Multibus-I Users ??

From: Joe <rigdonj_at_intellistar.net>
Date: Fri May 28 10:08:24 1999

Dick,

  I still play around with Multi-Bus. I'll see if I can find anything like
that in my catalogs.

    Joe

At 07:30 AM 5/28/99 -0600, you wrote:
>Are there any users of the old Multibus-I out there? I'm having difficulty
>identifying a board that is so "busy" that there was no room on which to put
>an identifier in the silkscreen. It's a FD/HD controller with a '186 and an
>8042 on it. Sound familiar?
>
>Dick
>
>-----Original Message-----
>From: Richard Erlacher <edick_at_idcomm.com>
>To: Discussion re-collecting of classic computers
><classiccmp_at_u.washington.edu>
>Date: Thursday, May 27, 1999 11:16 PM
>Subject: Re: Re[4]: Bringing up a CPM
>
>
>>Yes, '81 was pretty late . . . CP/M-86 came out then, as did PC-DOS.
>>Within a few years, nobody wanted to be limited by the same systems they
>>coveted only a few years earlier. By '81, the Apple][ could be equipped
>>with a Z80 board, a "real" FDC (Sorrento Valley Associates ?) an 80x24
>>display, and a hard disk if you could afford it. I recently sold the
>>prototype of the original Apple HDC I made up in the spring of '81 together
>>with my first ST-506.
>>
>>Those were the days . . . <sigh>
>>
>>Today I can still run CP/M but at an effective clock rate of 83MHz on my
>>notebook . . . designing hardware involves thousands of lines of HDL, weeks
>>in front of a simulation, and when it's done, I can't even hook up an
>>instrument small and fast enough to inspect it because even our government
>>can't afford one. One has to design circuits with 25% overhead so they can
>>be inspected. Oh, well . . .
>>
>>Dick
>>-----Original Message-----
>>From: Allison J Parent <allisonp_at_world.std.com>
>>To: Discussion re-collecting of classic computers
>><classiccmp_at_u.washington.edu>
>>Date: Thursday, May 27, 1999 8:54 PM
>>Subject: Re: Re[4]: Bringing up a CPM
>>
>>
>>><If you're writing your own, it might be well to keep in mind that the
>BIOS
>>><used in several late-generation CP/M systems used device drivers which
>>coul
>>>
>>>It was late generation in 1981! I started doing it then. CPM had a
>formal
>>>product called CP/M+ (CP/M3.0) to extend that idea.
>>>
>>><California Computer Systems (CCS) had a pretty nice boot process in which
>>><they loaded a skeletal BIOS in a 32K CP/M, since 32K was the smallest
>>memor
>>><in which they claimed they could run. It wrote that to the boot blocks,
>>>
>>>Actualy it was 20k for cpm2.2, as it was distributed as a 20k system that
>>>you would run movcpm on to get the xxK version you wanted.
>>>
>>><then, under the control of that skeletal system, they loaded a
>"full-size"
>>><(you get to define that!) CP/M and transfer control to it. It's pretty
>>><solid and makes the preparation of a bootable disk a straightforward if
>no
>>><a quick process.
>>>
>>>Yes and they were doing it a long time back, Compupro too. Kaypro was one
>>>of the few "boxed" system that had the rom mapped to get a large TPA.
>>>
>>><IIRC, the XEROX 820 used a swapped-in BIOS which lived in PROM and was
>>><mapped into the TPA during file transfers, or something on that order.
>If
>>>
>>>Classic.
>>>
>>><your machine can handle that, it saves on BIOS size, especially tables,
>>etc
>>><and, generally speaking, if the READ operations from the TPA are from
>>><temprorarily mapped-in PROMs, you can overwrite the TPA in the event
>you'r
>>><loading overlays, with complete impunity. That way your
>>blocking/deblockin
>>><buffer space can still reside in high memory.
>>>
>>>An IMSAI can neither handle that nor not handle that. The basic design
>>>had no rom! To do that you need a prom card with a little bit of hardware
>>>to map it with an IO port.
>>>
>>>The key here is to get a working system in whatever space... Why, it's the
>>>development platfrom for itself. Once you have it running and can poke
>and
>>>understand it the improvements will come.
>>>
>>>Allison
>>>
>>>
>>
>
>
Received on Fri May 28 1999 - 10:08:24 BST

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