriented description of the APOLLO
GN&C system ... revised as necessary to remain current",
but not targeted at specific missions. However, given
that it is dated July 1970, it is probably pretty accurate
for Apollo 14.<br>
<br>
Although we don't presently have the Apollo 14 CM software,
Niklas Beug, a developer and user of <a
href="https://github.com/dseagrav/NASSP">NASSP, the
Apollo-mission add-on for the Orbiter spaceflight
simulator</a>, tells us that it's actually possible to use
a modified form of Artemis (the Apollo 15-17 software) to
fly satisfactory Apollo 14 missions. Let me simply
quote Nik:<br>
<blockquote><small>We currently don't have any AGC version
available that was flown on Apollo 14, which causes a
few, mostly procedural issues for NASSP. Apollo 14 was
the only mission flown in the time period from July 1st,
1970 to July 1st 1971 and as such used a slightly
different coordinate system than the AGC versions before
and after that. And using a different coordinate system
means that a few hardcoded constants had to be changed
every year: star unit vectors, solar and lunar ephemeris
in the LGC and a few other numbers. These numbers for
the yearly coordinate system used by Apollo 14 are
available or can be calculated. So we did just that and
created our own AGC versions for Apollo 14. Both CMC and
LGC are derived from the AGC versions flown on Apollo
15, Luminary 1E and Artemis (Colossus 3). We determined
that these most closely match the programs and
capabilities of the AGC versions actually flown on
Apollo 14. One regular NASSP user (Alex Bart, ...)
tested Apollo 14 with these modified AGC versions and
flew the complete simulated mission with them. We are
very confident now that these AGC versions are working
as they should. As I said, they are essentially still
the AGC versions flown on Apollo 15, only slightly
modified to properly work with Apollo 14. ... <a
href="https://github.com/dseagrav/NASSP/tree/Orbiter2016/Config/ProjectApollo">They
are available here</a>,
as Artemis072NBY71.bin and Luminary210NBY71.bin,
[i.e.] Artemis072 and Luminary210 modified to work for
the Nearest Besselian Year (NBY) coordinate system of
1971.</small><br>
</blockquote>
<br>
</td>
</tr>
<tr align="center">
<td style="vertical-align: middle; white-space: nowrap; color:
rgb(255, 0, 0);"> Apollo 15<br>
</td>
<td><span style="color: rgb(255, 0, 0);">CSM-112</span><br>
</td>
<td colspan="1" rowspan="1" style="vertical-align: middle;
white-space: nowrap; color: rgb(255, 0, 0); font-weight:
bold;"> Colossus 3<br>
(Artemis)<br>
</td>
<td colspan="1" rowspan="1" style="vertical-align: middle;
white-space: nowrap; color: rgb(255, 0, 0);"> 72<br>
</td>
<td colspan="1" rowspan="3" style="text-align: center;"> <br>
<br>
<a href="listings/Artemis072/MAIN.agc.html">Colorized,
hyperlinked, HTML</a><br>
<br>
<a href="ScansForConversion/Artemis072/"> As scanned page
images (<span style="font-style: italic;">very</span>
big!)</a><br>
</td>
<td style="text-align: left;"> <span style="text-decoration:
underline;">GSOP (R-577)</span><br>
<ul>
<li><a href="Documents/HSI-208464.pdf"> Section 1</a><br>
</li>
<li><a href="Documents/HSI-208452.pdf"> Section 2</a><br>
</li>
<li><a href="Documents/HSI-208472.pdf"> Section 3 (rev 11)</a></li>
<li><a href="Documents/R577-section3-rev14.pdf">Section 3
(rev 14)</a><br>
</li>
<li>Section 4</li>
<li><a href="Documents/HSI-208454.pdf"> Section 5</a></li>
<li>Section 6</li>
<li><a href="Documents/HSI-208442.pdf"> Section 7</a></li>
</ul>
Programmed Guidance Equations for Colossus 3:
<ul>
<li><a
href="Documents/programmed-guidance-equations-colossus-3-001_text.pdf">Part
1<br>
</a></li>
<li><a
href="Documents/programmed-guidance-equations-colossus-3-002_text.pdf">Part
2<br>
</a></li>
<li><a
href="Documents/programmed-guidance-equations-colossus-3-003_text.pdf">Part
3</a><br>
</li>
</ul>
<p><a href="Documents/j2-80-E-2448-REV4_text.pdf">Users'
Guide to Apollo GN&CS Major Modes and Routines, Rev
4, Colossus 3 and Luminary 1E<br>
</a></p>
<ul>
</ul>
<a href="Documents/Apollo15_Colossus3_CMC_Data_Cards.pdf">CMC
Data Cards</a><br>
or<br>
<a href="CMC_data_cards_15_Fabrizio_Bernardini.pdf">CMC data
cards</a><br>
<br>
<a href="Documents/msc05225.pdf"><span style="font-style:
italic;"> Program Notes</span></a><br>
<br>
<a href="Documents/BwCsmHandbookGncSection_112-114.pdf"> CSM
Systems Handbook</a><br>
<br>
<span style="text-decoration: underline;">Operational Data
Book</span><br>
<ul>
<li><a href="Documents/HSI-41539.pdf">Volume 1, Part 1</a><br>
<a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">
</a></li>
<li><a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">Volume
3</a></li>
</ul>
<a href="Documents/Apollo15TechnicalCrewDebriefing.pdf">Crew
Debriefing</a><br>
<br>
<a href="Documents/Apollo15FlightPlan.pdf"> Flight Plan</a><br>
<br>
<span style="text-decoration: underline;">Checklists</span><br>
<ul>
<li><a href="Documents/Apollo15CSMEntryChecklist.pdf">
Entry</a></li>
<li><a
href="Documents/Apollo15CSMGuidanceAndControlChecklist.pdf">
Guidance&Control</a></li>
<li><a href="Documents/Apollo15CSMLaunchChecklist.pdf">
Launch</a></li>
<li><a href="Documents/Apollo15CSMSystemsChecklist.pdf">
Systems</a><br>
</li>
</ul>
</td>
<td colspan="1" rowspan="3" style="text-align: left;
vertical-align: middle;" valign="middle"> Also known as <span
style="font-weight: bold;">Artemis</span> build 072,
released (Fabrizio Bernardini tells me) January 31,
1971. A private collector has graciously allowed us to
digitize this program listing for use in Virtual AGC.<br>
<br>
Thanks also to:<br>
<ul>
<li>Henry Wesso, for constructing the special copy stand
used for the digitization.</li>
<li>Gil Guerrero, for providing advice and camera
equipment.</li>
<li>(In alphabetical order) Steve Case, Hartmuth Gutshe,
Onno Hommes, Jim Lawton, and Sergio Navarro, for
converting the page images to source code.</li>
<li>To Jim Lawton, for debugging the converted source-code
files.<br>
</li>
</ul>
Regarding the Programmed Guidance Equations document
hyperlinked at the left, it is basically a pseudo-code
description of the Artemis 72 program. Unfortunately,
pages ORBI-9 and ORBI-10 are missing.<br>
<br>
Regarding the Users' Guide hyperlinked at the left, it is "a
comprehensive, user-oriented description of the APOLLO
GN&C system ... revised as necessary to remain current",
but not targeted at specific missions. However, given
that it specifically references Colossus 3 and Luminary 1E,
that seems pretty specific to Apollo 15, 16, and 17.<br>
<br>
</td>
</tr>
<tr style="color: rgb(255, 0, 0);" align="center">
<td style="vertical-align: middle; white-space: nowrap;">
Apollo 16<br>
</td>
<td>CSM-113<br>
</td>
<td rowspan="1" style="font-weight: bold; text-align: center;">Colossus
3<br>
(Artemis)</td>
<td rowspan="1" style="text-align: center;">72<br>
</td>
<td style="text-align: left; color: rgb(0, 0, 0);"> <span
style="text-decoration: underline;">GSOP (R-577)</span><br>
<ul>
<li><a href="Documents/HSI-208464.pdf"> Section 1</a><br>
</li>
<li><a href="Documents/HSI-208452.pdf"> Section 2</a><br>
</li>
<li><a href="Documents/HSI-208472.pdf"> Section 3 (rev 11)</a></li>
<li><a href="Documents/R577-section3-rev14.pdf">Section 3
(rev 14)</a><br>
</li>
<li>Section 4</li>
<li><a href="Documents/HSI-208454.pdf"> Section 5</a></li>
<li>Section 6</li>
<li><a href="Documents/HSI-208442.pdf"> Section 7</a></li>
</ul>
<p>Programmed Guidance Equations for Colossus 3:<br>
</p>
<ul>
<li><a
href="Documents/programmed-guidance-equations-colossus-3-001_text.pdf">Part
1<br>
</a></li>
<li><a
href="Documents/programmed-guidance-equations-colossus-3-002_text.pdf">Part
2<br>
</a></li>
<li><a
href="Documents/programmed-guidance-equations-colossus-3-003_text.pdf">Part
3</a></li>
</ul>
<p><a href="Documents/j2-80-E-2448-REV4_text.pdf">Users'
Guide to Apollo GN&CS Major Modes and Routines, Rev
4, Colossus 3 and Luminary 1E</a></p>
<ul>
</ul>
<a href="Documents/msc05225.pdf"><span style="font-style:
italic;">Program Notes</span></a><br>
<br>
<a href="Documents/BwCsmHandbookGncSection_112-114.pdf"> CSM
Systems Handbook</a><br>
<br>
<span style="text-decoration: underline;">Operational Data
Book</span><br>
<ul>
<li><a href="Documents/HSI-41539.pdf">Volume 1, Part 1</a><br>
<a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">
</a></li>
<li><a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">Volume
3</a></li>
</ul>
<a href="Documents/Apollo16FlightPlan.pdf">Flight Plan</a><br>
</td>
</tr>
<tr style="color: rgb(255, 0, 0);">
<td style="text-align: center; vertical-align: middle;
white-space: nowrap;"> Apollo 17<br>
</td>
<td style="text-align: center;">CSM-114<br>
</td>
<td style="font-weight: bold; text-align: center;">Colossus 3<br>
(Artemis)</td>
<td style="text-align: center;">72<br>
</td>
<td style="text-align: left; color: rgb(0, 0, 0);"> <span
style="text-decoration: underline;">GSOP (R-577)</span><br>
<ul>
<li><a href="Documents/HSI-208464.pdf"> Section 1</a><br>
</li>
<li><a href="Documents/HSI-208452.pdf"> Section 2</a><br>
</li>
<li><a href="Documents/HSI-208472.pdf"> Section 3 (rev 11)</a></li>
<li><a href="Documents/R577-section3-rev14.pdf">Section 3
(rev 14)</a><br>
</li>
<li>Section 4</li>
<li><a href="Documents/HSI-208454.pdf"> Section 5</a></li>
<li>Section 6</li>
<li><a href="Documents/HSI-208442.pdf"> Section 7</a></li>
</ul>
<p>Programmed Guidance Equations for Colossus 3:<br>
</p>
<ul>
<li><a
href="Documents/programmed-guidance-equations-colossus-3-001_text.pdf">Part
1<br>
</a></li>
<li><a
href="Documents/programmed-guidance-equations-colossus-3-002_text.pdf">Part
2<br>
</a></li>
<li><a
href="Documents/programmed-guidance-equations-colossus-3-003_text.pdf">Part
3</a></li>
</ul>
<p><a href="Documents/j2-80-E-2448-REV4_text.pdf">Users'
Guide to Apollo GN&CS Major Modes and Routines, Rev
4, Colossus 3 and Luminary 1E</a></p>
<ul>
</ul>
<a href="Documents/msc05225.pdf"><span style="font-style:
italic;">Program Notes</span></a><br>
<br>
<a href="Documents/BwCsmHandbookGncSection_112-114.pdf"> CSM
Systems Handbook</a><br>
<br>
<span style="text-decoration: underline;">Operational Data
Book</span><br>
<ul>
<li><a href="Documents/HSI-41539.pdf">Volume 1, Part 1</a><br>
<a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">
</a></li>
<li><a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">Volume
3</a></li>
</ul>
<a href="Documents/Apollo17TechnicalCrewDebriefing.pdf">Crew
Debriefing</a><br>
<br>
<a href="Documents/Apollo17FlightPlan.pdf"> Flight Plan</a><br>
</td>
</tr>
<tr>
<td style="text-align: center;">Skylab 2-4<br>
</td>
<td style="text-align: center;">CSM-116<br>
CSM-117<br>
CSM-118<br>
</td>
<td style="text-align: center;"><span style="font-weight:
bold;">Skylark</span><br>
</td>
<td style="text-align: center;">48?<br>
</td>
<td style="text-align: center;"><br>
</td>
<td style="text-align: left; white-space: nowrap;"> <a
href="NARA-SW/SkylabDataCards.pdf"> </a><a name="Skylark"></a><a
href="NARA-SW/SkylabDataCards.pdf">Quick-reference cards</a><br>
<br>
<span style="text-decoration: underline;">GSOP (R-693)</span><br>
<ul>
<li><a href="Documents/HSI-208464.pdf"> Section 1 (same as
R-577)</a><br>
</li>
<li><a
href="Documents/R-693-GSOP-Skylark1-Section2-DataLinks.pdf">
Section 2</a></li>
<li><a
href="Documents/R-693%20GSOP%20Skylark%201%20Section%203%20Digitgal%20Autopilots.pdf">Section
3</a></li>
<li><a
href="Documents/R-693-GSOP-Skylark1-Section4-OperationalModes.pdf">
Section 4</a></li>
<li><a href="Documents/HSI-208456.pdf">Section 5</a></li>
<li>Section 6 (same as R-577)</li>
<li>Section 7</li>
</ul>
<p>Programmed Guidance Equations for Skylark 48:<br>
</p>
<ul>
<li><a
href="Documents/programmed-guidance-equations-skylark-001.pdf">Part
1</a></li>
<li><a
href="Documents/programmed-guidance-equations-skylark-002.pdf">Part
2</a></li>
<li><a
href="Documents/programmed-guidance-equations-skylark-003.pdf">Part
3</a></li>
</ul>
<ul>
</ul>
<a
href="Documents/MSC-06814-SkylabCommandServiceModuleSystemsHandbook-CSM116-119.pdf">CSM
Systems Handbook</a><br>
<br>
<span style="text-decoration: underline;">Operational Data
Book</span><br>
<ul>
<li><a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">
Volume 3</a><br>
</li>
</ul>
</td>
<td style="vertical-align: top;" valign="middle">Regarding the
Programmed Guidance Equations document hyperlinked at the
left, it is basically a pseudo-code description of the
Skylark 48 program. </td>
</tr>
<tr>
<td style="text-align: center;">Apollo-Soyuz<br>
</td>
<td style="text-align: center;">CSM-111<br>
</td>
<td style="text-align: center;"><span style="font-weight:
bold;">Skylark</span><br>
</td>
<td style="text-align: center;">TBD<br>
</td>
<td style="text-align: center;"><br>
</td>
<td style="text-align: left; white-space: nowrap;"> <a
href="NARA-SW/ApolloSoyuzDataCards.pdf"> Quick-reference
cards</a><br>
<br>
<span style="text-decoration: underline;">GSOP (R-693)</span><br>
<ul>
<li><a href="Documents/HSI-208464.pdf"> Section 1 (same as
R-577)</a><br>
</li>
<li><a
href="Documents/R-693-GSOP-Skylark1-Section2-DataLinks.pdf">
Section 2</a></li>
<li><a
href="Documents/R-693%20GSOP%20Skylark%201%20Section%203%20Digitgal%20Autopilots.pdf">Section
3</a></li>
<li><a
href="Documents/R-693-GSOP-Skylark1-Section4-OperationalModes.pdf">
Section 4</a></li>
<li><a href="Documents/HSI-208456.pdf">Section 5</a></li>
<li>Section 6 (same as R-577)</li>
<li>Section 7</li>
</ul>
<p>Programmed Guidance Equations for Skylark 48:<br>
</p>
<ul>
<li><a
href="Documents/programmed-guidance-equations-skylark-001.pdf">Part
1</a></li>
<li><a
href="Documents/programmed-guidance-equations-skylark-002.pdf">Part
2</a></li>
<li><a
href="Documents/programmed-guidance-equations-skylark-003.pdf">Part
3</a></li>
</ul>
<ul>
</ul>
<span style="text-decoration: underline;">Operational Data
Book</span><br>
<ul>
<li><a
href="Documents/SNA-8-D-027III-Rev2-CsmLmSpacecraftOperationalDataBook-Volume3-MassProperties.pdf">
Volume 3</a><br>
</li>
</ul>
</td>
<td style="vertical-align: top;" valign="middle">As far as the
GSOP and guidance-equation documents hyperlinked to the left
are concerned, note that internally they refer specifically
to Skylab missions and/or to Skylark 48, so I'm not sure of
the degree of relevance to the Apollo-Soyuz mission.
However, given the lack of Apollo-Soyuz specific data, I'm
provisionally linking them here as well!<br>
</td>
</tr>
</tbody>
</table>
<div style="text-align: left;"> <br>
<h2><a name="Source_Code_and_Binary"></a>Source Code and Binary</h2>
Both source code and (independently derived) binary code are
provided within the yaAGC tarball downlod. The files are
contained within a subdirectory named after the software version
(such as "Colossus249" and "Artemis072"). The more important
files supplied are these:<br>
<br style="font-style: italic;">
<div style="margin-left: 40px;">
<table summary="" style="text-align: left; width: 33%;"
cellspacing="2" cellpadding="2" border="0">
<tbody>
<tr>
<td style="vertical-align: top;"><span style="font-style:
italic;">Filename</span>.agc<br>
</td>
<td style="vertical-align: top;">Source code for major
subdivisions of the <span style="font-weight: bold;">Colossus</span>
program.</td>
</tr>
<tr>
<td style="vertical-align: top;">MAIN.agc<br>
</td>
<td style="vertical-align: top;">Organizer which treats
all of the other assembly-language files (*.agc) as
include-files, to form the complete program.<br>
</td>
</tr>
<tr>
<td style="vertical-align: top;"><span style="font-style:
italic;">Filename</span>.binsource<br>
</td>
<td style="vertical-align: top;">Human-readable form of
the binary executable as an octal listing.<br>
</td>
</tr>
<tr>
<td style="vertical-align: top;"><span style="font-style:
italic;">Filename</span>.bin<br>
</td>
<td style="vertical-align: top;">Binary executable created
from binsource (octal listing) file.<br>
</td>
</tr>
</tbody>
</table>
<br>
</div>
In other words, to create a <span style="font-weight: bold;">Colossus</span>
binary executable rather than using the one provided with yaAGC
(such as Colossus249.bin), one simply needs to assemble the file
MAIN.agc. Typically, if all files remain organized the way
they are in the yaAGC distribution tarball, the sequence of steps
for doing so (from a command-line prompt) would be something like
this:<br>
<div style="margin-left: 40px;"> <br>
<span style="font-family: monospace;">cd Colossus249</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">../yaYUL/yaYUL MAIN.agc
>Colossus249.lst</span><br>
</div>
<br>
The binary so produced, MAIN.agc.bin, should be byte-for-byte
identical to the binary (Colossus249.bin) provided with the yaAGC
distribution. Therefore, the following Linux command should
reveal no differences between the two<br>
<br>
<div style="margin-left: 40px;"> <span style="font-family:
monospace;">diff MAIN.agc.bin Colossus249.bin</span><br>
</div>
<br>
(Replace "diff" with "fc /b" in Windows.) <br>
<br>
<table summary="" style="width: 60%; text-align: left;
margin-left: auto; margin-right: auto;" cellspacing="2"
cellpadding="2" border="1">
<tbody>
<tr>
<td style="vertical-align: top;">
<h3 style="text-align: left;">Technically speaking....</h3>
A point which may not be completely appreciated is that
Colossus249.bin was <span style="font-style: italic;">not</span>
created from the assembly-language source files.
Therefore, the byte-for-byte equivalence mentioned above
actually has some significance. In fact, both the
assembly-language source code and Colossus249.bin (or
Colossus249.binsource) come from separate readings of the
original <span style="font-weight: bold;">Colossus</span>
assembly listing scan, so their equivalence provides an
important check on validity. (See below.) The
file Colossus249.bin was created from the
human-readable/editable ASCII file Colossus249.binsource
by means of the program <span style="font-weight: bold;">Oct2Bin</span>,
with the following steps:<br>
<br>
<div style="margin-left: 40px;"> <span
style="font-family: monospace;">cd Colossus249</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">../Luminary131/Oct2Bin
<Colossus249.binsource</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">mv Oct2Bin.bin
Colossus249.bin</span><br>
</div>
<br>
Admittedly, few people are likely to perform any
processing of this kind unless contibuting a new version
of the Colossus code to the Virtual AGC project. </td>
</tr>
</tbody>
</table>
<br>
<h2><a name="Validity"></a>Validation</h2>
I generally put a lot of effort into insuring that the executable
binaries being run in the simulated AGC are byte-for-byte (or in
the case of the AGC, word-for-word) identical to the original
binaries used in the spacecraft. Most people won't be
interested in this validation effort at all—just as we're not
usually interested in how food gets from plants and animals onto
the plates in front of us as long as we get our dinners on time;
we're happy to trust others to do the work for us—but for those
few of you who wonder if the simulated AGC really is running the
correct code, the following sections provide explanations.
The different program versions are presented in the order in which
they were worked on.<br>
<h3><a name="ValidityApollo9"></a>Validity of the Colossus 249
Code (Apollo 9)<br>
</h3>
The following description of validation was written prior to
having the <span style="font-weight: bold;">Colossus249</span>
software source code in machine-readable form, and therefore prior
to being able to the core-rope image against the source code as
described above. Not only that, but there were seven errors
in the core-rope not detected by the procedure described below!<br>
<br>
So the description is now obsolete. But I like it, and it's
my website, so it stays. (Actually, it continues to have
value, since we don't yet have all versions of the AGC source, and
since it describes how to proceed in the case of recovering
poor-quality assembly listings.)<br>
<h4><a name="A_Tour_of_the_Source_Materials"></a>A Tour of the
Source Materials</h4>
Let's look at a pages from the <a
href="ScansForConversion/Colossus249/0200.pdf"> source materials</a>
(actually, a greatly improved version) I've used in reconstructing
<span style="font-weight: bold;">Colossus</span> 1A (build
249). In appearance, what we have is a <span
style="font-style: italic;">scan</span> of a <span
style="font-style: italic;">photocopy</span> of an <span
style="font-style: italic;">assembly listing</span> of the
program. Significant portions of the assembly listing have
been corrupted (or even destroyed) after scanning, seemingly by
processing with the optical-character-recognition capabilities of
Adobe Acrobat. (The <a
href="ScansForConversion/Luminary131/0202.jpg"> source materials</a>
used for <span style="font-weight: bold;">Luminary</span> 1C,
build 131, are generally similar, except that the original
photocopy seems to be of better quality, the scans seem to have
been performed with much more care, and no destructive
post-processing has been performed. On the other hand, the
original <span style="font-weight: bold;">Luminary</span>
printout seems to have been on computer paper with green and white
color bars, and the remnants of the green bars make portions of
the listing very difficult to read with certainty. Most of
what I have to say will apply to <span style="font-weight: bold;">Luminary</span>
as well as to <span style="font-weight: bold;">Colossus</span>.)
With some luck, I'll be able to find (or will be given) better
source materials at some point in the future, but I've had no luck
so far in obtaining such materials and therefore have had to make
do with what's available.<br>
<br>
An <span style="font-style: italic;">assembly listing</span> is a
type of report created when a program's source code is processed
("assembled"), in this case by the assembler program called <span
style="font-weight: bold;">YUL</span>. (Actually, by <span
style="font-weight: bold;">GAP</span>, the successor to <span
style="font-weight: bold;">YUL</span>, but when I say "YUL" I
really mean "either YUL or GAP".) Such an assembly listing
contains not only a listing of the source code, but also other
helpful information such as the octal values which the source code
assembles to. The octal codes are what is needed to <span
style="font-style: italic;">run</span> the program, while the
source code is what is needed to <span style="font-style:
italic;">modify</span> the program. The general layout of
the <span style="font-weight: bold;">Colossus</span> (or <span
style="font-weight: bold;">Luminary</span>) assembly listing has
a series of sections, of which some of the more interesting are:<br>
<ul>
<li>A listing of the source code, side by side with the octal
codes created from the source code, side by side with the
addresses at which the octal values are placed. <a
href="853.pdf">Click here</a> to see a typical page (without
OCR). The source code is on the right-hand side of the
page, whereas the octal values, addresses, and other
miscellaneous notations are on the left-hand side of the
page. This section occupies about 1500 pages of the
assembly listing.<br>
</li>
<li>A symbol table, giving the addresses at which all of the
symbols created by the program are defined.</li>
<li>An octal listing, which is the same as the octal values
shown earlier side by side with the source code, but now
rearranged so that the values are arranged by memory
address. <a href="1714.pdf">Click here</a> to see a
typical page (without OCR). This section occupies about
150 pages of the source listing.<br>
</li>
<li>An octal-to-page cross reference, in which you can find the
page of the assembly listing at which the octal value for any
given address is defined.</li>
</ul>
<h4><a name="Proofing_in_the_Usual_Case"></a>Proofing in the Usual
Case</h4>
From the description above, you will have noted that source code
is listed once within the assembly listing, but that octal values
created from the source code are listed <span style="font-style:
italic;">twice</span>, and are therefore redundant.
Furthermore, knowing the source code, one can recreate the octal
values from it. (The reverse is not as easy.) Finally,
the octal listing is much shorter than the source-code
listing. Therefore, it shouldn't be surprising that it is
much easier to create a file containing a valid octal listing of
the program than it is to create a file containing a valid
source-code listing.<br>
<br>
It is also much easier to <span style="font-style: italic;">know</span>
that an octal listing is valid than it is to know that a
source-code listing is valid. This is true because the <span
style="font-weight: bold;">YUL</span> assembler has added
"checksums" to the octal values, which can be used to verify (or
at least give a high degree of confidence) that the octal values
are correct. The way this works is that the so-called "fixed
memory" of the AGC has been divided into 36 banks, numbered 0-43
in octal notation, each of which has a 15-bit checksum created by
adding up all of the 15-bit words within the bank.
(Actually, the rule for computing the checksum is more
complicated, but that's the basic idea.) Therefore, if we
compute the checksum of a bank and see that it is the same as the
checksum provided by <span style="font-weight: bold;">YUL</span>,
we can be fairly confident that the contents of the bank are
correct. (I should mention that I've provided a utility
called <span style="font-weight: bold;">Oct2Bin</span> which is
helpful in this connection. Octal codes can be placed in a
simple ASCII file, and then processed with <span
style="font-weight: bold;">Oct2Bin</span> to create a file
containing the actual octal/binary codes and to verify all bank
checksums.)<br>
<br>
Another helpful touch added by <span style="font-weight: bold;">YUL</span>
is that each octal value is accompanied by a <span
style="font-style: italic;">parity bit</span>, contrived to make
the number of 1-bits within the octal value (including the parity
bit) an odd number. This is useful in detecting single digit
errors of some kinds. (The digits 0, 3, 5, and 6 have <span
style="font-style: italic;">even parity</span>, while the digits
1, 2, 4, and 7 have <span style="font-style: italic;">odd parity</span>.
Therefore, examination of the parity bit could detect substitution
of a '2' for a '3', for example, but not substitution of a '5' for
a '6'.)<br>
<br>
In almost all cases, the following simple procedure suffices to
produce a valid octal listing:<br>
<ol>
<li>Manually proof-read a memory bank of the octal listing
against the original assembly listing, using the redundancy of
the octal values or manually assembling source code as
necessary to account for corrupted areas of the assembly
listing.</li>
<li>Compute and verify the checksum.</li>
<li>On failure, go back to step 1. On success do the next
memory bank.</li>
</ol>
Given a valid octal listing, determining the validity of a <span
style="font-style: italic;">source-code</span> listing is rather
trivial: simply run the source code through the <span
style="font-weight: bold;">yaYUL</span> assembler, and verify
that the same octal listing is produced.<br>
<br>
This procedure in fact suffices for the entire <span
style="font-weight: bold;">Luminary</span> octal listing, and
for all memory banks of <span style="font-weight: bold;">Colossus</span>
except banks 35 and 36 (octal). If you want to learn more
about proofing <span style="font-weight: bold;">Colossus</span>
memory banks 35 and 36, read onward. Otherwise, quit now!<br>
<br>
<span style="font-weight: bold;">Postscript</span>: After
writing all of the material below, I was fortunate enough to
receive some much-improved page scans of relevant portions of bank
36 from Mr. Gary Neff. Therefore, bank 36 is now capable of
being proofed by the simple method explained above. However,
it was previously proofed using the much more complex methods
explained below, and therefore I haven't bothered to change the
explanation that follows.<br>
<h4><a name="Proofing_in_Extraordinary_Cases_"></a>Proofing in
Extraordinary Cases<br>
</h4>
The simple proofing method outlined above fails when the scan of
the assembly listing for some memory bank is <span
style="font-style: italic;">so</span> corrupted that the bank
checksum or some value(s) within the memory bank are completely
unknown. Sadly, this condition occurs within <span
style="font-weight: bold;">Colossus</span> 1C (build 249) banks
35 and 36. <a href="1713.pdf">Click here</a> to see the
culprit page of the octal listing. This corrupted page from
the octal listing actually wads together the end of bank 35 and
the beginning of bank 36 in such a way that there is no chance of
figuring out any but a small part of them. In this case, one
has no choice but to use the redundant listing of the octal values
that appears side by side with the source code.<br>
<br>
Unfortunately, though, the redundant octal values in the source
code listing fail us here, though in different ways for bank 35
and bank 36. For bank 35, we encounter the problem that the
bank checksum appears <span style="font-style: italic;">only</span>
within the octal listing and is not redundant. Therefore, we
can theoretically know all of the octal values in the memory
bank—if our proofing is 100% accurate—but cannot use the bank
checksum to give us the degree of confidence we would like.
For bank 36, the checksum is intact but some of the octal values
cannot be directly determined because of corruption within the
source-code listing. (In other words, <span
style="font-style: italic;">both</span> the octal listing and
the source-code listing are corrupted in the <span
style="font-style: italic;">corresponding place</span>.)
As far as proofing is concerned, however, the conclusion is the
same: We need some method of proofing which gives us a high
level of confidence in the result, in the absence of a checksum.<br>
<br>
Here is the alternate method of proofing used in this cases, which
seems to offer a fairly high level of confidence:<br>
<ol>
<li>Note first that each memory bank actually occupies 4 pages
within the octal listing. For this method, we proof each
memory page separately from the others.</li>
<li>Manually proof-read the memory page, using either the octal
listing or the source-code listing as desired or
appropriate. While doing so, record the number of digits
which have been corrected.</li>
<li>Repeat step 2 until zero corrections have been made in two
successive proofings.</li>
<li>To the extent feasible, one of the 0-error proofings should
use the octal listing, and the other should use the
source-code listing.</li>
</ol>
The theory behind this procedure is that in any given proofing a
certain percentage of errors is corrected, and that by monitoring
the number of errors that have been corrected we can get a good
sense of the number of errors remaining. To take a "typical"
case, suppose that on the first proofing 100 errors are detected
and corrected, on the second proofing 1 error is detected and
corrected, and on the third and fourth proofings 0 errors are
detected. It would be reasonable to suppose that each
proofing pass detects 99% of errors, so the expected number of
errors remaining after the 4th pass is 100*0.01*0.01*0.01*0.01, or
about a millionth of an error. Of course, this reasoning
assumes that our ability to detect and correct different errors
has some quality of statistical independence, and that errors are
not remaining undetected through some systematic problem. We
try to overcome that objection by making sure that we use both the
octal listing and the source-code listing in the proofing process,
but how successful we have been is always debatable.<br>
<br>
As far as proofing is concerned, this technique suffices for <span
style="font-weight: bold;">Colossus</span> banks 35 and 36, but
does not actually give us a 100% knowledge of the octal values
within the banks. For bank 35, we can simply construct a
checksum and be done with it. But for bank 36, we need to do
a little more work. If you want to know more about that,
read onward!<br>
<h4><a name="When_All_Else_Fails"></a>When All Else Fails—Digital
Archaeology<br>
</h4>
In a case like bank 36, the technique above may give us confidence
that all octal values that are legible in the page images are
keyed accurately, but the proofing technique can't give us any
insight into the octal values that are simply missing from both
the source-code listing and the octal listing. One trick we
can try is to compare the <span style="font-weight: bold;">Colossus</span>
and <span style="font-weight: bold;">Luminary</span> source-code,
which actually have a high degree of overlap in general.
Unfortunately, this is not a case in which there is any such
overlap, so the comparison is of no help.<br>
<br>
Click <a href="850.pdf">here (p. 846)</a> and <a href="851.pdf">here
(p. 847)</a> to see the pages of the source-code listing that
are relevant to the problems in bank 36, namely:<br>
<ol>
<li>Address 36,2634: This source-code line is simply
missing. We have no clue as to what may have been in it,
except that it is seemingly the <span style="font-style:
italic;">first</span> part of a double-precision constant
whose <span style="font-style: italic;">second</span> part is
the word 00000 octal.</li>
<li>Address 36,2734: Appears to be interpretive code
reading "<span style="font-style: italic;">something1
something2</span>", but only a couple of pixel rows are
present, and so neither the octal code nor the
assembly-language code can be read.</li>
<li>Address 36,2742: Highly corrupted, but <span
style="font-style: italic;">may</span> have the octal code
00021 and <span style="font-style: italic;">may</span> have
interpretive source code reading "16D".</li>
<li>Address 36,2747: Pretty corrupted, but seems likely to
be the interpretive source code "CALL" with octal code 77624.<br>
</li>
</ol>
As far as points 3 and 4 are concerned, I think it's pretty easy
to convince ourselves that the proposed interpretations are
probably correct. If you want a challenge, you may like to
try solving problems 1 and 2 for yourself, before continuing to
read my proposed solution below.<br>
<br>
Point 2 is somewhat trickier than problems 3 and 4, because the
corruption of the page-image is so much greater. But with
some effort, we can still figure it out. Within the <a
href="851.pdf">offending page</a> of the source-code listing,
notice the notations "REF" and "LAST". These notations
appear only on source-code lines referencing variables.
"REF" gives the number of times the variable has been referred to
so far in the assembly listing, which "LAST" gives the page number
on which the preceeding reference occurred. The problematic
source line clearly contains REF and LAST notations (even though
we cannot read them), and so it is clear that <span
style="font-style: italic;">something2</span> is the name of a
variable. You should be able to convince yourself fairly
easily that the variable in question is <span style="font-family:
monospace;">RCON</span>. In other words, <span
style="font-style: italic;">something2</span>="<span
style="font-family: monospace;">RCON</span>". (In case
it's still not obvious <span style="font-style: italic;">how</span>
you would convince yourself of this, note that "REF 6" to <span
style="font-family: monospace;">RCON</span> is below the missing
source line, while "REF 4" is on the preceding page, but that "REF
5" is nowhere to be found.) Next, because this section of
code is AGC interpreter language (rather than assembly language),
we can narrow down the choices for <span style="font-style:
italic;">something1</span>; theoretically, the only
possibilities are <span style="font-family: monospace;">STORE</span>,
<span style="font-family: monospace;">STODL</span>, or <span
style="font-family: monospace;">STOVL</span>. Simply in
terms of appearances, it seems likely that <span
style="font-style: italic;">something1</span>=<span
style="font-family: monospace;">STODL</span>.
Unfortunately, the interpreter documentation (<a
href="hrst/archive/1687.pdf"><span style="font-style: italic;">Users
Guide to the Block II AGC/LGC Interpreter</span></a>, by
Charles A. Muntz) was last updated in early 1965, and contains an
incorrect numerical opcode for <span style="font-family:
monospace;">STODL</span>. Not to be deterred, though, if
we look at the other source-code lines near the missing line, we
see intact lines like "<span style="font-family: monospace;">STODL
RPRE,</span>" (the comma after "<span style="font-family:
monospace;">RPRE</span>", by the way, is actually part of the
variable name), from which we can deduce that the octal code for <span
style="font-family: monospace;">STODL</span> is 16000.
Noting that <span style="font-family: monospace;">RCON</span> has
the address 1635, therefore, "<span style="font-family:
monospace;">STODL RCON</span>" must assemble to the octal code
16000+1635+1=17636. But—and why, I'd like to know, does
there always seem to be <span style="font-style: italic;">another</span>
"but"?—the missing line of code is preceded by a line of source
code reading simply "<span style="font-family: monospace;">STADR</span>".
The <span style="font-family: monospace;">STADR</span> opcode has
the odd effect of complementing the code that follows it.
Therefore—finally!—the missing octal code for address 36,2734 is
probably 60141. This closely matches the remaining pixel
fragments (and expected parity bit) of the missing line, and so we
can feel good about it.<br>
<br>
Having now determined all of the octal values within the bank
except at address 36,2634, and noting the checksum for bank 36 is
known, we can consider the possibility of recreating the octal
value at 36,2634 simply by putting a value there that correctly
reproduces the bank's checksum. This is actually trickier
than you may suppose, since the checksum is unique only up to a
sign. (In other words, we don't know whether to insert a
value that produces the positive checksum or one that produces the
negative checksum.) Often, either the positive or the
negative checksum will be impossible to produce, thus removing the
uncertainty. Where it is possible to produce both the
positive and the negative checksum, we note that 90% of the memory
banks have positive checksums, so we have a much better chance of
being correct if we choose the positive checksum. All
of this turns out to be an anti-climax, however: Prior to
any of the reasoning listed above, our inclination was simply to
put 00000 at address 36,2634. Remarkably, this produces the
correct bank checksum without any additional work on our
part! Perhaps this is the first time in history that a gut
reaction has been confirmed by checksum.<br>
<h4><a name="Happy_Epilogue"></a>Happy Epilogue!</h4>
After the all of the intricate reasoning above was worked out—and
the description above written—Mr. Gary Neff was able to send me
some terrific replacement scans of the problematic
assembly-listing pages from bank 36, namely pp. 846-847. If
you examine locations 36,2634, 36, 2734, 36,2742, and 36,2747 on
the new scan, you'll see that they indeed contain exactly the
values deduced above! I still think the exploration I went
through before receiving the new scans is a valuable illustration
of technique, not to mention being soothing to my ego, so I'll
leave it in place for future generations to enjoy. :-)<br>
<h3><a name="ValidityApollo11"></a>Validity of the Comanche 055
Code (Apollo 11)<br>
</h3>
The Comanche 055 page images became available after the Colossus
249 and Luminary 131page images had already been converted to
source-code files, and prior to any other missions becoming
available. The conversion technique was very abbreviated
compared to that of Colossus 249, as follows:<br>
<ul>
<li>A small corps of volunteers—thanks (in alphabetical order)
Fabrizio Bernardini, Hartmuth Gutshe, Onno Hommes, Jim Lawton,
and Sergio Navarro!—took the existing Colossus 249 source-code
files, or on occasion the Luminary 131 source-code files, and
laboriously compared them line-by-line to the Comanche 055
assembly-listing page images, porting the differences they
found.</li>
<li>The resulting Comanche 055 source code was assembled using <span
style="font-weight: bold;">yaYUL</span> to produce a binary
executable, which was horribly wrong at this point (with
dozens of conversion errors), but was used to create a
"binsource" file (which is an octal listing of the entire
program).</li>
<li>The binsource file was laboriously proofed against the octal
listing in the page images (this time by me), and
corrected. As a double-check, the bank checksums are all
correct.</li>
<li>Finally, at every point where the binary created from the
source code by <span style="font-weight: bold;">yaYUL</span>
differed from the binsource file, the source code was compared
to the page images and corrected. After all corrections
were made, the binary created by <span style="font-weight:
bold;">yaYUL</span> was identical to the binary created from
the binsource file.<br>
</li>
</ul>
The binary thus produced by <span style="font-weight: bold;">yaYUL</span>
is supplied in the source tree and used for regression testing.<br>
<h3><a name="ValiditySource15"></a>Validity of Artemis 072 Code
(Apollo 15-17)</h3>
The Artemis 072 executable (Artemis072.bin) was created by
manually entering binary data from scans of an Artemis 072
assembly listing. The data was proofed and reproofed until
the bank checksums, as described above, were correct, and the
binary was made available to the public on 2006-01-10. On
2010-02-20 (more than 4 years later), source code was finally
available and assembled. <span style="text-decoration:
underline;">A single error</span> <span style="font-style:
italic; text-decoration: underline;">which did not affect the
memory-bank checksum</span> <span style="text-decoration:
underline;">was found</span> and corrected in the binary.
So we are <span style="font-style: italic;">now</span> confident
that what is being provided is both complete and correct.<br>
<br>
This is an interesting object lesson. My previous notes in
this section, prior to the availability of source code, made it
clear that I wouldn't be surprised if additional pairs or even
triplets of errors were found in the binary ... but the notion
that an unpaired error might still exist which did not affect the
checksum never occurred to me. The problem is a weakness in
the checksumming algorithm used in the AGC.<br>
<br>
If the AGC had used a "normal" checksumming algorithm (from the
modern point of view) with 2's-complement arithmetic, any <span
style="font-style: italic;">single</span> error in data would
have caused the checksum to change, and the error to be detected.<br>
<br>
But in the 1's-complement arithmetic of the AGC, simple
checksumming does not have the same desirable property. For
example, since there is both a +0 and a -0, which produce the same
result in an addition, a memory error in which +0 is replaced by
-0 (or vice versa) produces the same checksum and would be
undetectable. But algorithmically the problem is more
complicated than that, since a simple checksum algorithm was not
used. The actual algorithm used on a data-word by data-word
basis was this:<br>
<ul>
<li>The next data word is added to the running checksum.</li>
<li>If there is <span style="font-style: italic;">positive</span>
overflow, the result is reduced by 040000 (considered as a
positive number, thus preserving the sign of the result) and
then incremented.</li>
<li>if there is <span style="font-style: italic;">negative</span>
overflow, the result is incremented by 040000 (again,
considered as a positive number, thus preserving the sign of
the result), and then decremented.</li>
</ul>
For example, if the running checksum was 030000 (a positive
number), and the next data word was 020000 (another positive
number), then adding them would give 050000 (arithmetic
overflow!), which would be decremented (due to the overflow) by
040000 to give 010000, and then incremented by 1 to give a running
checksum of 010001.<br>
<br>
If you are amused by such stuff, I invite you to consider the ways
in which such an algorithm might fail to detect error. In
the case of the Artemis 72 binary, the now-corrected error was a <span
style="font-style: italic;">single bit</span> (the most
significant bit) of a single memory location.<br>
<h3><a name="ValidityApollo8"></a>Validity of Colossus 237 (Apollo
8)</h3>
The Colossus 237 program listing presented a special challenge,
because the only physical copy we've had access to is
truncated. It contains all of the source code, as well as
the binary words associated with the source code on a line-by-line
basis. But it is missing the octal listing that condenses
all of the binaries into an easily accessible form. Because
the octal listing is missing, the "bugger words" that are used to
make the memory-bank checksums compute correctly are also
missing. Thus, important redundancies and checksums that
normally would be used to provide confidence of correctness are
missing.<br>
<br>
Therefore, the following unique validation procedure was applied
instead:<br>
<ul>
<li>A "binsource" file was created by laboriously stepping
through the page images of the program listing, line-by-line,
and observing the listed binary words. The "bugger
words" are not available in this fashion, and are therefore
left at zero.</li>
<li>Since Colossus 237 and Colossus 249 are separated in time by
only a few months, the binsource files of Colossus 237 and
Colossus 249 — i.e., the binary files we create manually,
independently of the source listings, as part of the
data-entry process — were compared using automated tools
('diff' or similar). Where differences existed, the page
images of the Colossus 237 program listing were referenced to
verify (to the extent possible) that the differences were real
rather than being transcription errors. <br>
</li>
<li>Where complete memory banks were found to be identical by
the automated comparison, the bugger words were copied from
Colossus 249 to Colossus 237.</li>
<li>Source-code files were created from the page images of the
program listing.</li>
<li>The binary of the assembled source-code files was compared
in an automated fashion against the binary created from the
binsource file, and either the binsource file or the source
code (or both) were corrected when any discrepancies were
found. At this stage of the process, validation process,
it is very typical for "superbank" errors to show up; these
are errors not in the source code <i>per se</i>, but are due
to discrepancies between <b>yaYUL</b>'s assumptions about the
superbank memory settings in comparison to the assumptions of
the original YUL or GAP assemblers; thus, those superbank
problems were corrected as well.<br>
</li>
<li>For any banks remaining without bugger words in the
binsource file, the bugger words created by <span
style="font-weight: bold;">yaYUL</span> were added.</li>
</ul>
<p>Thus while we can't have as much confidence in the validity of
the Colossus 237 transcription, in comparison to almost all of
the other Colossus and Luminary transcriptions, the code has
nevertheless been double-checked both manually (visually) and in
an automated fashion as well.<br>
</p>
<h3><a name="Validity_of_Solarium_055_Apollo_4"></a>Validity of
Solarium 055 (Apollo 6)</h3>
Solarium 055 presented a big challenge because it is the first
Block I code processed, and no Block I support was previously
provided by the <span style="font-weight: bold;">yaYUL</span>
assembler. However, support for Block 1 was in fact added to
<b>yaYUL</b>, and after that validation of Solarium 055 differed
little from any other AGC program. Unfortunately there is no
way as of yet to run Solarium in yaAGC, so we have not had the
additional pleasure (and assurance!) of witnessing it run.<br>
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