IPS                             

The Oscar-40 satellite, like its predecessors P3A, Oscar-10 and Oscar-13, 
has as its "brains", a computer system based on the RCA COSMAC 1802 
microprocessor.

The computer is running an operating system called "IPS", and loaded into
that environment is the flight software that does spacecraft command and
control, housekeeping chores, battery charge control, navigation, transponder
switching, beacon data generation and so on.

Work is currently underway to develop a custom processor (currently codenamed the Am1601). 
This processor will be optimized for the IPS operating system and will be used in the 
flight computer for the new AMSAT-NA Project JJ satellite, and may be used
for the proposed AMSAT-DL P3E and P5A satellites as well.

             But how many people know anything about IPS?

Not many nowadays, I'll bet.  Well, here's an opportunity to discover
all about it.

IPS (Interpreter for Process Structures) was devised by Karl Meinzer DJ4ZC
at a time when 1802, 6502, 6800 and 8080/Z80 processors were state of the
art; around 1976-1979.

At that time there just wasn't an easy-to-use, robust, engineering-
oriented, multitasking and, above all, *portable* operating system for
cheap computers based on these CPUs and their tiny (boldly described as
"massive") 16 Kbyte memories. Computers at that time meant the Atari 800,
North Star Horizon etc.

An IPS Manual was written by Karl Meinzer in 1978, but never published
in any substantive form.  A hand corrected draft printout was circulated to
a few interested AMSAT engineers who then reproduced it ad hoc, minus
several chunks, via ever worsening photocopies.  But the paper original was
long lost.

Happily, in 1996 the manual was discovered to have survived on Atari 800XL
computer cassette tapes, and moreover in the mid '80s had been transferred
to floppy disc by Robin Gape G8DQX, a prominent IPS contributor at that
time.

Thus, after a gap of nearly two decades, it has become practical to publish
the document properly, and that's what I have done.

"The Book" as it is known is the ultimate reference guide to IPS, and is 
strongly recommended to anyone who is serious about learning the language.

Full details about "The Book" can be found here: 
http://www.jrmiller.demon.co.uk/products/ipsbk.html

There are both English and German versions of the language syntax. 
"The Book" is largely written using the English language variant. Whereas 
satellite flight software has always been coded using the German language version.

An IPS emulator system called IPSDOS is available for the PC, written 
by Paul Willmott, VP9MU. This was designed is run under pure DOS, and 
provides facilities for direct access to I/O and communication ports. 
IPSDOS can run in a window under Windows 9x and Windows NT/2000/XP. 
Full documentation and Source Code in Pascal are provided.

The English language version can be downloaded here:

<add URL to ipse.zip>

The German language version can be downloaded here:

<add URL to ips.zip>

Bug reports for IPSDOS should be sent to vp9mu@amsat.org

IPS is a brilliant piece of software engineering, as relevant today as it ever was.

James Miller G3RUH  1997 May 12
With edits/additions by Paul Willmott VP9MU  2002 August 29
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