Path: utzoo!attcan!uunet!mcsun!unido!uklirb!kirchner
From: kirchner@informatik.uni-kl.de (Reinhard Kirchner)
Newsgroups: comp.arch
Subject: Electrologica X8 ( Was Re: Looking for a really odd computer
Message-ID: <6924@uklirb.informatik.uni-kl.de>
Date: 12 Oct 90 14:26:57 GMT
References: <11791@pucc.Princeton.EDU>
Sender: news@uklirb.informatik.uni-kl.de
Lines: 43

From article <11791@pucc.Princeton.EDU>, by EGNILGES@pucc.Princeton.EDU (Ed Nilges):
> 
> On page 27 of Andrew S. Tanenbaum's book STRUCTURED COMPUTER ORGANIZA-
> TION (Prentice-Hall 1976), there is a list of computers that have
> been sold commercially and their word size.  All are even numbers
> save for one.  This is the "Electrologica X8", with "27 bits per cell."
> I have never heard anything else about this machine, which sounds
> like a vacuum cleaner.

When I started studiing at Karlsruhe University in Winter 1969 their
'Mainframe' was such a X8.

I still have some paper about it, but not at hand, so I will brouse through
my memory:

It had 64k words of 27 bits, addresslength was really 15 bits, so we had
low core and high core, programms run in one, don't remember how and why.

It had a stack, and some registers, an integer akku and a FP akku.
One interesting thing: FP-numbers where stored denormalized, so integers
where converted by just moving to the FP akku and vice versa.

There was a sophisticated inderect addressing scheme, so the lexical levels
of ALGOL60 programs could be easily addressed. ALGOL was the only language
we had ( exept assembler, which I tried one or two times, and still must
have the listings -:) )

There was a purely batch operating system, as far as I know not the
original one from Phillips, but may be developed in Karlsruhe univ.
We had RJE via TTY and normel batch via operator. There where no permanent
user files.

I don't know anything about disk capacity or speed, may have been in
the 100k - 300k ips. The RJE was handled by a PDP-8.

They also had a very nice system implementation language called LOLA,
where I made my first experiments with addresses etc.

This for now, there must be still some system administrators at the
computer center in Karlsruhe ( if not already retired ).

R. Kirchner
Kaiserslautern Univ. ( kirchner@uklirb.informatik.uni-kl.de )