26 Oct
2004
26 Oct
'04
noon
I recently acquired an exciting new (old) machine, an Intel MDS 800,
known as the 'Blue Box.' It's the 1975-era 8080 based box that kicked
off CP/M.
My particular machine was intended as an 8051 ICE box, it has the 8051
emulator pod and external PROM programmer.
The system came complete with a big box of what appears to be complete
docs and a lot of software on 8" disks. There are four or more
different versions of IRIS, a disk labeled 'CPM' which I hope is a
boot disk, and multiple versions of other Intel tools, including the
targeted 8051 development tools.
I paid a fair amount for this system, and am going to go slowly at
bringing it up. It's been stored a long time and there's a troubling
amount of surface rust on some of the screw heads and exposed
hardware.
I've popped it open and some of the ICs (mostly TTL) have corrosion on
the leads. I have a few opening questions for others who have
restored hardware in similar condition: should I remove the corrosion
on IC leads, or do I run the risk of 'removing' the leads. The
circuit boards look really good, so worst-case I will replace some of
the chips.
What is the opinion about this kind of servicing? The chips in
question are all (so far as I have investigated) common 7400 series
(some Schottky) TTL gates. Do people consider it as 'damaging' to the
'credentials' of a piece of classic hardware to replace chips with
others with significantly different date codes?
This is going to be a long term project for me, I fear, because I want
to do it right. This machine has a built-in CRT display so I might be
forced to do some (something I almost always refuse to do these days)
video monitor troubleshooting.
The machine has a built-in 8" floppy, which I assume is the
low-density original, and an expansion case (third party) with two
newer and higher density drives.
Is there a source for new or NOS 8" floppies out there? One thing for
certain that I'll be doing early after getting this machine up and
running is a backup of all the media that came with it (a fair amount,
probably 30-50 disks, many of which are Intel branded originals).
Lots more questions and comments likely to come on this project.
Scott
26 Oct
26 Oct
12:13 p.m.
Hi Scott, you must be the one that bought the "MDS800" from eBay recently.
I tried to tell the guy that it was a MDS2XX series which was the second
generation development system from Intel.
It is not a MDS800...
I used these systems back in the 70s and 80s as others here have done. In
bringing up the system verify power supply operation before powering
anything on. A system that I recently acquired has so far only yielded a
good internal disk drive and all the cards are non-operational.
The internal drive could be either SD or DD. If there is a 50 pin ribbon
connecting the drive to the back board in the system, then you have an
internal single density drive. If there is a cable running from one of the
front cards to the drive, then it has been hooked up as double density.
I don't have any comments on keeping its credentials.
best regards, Steve Thatcher
At 08:00 PM 10/26/2004, you wrote:
I recently acquired an exciting new (old) machine, an
Intel MDS 800,
known as the 'Blue Box.' It's the 1975-era 8080 based box that kicked
off CP/M.
My particular machine was intended as an 8051 ICE box, it has the 8051
emulator pod and external PROM programmer.
The system came complete with a big box of what appears to be complete
docs and a lot of software on 8" disks. There are four or more
different versions of IRIS, a disk labeled 'CPM' which I hope is a
boot disk, and multiple versions of other Intel tools, including the
targeted 8051 development tools.
I paid a fair amount for this system, and am going to go slowly at
bringing it up. It's been stored a long time and there's a troubling
amount of surface rust on some of the screw heads and exposed
hardware.
I've popped it open and some of the ICs (mostly TTL) have corrosion on
the leads. I have a few opening questions for others who have
restored hardware in similar condition: should I remove the corrosion
on IC leads, or do I run the risk of 'removing' the leads. The
circuit boards look really good, so worst-case I will replace some of
the chips.
What is the opinion about this kind of servicing? The chips in
question are all (so far as I have investigated) common 7400 series
(some Schottky) TTL gates. Do people consider it as 'damaging' to the
'credentials' of a piece of classic hardware to replace chips with
others with significantly different date codes?
This is going to be a long term project for me, I fear, because I want
to do it right. This machine has a built-in CRT display so I might be
forced to do some (something I almost always refuse to do these days)
video monitor troubleshooting.
The machine has a built-in 8" floppy, which I assume is the
low-density original, and an expansion case (third party) with two
newer and higher density drives.
Is there a source for new or NOS 8" floppies out there? One thing for
certain that I'll be doing early after getting this machine up and
running is a backup of all the media that came with it (a fair amount,
probably 30-50 disks, many of which are Intel branded originals).
Lots more questions and comments likely to come on this project.
Scott
12:46 p.m.
On Tue, 26 Oct 2004 20:13:15 -0400, you wrote:
Hi Scott, you must be the one that bought the
"MDS800" from eBay recently.
I tried to tell the guy that it was a MDS2XX series which was the second
generation development system from Intel.
It is not a MDS800...
Sorry to hear that, in terms of 'collectors value and esteem' stuff.
I did suspect something was 'up' when the datecode on the ID sticker
on back was 1978.
I used these systems back in the 70s and 80s as others here have done.
Mine seems to be a full 8051 ICE with all the trimmings, so I may even
attempt some embedded programming with it- the system came with a box
with four or five 'spare' 8051 'bond-out' processor chips in it, so it
is probably servicible even if the 'pod' is blown. (there's probably
been even at least one person, somewhere in the world, who would have
been willing to pay the price of a good used sports-car for one of the
spares, within the last decade)
I have at least a few tubes full of 8031s, and even a couple NOS tubes
of the elusive (RARE now) 8243 chip, so I can roll out a
psuedo-single-chip 8051 project or two if I want, even without an 8751
programmer.
In
bringing up the system verify power supply operation before powering
anything on. A system that I recently acquired has so far only yielded a
good internal disk drive and all the cards are non-operational.
Unless an EPROM is dead, everything else seems like standard
replacable parts. (rationalisation and hopeful thinking)
The internal drive could be either SD or DD. If there is a 50 pin ribbon
connecting the drive to the back board in the system, then you have an
internal single density drive. If there is a cable running from one of the
front cards to the drive, then it has been hooked up as double density.
Actually, there's an added-in non-Intel jack on the back (I think 37
pin 'D' shaped but as everybody knows, probably not a 'Dsub' due to
size) that the external dual-8" floppy enclosure plugs into. I
suspect the system may have had something third-party added to support
the two external drives, and some of the disks are labeled to indicate
they are 'higher' density than the internal drive will support.
This system has EVERYTHING, (including a plastic sleeve full of sales
receipts, etc.) and I'm hoping full docs for all the stuff that was
upgraded on it. There's a lot for me to go through yet.
No matter what, it does feel good to finally have a piece of hardware
with both Paper-tape in and and out jacks on the back.
I don't have any comments on keeping its
credentials.
best regards, Steve Thatcher
12:24 p.m.
Welcome, Scott, to the Intel MDS Fraternity. Joe R., Jay West (your
list owner), and I are members that I know of. Joe will likely have
lots to say about your endeavour. I've been intending on (and slowly
performing) a backup of my MDS software, probably to some form of
optical storage for archive. Probably CD-R's.
What you are describing is what is called an Intel MDS Series II. The
MDS 800 didn't have an integral diskette drive or an internal crt
monitor. Yours is like mine, the "second generation" or Series II. The
internal diskette drive can be single density or double density
depending on whether it has the optional double density controller board
set or was controlled by the internal "I/O Controller" or IOC board.
If you have an external drive system, you likely have the double density
board-set for them. It can (but not necessarily) also control the
internal drive making it double density. In any case, all your drives
will be single SIDED.
Intel's OS was called ISIS-II, as you know. CP/M was also available for
it. I wrote a custom BIOS for CP/M so that you could access both
double- and single-density drives in one system. ISIS-II could do that
"out of the box" from Intel.
There is much more, but I'm tired now. I've been on the phone with Dick
Hof in Denmark working on his Intel iPDS project. But that's another story.
Enjoy your restoration! Let the brothers know of your progress!!!
Dave
Scott Stevens wrote:
I recently acquired an exciting new (old) machine, an
Intel MDS 800,
known as the 'Blue Box.' It's the 1975-era 8080 based box that kicked
off CP/M.
My particular machine was intended as an 8051 ICE box, it has the 8051
emulator pod and external PROM programmer.
The system came complete with a big box of what appears to be complete
docs and a lot of software on 8" disks. There are four or more
different versions of IRIS, a disk labeled 'CPM' which I hope is a
boot disk, and multiple versions of other Intel tools, including the
targeted 8051 development tools.
I paid a fair amount for this system, and am going to go slowly at
bringing it up. It's been stored a long time and there's a troubling
amount of surface rust on some of the screw heads and exposed
hardware.
I've popped it open and some of the ICs (mostly TTL) have corrosion on
the leads. I have a few opening questions for others who have
restored hardware in similar condition: should I remove the corrosion
on IC leads, or do I run the risk of 'removing' the leads. The
circuit boards look really good, so worst-case I will replace some of
the chips.
What is the opinion about this kind of servicing? The chips in
question are all (so far as I have investigated) common 7400 series
(some Schottky) TTL gates. Do people consider it as 'damaging' to the
'credentials' of a piece of classic hardware to replace chips with
others with significantly different date codes?
This is going to be a long term project for me, I fear, because I want
to do it right. This machine has a built-in CRT display so I might be
forced to do some (something I almost always refuse to do these days)
video monitor troubleshooting.
The machine has a built-in 8" floppy, which I assume is the
low-density original, and an expansion case (third party) with two
newer and higher density drives.
Is there a source for new or NOS 8" floppies out there? One thing for
certain that I'll be doing early after getting this machine up and
running is a backup of all the media that came with it (a fair amount,
probably 30-50 disks, many of which are Intel branded originals).
Lots more questions and comments likely to come on this project.
Scott
4:40 a.m.
On Tue, 26 Oct 2004, Dave Mabry wrote:
Welcome, Scott, to the Intel MDS Fraternity. Joe R.,
Jay West (your
list owner), and I are members that I know of. Joe will likely have
I've got one but it's in need of some serious restoration.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
1:32 p.m.
At 09:40 AM 10/26/04 -0700, Sellam Ismail wrote:
On Tue, 26 Oct 2004, Dave Mabry wrote:
Speaking of that. If anyone needs any mechanical parts let me know. I
have a bunch of incomplete Series II (aka MDS-2xx) machines that I bought
just for the cases and such. No, there are no extra keyboards but there are
power supplies, CRTs with associated electronics and (I think) IOC cards
(the big card mounted vertically in the back of the machine) along with the
cases.
Joe
Welcome, Scott, to the Intel MDS Fraternity. Joe
R., Jay West (your
list owner), and I are members that I know of. Joe will likely have
I've got one but it's in need of some serious restoration. 
10:28 p.m.
On Tue, 2004-10-26 at 20:24 -0400, Dave Mabry wrote:
Welcome, Scott, to the Intel MDS Fraternity. Joe R.,
Jay West (your
list owner), and I are members that I know of.
*sticks hand in the air*
The museum were given one just a couple of weeks ago that was heading
for the dumpster otherwise. Afraid I know nothing about the systems (nor
did the chap who had it, it seems, describing it first as an IBM)
Anyone have any good resources for info on the machines?
From Dave's description it sounds like a series II
as I don't recall an
integral drive, just a pair of drives in an external box.
A *huge* amount of disks and docs arrived with it though, four or five
times the size of the machine itself!
I'll take a better look at it in the next few days if I get a chance...
cheers
Jules
27 Oct
27 Oct
1:35 a.m.
Jules,
I'd love to hear what kind of hardware, software and manuals you got with
your's.
Joe
At 10:28 AM 10/27/04 +0000, Jules wrote:
On Tue, 2004-10-26 at 20:24 -0400, Dave Mabry wrote:
Welcome, Scott, to the Intel MDS Fraternity. Joe
R., Jay West (your
list owner), and I are members that I know of.
*sticks hand in the air*
The museum were given one just a couple of weeks ago that was heading
for the dumpster otherwise. Afraid I know nothing about the systems (nor
did the chap who had it, it seems, describing it first as an IBM)
Anyone have any good resources for info on the machines?
From Dave's description it sounds like a
series II as I don't recall an
integral drive, just a pair of drives in an
external box.
A *huge* amount of disks and docs arrived with it though, four or five
times the size of the machine itself!
I'll take a better look at it in the next few days if I get a chance...
cheers
Jules
2:55 a.m.
On Wed, 2004-10-27 at 09:35 -0400, Joe R. wrote:
Jules,
I'd love to hear what kind of hardware, software and manuals you got with
your's.
Joe
I'll have a look and see if I can do some sort of inventory.
We've got a series 1 machine as it turns out too (blue case) - I always
thought it belonged to one of the group, but apparently it is owned by
the museum. I'll have a look-see as to exctly what that one is too (I
know there's no docs or disks with that machine though)
cheers
Jules
8:55 a.m.
At 02:55 PM 10/27/04 +0000, you wrote:
On Wed, 2004-10-27 at 09:35 -0400, Joe R. wrote:
AFIK all of the MDS2xxs (including the blue ones) are series II machines.
I've never heard of anything that Intel designated as a Series I. Most of
the Series II machines have blue cases but some of them have white cases.
The white ones are thought to be later machines but no one knows for sure.
Just to further confuse the issue, ANY of the MDS2xxs can be upgraded to
series III by adding a 8086 Resident Processor Card. I believe the MDS800s
can also be upgraded to Series III the same way.
Joe
- I always
Jules,
I'd love to hear what kind of hardware, software and manuals you got with
your's.
Joe
I'll have a look and see if I can do some sort of inventory.
We've got a series 1 machine as it turns out too (blue case) thought it belonged to one of the group, but apparently
it is owned by
the museum. I'll have a look-see as to exctly what that one is too (I
know there's no docs or disks with that machine though)
cheers
Jules
9:44 a.m.
Joe R. wrote:
AFIK all of the MDS2xxs (including the blue ones) are series II machines.
I've never heard of anything that Intel designated as a Series I. Most of
the Series II machines have blue cases but some of them have white cases.
The white ones are thought to be later machines but no one knows for sure.
Just to further confuse the issue, ANY of the MDS2xxs can be upgraded to
series III by adding a 8086 Resident Processor Card. I believe the MDS800s
can also be upgraded to Series III the same way.
Joe
I know! The white ones WERE the later ones. :)
Also, you are correct that the 800 can be a "series III". I've used an
RPC in my former :( mds 800. Just had to make sure it was in an odd
numbered slot.
And I don't know what a "series I" would be either.
11:46 a.m.
We've got a series 1 machine as it turns out too
(blue case) - I always
thought it belonged to one of the group, but apparently it is owned by
the museum. I'll have a look-see as to exctly what that one is too (I
know there's no docs or disks with that machine though)
If a 'series 1' is the sort that uses an external terminal, then I have a
fair few manuals, including scheamtics, for it. Let me know if you want
me to look anything up.
-tony
26 Oct
26 Oct
1:13 p.m.
Hi Scott,
Congradulations on buying a "real" computer instead of a toy like the
SB-180 :-)
I'm REAL familar with the MDS-800
<http://www.classiccmp.org/hp/mds-800/mds-800.htm>,
<http://www.classiccmp.org/hp/mds800_3/>,
<http://www.classiccmp.org/hp/mds800_4/>.
Can you make a list of the docs that you got. Here's a list of the ones
that I have; <http://www.classiccmp.org/hp/mds/mds-docs.txt>. I have more
but haven't had time to update the list.
At 07:00 PM 10/26/04 -0500, you wrote:
I recently acquired an exciting new (old) machine, an
Intel MDS 800,
known as the 'Blue Box.' It's the 1975-era 8080 based box that kicked
off CP/M.
My particular machine was intended as an 8051 ICE box, it has the 8051
emulator pod and external PROM programmer.
The system came complete with a big box of what appears to be complete
docs and a lot of software on 8" disks. There are four or more
different versions of IRIS,
That should be ISIS (Intel System Implementation Supervisor) not IRIS.
The ISIS disks should also be bootable.
a disk labeled 'CPM' which I hope is a
boot disk, and multiple versions of other Intel tools,
including the
targeted 8051 development tools.
I paid a fair amount for this system, and am going to go slowly at
bringing it up. It's been stored a long time and there's a troubling
amount of surface rust on some of the screw heads and exposed
hardware.
Take it apart and clean it. I use Lime-Away on steel screws. It contains
phosphoric acid and is similar to Naval Jelly. >>>>Make careful notes
about what cables go where and what cards go in what slots. They're not
entirely interchangeable. Many of the cards come in sets of two or three
and one particular card of the set has to go into an odd numbered slot and
the companion card has to go into the next higher numbered slot. This is
because Interrrupt signal is wired to different pin numbers in the odd and
even slots. ALSO the Front panel controller MUST go into slot one and the
CPU card MUST go into the second slot. I BELEIVE the RAM cards and Monitor
card can go into any slot.
I've popped it open and some of the ICs (mostly TTL) have corrosion on
the leads. I have a few opening questions for others who have
restored hardware in similar condition: should I remove the corrosion
on IC leads, or do I run the risk of 'removing' the leads.
I believe I'd leave them alone until I had the machine working. Then,
perhaps, I'd clean them one board at a time. That way I'd know what board
the problem was in if something screws up.
The
circuit boards look really good, so worst-case I will
replace some of
the chips.
What is the opinion about this kind of servicing? The chips in
question are all (so far as I have investigated) common 7400 series
(some Schottky) TTL gates. Do people consider it as 'damaging' to the
'credentials' of a piece of classic hardware to replace chips with
others with significantly different date codes?
This is going to be a long term project for me, I fear, because I want
to do it right. This machine has a built-in CRT display
???????????????? What! The MDS-800 doesn't have a display. It uses a
terminal. Oh wait. I'll bet you bought that mislabeled one off of E-bay.
Let's see, here it is
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4193&item=5130614411
&rd=1&ssPageName=WDVW>. If this is what you bought then it's NOT an
MDS-800. Look at the pictures of a couple of my 800s at the links at the
top of the message. This is a LATER MDS-220. Here's a page that describes
the differences between the various 2xx models;
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4193&item=5130614411
&rd=1&ssPageName=WDVW>.
The 2xx are similar to the 800s but have a built in CRT and a detachable
keyboard. They also have a space for a single disk drive but not every
model includes the drive. The drawback to the 2xx (IMHO) is the lack of
slots. They only have five slots where the 800 has 18. You'd think 5 slots
whould be enough but all the ICE units use two cards (some of them use
three!) A Double Density disk controller uses two cards. Most RAM cards are
only 16k so you need at least one slot for that or as many as four. Then if
want to use an 8086 CPU you need a slot for that card (in addition to one
for the regular CPU (8080 or 8085) card. That's probably why most 2xx
machines come with the optional expansion chassis. BTW there is a built in
disk drive controller. The internal drive is USUALLY hooked to it BUT if
you install the optional Double Density Disk drive controller you can hook
the internal drive to it.
I'm curious about your aftermarket drives. Are you SURE that they work
with the MDS? Intel monkeys with two of the signals inside of their drive
box (the box, not the drives themselves). IIRC one of the signals is the
READY signal from the drive and the other is the head load or spin signal
from the CPU to the drives.
so I might be
forced to do some (something I almost always refuse to
do these days)
video monitor troubleshooting.
Maybe I've been lucky but on my three 2xxs the monitor all started
working after I moved a couple of pot controls. It seemed like they had
built up a spot of corrision where the wiper was sitting but it cleaned up
after I moved the wiper a couple of times.
BTW were you aware that that EPROM programmer uses a 4040 CPU? I hate
to think of all of them that I passed up before I learned that.
The machine has a built-in 8" floppy, which I assume is the
low-density original, and an expansion case (third party) with two
newer and higher density drives.
The density is a function of the controller, not the drives.
Is there a source for new or NOS 8" floppies out there?
Yeah. I found a sealed box of DS DD ones just last week. BTW all the
drives for the MDSs (both 800s and 2xxs) are single sided. The low density
ones use the "standard" CPM format but the DD one have a format that's not
compatible with any other machine that I know of.
One thing for
certain that I'll be doing early after getting this
machine up and
running is a backup of all the media that came with it (a fair amount,
probably 30-50 disks, many of which are Intel branded originals).
Lots more questions and comments likely to come on this project.
Ask away! The MDSs are one of my favorite machines.
Joe
Scott
3:12 p.m.
I've popped it open and some of the ICs (mostly
TTL) have corrosion on
the leads. I have a few opening questions for others who have
restored hardware in similar condition: should I remove the corrosion
on IC leads, or do I run the risk of 'removing' the leads. The
circuit boards look really good, so worst-case I will replace some of
the chips.
What is the opinion about this kind of servicing? The chips in
question are all (so far as I have investigated) common 7400 series
(some Schottky) TTL gates. Do people consider it as 'damaging' to the
'credentials' of a piece of classic hardware to replace chips with
others with significantly different date codes?
Well, I don't go around replacing good chips :-). But I do feel that if
at all possible my classics have to work, and that means replacing parts
if necessary. My rule (of course) is to replaced the least amount
possible -- that it to replace a chip rather than the entire board. And
no, I don't care about date codes, or even families (in other words I
might put a 74LS-series chip in place of a plain 74-series one if it
would work). In fact I have an HP9810 calculator (1972 vintage) with the
odd 74Fxxx chip in the processor for that reason.
This is going to be a long term project for me, I
fear, because I want
to do it right. This machine has a built-in CRT display so I might be
All I can say here is that it often takes me a couple of months before
powering up a new toy. Better to be patient now than to have to track
down irreplaceable parts...
My MDS800 is the older one without the built-in terminal. I don't have
the Intel terminal for mine, I just use a PC running a terminal emultor
forced to do some (something I almost always refuse to
do these days)
video monitor troubleshooting.
Ah :-). Monitors actually are not that bad to work on.
-tony
30 Oct
30 Oct
5:02 p.m.
New subject: Intel MDS Further Information
This weekend I had the time to pull open the Intel MDS system I
mentioned last week, and record info and photograph all the Multibus
cards. I've put the info up on some personal web space. All are
invited to comment on and advise me on what I've got.
The URL is: http://sasteven.multics.org/MDS/Intel_MDS_Cards.html
Here's the 'text' of the page, which includes board numbers, etc. (go
to web page for a photo of each board)
----------------
These boards are out of my MDS system. It was targeted
as an ICE for
the 8051 microcontroller. The emulator POD plugs into one of the board
sets below.
This page is organized to document the boards as they are installed in
the Multibus cage from the bottom going up.
---------------------------------
Bottom Board on Rack-
Floppy Disk Interface
Double Density
PWA 123857-002
S/N 023767
This board has a cable plugged into it's top edge connector.
---------------------------------
Next Board Up
Floppy Disk Controller Channel
PWA 10000457-05
(may have copied down one extra 'zero' in above part number)
This board does not have a cable plugged into the 'top' edge connector.
Edge connector shows 'weathering' from not having connector on it.
---------------------------------
Next Board Up
Trace Board
PWA 162249-001
S/N 13904
J10 and J11 headers which are brought out to the Emulator Pod.
---------------------------------
Next Board Up
Controller Board
PWA 162380-005 Rev M
This board has an 8080A Processor on it.
The Multibus P2 board edge is 'bridged' to Trace Board (above) on a
two-slot interconnect board.
Has header on it brought out to Emulator pod and also power header to
emulator pod.
---------------------------------
Open Slot, second from top.
---------------------------------
Top Board
I.P.C. board
PWA 123192-003
S/N 084111
This board has an 8085 Processor and array of memory chips.
Also has two 8251 and two 8259 chips.
Board has row of buttons to generate interrupts that faces out to front
of system.
It appears I have here an 8085 based system. Is this correct. It
also appears that there's an 8080 controller as part of the emulation
system. I'm assuming (?) the system would run with the Emulator
boards (Trace Board and Controller Board) not installed.
Some questions:
1. Is the memory array on the top board (board with 8085 processor)
the main system memory. It looks like four rows of 4116x8, for a
total 64K.
2. The system has a built in CRT display, and a keyboard input.
Where is the video generated and keyboard I/O circuitry?
Any and all insights into this system are welcomed. Probably I'll add
in any info I receive into the HTML for the page.
Thanks,
Scott
31 Oct
31 Oct
12:10 a.m.
New subject: Intel MDS Further Information
At 12:02 AM 10/31/2004, Scott Stevens wrote:
It appears I have here an 8085 based system. Is this
correct. It
also appears that there's an 8080 controller as part of the emulation
system. I'm assuming (?) the system would run with the Emulator
boards (Trace Board and Controller Board) not installed.
yes, the system only requires the IPC board to run and even use the
internal single density drive
Some questions:
1. Is the memory array on the top board (board with 8085 processor)
the main system memory. It looks like four rows of 4116x8, for a
total 64K.
you have 64K of main memory. Actually only 62K is available because there
is a 2K rom monitor that overlays the top ram
2. The system has a built in CRT display, and a
keyboard input.
here is the video generated and keyboard I/O circuitry?
the vertical board in back is the IOC board and generates the vertical,
horizontal, and video intensity for the display monitor (the video
controller is the 8275 chip). The same board supplies the interface to the
keyboard which actually contains a 8041/8042 I/O processor (can't remember
exactly which one). One thing you will realize with Intel is that they were
not like all the CP/M computers. Intel used a processor nearly everywhere
to delegate control and increase speed. Each emulation set you will find
contains at least one processor. The IOC contains a 8080 along with its own
eprom control program, as well as another 8041 processor.
Any and all insights into this system are welcomed.
Probably I'll add
in any info I receive into the HTML for the page.
Thanks,
Sc
12:28 a.m.
New subject: Intel MDS Further Information
Hi Scott,
Nice pictures. I'm in the process of creating a photogrpahic catalog of
all the Multibus cards that I can get my hands on. Do you mind if I use
your pictures and dscriptions? I have so many loose cards to do that I
never got around to taking the cards out of my MDS 235 and photographing
them. More below.
At 12:02 AM 10/31/04 -0500, you wrote:
This weekend I had the time to pull open the Intel MDS
system I
mentioned last week, and record info and photograph all the Multibus
cards. I've put the info up on some personal web space. All are
invited to comment on and advise me on what I've got.
The URL is: http://sasteven.multics.org/MDS/Intel_MDS_Cards.html
Here's the 'text' of the page, which includes board numbers, etc. (go
to web page for a photo of each board)
----------------
64k is correct. It sounds like you have a model 225 with the Integrated
Processor Card with the 8085 CPU. The 225, 226 and 227 models came with an
IPC (Integrated Processor Card). It has a 4 MHz 8085A-2 CPU and 4 K of ROM
and 64K of RAM. All other (22x) models came with the IPB (Integrated
Processor Board). It has a 2.6 MHz 8080A-2 and 4K of ROM and 32K of RAM.
See <http://www.classiccmp.org/hp/mds.htm>.
These boards are out of my MDS system. It was
targeted as an ICE for
the 8051 microcontroller. The emulator POD plugs into one of the board
sets below.
This page is organized to document the boards as they are installed in
the Multibus cage from the bottom going up.
---------------------------------
Bottom Board on Rack-
Floppy Disk Interface
Double Density
PWA 123857-002
S/N 023767
This board has a cable plugged into it's top edge connector.
---------------------------------
Next Board Up
Floppy Disk Controller Channel
PWA 10000457-05
(may have copied down one extra 'zero' in above part number)
This board does not have a cable plugged into the 'top' edge connector.
Edge connector shows 'weathering' from not having connector on it.
---------------------------------
Next Board Up
Trace Board
PWA 162249-001
S/N 13904
J10 and J11 headers which are brought out to the Emulator Pod.
---------------------------------
Next Board Up
Controller Board
PWA 162380-005 Rev M
This board has an 8080A Processor on it.
The Multibus P2 board edge is 'bridged' to Trace Board (above) on a
two-slot interconnect board.
Has header on it brought out to Emulator pod and also power header to
emulator pod.
---------------------------------
Open Slot, second from top.
---------------------------------
Top Board
I.P.C. board
PWA 123192-003
S/N 084111
This board has an 8085 Processor and array of memory chips.
Also has two 8251 and two 8259 chips.
Board has row of buttons to generate interrupts that faces out to front
of system.
It appears I have here an 8085 based system. Is this correct. It
also appears that there's an 8080 controller as part of the emulation
system. I'm assuming (?) the system would run with the Emulator
boards (Trace Board and Controller Board) not installed.
Some questions:
1. Is the memory array on the top board (board with 8085 processor)
the main system memory. It looks like four rows of 4116x8, for a
total 64K.
2. The system has a built in CRT display, and a keyboard input.
Where is the video generated and keyboard I/O circuitry?
On the IOC (I/O Controller) board that stands vertically in the back of
the machine. It handles all the system IO except for the Interrupt, Run and
Reset Switches which are on the front panel and plug directly into the CPU
card and the interface to the ICE and Trace pods.
Joe
Any and all insights into this system are welcomed. Probably I'll add
in any info I receive into the HTML for the page.
Thanks,
Scott
7357
days inactive
7362
days old
16 comments
7 participants
participants (7)
-
ard＠p850ug1.demon.co.uk -
chenmel＠earthlink.net -
dmabry＠mich.com -
julesrichardsonuk＠yahoo.co.uk -
melamy＠earthlink.net -
rigdonj＠cfl.rr.com -
vcf＠siconic.com