Recalling Apollo-11 descent alarm....

Old paper on Apollo-11 just posted at
http://klabs.org/richcontent/MAPLDCo...artin_1994.htm

very interesting!

"James Oberg" wrote in message
.. .
very interesting!



"The operating system featured a multi-programmed, priority/event driven
asynchronous executive packed into 2K of memory"


Many of the post's to this NG are bigger than that!!!

--
Gareth Slee

http://www.garethslee.com
http://www.lapie.com

"Gareth Slee" wrote ...
"James Oberg" wrote in message
.. .
very interesting!

"The operating system featured a multi-programmed, priority/event driven
asynchronous executive packed into 2K of memory"

Many of the post's to this NG are bigger than that!!!

That's not necessarily a _good_ thing, though.

"Gareth Slee" writes:

"The operating system featured a multi-programmed, priority/event driven
asynchronous executive packed into 2K of memory"


Many of the post's to this NG are bigger than that!!!

That shows you what you can do when you can programm your own
operating system at the machine code level.

Jeff
--
Remove "no" and "spam" from email address to reply.
If it says "This is not spam!", it's surely a lie.

"Gareth Slee" wrote in message
...
|
| Quoting the Apollo 11 paper
| "The operating system featured a multi-programmed, priority/event
| driven asynchronous executive packed into 2K of memory"

That's not quite accurate. The computer supplied 1,024 15-bit words of
erasable storage. But it also had 16,000 words of read-only storage. This
corresponds to RAM and ROM in modern computers, except that Apollo magnetic
core RAM was not volatile; it retained its memory even if power was lost.

The OS and Apollo application program codes were stored in the read-only
storage. The erasable storage was meted out in "areas" to each active
program for use as scratch space and to store mutable values such as the
state vector. Some programs could not be run concurrently because their
allocations of erasable storage overlapped. In the case of Apollo 11, the
computer was overloaded and had run out of erasable memory to give to
programs.

Modern computers have only a small amount of permanent memory, just enough
to know how to load the operating system from some external storage into
memory, and vast amounts of volatile memory. Running programs and their
data are both stored in the volatile memory and must be brought into that
memory from an external persistent store (i.e., the hard disk) when needed.
This is a necessity for computers that must be mass-produced, yet be able to
run thousands of different application programs. The Apollo computer was
designed more according to the principles of an embedded controller. In
that case the computer is intended from the start to run only a certain
predetermined set of programs which can be installed by the manufacturer.

--
|
The universe is not required to conform | Jay Windley
to the expectations of the ignorant. | webmaster @ clavius.org

Gareth Slee wrote:

"The operating system featured a multi-programmed, priority/event driven
asynchronous executive packed into 2K of memory"


Many of the post's to this NG are bigger than that!!!



And many of them leave one looking for data also.

Pat

"James Oberg" wrote:
Old paper on Apollo-11 just posted at
http://klabs.org/richcontent/MAPLDCo...artin_1994.htm

very interesting!


It's also in grave conflict with other accounts... It does not tell
of the problems in the sims prior to 11's flight. The author of the
referenced paper would have us believe that the alarms were handled
during the descent by the seat of the pants, rather than by a ad hoc
procedure as recounted in Murray and Cox as well as other places.

OTOH, the author of the referenced paper is far enough back in the
food chain he made not have been explicitly aware of the work done in
the days before the landing.

D.
--
The STS-107 Columbia Loss FAQ can be found
at the following URLs:

Text-Only Version:
http://www.io.com/~o_m/columbia_loss_faq.html

Enhanced HTML Version:
http://www.io.com/~o_m/columbia_loss_faq_x.html

Corrections, comments, and additions should be
e-mailed to , as well as posted to
sci.space.history and sci.space.shuttle for
discussion.

On Mon, 15 Sep 2003 13:50:45 -0400, "Scott Hedrick"
wrote:

Heck, even with something like BASIC, with 4K on the Trash-80, you had to
write tight. Before my Timex-Sinclair died, I managed to write pretty tight
with the 1K memory, and if it still worked I'd still be coding on it just to
keep in shape. Today's bloatware is shameful.

One of the major reasons for software bloat is object-oriented
programming. There are packages that you use in your program that may
contain hundreds or thousands of features. With procedural
programming, the linker could tell which parts of the package are
actually used and put only those part in the final executable file.
With object-oriented programming, the linker can't tell which features
will actually be used, so it has to put all of them in the executable
file.

On Mon, 15 Sep 2003 13:19:56 +0100, "Gareth Slee"
wrote:

"The operating system featured a multi-programmed, priority/event driven
asynchronous executive packed into 2K of memory"

....And this was without PKZip :-P


OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

On Mon, 15 Sep 2003 13:50:45 -0400, "Scott Hedrick"
wrote:

"jeff findley" wrote in message
.. .
That shows you what you can do when you can programm your own
operating system at the machine code level.

Heck, even with something like BASIC, with 4K on the Trash-80, you had to
write tight. Before my Timex-Sinclair died, I managed to write pretty tight
with the 1K memory, and if it still worked I'd still be coding on it just to
keep in shape. Today's bloatware is shameful.

....Oh yeah, it is. Back in the mid-80's, I did artsy video graphics
for a nightclub here in town in exchange for an unlimited bar tab. I
even did their club logo and animated it to run in between art
routines. The idea was to keep the drunks entertained by giving them
pretty pictures to hallucinate to while the "X" was taking effect.

All this was done on a VIC-20 with the 3K graphics expander cart, a
cassette tape drive, and a cheap VCR.


OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr