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John Ahlstrom
Guest
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 Posted:
Tue Aug 16, 2005 11:41 pm Post subject:
Re: Silly new instructions |
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Tom Linden wrote:
| Quote: | On Mon, 15 Aug 2005 17:11:45 -0400, Dan Koren <dankoren@yahoo.com> wrote:
We ported PL/I Fortran and Pascal beginning with the 16032 and ending
with the 32032. It wasn't so much that it was bugging from a prograsmming
POV, it was early silicon bugs that plagued us. The 32032 was far more
stable, but that was largely due to the TI fab that made them. In fact,
National had lost some of the tapes so TI had to put in a lot of effort
to rebuild the date for the fabs. The instruction set was largely a VAX
knock-off.
IIRC it would have been easier to decode 'cause the address-type specs were |
grouped following the OpCode rather than distributed among the rest of
the instruction.
JKA
--
"If you can't drink their booze, take their money, and then vote
against them anyway, you don't belong in this game."
L O'Donnell, Jr |
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John Ahlstrom
Guest
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| Posted:
Tue Aug 16, 2005 11:43 pm Post subject:
Re: Silly new instructions |
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Joe Pfeiffer wrote:
| Quote: | John Ahlstrom <ahlstromjk@comcast.net> writes:
John Savard wrote:
On Sat, 13 Aug 2005 12:53:48 -0700, John Ahlstrom
ahlstromjk@comcast.net> wrote, in part:
I believe using a GPR as SP or PC (or both) was also patented
thus preventing PDP-11 knockoffs. A very considerable benefit.
It was the UNIBUS patents that did in DCC...
DCC, as in Digital Computer Controls? The DCC-116 I used in a
computer interfacing class in the mid-1970s was a Data General Nova
knockoff, not any kind of DEC. I was under the impression DG got rid
of them by buying them.
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There were two companies doing Nova knock-offs. I don't remember the
other one's name. One of them got burned down.
--
"If you can't drink their booze, take their money, and then vote
against them anyway, you don't belong in this game."
L O'Donnell, Jr |
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John Ahlstrom
Guest
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| Posted:
Tue Aug 16, 2005 11:43 pm Post subject:
Re: Silly new instructions |
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Dan Koren wrote:
| Quote: | "John Ahlstrom" <ahlstromjk@comcast.net> wrote in message
news:Ar-dnZ2dnZ31dPK3nZ2dnWt7nd6dnZ2dRVn-0J2dnZ0@comcast.com...
John Savard wrote:
On Sat, 13 Aug 2005 12:53:48 -0700, John Ahlstrom
ahlstromjk@comcast.net> wrote, in part:
I believe using a GPR as SP or PC (or both) was also patented
thus preventing PDP-11 knockoffs. A very considerable benefit.
It was the UNIBUS patents that did in DCC...
What did in National Semiconductor?
Its management and brilliant marketing people.
I happen to know as I was there... 8-((
(of course not in marketing)
They had built a knock-off uProcessor PDP-11,
No, it was a 32-bit VAX knock-off. Looked good
on paper.
advertised it heavily and then cancelled it just before delivery, IIRC.
Incorrect. National's 32032 actually shipped,
and systems were built using it (e.g. Tolerant),
The problem was that it shipped late and never
reached sufficient numbers to become sustainable.
dk
It wasn't the 16xxx -> 32xxx that I was talking about |
but an -11 knock off. I don't think it was Unibus
patents that killed it because they were trying to sell
a chip not a system. Maybe they couldn't get any customers
becuase the customers couldn't get past the Unibus patents,
but I do recall that it was PC and/or SP in GPRs patents that killed it,
--
"If you can't drink their booze, take their money, and then vote
against them anyway, you don't belong in this game."
L O'Donnell, Jr |
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Terje Mathisen
Guest
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| Posted:
Wed Aug 17, 2005 12:15 am Post subject:
Re: PART 3. Why it seems difficult to make an OOO VAX compet |
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Tim McCaffrey wrote:
| Quote: | While I don't have numbers handy, I can see why the ARM folks
have PC as GPR, if you want to load a big constant (like an
address), you have to load the word from memory. Putting it
near the code and doing a PC relative load makes sense. I can't
prove it, but I bet this is painful for the caches, as the data
cache and code cache end up overlapping quite a bit (at least
for the XScale, the caches don't do any snooping, so they
probably don't thrash, but they may end up with a fair amount
of cruft in them).
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Easy fix (or not?)
PC-relative loads work only in the code segment, i.e. they are
effectively code?
I can see how this could stall the fetch unit though. :-(
Terje
--
- <Terje.Mathisen@hda.hydro.com>
"almost all programming can be viewed as an exercise in caching" |
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Eugene Miya
Guest
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| Posted:
Tue Sep 13, 2005 5:52 am Post subject:
Re: PART 3. Why it seems difficult to make an OOO VAX compet |
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In article <Pine.LNX.4.61.0508091631400.9761@tyr.diku.dk>,
"Peter \"Firefly\" Lund" <firefly@diku.dk> writes:
| Quote: | |> > You don't HAVE a separate TLB entry. The correct solution is to put
the
|> You don't like paging much, do you? ;)
|
Ever run on the VAX 9000?
"Nick Maclaren" <nmm1@cus.cam.ac.uk> wrote in message
news:ddafe4$j5j$1@gemini.csx.cam.ac.uk...
In article <42fdc30c$1@news.meer.net>, Dan Koren <dankoren@yahoo.com> wrote:
| Quote: | Reminds me of the following episode:
Shortly after Cray Computer Corporation went out of
business in March 1995 I interviewed a middle aged
fellow who had worked there and whose title had
been "(principal?) software architect". I do not
recall his name (and would not disclose it if I did).
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Yes. I know him.
I have signed past NDAs with various Cray firms and DEC.
| Quote: | I asked for a brief overview of the system's
architecture. The conversation wasn't flowing and
I felt I wasn't getting from him much information
from which to form an opinion, so I started to ask
more focused questions.
DK: "How would you describe the cache architecture?"
Had you not done homework on Cray architectures?
SA: "There are no caches."
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In that circle: Caches are for non-customers who can't afford real memory.
| Quote: | After an awkward silence lasting a few seconds:
SA: "Seymour does not like caches."
A few questions later:
DK: "Please describe the virtual memory architecture."
SA: "The system does not have virtual memory."
Again, after a pregnant silence:
SA: "Seymour does not like virtual memory."
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Steve must be gone.
Some will claim (like Mash [I'm not a jock so I don't follow his
football bad knees analogy]) Seymour's machines were dinosaurs.
| Quote: | I found it rather amusing that "Seymour does not like X"
was the only explanation offered for key aspects of the
system's architecture. One could have thought of a few
other reasons ;-)
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You could get the same analogy of the guys who worked at the Lockheed
Skunk works for Kelly Johnson on the SR-71, the P-38, and all their
planes in between.
As DEC is no longer an entity: I was invited to Marlborough to see
and consider the acquisition of the VAX 9000 (then running only VMS,
at a time when our facility was accepting only Unix systems).
We were shown a cardboard box (I should really try to lcate it for the
Museum). One VMS prototype was running. Ultrix would have been OK.
We went over the 9000 architecture was highly and very proudly based on
the Cray-1. We heard this in horror. We (and others at LANL, LLNL,
etc.) said, You should have studied the Cray X-MP or Y-MP.
Only 2 figures of 9000s were sold. I never had a chance to exercise
their compilers. I have one under the roof of the Museum.
Few will ever remember the VAX 9000. The Cray 1 while obsolete, remains
a household name. And the VAX as a line will also slowly fad from
huamn memory (M. Kalos did cite the desire for VAX 10,000 times the
speed of a 780, that says something for it).
--
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