Hide 2022 change notes?
Several documents added to the library:
  • Apollo Training course A-324 slides on the various CSM sequential systems (SECS, EDS, LES, ELS)
  • The Preliminary Reliability Profile report for mission 204A (i.e. Apollo 1)
  • A report on communication system performance during AS-202
  • A communications performance and coverage analysis for Apollo 5 / LM-1
Several additional documents were added to the library.  Mike Stewart, who sent them, categorizes them like so:
  • The final pre-flight thermal analysis for LM-3
  • A training document for the CSM mechanical subsystems
  • An odd set of Block II CSM slides? It's missing the first 300+ pages and I have no idea what it is exactly.... it kind of strikes me as design review material or something like that. It came in a big lot with other more interesting things that I've already sent over. But it has things that are interesting in their own right, like some CSM drawing trees, listings of ICDs for subsystems, and rundowns of Block I/II differences.
  • A lovely set of photographs of Apollo 6's instrument unit.

As far as the "odd set of Block II CSM slides" is concerned, while I haven't had the chance to look at them too closely yet, I'd add that the most-notable part to me so far is the following illustration (which I'm showing in reduced form):

While I can't claim to understand all of the symbolism in this picture, I will say that the pistol sticking out of the bottom of the spacecraft and aimed at the ocean seems just as relevant to America in 2022 as it did in 1965.  So those of us who are worrying that America no longer is what it was back in the good old days may be barking up the wrong tree.
A major document has been added to the library, namely a North American Rockwell document titled "Spacecraft Operations for SV Countdown / Countdown Demonstration".  It's the countdown procedures for the Apollo 11 CSM, prior to backup crew ingress.   In other words, everything done by ground crew to prepare the spacecraft before any astronauts show up, all in 700 compact pages.
Two more documents, related to the LEM Mission Simulator situated at the Cape, were added to the document library:
  • The Lunar Module Mission Simulator Instructor's Handbook Volume I, Simulator Description. This manual contains detail on every switch and display, as well as information about how all of the subsystems are simulated.
  • The Proposal for LEM Mission Simulator Volume II, Technical Addendum: Glossary of Symbols. Despite the unimpressive name, this document includes a lot of flowcharts showing the mathematical equations backing the LMS.
Three more documents were added to the document library.

Mike's summary:  More of the same, but this time for the LM! These three documents are all Elementary Functional Diagrams from Grumman, which were the equivalent of NAA's Functional Integrated System Schematics. Just like their CSM counterparts, they are schematic redrawings that show LM wiring down to the connector and pin number. The LM groups covered are:
  • LTA-8 (thermal-vacuum testing)
  • LM-7, 8, and 9 (Apollo 13, 14, and the unflown LM on display at KSC)
  • LM-10 and subsequent (Apollo 15+)

[To Mike's comments, I'd add that while a lot of folks would think it's natural to just skip the LTA-8 version and move right on to the Apollo 13+ versions, the LTA-8 version is in far better shape than the other two versions.  So where the documents overlap, it may still be worthwhile consulting the LTA-8 version even if you don't actually care about LTA-8 specifically.]

Nine documents were added to the document library. All of them integrated functional system schematics for the Block I CSM or its associated GSE from North American Aviation.  Specifically, they are for spacecraft SC-008 (Thermal Vacuum Tests), SC-011 (AS-202 mission), SC-012 (Apollo 1 mission), and SC-014 (Apollo 1 investigation, Apollo 6 mission, testing).  Here's Mike Stewart's synopsis: 
  • V14-900111 volumes 5 (GNC), 8 (RCS), 10 (SECS), and 13 (ACS), of various revisions. These are functional integrated system schematics for the command module SC-011.
  • V14-900112H volume 2, the functional integrated system schematics for command modules SC-012 and SC-014.
  • A partial, in-development copy of V14-900208, an apparent re-release of the functional integrated system schematics for SC-008.
  • G14-900708 Volume 2, revision C. This is a full combined system-level schematic for the thermal vacuum testing of SC-008 at the Space Environmental Simulation Laboratory at MSC, showing interconnections between different pieces of GSE, and between the GSE and the spacecraft.
  • G14-900708 Volume 2, partial revision D, containing some changed drawings for the above.
  • G14-081168, the functional unit schematic for the fuel cell heater power supply.
If you notice an Apollo 11 landing telemetry transcript among the recent additions to the document library, don't get too excited.  The document isn't new.  The poor condition of its legibility has led to some recent discussions about workarounds for trying to read it.  The reason the document is marked as new now is that I've
  • Removed links to its super-duper poor PDF, leaving behind a link only to the "merely" super-poor highest-quality scans at our archive.org site; and
  • Correspondent "jumpjack" has been trying to decipher it, so I've added a link to their notes on the topic in our GitHub repository's issue list.

Obviously the dream (in lieu of finding a better copy of the document) would be a fully-legible transcription of it.  Whether that will ever happen, I can't say.  It turns out there actually is a prospect for getting a better copy of the document, but that prospect is vague, without any definite roadmap for doing so, so I wouldn't hold my breath!

On a completely different topic (but also thanks to "jumpjack"), I've set up a feature in our GitHub repository called "Discussions".  Virtual AGC Discussions on GitHub work like a souped-up version of our Virtual AGC mailing list, which frankly has been a source of problems over the years.  So if I can move away from the mailing list to something that's not only better but also less of a problem for me, it's a win-win!  Admittedly, since I just now set it up, there's no content on it yet other than my welcoming thread.  There are bound to be some teething problems.  Anyway, I invite you to use it.

Two more documents were added to the document library; here's Mike Stewart's synopsis:
  • A partial revision to the SA-513/SL-1 Launch Mission Rules Input Document. While it's not the full version, it is interesting in that it is first document of this type for us.
  • Revision H of V34-90001, the Elementary Functional Integrated System Schematics for the Block II Design Reference Mission. We already have the later and more accurate revision K, but this early one shows some interesting differences along the development history of the CSM.

Besides that, you may notice that there's a digital simulation of an Apollo 11 landing that appears among the recent additions to the library.  But don't get excited, because it's not new.  It's simply that I've been told (thanks to correspondent "jumpjack") that the PDF I had formerly linked as the preferred document version was unreadable.  Consequently, I've substituted a link to a more-legible version.  But it's the same physical hardcopy and scan.

Ten more documents added to the document library, all of them Grumman study guides.  Here's Mike Stewart's synopsis:
  • Control Electronics Section and Abort Guidance Section. The AGS section is very good, and includes a large 2D foldout of the AEA architecture as well as descriptions of all of the instructions.
  • Communications Subsystem
  • Crew Systems
  • Environmental Control Subsystem
  • Electrical Power Subsystem (1966)
  • Electrical Power Subsystem (1967)
  • Electrical Power Subsystem (LTA-8; diagrams only)
  • Propulsion and RCS
  • Radars
  • Structures, Mechanical Systems, and Electroexplosive Devices

I realized belatedly that perhaps the Document Library should have an entire section dedicated to training and study guides, which it has lacked so far.  So I've added one.  Whether all (and only) the appropriate documents have been included in that section is debatable, and probably will have to be tweaked over time.  On the other hand, you could probably say that about all of the other sections in the library as well.

On an only-slightly-related note, I've also realized belatedly that in some of the library sections organized principally by publication date, it would be slightly less confusing if undated documents were specifically marked as being undated (as opposed merely to not showing a date).  So I've added that little feature as well.  Beyond that, the primary culprit in this confusing-organization regard is the Everything section of the library, which is organized by date but contains literally thousands of entries; to that section only, I've added horizontal lines between year changes as (hopefully!) gentle guidance to the eye.

  • Regarding the AGS, there have been a couple of changes, both thanks to a reader identifying themself as "spacex15":
    • A potential fix has been put into place for a bug in the treatment by yaAGS (the Abort Guidance System's CPU emulator) of overflow in the 'MPR' opcode.  I say "potential" merely because the AGS documentation is not extensive enough to unambiguously tell us that the fix is fully correct.  But I've been told that the bug affects radar updates by the AGS in NASSP, and that the fix fixes that (or at least makes it better than it was), so I'm inclined to think the change is a pretty good one.
    • The encoding of the decimal integer -1 and the fixed point number -1.0 differ from each other in the AGS, and this explains a discrepancy in the documentation of how the AGS encodes -1 that I had written a few nasty words about on the AGS web-page.  Well, semi-nasty.  Well, not gushing with praise.  Well, I had said the AGS documentation was wrong.  So I've toned down my language a tad to simply point out the reason for the documentation's discrepancy, rather than applying the W-word to it.
  • I've been told (thanks Thymo van Beers!), and verified for myself, that certain hyperlinks on the website have stopped working in the last week or so.  I refer to links that are targeted at folders on the website, as opposed to specific files on the website, thus allowing you to see the contents of the folders for yourself without my having to go to the effort of creating web-pages.  For example, a couple of weeks ago, a hyperlink like this one would have allowed you to browse the contents of a folder that contains all of the colorized, syntax-highlighted listings of AGC software we've transcribed ... whereas now, it just gives a "403 Forbidden" error.  To be clear, the files themselves are still accessible from hyperlinks to them on our web-pages; it's just that you can't browse through them on your own by viewing the folder's directory listing.  Fortunately, there aren't too many links like this that people would find helpful, so for most people this is probably not even an inconvenience; but for some it's a real irritation.  Presumably this is some change ibiblio.org has made globally for security reasons, and I don't immediately have any workaround for it.  The "staging" version of the website exhibits the same problem, so presumably GitHub is using the same webserver security restrictions in this regard as ibiblio.  At any rate, the problem has been kicked upstream to ibiblio.org's support team.  Hopefully they'll be able respond (some day) with helpful information, at which point the links will start working again.  For now, though, I fear it's just something that must be endured.
  • On a more-pleasant note, a couple of Grumman documents Mike Stewart got from somewhere have been added to the document library:
    • OCP-B-90000-B-1, the LTA-8 Manrating Test. This is the full test procedure for the 1968 manned thermal vacuum tests of LTA-8 in Houston's Chamber B.
    • OCP-B-90008-LM-2, the LM-2 Landing Simulation Test Post Test Baseline -- which is a confusing title. In April 1968, LM-2 underwent a drop test. After being attached to the drop fixture, it underwent a full system functional test to establish vehicle health. It was then dropped to simulate a landing, and then essentially the same test was run again to make sure everything still worked correctly after the shock and stresses of a simulated landing. This as-run procedure is for that post-drop functional retest.
Added another batch of 56 documents (though one is a kind of duplicate) to the Document Library today, as usual in recent history thanks to Don Eyles and Mike Stewart.  As far as I know, this completely clears out the backlog of documents that had been scanned but weren't yet in a usable digitized form for being posted here.  Here's Mike's summary of them:
  • A handful of PCRs and PCNs
  • DG Memo 145, "A Manual Abort Guidance Procedure Based On Range and Altitude Measurements", is a really interesting early memo by Allan Klumpp that presents a mechanical geared calculator for LM abort and CSM rendezvous.
  • A set of memos related to the DPS throttle oscillation problem caused by an incorrect THROTLAG value.
  • A set of memos concerning an unexpected yaw at the end of P64.
  • E-1551, "Functions and Mechanization of the Apollo Guidance and Navigation System", contains early diagrams and descriptions of the inertial subsystem and its interfaces to the AGC.
  • A few "Luminary Development Note" memos, which have good detail on testing.
  • Most of the "Luminary Project Memos", which were started by Russ Larson around the time of Luminary 1D. They're mostly procedural meeting scheduling, but some of them have good/useful information.
  • Another set of XDE (Engineering Design Information Exhibit) documents, concerning the AGC, CDU, PIPAs, optics.
Added the 2022 section to this change-log page.
Hide 2021 change notes?
Added another batch of 38 documents to the Document Library today, thanks to Don Eyles and Mike Stewart. Here's Mike's summary of them:
  • ACB-40 for Luminary 1B, which looks like it was formerly missing
  • Some Apollo 17 checklist/procedure documents
  • Something called "Apollo Block II Command Module and LEM Guidance Navigation and Control System Mechanization and Block Diagrams", which turns out to be pretty much entirely foldouts containing 2015xxx and 6015xxx engineering drawings in foldout form -- plus a handful of drawings that had not (yet?) been assigned a drawing number.
  • E-1087, the Documentation Handbook and Plan, which looks potentially very interesting and useful in a meta/archival kind of way.
  • The very first revision of the LEM Familiarization Manual, which describes an extremely early version containing a front document port instead of a front hatch.
  • A technical description for the Traverse Gravimeter designed by MIT/IL for later missions
  • A set of MIT Management Development Plan meeting notes, with lots of more management-y type stuff like delivery dates, personnel assignments, etc.
  • Assorted other memos and documents
Mike Stewart has sent over a batch of 26 documents he has scanned from Don Eyles's collection, so a big thank-you to both of them for a Christmas present in the midst of a pandemic.  Alas, I didn't get them anything in return, because I'm a thoughtless pig.

As usual, to see what's been added, just look in the Recent Additions section of the document library.  Here's Mike's list of the most-notable additions among them:
  • Programmed Guidance Equations for Luminary 1D (specifically 173).
  • Software Anomaly Report LNY-70.
  • R-599, the user's guide for the digital simulator, which goes into great detail about how to use the thing that produced all of those simulation outputs that Don had.
  • The LM-1 Operations Team Report is a giant document filled with a report from every flight controller on Apollo 5, including things like a complete time-tagged list of every command they sent to the AGC.
  • Section 4 of the Apollo 1 GSOP, which wasn't included in our other, partial copy of that GSOP.
  • A draft addendum to the Apollo 11 program notes, explaining the problem caused by LNY-77, before they decided to just fix the program and make LMY99 Rev 1.
  • The initial revision of the User's Guide to Major Modes and Routines.  We already have two later revisions of the document, but they span Apollo 13 through 17, so this earliest revision may be more-specific to Apollo 13.
Sometimes I have to marvel at my own stupidity.  A while back, John Pultorak (of AGC Block 1 simulator fame) had been working on a Gemini On-Board Computer (OBC) simulator along the same lines as his Block 1 AGC simulator.  10+ years ago, he sent me a trio of documents on the subject, which over time I managed to forget all about.  So today, as I was trying to do a little reorganization of my home office and happened to come across a printout of one of these documents, I was a bit surprised.  Or perhaps "stunned" is a better word.  After an interval in which I occupied myself by saying "Whaaaaat?!!!" in a foolish manner, it eventually occurred to me to dig back into the original correspondence with John, whereupon I found (hopefully) all the related documents, and have added them to the document library.  You can see them at the top of the list of recent additions.  In brief, though, there's:
  • John's description of the actual OBC architecture.
  • His description of his own simulator for it, which he called the Simple Gemini Spacecraft Computer (SGSC).  His is a hardware simulation rather than a software simulation, so his description includes circuit diagrams rather than software.
  • An extremely brief coding example of how to assemble OBC assembly-language into a form in which it can be executed on is simulator.

Since John didn't provide an assembler, his coding example is hand assembled.  Of course, we have an OBC assembler, though I doubt it's in as debugged a form as our LVDC assembler.  Still, I'm sure it could be pepped up to a 100% working state, if anyone chooses to build the OBC simulator and wants to run some code on it.  By the same token, I suppose you could adapt John's OBC simulator into an LVDC assembler, and that might be even better.

Either an OBC or LVDC hardware simulator would be of great use in debugging our software-based OBC/LVDC simulators.  It wasn't until Mike Stewart came along with his Block II AGC hardware simulation and ran it side-by-side with our software AGC simulator that we (well ... to be honest, he) was truly able to ring the bugs out of both of them.

Ludo Visser (thanks, Ludo!) has sent along some instructions for building Virtual AGC on MacOX 12.0.1 (Monterey).  It apparently works after he builds it as well.  Which is very welcome news since I don't personally have a Mac new enough to try it myself.
It used to be that on the yaDSKY page I depicted the indicator lamps of the Apollo 15-17 LM's DSKY as differing from those of Apollo 11-14.  The difference was that there were 2 (out of 14) indicator lamps unused in Apollo 11-14, whereas those 2 were the NO DAP and PRIO DISP warnings in Apollo 15-17.  But then, 2-3 years ago, we acquired the actual DSKY engineering drawings for Apollo 15-17, and what did they show?  Two unused indicators in Apollo 15-17, with no NO DAP or PRIO DISP indicators, just like in Apollo 11-14!  You can't argue with engineering drawings, so I dutifully changed the yaDSKY page to match the engineering drawings, with the Apollo 11-17 LM DSKYs all being exactly the same in terms of their indicator lamps.

I should of stayed in bed that day.  Fabrizio Bernardini (thanks Fabrizio!) has pointed out that the contemporary documentation for Apollo 15-17 says that the NO DAP and PRIO DISP legends were added to the LM DSKY by means of decals, as opposed to being directly engraved or printed or whatever technique was used to get the legends onto the other indicators.  Presumably the decals were applied after the manufacturing described by the DSKY engineering drawings.  In other words, yes there were NO DAP and PRIO DISP indicators in Apollo 15-17, in spite of the drawings.  Stupid old me!  So naturally I've now changed the yaDSKY page yet again, hopefully correctly this time.

The good news is that back when I changed the yaDSKY page before, I apparently forgot to update the VirtualAGC GUI software ... so it continued to have the NO DAP and PRIO DISP indicators all along, and doesn't need to be fixed now.  Two wrongs ended up making a right.

I also added a pair of "news reference" documents to the Document Library, one for the CSM and one for the LM, the latter of which had apparently gotten Fabrizio started thinking about this topic.
  • 3 new documents added to the Document Library page.  The prizes are AGC telemetry dumps from the Apollo 11 and Apollo 12 landings, formatted in a relatively friendly way for human consumption, and with some hand-written annotations.
  • More progress on Comanche 67 reconstruction, now with 8 memory banks having correct checksums, and the number of overflowing banks reduced to 2.  With a total of 36 memory banks, and only 8 cleared, there's a long way to go.  But better 8 than never.
  • In the Document Library, lots more titles of PCRs, PCNs, and Software Anomaly Reports were found and added.
  • Some progress has been made in the Comanche 67 reconstruction recently, in that we now have 6 memory banks with correct checksums, whereas a week ago there were only 4.  On the other hand, there are now 3 memory banks which overflow at assembly time (which is more than before).  But progress is progress, however slow and halting.  All of the known PCRs, PCNs, and Software Anomaly Reports pertaining to Comanche 67 have been reanalyzed from scratch, without reference to the analysis that had been done before.  The ongoing investigation is now temporarily but systematically being documented in a wiki framework, and it's much cleaner to work with and follow than the confused mess the old documentation (as an "issue" in our github repository) had been.  I guess using appropriate tools really does affect the quality of the work.  Who would have guessed?  But even using appropriate tools doesn't compensate very well for a lack of appropriate information.
In the Document Library, various corrections were made and a number of new PCR/PCN/Software Anomaly Report titles were added, as well as additional associations of PCRs/PCNs/Software Anomaly Reports to specific missions (i.e., to specific software revisions, particularly Colossus 2C and Luminary 1B).  Or to put it differently, I've been working to firm up the list of PCRs/PCNs/Software Anomaly Reports being used in the reconstruction of Comanche 67.
I made some corrections and additions to the PCR/PCN/Anomaly material added yesterday, such as adding missing titles to some SUNDANCE PCRs, adding a few missing COLOSSUS software anomalies, and so on.

By the way, I understand why many folks mightn't be too interested in PCRs, and might be doubly-uninterested in just lists of PCRs without even having the PCRs themselves.  Why would we want them, other then from pure obsessiveness?  (Or is it compulsiveness?  Or perhaps some less flattering, but even more dismissive buzzword?)  From my own perspective, the PCRs, PCNs, and Software Anomaly Reports are the principal resources you have, other than the memory-bank checksums, when you're forced into the position of having to reconstruct an AGC software version because you haven't an actual listing of the source code.  Even just the title of the PCR (without the text) can be very useful.  How it works is this:  From the PCR/PCN/Anomaly (or even just its title), you may be able to isolate which portions of the AGC code are relevant.  For example, if a PCR's title is about something called THROTLAG, there are only a few portions of any given AGC program that deal with THROTLAG.   If you have earlier version of AGC code in which the PCR has not been implemented, as well as a later version in which the PCR has been implemented, you can then compare them to see how they differ.  You then can pull the THROTLAG-related changes into the software revision you're trying to reconstruct.  Voila!  Your reconstruction now has corrected THROTLAG code!  In practice it's often much trickier than that, but that's the basic idea.

Yes, it's not something everyone would be excited by.  Personally, I dread it.  But in this kind of digital archaeology you work with what you have, and not with the material you wished you had.  Think of it like gold mining:  You'd naturally prefer to just find big chunks of gold sitting on the ground.  But if you instead find a vein of gold that requires a lot of digging, that might not be too bad either, if you can find enough of it!
The PCR/PCN section and Software Anomalies section of the document library have been overhauled reasonably drastically.  For some reason, I got the whim to list all known PCRs/PCNs/Software Anomalies, and not just those for which we currently have copies in the library, and not just those which had been "approved" back in the day.  For one thing, showing all of them gives a better picture not only of the great evolutionary sweep of the AGC software, but also gives a better idea of where the gaps in our coverage are.  Maybe.  Regardless, it's pretty impressive to see them all sitting there in one big lump.

This has greatly increased the number of PCRs/PCNs listed, which in turn has made me recognize some limitations in how I was displaying them.  One action I've taken is to prefix a short characterization to the front of each PCR/PCN entry telling which AGC program the entry applies to:  SUNDISK, SUNDANCE, COLOSSUS, LUMINARY, or SKYLARK.  By the way, SUNDISK, you may recall, was the software for Apollo 7.  The Software Control Board meeting minutes at which SUNDISK PCRs were approved notes the event as follows, closely mirroring my own reactions:
SUNDISK PCR’s Approved at SCB ! ! !

There was a flurry of excitement among SCB members when a SUNDISK PCR was introduced. The excitement subsided when the members found out that only the GSOP was being changed.

With software anomalies, on the other hand, I find that the entries are easier to locate when sorted by document number (which they are, as of today) rather than by date (as they had been), and that the "titles" for many of them were susceptible to some improvement.

On a more-general note, the tag that I used to put next to "new" documents in the library has now returned after a hiatus of about a month.  I had removed these tags when I added a "Recent Additions" section to the library.  In removing them, what I failed to realize is that while it was true that the recent-additions section itself didn't need any additional bling to highlight which files were new, all of the remaining sections in the library could still benefit from them.  For example, if you were looking at just the PCR/PCN section of the library, it would be nice to see which PCRs had recently been acquired, without having to consult the recent-additions section.  Now you can.  On the good side, though, since the document-library page is now auto-generated, there's no danger of the badges getting out of hand by endlessly proliferating and never being removed, as they had before; they will die off and disappear naturally as time passes, and thus are rather harmless other than whatever bandwidth and page-load time they consume.  I've also shortened up the time scale, so that documents are only "new" for two months after they're added, rather than for three.  But that's not exactly set in stone and I could change my mind later.  In the short time that we've had the recent-additions section, I've waffled all over the place, using a timescale as long as 6 months and as short as 1 month.  Since we've had an atypically large number of documents added in the last few months, it's still a bit hard to judge right now what the best timescale setting should be, on a go-forward basis.
Apparently I had goofed up COLOSSUS Memo #267, duplicating p. 4 and leaving out p. 5.  That has been fixed, causing also an update to ARTEMIS revisions 37-40 in the big software-version pictorial.  All of this affects only the Document Library.
Pepped up the huge pictorial chart of all AGC/AGS revisions I mentioned yesterday, adding annotations and various software versions (SHEPATIN, DAP AURORA, AP11ROPE, SUPER JOB, etc.) which I had chosen to omit yesterday.  In retrospect, I wanted to at least make sure the chart included all AGC software versions for which we actually possess contemporary printouts.  I suppose I should also have given a direct link to the chart yesterday, rather than a simple link to the document library page.  It's really pretty sweet eye candy — at least, given my personally-limited innate ability to create eye candy! — even if it would take you a lifetime to work through its incredible detail were you to do anything other than just scroll through it like a sightseer.
On a whim, I decided to make a huge chart showing all of the revisions of every AGC and AGS program, starting from ECLIPSE and RETREAD, and flowing through to SKYLARK, showing what programs branch from what revisions of what other programs, and what PCRs/PCNs/etc. went into making one revision from another.  Admittedly, while we have a lot of the information needed for making the chart, there's a lot of information missing too, and hence quite a lot of guesswork ... and thus likely quite a lot of error if you focus on the minute detail.  Still, it ended up being an impressive bit of eye candy by my standards, and probably catches the spirit of the development effort pretty well.  (If you want to point out my errors, please do so; but supply documentation to prove your points, please.)  You can check it out in the Software Listings section of the Document Library.  The chart is about 40× taller than its width, so I considered turning it into an animation that continually scrolls from top to bottom, possibly while playing impressive music.    Ultimately, I decided that that could be a bit of overkill; if you want to scroll through the chart, I'm afraid you'll have to do so manually.
The writeup I supplied yesterday on the Luminary page for the Apollo 13 LM software release, as complicated as it was, turns out to have been too simplistic according to additional documentation Mike has dug up!  So I've completely rewritten it, expanded it, even added a picture to it.  The end result seems to me to clearer and more interesting, even if expanded.
  • Various miscellaneous improvements to the document-library page, including a new mission-specific LTA-8 section, additions to various other sections based on improved characterization of some documents (an ongoing process), and additions/fixes to the table of known AGC software releases for rope manufacture (another ongoing process).
  • It had been pointed out to me that I had been playing fast and loose with the naming of certain AGC software revisions, and that this could lead to confusion ... particularly confusion as to flight software, which is the worst kind of confusion.  So I've hopefully fixed up the Luminary and Colossus pages to cover up my faux pas in this regard.  The specifics are that the flight programs MANCHE45, MANCHE72, LUM69, LMY99, and LM131 (and the development software LUM131) for Apollos 10, 11, and 13 were not, strictly speaking, revisions of COMANCHE and LUMINARY, but were rather side-development branches from them, and thus bear different program names and incompatible revision levels.  Indeed, LUM131 was branched from LUMINARY 131, and then LM131 was branched (again!) from LUM131.  It makes for a more-confusing story, but a more-accurate one than I (and some of the contemporary memos) had been telling.
  • Rewrote the opening blurbs for the Document Library's sections on PCRs/PCNs and ACB Requests/Software Anomaly Reports.  It turns out it's helpful to actually find out what things are before writing about them.  Who knew?
  • Speaking of the Document Library, you'll find hundreds of supposedly recently-added documents today.  Actually, not a single one of them is truly new to the library.  It's just that I belatedly realized that over time I had accumulated quite a few PDFs which were lacking searchable text.  So I've added searchable text to them, and now they're interpreted as being "new".  In point of fact, I did this to every PDF file on the website that needed it, not just those in the library.  Ultimately, 716 PDF files in all were fixed up; but only 232 of them show up among the recently added to the Document Library, which is about 8% of the library.  The principal advantage to having searchable text is that these files will now show up more usefully in our Google search bar (at the top of every page of the website).  As it happens, they showed up in the search results even before I added searchable text to them, but if they were hundreds of pages long they were simply useless once you opened them up locally because you could never search within them to find what Google had promised you they contained.  I guess that Google must do its own OCR'ing process when it finds unsearchable PDFs, even though it ends up being of limited use when your documents are longer than 1-2 pages.  This will be better.
  • For reasons with which I won't bore you, I've put together a table of all AGC programs/revisions which I could find had been released for manufacturing of their core-rope memory modules.  This table is pretty big, and I've added it to the lead-in for the Assembly Listings section of our Document Library.  If I recall correctly, nearly 75 software revisions of Luminary, Colossus, and other programs like Skylark, Sundance, and so on, were manufactured as ropes; leaving 500-1000 revisions for which ropes were not manufactured.  (Recall that there were 210 revisions of Luminary, 249 of Colossus 1, 108 of Colossus 2, 72 of Colossus 3, 88 of Aurora, ..., well, you get the idea.)  I had previously begun our Luminary and Colossus pages with much-more-abbreviated release data, so I've rewritten the openings of the Luminary and Colossus pages to remove that abbreviated discussion and instead point to the big table.
  • Another load of 26 documents from Don Eyles's stash added to the Document Library.
  • More nailing-down and additional explication that SOLARIUM 55 was used in Apollo 4 as well as Apollo 6.  Our huge stash of G&N engineering drawings nails this down, which I'd regard that as the most-convincing argument yet.
For some time, we've realized that the listing we have of the AGC program AURORA 12 really represents quite a late stage of AURORA development rather than a very early stage ... in spite of the fact that AURORA 85 and 88 were the endpoint.  But for some reason, I had neglected to alter the description on the Luminary page — and now on the Document Library page — to reflect this understanding.  So I've done that now.  The executive summary is that what I've been calling "AURORA 12" all this time, is not really AURORA at all.  Rather, it was forked from the true AURORA program at AURORA 86 or 87, and then new code was added to it without materially affecting those areas of the program of particular interest to us ... i.e., the AGC self-test software.  On a go-forward basis, I'm now calling this forked program "DAP AURORA" to help avoid some of the confusion.  So what we have is DAP AURORA 12 rather than AURORA 12.
  • Kondoization of the Colossus page has been completed, as well as cleanups of yesterday's work on the Luminary page.  If you have beefs, lay them on me!
  • Up to now, we've speculated (and have had good reason to do so) that SOLARIUM 55 was the software used in both the Apollo 6 and Apollo 4 unmanned missions, even though in theory Apollo 4 used SOLARIUM 54.  I now regard our speculation as a proven fact, and have altered the descriptions on the Colossus page and the Document Library page accordingly.  (In brief, I have belatedly noticed that Table 4-I of report R-700, vol. 3, simply says it was used on both, and unambiguously identifies our SOLARIUM 55 source-code listing, by both name and part number, as being the software it's referring to.)
  • Spent a little more effort trying to track down the SUNSPOT revision number that would have been used for Apollo 1.  No luck with that, but I did find what I can assert with reasonable confidence is a log-section by log-section allocation of fixed memory; i.e., the list of log sections in the program, and how many words of memory each of them took.  I've added this info the Colossus page ... which now that it's Kondoized, doesn't affect the comfort in navigating the page.  A great discovery!  I can write and write endlessly detailed discussions (which I'd never have the patience to read myself), and as long as they're on the Colossus or Luminary pages, I don't have to worry about how incredibly boring they must be.  An amazing innovation indeed.
  • Fixed up links on several pages to point to the new Document Library rather than the old.  But there is a lot more cleanup to do in that respect.
  • Realized that neither the new nor the old Document Library page had a section for Block I specific documents.  I've corrected that — new page only, of course!
  • Realized that none of the Apollo mission-specific sections of the (new) Document Library page included the LUMINARY or COLOSSUS Memos related to the software changes leading up to the software releases for those missions.  Nor indeed, any documents keyed by the missions' software revisions (as opposed to mission number).  So I fixed that.  But there may be more work to do in that area, particularly in regard to PCR/PCNs and Software Anomalies.
  • I've "Kondoized" the big table of LUMINARY revisions on our Luminary page.  I haven't actually removed anything from it, except incidentally, but I've reorganized it by liberally taking advantage of the mission-specific sections on our improved Document Library page and by superficially shortening up most of my long-winded descriptions of the various Luminary revisions with lots of "Read more" buttons.  So the end result seems much less intimidating and seems easier to navigate.  I'll probably Kondoize the Colossus page as well tomorrow, if time permits.
The replacement Document Library page is now considered "live".  It's now what appears in the menus at the tops of all the other pages.  The old Document Library page will remain available (and there's a link to it listed on the new page) for anyone who has learned how to use it and doesn't want anything different, but I don't anticipate updating it much, if at all.  Obviously, the new page probably has plenty of deficiencies, so feel free to inform me of them, even if they're subjective.  My immediate goal was simply to make something that was pretty much like the old page ... but better!  So while I think I've succeeded in doing that, I won't claim that it can't be improved in the fullness of time and feedback.
I'm up-to-date again with respect to the documents that have piled up for inclusion into our Document Library ... however, I'm up-to-date only on the "replacement" Document Library page I've been developing, because I'm loath to spend more effort maintaining an older page that I'm convinced will soon begin spending its days in sweet, sweet retirement.

A word to the wise, however:  Most of the documents added today are simply old files that appeared on one or the other of our web-pages, but which I had neglected to put onto the Document Library page itself.  In other words, while most of them are new to the Document Library page, they are not new to Virtual AGC more broadly.  The documents that really are new today are the ones from the "Apollo Guidance Computer Information Series", of which we already had a handful, but now have two hands full and two feet full as well.  I've also tagged them, at least temporarily, so that they also show up in the "Programmer's Manuals" section of the library.
I've finished up drafting the structure of the replacement page for the current Document Library page which I've been working on, as well as database entry of all items currently in our library.  In other words, the new page is "complete" and "ready to go", except that there's a lot of double-checking that needs to be done before I have any intention of swapping it in.  At a first glance, the new page looks pretty similar to the old one, but there are a number of improvements that I hope will make the whole thing easier to navigate.  Here are some of the improvements that occur to me off the top of my head:
  • The old page was very unsystematic in how it presented bibliographic entries, whereas the new page is perfectly regular in how it formats entries ... within the constraint, of course, that the information it wants display doesn't always exist.
  • New entries are easier to find.  No more foolish  icons!  Instead, there's simply a section (Recently Added Documents) that lists the last couple months of items, from newest to oldest.  Which means that I can also stop listing the "significant" new entries here in this change log.
  • Items may appear in several relevant sections of the library, if they're all relevant, rather than just appearing in whatever (single) section I had a whim to put it.  (And then being unfindable if I had chosen poorly.)  For example, the Apollo 17 guidance-equation document would appear both in the section on guidance equations and the section on Apollo 17, and maybe in other sections as well.
  • All of the documents on the Virtual AGC site are included, whereas before, some very important items like the AGC program listings appeared only on the LUMINARY and COLOSSUS pages, and didn't show up on the library page at all.  Similarly for the engineering drawings such as the AGC or DSKY electrical schematics.  If you were to look (say) at the Apollo 17 section on the replacement document-library page, you'd find all documentation we have about Apollo 17, including the electrical and mechanical diagrams for the AGC/DSKY (and the remainder of the Apollo 17 G&N system) and the AGC and AGS software listings.
  • The replacement page has more information about the documents than the old page, but doesn't insist on cluttering your screen with a lot of it.  For example, if you can hover the mouse cursor over the link for a document, a small pop-up will tell you the download size and who contributed the document to us.  No more enormous screen space taken up by my profuse thanks to people you've never heard of!  The thanks are still there, but fat less intrusive.

And so on.  I won't continue to rant about it, since if you're not interested, you won't care, and if you are interested, you can certainly discover whatever you like or don't like about it yourself.  My point was simply that the thing looks remarkably similar to the old thing, but seems to me to be greatly improved.  And certainly easier for me to maintain.  Which is good, since I've fallen behind again in adding new documents, whilst I was spending all that time reworking the document-library page from scratch!

The information at the tops of the LUMINARY and COLOSSUS pages about released versions of the original software was upgraded to include the SUNRISE, AURORA, and SUNDIAL programs used for checkouts of the Block 1, LM, and Block 2 guidance systems, respectively.
I've experimentally moved the new under-test replacement Document Library page to this link.  (The link I gave to it before is now defunct.)  The existing Document Library page is unaffected. I'm doing this because I want to do some testing, not because I expect feedback, but you're naturally free to look at it as well, and to offer any opinions that come to mind.  But mainly I just wanted to correct the now-bogus link I had given a few days ago.
And similarly, a manual containing mathematical-subroutine software for the RCA 110A computer which Dimitri Marinakis sent me some 12+ years ago but has been languishing for all that time as a bzip2 tarball (if you know what that is!) of JPGs, has now been replaced by a PDF, with the original images now on our Internet Archive site.
As I mentioned a couple of days back, I've been reworking our document library page from ground up ... soon to be replaced by an entirely-new version that will seem very similar but will hopefully be better in a lot of ways I won't bore you with until it's ready to go.  But, the process of doing that has turned up a number of instances in which I was guilty of some pretty shoddy handling of the material that was entrusted to me.  I've been handling some clean-ups of those situations in the background, even though some of them do eat up the time quite a bit.  At the moment, I just want to point out a couple of notable instances:
  • Over 16 years ago, Fabrizio Bernardini had sent in images of Apollo 15 LGC Data Cards, which I had simply posted as a folder of JPGs all this time ... very tough to page through or download with a browser!  So last week, I had silently replaced the folder of JPGs with a PDF.  (Perhaps even more irritating, Fabrizio had apparently originally sent me higher-resolution images than I actually posted, so it would have been nice to make the PDF from those higher-resolution images.  If only I could find them, 16 years later!)
  • Nearly 3 years ago, James Berry let me scan his AC Electronics Apollo 11 manual.  But I was crushed for time, and couldn't spend the time processing the imagery that I should have, so I ended up posting a crummy PDF back then.  Today, I've done the extra work, and have replaced that crummy PDF with a less-incompetent one.  (Of course, if I were scanning it today, the raw scanned imagery itself would have been much better as well.  In the end, you can't win!)
Caught up once again with new document postings to the document library!  Mercifully, the new ones are relatively easy to find, since they're localized as follows:

The first two groups are from our continuing series of scans (by Mike Stewart) of Don Eyles's seemingly-endless collection.  It is the final item, however, which stands out for me in this batch. By the way, many thanks to the Echoes from Apollo website for sending me the images, not without suffering a bit of inconvenience in doing so, I imagine! The G&N Dictionary documents, in case you haven't looked at them before — we currently had only the ones for Apollo 11, 12, 13, and 17 missions — are a kind of quick-reference for the crew for everything G&N related, and as such, most of the information in them is pretty reasonably accessible anyway ... if you happen to have the AGC source code or other significant documentation for the mission.  But not everything in the G&N Dictionary is so readily accessible for us.  In fact, some of the information in it is unique at the present time.  Why?  Well, because it covers not only AGC use, but also Abort Guidance System (AGS) usage, including not only basic procedures for using the AGS software for various tasks; it contains lists of some octal addresses of variables in the AGS software as well.  And while we have the AGS software used for some Apollo missions — namely, Apollo 11, 12, 15, 16, and 17 — we do not have the AGS software for Apollo 5, 9, 10, 13, or 14.  Consequently, at least some of the the information summarized in the Apollo 9 Flight Crew G&N Dictionary is the only information we have about AGS Flight Program 3 at present.  Whether we're clever enough to actually use that information for anything remains to be seen. 

More new (to us) documents are in the hopper, but I haven't processed them yet, and so haven't uploaded them; perhaps tomorrow.  Instead, I've been looking at cleaning up the document library, which over the decades has become very inconsistent in terms of how it presents the documents, and well as very quirky in the way it categorizes them, sometimes making it difficult to find what you want.  Well, nothing's perfect, so I can't make it work perfectly for everybody, but at least I can improve it somewhat.  To me, the poster child of awfulness is the  icon, which is not only usually out of date, but (as seen with all the recent additions to the library) not even very helpful in figuring out what's new.  A better approach to that problem, I think, instead of the icons, is to simply have a section of the document-library page that lists (in reverse chronological order) the last few months of additions.  Here's a sample of what it might look like when I've finished working on it, but don't take the data it shows seriously, because at them moment it's only aware of about a third of the documents in the library, so lots of new ones are missing from the sample!  Besides, it's just a first cut, so undoubtedly the formatting an other styling will change drastically.  Nevertheless, when completed, it will not only be helpful in itself, but you can see that it presents documents in a very clean and regular presentation, and that regularity will be inherited by the Document Library page as a whole.
Added another 30+ documents to the library.  To me, the highlights are:
Quite a bunch of corrections, mostly typos rather than anything that you could regard as content changes, on the Gemini OBC page.  (Thanks, Brian Cockburn!)
Except for a couple of items I'm still cogitating over, I'm finally caught up with additions to the document library ... barring some terrible boo-boo on my part.  In addition to the documents Mike has been feeding me, Don Eyles sent in a comprehensive list of the scans he had made, and there were a couple dozen scans he hadn't sent me before.  Or I suppose, that he sent me and I had lost; there's really no way to know at this point.  Beyond the few individual docs I chose to highlight in the last few change-log entries, an additional list of some of the more-significant additions to the library might include:
  • The "User's Guide for the General Assembler Program (GAP)".  Even though we almost invariably call the AGC assembler program "YUL" on this site, YUL was just the original version of the assembler, and was only used for early AGC software like RETREAD or SOLARIUM.  YUL was superseded by GAP, which was an entirely new program, which ran on an entirely different computer model.  Most the AGC program listings we have were thus intended to be assembled by GAP, rather than by YUL.  The GAP User's Guide is quite a treasure trove of information.
  • A memo by Jack Garman, the "Apollo 11 Post-Flight Summary".
  • Section 7 ("Erasable Memory Programs") of SKYLARK's GSOP document.  SKYLARK, if you'll recall, is the AGC software for the Skylab and ASTP missions.  Since we don't have the actual AGC software listings for those missions, every little bit of relevant documentation is precious.
  • And various little odds-and-ends I won't bore you with that are relevant to my ongoing struggle to recreate the COMANCHE 67 source code.  Well, I'll bore you with one thing, because it illustrates the way that valuable info can be hidden in the most unlikely places:  The GAP User's Guide I mentioned above has an Appendix containing a complete octal dump of one of COMANCHE 67's memory banks, and partial dumps of two other banks.  Who woulda thunk it?
Lots more document additions to the library.  Though I may have gotten more in my inbox since my last entry than I managed to process and remove to my outbox, so I may be falling behind.  But I think the glut is drawing down shortly.  One significant fact is that among the new documents was LUMINARY Memo #90 Rev. 1, which is a list (up to the time it was written, of course) of all the COLOSSUS Memos and the other LUMINARY Memos.  Since our tables of memos, particularly the COLOSSUS Memos, include not only the memos we have in hand but also the ones we know about, it actually took a fair amount of works to update those tables to include all of the missing memos, which naturally slowed me down in processing all of the other new documents.  Well, that was a one-time thing, and fortunately it's done now.
And the document parade continues!  Among the significant things being added are:
  • Apollo 7 Final Flight Plan.  (Previously, we had only the preliminary plan.)
  • A better scan of AGC4 Memo #9, on which our AGC emulator (yaAGC) is principally based.  But also, a later revision of the Memo and an "appendix" to a separate previously-unknown Memo #8 (but not the body of Memo #8) explaining the AGC's control pulses similarly to Memo #9.

I notice that I've been giving no credit for all these new docs.  Mike has gone to Boston and has been getting stuff from the MIT Museum and from Don Eyles's secret stash, the latter of which I had foolishly thought was exhausted long ago.  Thank goodness Marie Kondo had never gotten her evil clutches on Don.  (Joke!  Sort of.)

In the event that someone in the far distant future reads this, and wonders just what I'm talking about, Marie Kondo is a currently-influential advocate of making your life better by ruthlessly eliminating clutter.  Which would have been an absolute disaster for the Virtual AGC Project.  If you knew the stories developers have told me even within the last few weeks of the material which had been thrown away because it was taking up too much room in the house ... well, you'd be heartbroken.  I won't tell you, though.  It's too devastating.

Another heap of documents being added to the library today.  Again, many are things like Luminary and Colossus memos, software anomaly reports, PCR/PCNs, or similar items helping to track AGC software revision-to-revision changes.  Alas, to paraphrase Nathan Hale, I regret that I have but one  icon to give to the document-library page, so it's going to be tough to distinguish between the documents added today vs those added in the last couple of days.  Still, I guess that's why browser links change colors once you follow them!
Lots and lots of new documents in the library today.  I won't try to summarize them; just look for the icons.  (A very nice specific, though, is the addition of "Guidance, Navigation, and Control Lunar Module Functional Description and Operation Using Flight Program Sundance", volume 1, to the SUNDANCE 306 (Apollo 9) section of the Luminary page.)

I haven't processed most of the new documents yet, though, so it's a work in progress and this is just a preliminary note on it so that I can get the uploads out there as quickly as possible.  So far, most of the items I've been dealing with are memos, software anomaly reports, and program change requests/notices (PCR/PCNs) for Luminary and Colossus, and I've had to restructure somewhat the sections of the library dealing with those types of items.  Indeed, sometimes there are so many of these items that I've been obliged to add tables of them, or even entire new sections, and mark the tables or sections themselves as rather than the items individually.  I hope there aren't many I've forgotten to mark!
We have a load of "new" COLOSSUS Memos in the library today ... 16 of them, I believe, which are marked in the library with the icon.  Thanks to Mike Stewart and the MIT Library.  These particular memos track the changes in the CM AGC software in ARTEMIS revisions 1 through 70.
You may recall that we don't have an actual listing of the CM's AGC software for Apollo 10, namely Comanche 45 rev 2, but that Mike Stewart reconstructed the source code for Comanche 45 rev 2 from Comanche 45 source code ... which was itself reconstructed from Comanche 44 ... which was itself reconstructed primarily from (finally!) actual source code listings of Colossus 249, Comanche 55, and others.  And you may recall also that we do have official lists of all the memory-bank checksums for each of these software revisions, and since the checksums of the reconstructed software are correct, we have a reasonable level of confidence in the accuracy of the reconstructions.  Still, that's a lot of reconstructions steps, so any additional info that would give us added confidence is welcome!  It turns out now that a complete list of the octal differences between Comanche 45 and Comanche 45 rev 2 has been found, tucked away in an Appendix at the back of a user's manual for the GAP program.  And it turns out as well that this set of differences precisely corresponds to the octal differences between the reconstructions of Comanche 45 and 45 rev 2.  I've rewritten portions of the Comanche 45 rev 2 notes on our Colossus page to take this new discovery into account.
  • There has been some significant restructuring and rewriting of the Apollo 11 LM software on our Luminary page.  The software revisions presented there have changed: Luminary 96 (new reconstruction!) has been added and Luminary 99 rev 2 has been dropped.  (Of course, all source code has remained unchanged, and Luminary 99 rev 1 continues to be correctly continues to be presented as the flown revision.)  The presentation before the change was strongly influenced by some recollections of AGC developer Jim Kernan, who maintained that there was a Luminary 99 rev 2, even though all documentary evidence denied its existence; so I had presented a reconstruction of Luminary 99 rev 2 based on Jim's story, even while asserting that it had never been flown.  However, Mike Stewart has just found a software anomaly report (LNY-59), not only allowing him to reconstruct the previously-missing revision Luminary 96, but also to conclude (with Don Eyles concurring) that Jim Kernan's recollections apply not to Luminary 99 rev 1/2, but to Luminary 96/97 instead.  So as I said, Luminary 96 is now in, Luminary 99 rev 2 is a fantasy and is out!
  • In our software repository, Luminary 96 is now built by default and 99 rev 2 is not, while the VirtualAGC GUI program has been updated to add Luminary 96 and remove Luminary 99 rev 2.  Moreover, the AGS tips in the GUI have been fixed to account for the fact that Apollo 12 is now known to use AGS Flight Program 6 rather than 7 (see entry from 2021-08-03) ... although the GUI software apparently does not pick the AGS Flight Program version on the basis of the Apollo mission number, just leaving it up to the discretion of the user, so I suppose that's something I'll want to look at in the future.
  • I'm in the process of slowly integrating new info about the LVDC software ... although so far it's more about the LVDC software developers than about the software itself.  I expect a number of changes to the LVDC page in the near future, though probably no earth-shattering revelations.  It's a work in progress.
  • There has been a slight reorganization in the document library, in that the "Checklists" section has been renamed "Flight Data Files (Checklists, G&N Dictionaries, ...)", and some documents previously residing elsewhere have been moved to it.  There are several overlapping rationales.  Apparently, "flight data files" is the generic term for all flown documentation, including both checklists (of which several more were added today, and of which I'm told to expect an influx in the relatively near future) and G&N dictionaries (of which several were added a couple of weeks ago, and an additional one was added today).  Thanks to Nik Beug for the new docs and the suggested reorganization.
  • Nik has dropped an additional gift on us, in that he has completed his work on simulating the unmanned Apollo 4 mission in the Orbiter spaceflight simulator's NASSP add-on, using the actual Block 1 AGC SOLARIUM software.  Check out his videos.
An item we're calling the "Grumman Binder" has been added to the document library.  It's a 200 page collection of somewhat-miscellaneous stuff from 1963-1965, related to math flow, the AGS, the steerable antenna, and so on, along with a nice — and apparently very big, since I'm told it's 8 feet long — interface control drawing (ICD) of the communications portion Grumman's LM simulator.
  • Added to the mission-specific section of the document library some samples of an important class of document that I had previously been unaware of, or perhaps for which I hadn't had sufficient vision to recognize their value.  I'm referring to the "Flight Crew G&N Data Dictionary" (or sometimes "LM G&N Data Dictionary).  These documents include mission-specific information such as star charts, lists of AGC programs, verbs, and nouns, and concise explanations of using those for various procedures, and so on.  Of course, many of those things are available elsewhere in one form or another, making their collection into a separate document somewhat less exciting.  What isn't available elsewhere — so far as I know right now — is that the Data Dictionaries also provide the same kind of information for the LM's abort guidance computer (AGS).  And since the AGS does not use numbered programs or "nouns" and "verbs" the way the AGC does, all of the AGS programs and variables are listed specifically by numerical address.  Of course, for any version of the AGS Flight Program for which we actually have source code, we already know those numerical addresses directly from the code.  But for the Flight Program versions for which we have no program listing?  Then the associated Data Dictionary is the only available source, I think, for this very specific AGS info.  At the moment, we have the Data Dictionaries only for Apollo 11 and 12 (AGS Flight Program 6) and Apollo 13 (AGS Flight Program 7).  And among those, we already had the source code for Flight Programs 6 anyway.  But we have no source code for Flight Program 7, nor any obvious prospect for acquiring one; hence making the Apollo 13 Data Dictionary of unique value for insight into AGS Flight Program 7.  As far as other versions of the Data Dictionary are concerned, of particular interest in regard to AGC would be the versions for Apollo 10 (AGS Flight Program 5), Apollo 9 (AGS Flight Program 3), and Apollo 5 (AGS Flight Program 2).  There are pictures of random pages from other Data Dictionary versions on the internet, but I've had no luck obtaining any of their full content, or even any response to inquiries on the subject.  Unfortunately, this seems to be the kind of document which tends to be auctioned off, thus permanently disappearing from public view, or even in some cases being split apart in order to use the star charts decoratively on plaques!
  • Added some notes to the AGS page about potentially reconstructing AGS Flight Program 7.  The prospect is slim, to say the least, but ....
  • The build instructions for yaAGC's WebAssembly target have changed slightly, due to changes in Michael Franzl's WebAssembly port.
  • Nik Beug has recently been working toward the goal — not complete yet! — of integrating the Virtual AGC Block 1 CPU emulator (yaAGCb1) into the NASSP add-on for the Orbiter spaceflight simulator.  The eventual goal, of course, is to be able to fly the Apollo 4 and Apollo 6 unmanned missions in NASSP/Orbiter, though since these were unmanned missions they naturally don't require a crew, and will probably be most interesting to people — particularly unqualified ones such as myself — as video captures of the simulated mission.  Naturally, Nik has been uncovering problems that I had been too daft to notice when I wrote the Block 1 emulator.  Meanwhile, Mike Stewart has been trying to run the SOLARIUM program's self-check in yaAGCb1, which I had also neglected to do myself!  And he has also uncovered problems with yaAGCb1 while trying to do so.  Recall that SOLARIUM 55 is the Block 1 AGC software that was actually used in Apollo 6, and probably in Apollo 4 as well.  Fortunately for us, or at least for me, Mike has been industriously fixing the yaAGCb1 problems he has found, which has also fixed the problems Nik has encountered in NASSP.  So far!  To reiterate, this does not mean that all problems in yaAGCb1 have been fixed yet, nor that the Block 1 AGC emulation in NASSP is ready to go.  But it does represent substantial progress, and does mean that anyone who's interested in the Block 1 AGC emulator would be well-advised to download the latest version of it rather than continue using the one that has been in the software repository for the last 3-4 years.  (By the way, you may recall that there are actually two Block 1 emulators in our repository:  my yaAGCb1 program and John Pultorak's yaAGC-Block1 program with my corrections in it.  Mike's new corrections to yaAGCb1 have not been migrated to yaAGC-Block1, but it is unlikely that John's program would have suffered from the same specific defects as my independently-written program would have anyway.)

This is the power of open-source software, friends!  Regardless of any little *cough!* "competence deficit" of the original author of the open-source software, it's always possible for someone else to step in and correct whatever problems there may be.

After some more research by Cooper, I think we now can firmly document the relationship between each Apollo mission and the AGS Flight Program version used in it, except that Apollo 5 is still slightly speculative.  In particular, both Apollo 13 and 14 used AGS Flight Program 7, of which we don't presently have any copy.
Unlike the AGC software, our documentation for the AGS (LM's abort computer system) is relatively meager, to the point where it's tough even to be certain which of the known versions of the software were used for which of the Apollo missions.  In other words, we haven't yet uncovered any convenient table in the contemporary documentation that just lists all of the installed AGS software versions.  Recall that there are 8 known versions of this abort-system "flight software", of which we have copies of only 2 (namely, Flight Program 6 and 8).  Well, Cooper Lushbaugh (thanks, Cooper!) has taken it upon himself to dig more deeply into the various abort-system documents than I had done, and to come up with some of those missing answers.  The bad news is that Apollo 14 turns out to have used Flight Program 7, of which we don't have a copy.  And Apollo 13 may have used Flight Program 7 too.  (But it's still possible that Apollo 13 may have used Flight Program 6; even Cooper's extra digging hasn't told us for sure.)  As far as Apollo 11-12 and 15-17 are concerned, though, we seem to remain on solid ground that they used Flight Programs 6 and 8, respectively.
  • On the document-library page, I reset the  indicators — last reset nearly two years ago, so no wonder they had become pretty useless!  They'll only adorn newly-added documents from today forward.
  • Added the North American Aviation document "Apollo Electrical Installation" to the document library, thanks to Mike Stewart.  The document happens to contain a partial explanation for NAA's CSM drawing-number scheme, which we didn't previously have, so our electro-mechanical page was also updated with some of that information.
  • Added several documents related to the Apollo 11 flight readiness review to the document library.
  • Added a memo titled "June 5th Apollo Spacecraft Software Configuration Control Board (ASSCCB) meeting" to the document library.  Yes, sounds pretty dry, I know, but it contains the full texts for PCR 780 and PCR 815, relevant (particularly the latter) to the somewhat-ongoing effort to reconstruct Comanche 67 (Apollo 11 CM) software from Comanche 55 (Apollo 11) et al.
  • I made some additional clarifications for the build instructions for yaAGC's WebAssembly target on the download page.
  • Andy Smith has just completed his rather major effort to find and correct symbol misspellings in the AGC code base, as well as correcting various other bits of formatting discrepancies (vs the original listings) he found along the way.  These changes are now present in the AGC source-code files in our GitHub software repository, as well as in the colorized, syntax-highlighted code listings on this site.  In case you wonder what I mean when I say "major", there are presently 2575 AGC source-code files, of which Andy's effort affected 2456 of them.  That's not to say that the files were completely riddled by errors, but that a single misspelling can infect a large number of source files.  For example, the symbol ENDDCM, misspelled as ENDOCM, infected 26 files.  (Naturally, none of these typos resulted in any errors in the core ropes, which were and remain good.)  If you're curious, the complete set of file diffs can be viewed at this link.  Great job, Andy!  The only code not affected by Andy's audit is the Comanche 67 reconstruction I've been intermittently working on, and of course that's not because it doesn't have misspellings — which I'll have to take care of later — but because I've never merged it into the main branch of the repository.

As you may infer from earlier entries in this change log, Andy employed a smart method for this audit, rather than relying on the brute-force approach of simply eyeballing all of the original source listings.  His method instead involved comparing the symbol tables found at the end of each of the original listings against the symbol tables output by a modern assembly of the source files.  He used an AGC assembler he had created himself, which listed the symbols in the same order as the original assembler did, and formatted the printouts the same way as the original assembler did, thus making a comparisons easy. 

Which is not to say that he compared every entry of every symbol table.  No, he merely compared the first row of each column on each page of the symbol table, which is adequate to catch the vast majority of problems.  But not all!  So it's still possible that a much smaller number of misspellings continue to lurk, undetected.  Admittedly, I kind of doubt it.  If anyone wants to volunteering for the mind-bending task of checking the symbol tables more closely, I'm sure it would be appreciated.

When Andy started this audit, Virtual AGC's assembler (yaYUL) neither sorted the AGC symbols in precisely the same collating sequence as the original assemblers (YUL, GAP) and Andy's assembler, nor formatted/paginated the symbol tables similarly.  Andy has woken me up to the value of this, and as you may recall from a change-log entry a month or two ago, yaYUL now sorts, formats, and paginates symbol tables in a way that facilitates such comparisons.  That's one of the changes incorporated as of today in the colorized, syntax-highlighted AGC listings on this site.

On the download page:
Updated the description of the WebAssembly target on the download page to cover the exact steps (at least on Linux Mint 19) for loading the ported yaAGC into the demo web page, and running the demo web page on the local computer.
On the download page (and the GitHub code repository), there's now a WebAssembly target for building Virtual AGC from source.  The WebAssembly target is a way of running the AGC CPU emulator (yaAGC) natively within a web-browser.  Many thanks to Michael Franzl for working out how to do this, as well as providing demo HTML/JavaScript for actually running the simulation in a browser.  This target is not built by default when you build Virtual AGC, since it relies on some one-time setups most people wouldn't normally have in place on their computer systems, but nevertheless can be manually built in a simple, straightforward fashion.

You may recall that Shahriar Iravanian had earlier provided a pure-JavaScript port which serves a similar purpose.  However, the WebAssembly version should be somewhat faster than the JavaScript version of yaAGC.
Updated the description of yaYUL command-line switches to include the --reconstruction switch, whose was merged today from the "comanche67" branch of the GitHub repository into the main branch.
I decided to follow up on yesterday's improvements to the modern assembler's (yaYUL) sorting of symbol tables.  I've revised the format of the symbol tables so that they end up being much easier to compare them side-by-side with the original symbol tables created by the YUL/GAP assemblers.  The reason one would want to do that, it has been pointed out to me, is that comparison of properly-sorted symbol tables makes it much easier to detect and correct misprints of symbol names in the transcribed AGC source code.  For example, the difference between symbols like POO (pee oh oh) and P00 (pee zero zero) may not be very apparent visually a digitized printout, and won't affect the assembled ropes if misspelled consistently in any given version of an AGC program, but will be very obvious in a properly-sorted symbol table since a misspelled symbol will appear at a completely different place in the table.  Plus, it's just kind of nice when the output from yaYUL is a little more consistent with YUL and GAP.

The source code for yaYUL now in the github repository has these changes to the symbol-table formatting in it.

Besides that, an effort to find misspelled symbols in the transcribed AGC source code is actually underway right now, using just the methods I mentioned.  I'm not doing this personally, as it preceded the symbol-table changes in yaYUL.  (Various folks have amused themselves over the course of time by creating AGC assemblers of their own, rather than using yaYUL, and some of them were cleverer than I in formatting the symbol tables.  )  At any rate, I don't see much reason to update the colorized, syntax-highlighted AGC source code on this site until at least a first pass on searching-and-destroying those misspelled symbols has been completed, and thus I haven't done so as of yet.  Hopefully that will be in the not-too-distant future.  Anyone who's particularly interested can follow the effort by reading issue #1141 in our github repository.
  • The link on the Luminary page to the raw scans for the listing of RETREAD 44 was incorrect (it pointed to AURORA 12), and has been fixed.
  • The assembler (yaYUL) in the github repository can now produce symbol tables of assembled AGC code using the collation order of the original Apollo-era assemblers.  Up to now, it has simply been using the native collation (presumably ASCII) of the platform on which yaYUL is being run.  Symbol-table files (*.symtab) that yaYUL creates for use with a debugger remain in the native order, since otherwise the debugger might not be able to interpret them properly.  The original YUL assembler, however, used the native character encoding of the Honeywell H-800 computer system on which it ran, and the printed symbol tables in the assembly listings it created were in that collating order.  Likewise, the original GAP assembler which succeeded YUL used the native IBM character encoding, namely EBCDIC, for sorting symbol tables.  Thus, while the assembly listings created by yaYUL had all the same symbols as those created by YUL or GAP, the symbols were in a different order, and the symbol tables were consequently difficult to compare.  In general, after today's update, all versions of the RETREAD, AURORA, SUNBURST, TRIVIUM, and SOLARIUM programs were originally assembled with YUL and now use yaYUL's H-800 ordering, while all other versions of AGC programs that are available to us were originally assembled with GAP and now use the EBCDIC ordering.  Admittedly, I haven't checked the new assembly listings vs the original scans in full detail, since the combined symbol tables of all the AGC versions we now have available undoubtedly total more than 100,000 symbols.  Yikes!  Nevertheless, even if there are some errors, I'm sure yaYUL's symbol-table ordering is very close to being correct.  The colorized HTML versions of the AGC source code here at the Virtual AGC website don't yet reflect the H-800/EBCDIC ordering, because some corrections to the AGC code base are in the works and I'd like to avoid unnecessary churn.  Once the HTML listings are updated, however, their symbol table ordering will hopefully match those of the scanned original assembly listings.
Several new documents have been added to the library:
Thanks to Mike Stewart for the first two documents, and to the Computer History Museum for the final document.
Continued adding mission reports and their supplements to the "Mission Report" section of our document library page.  I expanded the section to include a number of postflight trajectory documents as well.  Over the past couple of days, the documents added to that section have so outnumbered the handful which were present originally that the icon I typically put on newly-added library documents had become pointless.  When the icons were there, it just appeared as though every document was new.  Since the icons weren't helpful under these circumstances, I've temporarily removed all of them in that section of the library.
I have found out somewhat belatedly that "Apollo X Mission Report" documents actually contain useful info vis-à-vis the guidance system, including for example some postflight trajectory data.  While we already had a "Mission Report" section of our document library page, I have now examined that section with new eyes and found it severely deficient.  Anyway, I've pepped up that section of the library considerably, adding so many documents that it hardly even seems like the same section any longer.  (I don't claim that this pepping up has any great value, since all the documents I added were online elsewhere; all anybody had to do was google them.  But still, it's nice to have stuff collected in one place.)  There are still various missing supplements to the mission reports that I haven't yet made any effort yet to find, so the section may still undergo some expansion in the future.
Added the first half of section 5 (guidance equations) of the Comanche 72 (Apollo 13 CM) GSOP to the document library, from a scan at UHCL.  Fortunately, section 5 has only three PCR/PCN's, but the missing half of the document will nevertheless likely be seriously inconvenient if/when we're ever in a position to reconstruct Comanche 72's source code.  The "good" news is that the Comanche 67 reconstruction, which is a prerequisite for reconstructing 72, is seriously languishing right now, so there's no immediate need for the 2nd half of the Comanche 72 document.
Updated instructions on building Virtual AGC from source for MacOS X, due to the fact that (I'm told) the old instructions no longer work on newer Mac versions.  The essential difference is that wxWidgets 3.1.x (and eventually 3.2) must be used rather than 2.8 or 3.0.  Linux build-from-source instructions have also been so updated with optional use of wxWidgets 3.1/3.2, although 2.8 remains the recommended version.  Exploiting this update requires the latest Virtual AGC source code.
The instructions for building Virtual AGC from source code have been updated to include Slackware 14.2 and Chromebooks.  Thanks to Nick Warne for the info!  (I haven't actually personally tried those platforms.  So many platforms ... so little time.)
Building on what I said in yesterday's post, Dan Kosko has also sent in a couple other docs, now added to our library page:
  • The Saturn V Flight Manual for SA-504, thus adding to the collection we already had of Saturn IB and Saturn V (SA-503, SA-507) flight manuals.
  • An improved (or at any rate different) scan of the Lunar Excursion Module Familiarization Manual.  The thing that stands out about the new scan (as opposed to the old one) is that some attempt was made to rejoin wide drawings that the first scan had left as separate frames.  For example, in the old scan, Figure 3-3 comprises PDF pages 50-52, while in the new scan it's simply page 41.  But the effort to rejoin the drawings wasn't consistent, so you can certainly find some large drawings in the new scan that still show up as 2 or more frames.  For example, in the new scan, Figure 3-26 is 3 pages (PDF 91-93).  Even at that, in the old scan Figure 3-26 is 5 pages (PDF pages 122-126).  Yikes!  So one can't really complain too hard.
Apologies for the infrequent site updates.  I've been involved for quite a while in a possibly-futile attempt to reconstruct Comanche 67 (Apollo 12 CM AGC software); it's making progress, but it's slow, Slow, SLOW, which is why there's never any news about it. 

We do have a new website addition, though, in the form of a document added to our electro-mechanical page (as opposed to our document-library page).  It's North American Aviation's "CSM Functional Integrated System Schematics, Block II".  This is a doc I found several years ago at the U.S. Space & Rocket Center archives, but ended up failing to get digitized.  Dan Kosko (thanks, Dan!) has followed up on it, finding that the University of Alabama, Huntsville, (thanks, UAH!) had made a beautiful scan of it a decade ago, years before my own unsuccessful efforts to get it.
Paul Koning has sent me some feedback on our How to Digitize page, in which he chides me for recommending the use of the JPG file format for storing, as opposed to lossless image-file formats such as PNG.  I've updated the page both to clarify the conditions under which I recommend JPG vs PNG, and to point out that every recommendation I make is probably obsolete anyway, now that relatively cheap book scanners (overhead scanners) are on the market.
17 years ago, Sandy Brown, then associated with David Mindell's now-defunct HRST website, sent me a finding aid he had made for AGC-related materials he had found at the MIT Museum, some of which were used as part of the foundation for HRST.  For some reason, I apparently didn't think to post his finding aid online and forgot all about it.  A few years ago, Debbie Douglas, the MIT Museums' curator, sent me this list, which I didn't recall ever having seen before, and once again I didn't post it online.  Last year, she sent the list to Mike Stewart, who sent it to me again, at my request.  Yet again, I apparently didn't post the thing online!  Or at least, I've just spent 20 minutes scouring everywhere before finally finding it (in my email, not online).  So if I had put it online, it's well hidden.  Well, the fourth time's the charm, I hope, and it now has an entire, one-sentence-long section on our website page about finding material.  It can't be missed now.  Maybe.

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