Aucbvax.4969
fa.works
utzoo!decvax!ucbvax!works
Thu Nov 5 03:53:00 1981
WorkS Digest V1 #31
>From JSol@RUTGERS Thu Nov 5 03:22:56 1981
WorkS Digest Thursday, 5 Nov 1981 Volume 1 : Issue 31
Today's Topics: More On Smalltalk
Programming Personal Workstations
Smalltalk, Paging/mmu on the 432
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From: Chris Ryland <RYLAND SRI-KL AT>
Re: Smalltalk info
Peter Deutsch is probably the best person to reply to the query about
Smalltalk, but here's something: Smalltalk-80, the only Smalltalk to
make it out of Xerox, will be available sometime around the end of the
year. Adele Goldberg's group, (formerly?) called the Learning
Research Group, is going to publish "the book", which will tell you
all about the language, styles of use, etc., as well as the
nitty-gritty of what it takes to bring up the system (via a virtual
machine) on your favorite hardware; and, they'll license "the tape" to
organizations, said tape containing the "virtual image" and all the
system sources. With that tape, and the book, you can bring up
Smalltalk in its full glory by merely implementing the virtual
machine.
The big question at this point is how the tape licensing goes.
There'll be no problem or real expense for universities, of course,
but commercial firms will have to negotatiate with Xerox lawyers
according to their intended use of Smalltalk (e.g., for internal use
only, or for resale).
Adele may want to say something over this medium to clear up any
confusions, but, then again, we might as well wait the couple of
months it still seems to be before the book is published and the
licensing arrangements announced.
(There are said to be pirate copies of the book floating around, but
they're useless at this point, in any case, as they're rather out of
date. This is by hearsay.)
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Date: 4-Nov-81 11:26:04 PST (Wednesday)
From: Hamilton.ES at PARC-MAXC
Subject: Re: Programming for Personal Workstations
Reply-To: Hamilton.ES @ PARC-MAXC
cc: DREIFU at WHARTON-10 (Henry Dreifus), Hamilton.ES
"Reduced scale" my eye! Over a thousand man-months and a
quarter-million lines of Mesa have gone into Star, with roughly thirty
programmers going at it for roughly three years. And that doesn't
include the underlying Pilot/ Mesa/ Communications stuff, which would
add another 50 to 100 %. I don't know how that compares with OS/ 360,
but it certainly qualifies as a large system. And one can imagine all
sorts of applications built on top of Star or similar workstations
(data base, information retrieval, realtime data acquisition and
analysis, ...) that would be of a similar scale. In fact, almost any
application more sophisticated than running the payroll is probably
amenable to a distributed implementation.
--Bruce
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Date: 4 Nov 1981 1139-PST
From: Rubin at SRI-KL
Subject: Smalltalk on the 432
cc: kendall at HARV-10
Actually, the iAPX 432 would make a very good Smalltalk engine. It
supports 16M segments, not 64K, so object address space is not a
problem (64K is the size limit for any one segment -- probably not a
problem for Smalltalk, but a big limitation otherwise). The 432's big
win for Smalltalk would undoubtedly be its fancy context switching
(with dynamic memory allocation, even!) and hardware support of typed
domains. Since domain objects can be linked into complexes, the 432
also lets you realize the Smalltalk concepts of classes and instances
almost at the hardware level.
People seem to think the 432 will be really slow, but I'd be
interested to know if Intel has got any benchmarks yet. Based on
their initial literature, the 432 looks about as fast as a mid-range
mini for typical stuff, but it is faster than probably anything else
if you look at its operating system primitives (e.g., send message is
80 microsecs, and their send primitive is fancy). Of course, the
question is whether those primitives are useful as they stand, or
whether you need to crust a lot of software around them to get a
decent kernel. If not, response time and throughput at the
application level should be quite high (except for number crunching)
because of the incredibly low OS overhead.
By the way, my guess for the iAPX acronomym is: i -- Intel, A --
Advanced, P -- Processor, X -- makes it sound scientific (or maybe the
X stands for *, in other words, multiprocessing).
--Darryl
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Date: 4 Nov 1981 20:31:41-PST
From: ARPAVAX.hickman at Berkeley
Subject: paging/mmu on 432
1) As for the 432 segmentation setup being too small, that is what
Prime uses for their segments, and it works just fine. As for
arrays that are larger than 64k, lifes tough all over, isn't it?
2) The nastiest page fault problems come not from auto{inc,dec}rement
stuff, but from instructions which modify memory/registers in a non
un-doable way...That is, the AND/OR type instructions....Apparently
(I am told) on the 68000 it IS possible (using the 2 chip) scheme
AND limiting the instrucitons generated by the compilers (and
assemblers, for good measure). This scheme is used in the Micro Da
Sys 68000 system and works fine...
3) If I can buy a personal computer that runs virtual vax unix on a
68000, even with the pageing brain damage, I'll take it.
kipp
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End of WorkS Digest
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