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Post: # 1185Post falkor
Tue Jul 25, 2006 11:26 pm

who remembers the old Commodore 64 computer?


well - believe it or not the computer running the Apollo 11 way back in July 1969 was a 64k RAM computer

in those days 64k ram was HUGE

and when I say huge consider this, I went to Merton Tech to do "A" level Computer Science in 1974, the college had it's own computer suite with a "main frame" computer

One of the things that the print out always boasted about, was the twin 4k banks that the computer offered!! 4k YES THAT'S WHAT I SAID!!!

so back in 1969 a 64k RAM computer was totally gigantic

now of course, even a humble PS2 has an 8MB memory card, with onboard RAM of 32MB. so 64k is just a total laugh, BUT THAT'S WHAT THE APOLLO 11 had

I was watching Channel 5's "Apollo 11 – the Untold Story" last night .....
Five's Controller of Science, Justine Kershaw, has ordered a second series of Stranger than Fiction, it was announced today (THURS).

The 4 x 60 minute Science series, due to air in the spring, kicks off with Apollo 11 – the Untold Story which reveals what really happened on the first voyage to the moon in 1969.

Everyone thinks they know about Apollo 11 – Neil Armstrong's 'One small step for man', the Stars and Stripes planted firmly on the moon rock and a triumphant return to earth, but this film reveals just how complicated that mission really was.

Drawing on first hand testimonies from Buzz Aldrin, Apollo 11 flight director Gene Kranz and key personnel from the mission this film tells how, for a group of pioneering men armed with experimental 1960s technology, Apollo 11 was a triumph against the odds that came close to ending in disaster.
Image the most incredible part came for me when the Lunar Module was coming into land on the moon's surface

It was effectively under AUTO PILOT viz. via it's own "Commodore 64 computer" :P suddenly there was this
COLLINS: At five minutes into the burn, when I am nearly directly overhead, Eagle voices its first concern. "Program Alarm," barks Neil, "It's a 1202." What the hell is that? I don't have the alarm numbers memorized for my own computer, much less for the LM's. I jerk out my own checklist and start thumbing through it, but before I can find 1202, Houston says, "Roger, we're GO on that alarm." No problem, in other words. My checklist says 1202 is an "executive overflow," meaning simply that the computer has been called upon to do too many things at once and is forced to postpone some of them. A little farther along, at just three thousand feet above the surface, the computer flashes 1201, another overflow condition, and again the ground is superquick to respond with reassurances.
Heeeey!! any Commodore 64 enthusiasts out there? Remember the OUT OF MEMORY error we used to get?

Hehe we were told at the time that the C64 had an 'elephantine memory,' because it was so huge compared to anything before, but it wasn't long before the high level basic - that it came with on ROM - used all that up

hoooboy what a let down. Lo level programmers using machine code could publish some truly wicked games in that 64k, but comparing machine code against the lumbering basic that the average C64'er used, is like comparing a fluent german, to a London cockney who just got the "learn german in a day" CD off the Daily mail :twisted: NO CONTEST!!

so it was that C64'ers would see 'OUT OF MEMORY' on a regular basis and I knew it well myself, it was a limitation that was like putting a 20 mph regulator on a Ferrari :x

anyway I couldn't help coming over all queer, as I realised that the Apollo 11 was actually experiencing an OUT OF MEMORY error from their onboard C64, which was struggling like crazy to plot and execute a landing route to the surface of the moon

not just one OUT OF MEMORY errors displayed, but several. In the C64 situation, just one OUT OF MEMORY error was enough to stop the whole program that you were running and there was no restart, that was it, back to the drawing board :wink:

however, in the Apollo 11 case, I believe the "executive overflow," they got, was in fact a more sophisticated version of the OUT OF MEMORY error so well known to C64'ers

I believe the "executive overflow," was set to trip at a slightly lower threshold, in fact what it was saying I think, was "go any further down this road chums and an OUT OF MEMORY is 10 seconds away"

Several times the "executive overflow," lit up and according to the Channel 5 programme the Lunar Module was now way off course

the auto pilot programme WASN'T WORKING!!! the "executive overflow" errors were showing that the onboard computer was buckling at the core and COULDN'T MANAGE THE JOB :shock:

the Channel 5 programme reported that the auto-pilot function was then DISENGAGED and the astronauts landed the Lunar Module manually MANY MILES from where the onboard computer had been designed to put down

WOW what a superb programme!! :mrgreen: anybody else see it? real corker

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Post: # 1188Post BRIGHTON121
Mon Jul 31, 2006 12:00 pm

I remember a program on the Apollo 11 landing and somewhat remember a problem with the on board computer but did not know it was failing due to being out of memory.

How time has moved forward at a warp factor 10 :shock:

Nice post. I learned something and that is always a good thing :D

What will be the next big thing that will change the way we go about our day to day lives :?: I shudder to think. We are due for another big invention :!:

Live Long and Prosper!

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