The Appollo Guidance Computer - AGC, not AVR

Go To Last Post
7 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Not for the kids - it's like trying to interest them in the Wright Brothers work - but for those of us who lived and worked in the emerging digital era of the 1960s, this looks like a great book.

Here's a link where you can download it

[link to stolen book removed - see my post below - clawson, moderator]

Roger

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

IIRC, it was overloaded during the descent and the module had to be landed manually. Perhaps is was a different computer in the module.

Leon Heller G1HSM

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:
...it was overloaded...

Some things never change...
Roger

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

There's an interesting read on the wiki article about what exactly went wrong during the approach :

Quote:
The cause was a rapid, steady stream of spurious interrupts from the rendezvous radar ...

But it seems the scheduler was able to recover from the high cpu load caused by the spurious interrupts..

http://en.wikipedia.org/wiki/Apo...

"Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it"

Last Edited: Wed. Dec 1, 2010 - 01:14 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

laserman wrote:
Quote:
...it was overloaded...

Some things never change...
Roger

http://en.wikipedia.org/wiki/Apo...
Quote:

The problem was not a programming error in the AGC, nor was it pilot error. It was a peripheral hardware design bug that went undetected by inadequate test procedures and simulations.

No, some things never change... Still:

Quote:

During this part of the approach the processor would normally be almost 85% loaded. The AGC spent just enough time servicing these spurious interrupts—about 13% -- to run out of real time during peak loads. Happily for Apollo 11 the AGC software had been designed with priority scheduling. Just as it had been designed to do, the software automatically recovered[...]

As of January 15, 2018, Site fix-up work has begun! Now do your part and report any bugs or deficiencies here

No guarantees, but if we don't report problems they won't get much of  a chance to be fixed! Details/discussions at link given just above.

 

"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Sorry but does that site have a legal right to provide that book as a free PDF download? If it were the case do you know why Amazon want to charge £32 (>$50) for the same thing?

http://www.amazon.co.uk/Apollo-G...

EDIT: it seems I have answered my own question:

http://www.associatedcontent.com...

Quote:
Of course ebokee.com is indulging in gross copyright violation and illegally distributing unlicensed copies. It is likely affecting sales at the publishing houses, book-sellers like Borders, Barnes and Nobles, amazon.com and college bookstores noticeably. If not, it will soon. What is surprising is no significant action appears to have been taken against the unauthorized distribution of copyrighted materials. There is one message on the site (http://www.ebookee.com/NOTICE-Copyrighted-materials-plz-DON-T-download-_114587.html) asking that the unlicensed ebooks not be distributed. The site claims that the books were removed but many of those ebooks are available on the site again. Reminds me of napster!

As such: link above removed.

Last Edited: Wed. Dec 1, 2010 - 02:46 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

There are a lot of good reads out there, I like this one:

http://klabs.org/history/apollo_...

that URL is from from here:

http://klabs.org/index_klabs_dot...

john mitchell