From sentto-2719433-16-980657334-gtoal=vt.com@returns.onelist.com Sat Jan 27 22:15:49 2001 Received: from mv.egroups.com (mv.egroups.com [208.50.144.81]) by admin.vt.com (8.8.5/8.7.3) with SMTP id WAA08244 for ; Sat, 27 Jan 2001 22:15:48 -0600 (CST) X-eGroups-Return: sentto-2719433-16-980657334-gtoal=vt.com@returns.onelist.com Received: from [10.1.4.53] by mv.egroups.com with NNFMP; 28 Jan 2001 04:48:55 -0000 X-Sender: gtoal@admin.vt.com X-Apparently-To: edinburgh-computer-history@egroups.com Received: (EGP: mail-7_0_2_1); 28 Jan 2001 04:48:53 -0000 Received: (qmail 444 invoked from network); 28 Jan 2001 04:48:53 -0000 Received: from unknown (10.1.10.26) by l7.egroups.com with QMQP; 28 Jan 2001 04:48:53 -0000 Received: from unknown (HELO admin.vt.com) (204.117.188.10) by mta1 with SMTP; 28 Jan 2001 04:48:53 -0000 Received: (from gtoal@localhost) by admin.vt.com (8.8.5/8.7.3) id WAA08237 for edinburgh-computer-history@egroups.com; Sat, 27 Jan 2001 22:15:45 -0600 (CST) Message-Id: <200101280415.WAA08237@admin.vt.com> To: edinburgh-computer-history@yahoogroups.com From: Graham Toal MIME-Version: 1.0 Mailing-List: list edinburgh-computer-history@yahoogroups.com; contact edinburgh-computer-history-owner@yahoogroups.com Delivered-To: mailing list edinburgh-computer-history@yahoogroups.com Precedence: bulk List-Unsubscribe: Date: Sat, 27 Jan 2001 22:15:45 -0600 (CST) Reply-To: edinburgh-computer-history@yahoogroups.com Subject: [ed-comp-hist] Chris Whitfield's notes Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Status: RO I've lightly edited two emails from Chris Whitfield together, to summarize his recollections: > Things that spring to mind ... and I hope I still have m/c readables .... > > * PDP-8 imp syntax checker dating from when paper tapes were punched on > exceeding unreliable teletype 33s for transmission to Manchester. This > thing scanned the tapes and attempted to locate as many mispunchings as > possible. Summer 1966 > > * PDP-9 Inktronic printer driver .... the dreaded Inktronics > > * PDP-9 Editor > > * PDP-9 bootstrap tape .... booted both manufacturers OS and Hamish D's > Imp System. 10 instructions long (1" of tape!) so it could be taped in a > loop and left in the reader. > > * Text Layout program .... used for 2 years by ERCC. > > * PDP-9 "interpreter" .... checked student programs dynamically. Checked > each instruction before allowing it to be executed. Prevented beginning > assembler coders wasting time trying to find faults. Could check only part > of a program so was of practical value quite apart from helping students. > > * Mouses Operating System with Peter Robertson. > Used heavily at Moray House (_M_oray '_ouse_ _s_ystem !) and by CS undergraduates > I still have the complete source of this on a 1600 bpi 1/2" tape which may > or may not still be readable. > (c) Just been talking with Peter Robertson. We're both happy for > the source of the whole Mouses system, compilers and other support > software to be made available. Depends on that 1600 bpi tape I have > still being readable though. > * Yet another assembly code version of ECCE for Perkin-Elmer 32-bit mini. > I infiltrated Newcastle University's purity in 1972 or so by porting the > ERCC Imp and Fortran compilers to MTS. The professional support people > there, staunch handcoders to a man, were completely gobsmacked at the code > IMP could generate. Their view of high level languages was utterly > conditioned by things like AlgolW and PL360. > Incidentally, the *original* ECCE was written by Alan Freeman for the PDP-8 > in around 1964. I think he's a financial analyst in London now ... at > least I saw someone called Alan Freeman on a financial talk show on the box > who was his spitting image. > (b) Alan Freeman or a PhD called Brian Read .... I think Alan.... was > responsible for a PDP-8 game .... ca. 1965. > Push buttons, a CRT display and a loudspeaker. Two highly stylized > tanks drawn on the CRT. You chase the other tank and fire your gun at > it with much bleeping from the loudspeaker. All 2D and crude by today's > standards .... but must have been one of the early examples of such a > thing? (I remember playing this - GT. I think it predated arcade games like asteroids. The tanks were in a very similar vein to Asteroids but it was a much simpler game. Two player, however!) > I have a fair pile of the original departmental reports. Unfortunately > about half were chucked only 6 months ago so those left tend to reflect my > particular soft spots. > (d) An outfit called the English Language Research Unit was (I think) > merged into the newly formed Computer Science Dept. bringing Hamish Dewar > and Paul Bratley. ELRU had produced a program which could produce > all the parses of ambiguous English sentences more or less in real > time. Consider "He rolled up the red carpet"! > The interesting thing about this was that it had a fixed dictionary > of only about 600 words .... no content words. I don't know where > Paul Bratley ended up. > (e) David Rees was a PhD student at about this time. He designed a string > handling language called Astra and wrote a compiler for it. These were > in essence the string handling extensions to Atlas Autocode which were > subsequently incorporated into IMP. > He may also be able to fill in details of what Paul Bratley did. I've asked DJR about Astra. > EMAS had substantial performance advantages over standard ICL operating > systems running on the same hardware. It in fact ran ICL programs on a VME > emulator faster than the real VME. I still wonder whether the "Director" > based scheduling strategy and mapped filesystem was in fact more effective > than the strategies used in currrent day multi-programming systems. > > IMP in its day was practically unique in being a language with substantial > diagnostic assistance which could also be used "in anger" as a fast > economical systems language. Subsequently Ada is perhaps the only > mainstream language of which this can be said? > > The "3rd pass" - consolidation phase - of the Peter Robertson compilers was > again in its day unique. I remember being told at Cebit about 8 years > later by a very proud compiler writer that they'd dreamed up this wonderful > way of fixing short jumps -- which featured heavily in their > advertising. Peter's compilers did far more long before and the Mouses > 32-bit Perkin-Elmer variant did a whole lot more again. > > Prof Wulf's "Optimising Compiler" book contains a PDP-11 coding sequence > for Ackermann, generated by his compiler, which he asserts was optimal > because he himself could not handcode it more tightly. Unfortunately > Peter's PDP-11 IMP compiler takes 2 instructions off the "optimal" code > displayed in the book. ------------------------ Yahoo! Groups Sponsor ---------------------~-~> eGroups is now Yahoo! Groups Click here for more details http://click.egroups.com/1/11231/1/_/_/_/980657334/ ---------------------------------------------------------------------_-> To unsubscribe from this group, send an email to: edinburgh-computer-history-unsubscribe@egroups.com