[vcf-midatlantic] changing my bus route
kd2dhp at gmail.com
Thu Jan 13 21:26:26 UTC 2022
Herb et al.
Yes, I think I'm caught up by now. What got me thinking about multibus is
the two multibus systems I have sitting in storage that I'll probably never
do anything with. They are two paired machines, as in two computers in one
chassis and lots of electrical connection between them. Each is based on a
68000 processor card, accompanied by a RAM expansion, a multiple port
serial interface, a floppy disk controller and a Winchester hard disk
Aside from pull one of them apart to see what was inside, I haven't done
anything with them nor do I have any plans. If their adventures to someone
here, it would make me very happy not to have to keep moving them. Are very
On Thu, Jan 13, 2022, 3:19 PM Herb Johnson via vcf-midatlantic <
vcf-midatlantic at lists.vcfed.org> wrote:
> [A lot of old-school tech chatter today!]
> Discussion of Multibus vs S-100 bus
> Joe apparently missed both Jeff's message about retrobrew computers, and
> my message on auction-site prices for S-100 boards. On price S-100
> boards will be cheaper than Multibus (except collectables). I imagine
> he's caught up now.
> And a S-100 board of 5 X 10 inches is an awful lot of space. Multibus is
> about 6 X 12: whadda gonna do with either size? It's a lot of chips,
> especially modern chips.
> Jonathan makes the point: do something with something, then see where
> you go next. You don't have to start with your destination design, in
> fact it's advisable to start simpler and make your mistakes early.
> I'm relatively active in vintage Multibus. Certainly enough to agree
> with Jonathan Chapman's assessment of Multibus. It's a little more
> complicated than S-100 and IEEE-696. It can get a lot MORE complicated
> because these were used in complex industrial settings and industrial
> products (as were some S-100 systems).
> As David Guesswein suggests, there's not widespread vintage interests in
> Multibus, as those who worked on Multibus have aged-out of the vintage
> computing discussion. Also Multibus was an industrial product, whereas
> S-100 was both industrial and popular-computing in its lifetime.
> Essentially S-100 was the cheaper alternative to Multibus.
> Today there's a somewhat private Google group who have revived
> Intel-based Multibus development systems.
> Otherwise a Web search may find various Multibus pages and sites with
> information (including mine). I'm not aware of all that many, but i
> don't engage much with many online discussion groups. If you find more
> activity online about Multibus, let me know!
> So discussion about Multibus that I'm aware of, quickly becomes
> discussions with engineers of decades of experience in programming or
> hardware design, about fairly busy systems that performed control or ran
> 20th century operating systems. I get intimidated, and I know some stuff.
> But the early bussed stuff - Multibus or S-100 bus or say STDbus - is
> approachable for the technically minded. Jon Chapman has revived the old
> OSI bussed systems and one 8080 multibus board. There's SWTPC, the SS-50
> bus, with some revived new boards by corshamtech.com, that's a 6800 6809
> classic bus. Busses get more obscure from there.
> There's many points of entry, for people who want to design up something
> at the vintage processor-chip level. and for each kind of "entry",
> there's of course people who have been there and know what's went on.
> But some of these are pretty complicated and busy, with lots of legacy
> stuff that can be intimidating or simply not of interest. Others are
> simpler: the single-board stuff was intended to be simpler and
> As I and others said: Joe, where you start may not be where you end up.
> There's good reason to make a few simpler things first, then more
> complicated things later. from the experience of doing so, you'll know
> what to look for and what's of interest to you in the next step.
> Put another way: I've had lots of people contact me (I have some
> reputation in the S-100 world) about their "ultimate S-100 system" who
> never got there. One reason may be, they didn't get enough prior
> experience on simpler systems or projects, and so were not able to "get
> traction" on critical S-100 concepts or complexities or about CP/M (the
> predominant OS for S-100). So they gave up.
> Regards, Herb Johnson
> Herbert R. Johnson, New Jersey in the USA
> http://www.retrotechnology.com OR .net
> preserve, recover, restore 1970's computing
> email: hjohnson AT retrotechnology DOT com
> or try later herbjohnson AT comcast DOT net
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