Apollo 11's Source Code on GitHub


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It is kinda entertaining.  

 

For example ... in 

 

BURN_BABY_BURN--MASTER_IGNITION_ROUTINE.s

 

line 446		CA	Z		# ASSASSINATE CLOKTASK

whereas other similar lines just say "kill clocktask"

 

lines 796-801

		TC	NOULLAGE	# TURN OFF ULLAGE ...
		TC	KILLTASK	#	DON'T LET IT COME ON, EITHER ...
		CADR	ULLGTASK
		TC	PHASCHNG	#		NOT EVEN IF THERE'S A RESTART.
		OCT	1
		CA	Z		# KILL CLOKTASK

 

lines 904-925  (deleted all but lines 904 and 925)

P40AUTO		TC	MAKECADR	# HELLO THERE.

		TC	BANKJUMP	# GOODBYE.  COME AGAIN SOON.

 

 

 

In THE_LUNAR_LANDING.s

 

lines 245-255

		CAF	CODE500		# ASTRONAUT:	PLEASE CRANK THE
		TC	BANKCALL	#		SILLY THING AROUND
		CADR	GOPERF1
		TCF	GOTOP00H	# TERMINATE
		TCF	P63SPOT3	# PROCEED	SEE IF HE'S LYING

P63SPOT4	TC	BANKCALL	# ENTER		INITIALIZE LANDING RADAR
		CADR	SETPOS1

		TC	POSTJUMP	# OFF TO SEE THE WIZARD ...
		CADR	BURNBABY

 

line 317	CAF	V06N43*		# ASTRONAUT:  NOW LOOK WHERE TO ENDED UP

 

 

 

In LUNAR_LANDING_GUIDANCE_EQUATIONS.s

 

lines 176-181

		CAF	TWO		# WCHPHASE = 2 ---> VERTICAL: P65,P66,P67
		TS	WCHPHOLD
		TS	WCHPHASE
		TC	BANKCALL	# TEMPORARY, I HOPE HOPE HOPE
		CADR	STOPRATE	# TEMPORARY, I HOPE HOPE HOPE
		TC	DOWNFLAG	# PERMIT X-AXIS OVERRIDE

also line 130 .... which I'm assuming is a Shakespeare reference of the Rosencrantz and Guildenstern play .....  

 

"HERE IS THE PHILOSOPHY OF GUILDENSTERN:"

 

 

Anyway, I'm sure there are a lot more.  Will be interesting to see if anyone can point other little references (or Easter eggs). :) 

 

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This made my day....:D

 

 

The assembler has been available for quite some time at various universities and libraries...but in text or pdf form.

 

command module assembler 1746 pages pdf  1968 revision MIT

 

AGC Instructions and memory map MIT 1966 pdf 52 pages

 

The amazing part is that someone took the time to transcribe this line by line and create a source code for others. The original stack of instructions was almost as tall as a person and was entered by punch cards. (which I still liked a lot more than paper tape splicing)

 

The hardware did not fail for the command module or lunar lander....but...coding issues were present and could have been catastrophic if it were not for some real smart safety coding...the hallmarks of tight control assembler.

 

I consider myself very privileged to be in the field shortly after this and to witness the astounding growth of technology. The new equipment that kept rolling into the lab was nothing short of stunning as solid state slowly pushed analog into niches.

 

Back on topic, The coding and command/lander computers were a triumph obviously and no one can take that away.

 

But one needs context here.

 

A battle was fought with NASA, MIT, IBM and Congress as to what and how it would be built. In the end, MIT did the design and coding, Grumman built it and NASA controlled it.

 

The system had triple redundancy and was built from using only dual 3 input NOR gates in silicon chip format from Fairchild Semiconductor. Shortly after this a few of Fairchild's designers went of and formed their own company....Intel...and one of them was Gordon Moore...yes, Moores law.

 

Many decades have passed, allowing a bit of after thought on decisions made. NASA was still unsure of the reliability of solid state and got caught in a turmoil with industry, educational institutions as well as politics. A decision was made to use the early Fairchild RTL gates, in one form only, which allowed thorough simplified testing for NASA. IMHO and many others, this was a poor call since the RTL was susceptible to radiation and had issues with noise tolerance. The real issue was that an entire family of RTL was available. In 1962, DTL was out as well as Motorolla's high speed ECL circuits and in 1963, TTL entered to dominate with MOS entering in 1965. Entire families of dominate chips existed and MIT chose a RTL dual 3 input NOR gate only, of which took approximately 5000 to build each computer. An example was the LM computer, which over 7 years, cost 46 million in 1966 dollars. Enough of my rambling.

 

11661h.jpg?itok=5OGaeW72

Microscopic view of dual, three-element NOR gate, the inside of a silicon chip, used in Apollo. Photo: Lisa Young, Smithsonian

 

 

This was a great achievement and led industry to the multi nerds, the early Intel adopters, early Texas Instrument geeks, IBM followers and my group, Motorola nerds. This was a time when we designed, built, coded, installed and ran our own toys....great days indeed.

 

:D:D:D  This deserves a triple redundancy happy.  

 

 

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That's not rambling, DD. It's history, and important history at that. I could read about it all day. :yes: Please feel free to share whatever memories, experiences and stories you care to! I personally enjoy them.

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