15 Oct
2000
15 Oct
'00
3:33 a.m.
At 01:55 AM 10/15/00 -0000, you wrote:
Dwight Elvey <elvey(a)hal.com> wrote:
Correct. There are a couple of ways you can go with this. (1) Option 730
just adds a pair of external drives but they're connected to the existing
controller and it determine what density you get so you'll end up with all
of the drives being single desity. (2) OR you install the 503 mod along
with option 720. The 503 mod replaces the original controller to a double
density one so now all the drives are DD. (3) OR you can add option 720
which gives you the external drives along with a second drive controller
uses a 8272. In this case your internal drive will be single density and
the external ones will be double density. (4) Again you can add the 503 mod
aand all the drives will then be DD but you'll have two controllers
installed instead of only one. The addition of a pair of external drives
changes a 22x model to a 23x model.
FWIW There is also a 740 option, it adds a 7.3 Mb hard drive to the system.
The 220 model and the 225 model come with a single density drive
controller. The Intel book implies that all (most?) other models come with
double density controllers but I don't think they do. For example,
according to Intel, the 221 model is nothing but a 220 that was converted
at the factory to operate from 230 VAC instead of 115 VAC so it should also
have the SD controller.
It sounds like you have what
was generically known as a series II type machine, although
there was usually one drive in the main cabinet next to the
CRT. The machine can be made into a CPM machine if you like
but the disk may not be compatable with other machines. These
most likely used M2FM soft sectored formats.
I thought they *always* had a drive next to the CRT, but recently
I got one that didn't.
AFAIK, the internal drive only supports single density FM, since
it is wired to the 8271 FDC on the IOC board. External drives
can either be FM or double density M2FM Unless someone ha put in the 503 mod which replaces the
tow drive
controller cards. The 503 cards use a
(which is unfortunately
not compatible with anything else).
Righto. Paxton and I were trying to sort this out. I finally had to go
dig out my Intel books and figure it out. The difference between a Series
II and a Series III is the ADDITION of the iMDX 557 Resident Processor
Card. The card is a RPB-86 and it has a 8086 CPU. Note that the original
processor is left in the machine and is still used for some tasks. I have
an extra set of these cards that I'll swap for other Intel stuff is anyone
is interested.
You can even get a 8086 card for them if you look
around.
With the 8086 card (an RPB or RPC), it's called a Series III.
Many units were field upgraded, so even a 225 might really be
a Series III.
Earlier Series II have the 8080 IPB (Integrated Processor Board);
later ones and all Series IIIs have the 8085 IPC (Integrated Processor
Card).
The models that I know of are the 220, 221, 222, 225, 226, 227, 230,
231, 232 and 240. Whew!
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. The 23x models were nothing more
than a 22x with the addition of the external dual disk drive. However,
they also added a second 32K RAM card to 23x models that only had 32K
originally (the ones with the IPB). There was also a 240 model, It was a
220 but came with a hard drive, I don't know if there were any other
changes to it. I THINK a 225 was a 221 but with a IPC instead of an IPB. I
think a 227 was a 222 with an IPC installed. But I don't know what a 222 was.
Confused yet? OK here's how it works in a nut-shell. You start with a
220. If the factory changes it to 230 VAC you have a 221. If you make
another (unknown) change you get a 222. You take those models and pull out
the IPB card and replace it with a IPC and you get the 225, 226 and 227.
If you take any of those six and add the external drive box and you get the
230, 231 and 232. (Notice that a 230 may have a IPB or a IPC card in it.
Same with the 231 and 232.) Add a hard drive to a 220 and you get a 240.
Add a Resident Processor Card and it becomes a Series III instead of a
Series II. AFIK a Series III can be any configuration of RAM, drives and
IPB or IPC processor.
You can see that there are a LOT of combinations that don't have a
specific model number. That's makes it confusing enough but then you have
to remember that Intel offered lots of other cards and accessories for
these and many of them were upgraded/modified by their owners so the
variations are endless. FWIW Intel wasn't the only one that made parts for
these. I have a A/D card from Burr-Brown and I have a list from Intel that
lists at least twenty manufactures of MultiBus cards that would work in the
MDS.
I went through part of my spare Intel stuff and found an extra ICE-85
setup including the emulator and tradc pods and the cards for them. I'll
swap them for other Intel stuff that I don't have. I also have various
extra cards that I'll trade.
Joe