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From: eugene@ames.UUCP (Eugene Miya)
Newsgroups: net.columbia
Subject: Re: Old fashion computing practices @ NASA
Message-ID: <1088@ames.UUCP>
Date: Thu, 15-Aug-85 20:13:32 EDT
Article-I.D.: ames.1088
Posted: Thu Aug 15 20:13:32 1985
Date-Received: Mon, 19-Aug-85 21:30:34 EDT
References: <1079@cbdkc1.UUCP> <46@escher.UUCP> <239@pyramid.UUCP>
Organization: NASA-Ames Research Center, Mtn. View, CA
Lines: 35

> 
> I thought the shuttle software was done by Intermetrics...?
> the compilers? In general, how can one find out more about computing on the
> shuttle?
> -- 
>       -m-------     Carl S. Gutekunst, Software R&D, Pyramid Technology

Again best reference was the CACM several months ago on the shuttle
CPUs [IBM], and the recent issue of the Annuals of Computers.

The programming language developed by Intermetrics for NASA in 1973 is
called HAL/S.  I have a manual [since you are in Mountain View] if
you want to read it.  It is supposed to be "FORTRAN-like" but after
inspection it is closer to PL/1 without dynamic memory and other
sophiticated features, oh yeah, there is no multiple operator '*'
instead two adjacent variables are multiplied like in algebra [big
mistake!].  Intermetrics modified HAL/S into a real time ground
form called HAL/G.  They also tried to submit a modified version as a
candidate language for Ada and was one of the four finalists.
There is a HAL/S user's group run by an old friend, but only NASA uses it
to any degree.  HAL/S is written in PL/X or something and was
hosted on 360/370s for cross compilation to the Shuttle's computers.

My short bit of work was to help evaluate whether it was worth $1 million
to spent hosting HAL/S to Univac 1100/81s for Galileo's onboard
computers.  NASA is now considering Ada for future space work, but
the dynamic memory and lack of instruction space on most spacecraft
computers has old timers talking about a restricted Ada.  [e.g.
"Oh no! . . . recursion is inefficient, dangerous, and difficult to
comprehend...." much less pointers]

--eugene miya
  NASA Ames Research Center
  {hplabs,ihnp4,dual,hao,decwrl,allegra}!ames!aurora!eugene
  emiya@ames-vmsb