From: gsipe@atlpyr.ga.pyramid.com (George M. Sipe)
Newsgroups: comp.misc,comp.sys.misc
Subject: Re: What is a Data General ECLIPSE ??
Date: 30 Sep 92 17:59:15 GMT
Organization: Pyramid Technology

In article <FISCHER.92Sep29203457@steiner.iesd.auc.dk> fischer@iesd.auc.dk (Lars Peter Fischer) writes:
>
>>>>>> "Michael" == Michael Schommer (schommer@rhrk.uni-kl.de)
>
>Michael> The Subject nearly says it all. The company which a friend of mine 
>Michael> works for at the moment has a Data General ECLIPSE computer, and he
>Michael> asked me about information about this thing. Anyone knows ??
>
>The ECLIPSE, or MV line of computers is a proprietary architecture
>minicomputer running a proprietary operating system. The ECLIPSE was
>developed back when 32-bit "super"-minicomputers was the best thing
>since sliced bread. ECLIPSE was DGs first 32-bit system and their
>answer to the VAX. The MV-8000 (and later MV-10000) sold quite well

The first Eclipses were S/100, S/200, and C/300.  These were 16-bit
machines, binary compatible with the Nova.  There were faster and
microcoded.  They added some additional instructions, particularly
stack instructions, by redefining Nova instructions which were register
to register, did not "skip", and did not "load" (i.e. NOPs).

The S/100 was like the S/200 except contained fewer slots (for imbedded
applications).  The "S" stood for "Scientific".  The C/300 was like the
S/200 except included additional "Commercial" instructions.  Each
system ran RDOS (2 partition real-time DOS OS) plus RTOS (like a 1
partition RDOS without disk), and SOS (stand-alone OS, actually could
run but no one did).  The C/300 could also run Infos, RDOS with
hierarchial database support built in.

Later, AOS (which almost was introduced as IRM) was created for the
Eclipse line.  This OS added true multiuser capability (vs. the
multiuser BASICs or CS/COBOL which were multitasking monitors running
in an RDOS partition).

At the time that the Eclipse line was introduced, the only 32-bit
minicomputers were from Interdata.  If I recall correctly, they may
have actually had a 16-bit bus but used 32 bit instructions.  The big
selling minicomputers were PDP-11s.  The MV/8000 came much later and
was in response to VAX 11/780.  (See "The Soul of a New Machine" by
Tracy Kidder for background on MV development vs. the ill fated FHP.)

The MV redefined some of the few remaining NOPs from the Nova
instruction set to act as flags for long instructions which followed.
This allowed the MV to remain binary compatible with the Nova without
resorting to a mode bit as the VAX 11/780 did for compatibility with
the PDP-11.  DG made a big deal about this at the time.  In reality it
meant nothing.

The OS for the MVs was AOS/VS (AOS extended for true 32-bit processing
and virtual memory).  Also available was AOS/RT32 (to AOS/VS as RTOS
was to RDOS)... which (practically) no one ever used.

>for a while, but DG rested on its laurels and was caught even more by
>surprise than DEC by the UNIX and "killer micro" phenomenon and both
>company and ECLIPSE line suffered. Like all proprietary lines, ECLIPSE
>has its dedicated followers and it was quite nice for its time, but
>most people has moved on.

Interesting historical note:  when DG noticed UNIX as a serious threat,
it created the first version of DG/UX which essentially attempted to
emulate UNIX via libraries and ran under AOS/VS.  It was terrible
(again, practically no one actually used it).

>The ECLIPSE lines most important claim to fame is its development
>history. DG was founded by former DEC people who left to form their
>own minicomputer company (this was the time of the minicomputer) and
>pressed the DEC 16bit PDP line. DEC then introduced the VAX (a 32-bit

Edson DeCastro left DEC because they would not build the 16-bit mini-
computer he designed.  At the time, DEC was selling 12-bit PDP-8s.

>machine and therefore called a supermini at the time), and DG found
>themselves without an answer. This led to a hectic (to say the least)

Later, DEC responded to DG with the PDP-11.  Much, much later DEC
introduced the VAX 11/780 then DG introduced the MV.

>development effort to meet the challenge. A journalist, Tracy Kidder,
>was allowed to follow this effort and it is documented in "The Soul of
>the New Machine", probably the best portrait of the environment and
>social life in and about high-tech development ever written. Every
>hacker should read this book.

DG's real answer to the VAX was to have been the FHP, a soft
instruction set, huge address space, disk mapped, string oriented
machine.  The MV effort was only semi-official.  When FHP was running
late and the MV worked, DG went with it.  (BTW:  DG's best products
were from semi-official development efforts - including the Nova 2
which really got the company going, created by a summer intern.)

>/Lars
>--
>Lars Fischer, fischer@iesd.auc.dk | It takes an uncommon mind to think of
>CS Dept., Aalborg Univ., DENMARK. | these things.  -- Calvin

So much for this trip down (my - previously DG badge #5297) memory
lane.  There are of course tons and tons of details, not to mention
opinions.

-- 
		-=---------	George M. Sipe
	      ---===-------	Manager of Strategic Services
	    -----=====-----	Pyramid Technology Corporation
	  -------=======---	2970 Clairmont Road, Suite 850
	---------=========-	Atlanta, GA  30329

	Phone:  (404) 728-8977	E-mail:  gsipe@pyramid.com