>> > slight difference in PUSHF & POPF
>> > has ENTER and LEAVE instructions
>> >
>> > Anyone else remember anything else?
>
>I believe that the NEC V40 was a drop in (enhanced) replacement
>for it.
> - don
It was similar but not drop in.
>> Has two *really* fast DMA channels. It was used alot in embedded
DEC TK50 drive used it. Also the TKQ50 inteface did as well.
Allison
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
>Why limit yourself to 8-32 bits, though? What's wrong with 4 bit
>machines, 64 bit machines, etc :-). I have a few of the former (mostly
as
>embedded systems in measuring instruments). Can't hink of anything I've
>got wit a wider-than-32 bit data path, but I certainly wouldn't refuse
>such a machine...
Yes, 10, 18, 24 bits are some of the more interesting of the oldies.
I've found with builing or at least designing on paper that unless you
want to do an existing machine there is little reason to do what
others have. Sizes like 8 and 24 bits are very useful but 4bits
can make the ALU core very simple without ruling out complex
capability (though slow).
The other direction is control oriented machines that are programable
but otherwise specific.
Allison
From: Thomas P. Copley <tcopley(a)best.com>
>This 8800 is for sale by the first owners. It has the original
>switches that are a rare variation--the switch handles are the
>flattened "paddle" type as used on the 8800b instead of the "bat
>handle" type usually used on 8800s. It includes a MITS 1K RAM board.
>The original manual is not included, but is available for an extra,
>negotiable price.
The switches that were flattend were of the later rev bump, not the very
first version. They are essentailly the same part but higher cost
(8cents then @ quan 10+).
What people forget is there was the 8800, 8800A and 8800B. The A revbump
was about a 8months to a year out from first release and had a several
desperatly needed fixes.
I know I have the early version (SN the 200range) and have built at least
three others including an 8800B with friends back then.
Allison
>
>I'm looking for a way to access a RX0? drive from a PC! I'd like to
>archive all the 8" floppies that came with my '780 (including some
>CPM/68K distributions) for long-term preservation.
>
>Anybody done anything like this? I'm still looking for the pinout
>of the 10? pin ribbon cable that comes out of the dual floppy box.
>
>clint
>
I took the approach of writing a program for the PDP-8 to dump the
data out the serial port so I could capture (and restore) the disk images
on a PC. If you have an pdp-8 the program dumps the floppies in 8 bit
mode so 11 floppies will be correctly dumped also.
ftp://ftp.pdp8.net/software/dumprest.zip
I haven't spent too much time looking at the interface but most of the
smarts are in the drive and serial communication is used to send
commands to it. I have a bunch of information on the RX01, the RX02 should
be similar.
http://www.pdp8.net/pdp8cgi/query_docs/query.pl?Search=rx0&stype=Partial+Wo…
Or if that excessivly long link doesn't work search for rx0 at
http://www.pdp8.net/pdp8cgi/query_docs/query.pl
If you need more I can see if I have more information I haven't scanned,
email me with what you are needing.
The cable I made to hook my 8 to the DB25 on the RX02 has 22 wires in it, I
don't remember how many are grounds.
David Gesswein
http://www.pdp8.net/ -- Old computers with blinkenlights
This note is from http://www.multicians.org/
What a debt we all owe to Multics! Long live Multics! (1965-2000)
-Mike
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A Letter from Prof. Corbats (10/30/00)
Dear Multicians,
It is hard to believe that the last instance of Multics hardware is about to
be extinquished. But of course the influence of Multics has probably achieved
immortality through the admirable evolution of Unix and more recently Linux.
I have often wondered why we so stubbornly worked so hard to make the system
survive. My own take on it is that we were young and wanted to make a dent in
the psyche of the industry which in those bad old days was incredibly
shortsighted. And I think we did. With the creation and persistence of
working systems, Multics became a paradigm for a comprehensive solution to a
host of system problems that even today are not fully addressed in many
systems. In no particular order, some of the key ideas I think of are: a
hierarchal file system, system backup policies, rings and memory protection,
symmetric multiprocessing, paging and memory management, dynamic linking,
access control, and a full character set.
I can think of two reasons Multics survived so long. One was its malleability
and evolvability which I attribute to the use of a higher level language
(despite PL/1!), the major effort to organize and maintain the system with
functional modularity, and the avoidance of cute or obscure names in
modules. And the second reason was the idealistic zeal of all the Multicians
who worked so hard on a system they believed in.
And I think we also owe a special debt of gratitude to the original
triumvirate of Bob Fano, Ed David and John Weil who had the guts to start it
all, to John Couleur and Ted Glaser for their courage in messing with the
hardware when the system was nothing but silly putty, and to Elliott Organick
who told the world what we were up to.
With fond memories,
Corby
From: Douglas Quebbeman <dhquebbeman(a)theestopinalgroup.com>
>> An 80_1_86? Really. I guess I was never aware that there was one
like
>> that ever made. I always thought they jumped from the 8086 to the
80286
>CPU.
>>
>> Do you have any stats on this little baby?
>
>Same as the 8086/8086 except:
>
> slight difference in PUSHF & POPF
> has ENTER and LEAVE instructions
>
>Anyone else remember anything else?
Extended set of IO instructions as well. (V20 had
instruction set differences but, they were different!)
The major difference was the presence of on chip
colock gen, DMA controller (non 8237 compatable),
interrupt logic (not totally 8259 compatable). As a result
any PC made with it was a bit different. Fast parts went
to 12mhz and were also developed in CMOS.
The 186 was 16bit wide bus like 8086 and 188 was like
the 8088 with 8bit busses.
The embedded controller market liked it.
Allison
For VCF next year I'm home brewing a digital computer. The goal is to
produce something akin to a CARDIAC that could be used by interested students.
This is what I have so far, comments/criticisms/suggestions are welcome:
On Fri, 10 Nov 2000 12:12:07 -0500 Douglas Quebbeman
<dhquebbeman(a)theestopinalgroup.com> writes:
> > >I am restoring a TRS80 model 2000 (1983), one of the rare machines
> to
> > >use an actual 80186 Intel CPU.
> >
> > An 80_1_86? Really. I guess I was never aware that there was one
> like
> > that ever made. I always thought they jumped from the 8086 to the
> 80286
> CPU.
> >
> > Do you have any stats on this little baby?
>
> Same as the 8086/8086 except:
>
> slight difference in PUSHF & POPF
> has ENTER and LEAVE instructions
>
> Anyone else remember anything else?
Has two *really* fast DMA channels. It was used alot in embedded
applications where you hade to move a lot of data really fast.
Frequently found on SCSI disk controllers (among other things).
The MAD-186 by MAD computers was a PC 'sorta compatible', I used
to have (it was re-badged by TELEX). It used an 80186.
The 3Com 3Server3 was another computer (well, okay, fileserver)
that ran a modified MS-DOS (2.x, IIRC), had embedded SCSI (actually
SASI), ethernet, and serial/parallel interfaces. It also used
the 80186.
Jeff
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This 8800 is for sale by the first owners. It has the original
switches that are a rare variation--the switch handles are the
flattened "paddle" type as used on the 8800b instead of the "bat
handle" type usually used on 8800s. It includes a MITS 1K RAM board.
The original manual is not included, but is available for an extra,
negotiable price.
See its Ebay auction at:
http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=491031767
The current bid is $1,725.00 and the reserve has been met. Bidding closes
Sunday night.
I am located in Berkeley, California. Questions are welcome.
-------------------------------------------------------------------
Thomas P. Copley E-mail: tcopley(a)best.com
