On 2020-10-05, Jonathan Peart <jonath...@gmail.com
> On Sunday, October 4, 2020 at 9:14:34 PM UTC-4, DoN. Nichols wrote:
>> On 2020-10-04, Jonathan Peart <jonath...@gmail.com
>> > My 3B1 stopped booting from the hard disk. I booted from a diagnostic floppy and ran the hard disk test. I get the following:
>> > Test : Hard disk test
>> > Subtest : Recalibrate.
>> > Error : WINCHESTER:Can't Recal:Response = 1
>> > Enter y [Y] to Abort, Return to continue:
>> > I tried return several times but keep getting the same error message.
>> > Does this mean my hard drive is completely toast?
>> What it means is that the drive's heads are stuck to the
>> platter, so the platter can't spin, and the heads can't read data.
>> Which is this -- the 40 MB drive (which I think was standard
>> with the 3B1)?
> The front of the computer says 67MB on it so I am assuming the drive
> is a 67MB drive. Sounds like even if that rotation trick frees up the
> heads I'll need to replace the drive.
Yes. The rotation trick is to give you a chance to recover
information off the drive (if you have any which matters on there.)
> Not sure where to find
> replacements but I'll look around for MFM drives. I'm betting if I do
> find any they will be expensive.
Likely so -- if it is *known* to work.
With both mods to the system (The ICUS and the WD-2010) you can
go up to something like a 160 MB drive -- there were two -- the first
one I was not able to get back then, but there is a different brand
clone of it which I was able to get back then -- and ran the system with
a mix of the 67 MB one which I mentioned in the previous article, and
the 160 MB (or whatever it was) -- both in a 3B2 external disk drive
housing, also including the tape backup system. That system had a power
supply which could be turned on by a 5V signal, so the 5V which used to
power the internal disk drive was routed to the outside.
The MFM drives included two ribbon cables -- the control one
(like what was on floppys) and the data one. The data one uses less
than half the pins for data in and out -- so it was possible to put both
drive's data flows on the same ribbon cable -- starting from two ends in
> I don't think I want to invest in the
> drive modification as it looks more involved than I want to tackle.
O.K. I was using it as my serious computer for a while, so the
dual disk drives were a benefit back then. If you just want to make the
computer act as it was designed to, the original drive (or a duplicate)
is worth considering.
Another thing which I discovered was the system would not back
up the files which were installed from the "foundation set". This is
no serious problem, if you have the floppies for re-building -- unless
you do something like I did. The "mkdir" command did not have certain
additional features (such as the '-p' option, which if needed makes
using the default mkdir would fail, unless /junque and /junque/whatever
were already present. Add the "-p" option, and it will. I had compiled
a program to do that, and after a new drive, a rebuild from the
foundation set, and then recovery from a backup -- the /bin/mkdir was
not backed up and recovered. Luckily, the source tree was still
present, so I could re-compile and re-install. :-)
Aha! I remember the brand for the largest 8-head one which
would fit even in a 7300 (half-height drive). It came from Miniscribe.
The Miniscribe 6085 gives you the same 67 MB as the full-height
drive which came in some 3B1s.
And the biggest full-height 16-head drive was Maxtor.
And the clone was made by Priam.
Hmm ... it looks like this might be a good way to go.
It lets you use CF cards to replace the ST506 disks. And it looks like
you can get it to emulate the Miniscribe 6085, so you get the 67 MB you
want/need. You might need to replace the WD-1010 with a WD-2010 to
access all the cylinders.
And -- apparently it can duplicate the Priam V519 (160 MB) drive, but
you would need the modification to the board to use all of it.
Can you find the disk drive number for your current 67 MB one?
Go to the "emulated hard disk's list" link, follow the link for the
brand, and look for a match for the model number. If it is there, you
should be able to use this to replace your disk. Check the number of
cylinders. If it is 1024 or smaller, you should be fine with no mods to
the system board.
I don't know what it costs -- it seems to be in the UK, not US
made, but it looks like a good solution for a replacement drive. It
should use a lot less power, so the system should last longer.
> Thank you for the information Don.