The Perfect Computer - 36 bits?
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From: jmfbahciv on 29 Mar 2007 09:10 In article <eug7fe$js8$1(a)gemini.csx.cam.ac.uk>, nmm1(a)cus.cam.ac.uk (Nick Maclaren) wrote: > >In article <tn4n03l2c0if65pkp44cg6e9fb85a2ab6c(a)4ax.com>, >Brian Inglis <Brian.Inglis(a)SystematicSW.Invalid> writes: >|> >|> >What DEC should have done (and was told so at the time) was to produce >|> >a 32-bit PDP11, specialised for such purposes, and capture the computer >|> >communication market. This would have been a completely separate range >|> >from the VAX, but would have needed very little software support, and >|> >not all that much in the way of peripheral support. >|> >|> The Z80 was already in that market using Intel?/Zilog? Sync/Async comm >|> chip, using that pair of chips per channel. Doubt any PDP11 could >|> compete on price or performance. > >No, but nor could the Z80 compete on industry-quality functionality and >reliability. I know quite a few people who used Z80s for that, and they >never really cut the mustard for mission-critical tasks (despite being a >factor of 10 or more cheaper). What about production numbers? ISTR that there were flaps about production lines not able to provide enough of thingies. Could we really have a production line that made that many -11s. I don't remember any talk about chip factories until the late 80s. That's a long time after first customer ship of the VAX. /BAH
From: Jan Vorbrüggen on 29 Mar 2007 09:21 > And it got REALLY unhappy if you enabled reliable numeric error detection, > especially in combination with the previous problems. Later versions of GEM (the code generator used by almost all compilers) were significantly better at generating code that allowed precise FP exceptions to be emulated. I agree the naive first cut was pretty dismal. Jan
From: Nick Maclaren on 29 Mar 2007 09:23 In article <eugds5$8qk_014(a)s879.apx1.sbo.ma.dialup.rcn.com>, jmfbahciv(a)aol.com writes: |> |> What about production numbers? ISTR that there were flaps about |> production lines not able to provide enough of thingies. Could |> we really have a production line that made that many -11s. I |> don't remember any talk about chip factories until the late 80s. |> That's a long time after first customer ship of the VAX. Dunno. I wasn't talking at that level anyway. If DEC had taken the decision to produce a new micro-PDP-11, there would have been a LOT of such issues to resolve. Regards, Nick Maclaren.
From: Anne & Lynn Wheeler on 29 Mar 2007 09:26 Jan Vorbrüggen <jvorbrueggen(a)not-mediasec.de> writes: > Customizing on such a large scale that you need source to the OS? I > don't believe even the IBM customers, who were notorious for > customizing the hell out of their installations, did that. > > But DEC customers were very different: They always expected DEC to do > that kind of work for them, and complained when they didn't (often due > to lack of resources on DEC's side). It was only very late in VMS's > life that DECUS guys got their act together in this respect. there was big distintion between the os/360 genre of operating systems and the vm/cms genre. customers could get microfiche for the os/360 genre ... at least up until OCO announcement ... recent reference http://www.garlic.com/~lynn/2007f.html#67 The Perfect Computer - 36 bits? .... but typically didn't have machine readable source. In fact, there was situation where some gov. agency requested that they be provided source that was guarenteed to exactly match the executable they were running. after spending several million dollars investigating the problem, it was decided that it wasn't practical. it wasn't just that there was a large amount of source ... in large number of different components ... supported by large number of different groups ... but many of the groups were in several different physical locations around the world (doing their own builds and test .... and then would forward executables for final integration, test and release). a couple past posts mentioning the agency request: http://www.garlic.com/~lynn/2001n.html#26 Open Architectures ? http://www.garlic.com/~lynn/2002q.html#32 Collating on the S/360-2540 card reader? the vm/cms genre was quite a bit different ... where source and (machine readable) source maintenance distribution to customers were part of the culture. around the time of the OCO announcement, there was study of amount of customized source changes ... looking at both internal accounts as well as external customer accounts. The external customers had the SHARE (univ. of) Waterloo tape ... and internal accounts had a couple internal packaging operations ... including ones that I would do periodically over the years ... a couple old email references (i.e. large body of code changes that I would package for production systems) http://www.garlic.com/~lynn/2006w.html#email750430 http://www.garlic.com/~lynn/2006u.html#email800429 http://www.garlic.com/~lynn/2007c.html#email830711 the study found that the total amount of code in the customized source changes were larger than the base source ... and the total amount of code changes on the SHARE waterloo tape and the internal customized packages were about the same (i.e. both external customer installations and internal installations had similar requirements).
From: jmfbahciv on 29 Mar 2007 09:18
In article <571ro8F2bdosvU1(a)mid.individual.net>, =?ISO-8859-1?Q?Jan_Vorbr=FCggen?= <jvorbrueggen(a)not-mediasec.de> wrote: >> Only for small problems. What do you do in the cases where a >> reassembly is the way to make the problem go away? > >Do a complete SYSGEN? Yes. <snip> /BAH |