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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 ----------------------------------------------------------------------

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said to be pirate copies of the book floating around, but they're useless at this point, in any case, as they're rather out of date.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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