Re: Instruction Tracing

John Levine <johnl@taugh.com> writes:

I also heard that the ROMP was originally intended for some sort of
word processor from the Office Products division (the O in ROMP) and
was repurposed into a workstation.

late 70s, circa 1980 ... there were efforts to convert myriad of CISC
microprocessors to 801/RISC microprocessors ... Iliad for low/mid range
370s (4361/4381 following on to 4331/4341), ROMP (research/office
products) for Displaywriter follow-on (with CP.r operating system
implemented in PL.8), also AS/400 follow-on to S/38. For various reasons
these efforts floundered and some of the 801/RISC engineers left IBM for
other vendors.

I helped with white paper that showed that nearly whole 370 could be
implemened directly in circuits (much more efficient than microcode) for
4361/4381. AS/400 returned to CISC microprocessor. The follow-on to
displaywriter was canceled (most of that market moving to IBM/PC and
other personal computers).

Austin group decided to pivot ROMP to Unix workstation market and got
the company that had done AT&T UNIX port to IBM/PC as PC/IX to do one
for ROMP (AIX, possibly "Austin IX" for PC/RT). They also had to do
something with the 200 or so PL.8 programmers and decided to use them to
implement an "abstract" virtual machine as "VRM" ... telling the company
doing the UNIX port that it would be much more efficient and timely for
them to implement to the VRM interface (rather than bare hardware).
Besides other issues with that claim, it introduced new problem that new
device drivers had to be done twice, one in "C" for the unix/AIX layer
and then in "PL.8" for the VRM.

Palo Alto was working on a port of UCB BSD to 370 and got redirected to
port to the PC/RT ... they demonstrated that they did the BSD port to
ROMP directly ... with much less effort than either the VRM
implementation or the AIX implementation ... released as "AOS".

trivia: early 80s 1) IBM Los Gatos lab was working on single chip "Blue
Iliad", 1st 32bit 801/RISC, really hot, single large chip than never
quite came to fruition and 2) IBM Boeblingen lab had done ROMAN, 3chip
370 implemention (with performance of 370/168). I had proposal to see
how many chips I could cram into single rack (either "Blue Iliad" or
ROMAN or combination of both).

While AS/400 1st reverted to CISC chip ... later in the 90s, out of the
Somerset (AIM, apple, ibm, motorola) single-chip power/pc ... they got a
801/RISC chip to move to.

--
virtualization experience starting Jan1968, online at home since Mar1970