At 09:35 PM 5/17/99 -0700, you wrote:
>On Mon, 17 May 1999, David Williams wrote:
>
>> I suspect it will take more than an LLF. I've now notice that
>> sometimes when I power it on, it fails the startup tests and never
>> reaches a ready state. Of course maybe an LLF would fix that but
>> I don't know. I haven't been able to get it to access the catalog on
>> the drive though formatting under ProDOS now always claims to
>> work where it would fail before. The clicking sound it makes is
>> pretty loud and annoying and I'm sure a LLF won't help that. Does
>> anyone know if you used the same Apple II interface card for the 5
>> meg and 10 meg ProFILEs?
>
>Sounds like its dying. Might be time for a little home clean room to
>repair it. Go back and find the dicussion from several months back that
>talked about building a clean box.
Ok, going out on a limb here (not my first time)...
The infamous 'low level format' may indeed address the problem, but it's
not nearly as easy to do in this case as one might expect...
First: a couple of data points about the 'ProFile' drive subsystems.
1) The interface is just an over-glorified bi-directional parallel port!
(witness that to use it with a LISA, you run a straight-thru cable from the
ProFile to the parallel port on the LISA)
2) the drive in the ProFile is a 5 or 10 meg Shugart 4XX series mechanism,
but with an Apple custom logic board installed. So forget just about
everything you know about formatting hard drives...
3) you never directly address the drive in a ProFile, you issue commands to
the logic board in the ProFile, and it talks to the drive...
4) IIRC: one of the power up tests that the ProFile does (it has been a
while since I went thru Apple training on this critter) is a read test on
selected tracks on the drive. If this test fails (due to mechanical
failure or bit-rot) the drive will never come 'ready'
5) There is no inherent 'format' command in the ProFile controller logic.
To enable formatting capability you have to install a special chip
(according to rumour: a Z-80 with a piggyback EPROM) into a vacant socket
on the ProFile logic board, power up the unit and issue a special command.
(I doubt it matters what machine it is connected to at the time)
6) Running the 'format' command from ProDos (LISA office, etc...) does
little more than initialize the directory tracks in a form that ProDos (or
whatever) expects. It does no actual 'formatting' of the drive proper...
(man, where have we heard of THIS strategy before?)
Now, having said that...
It's quite possible that the problem may be little more than bit-rot due to
the degredation of the magnetic domains on the drive platters. (or it
really could be busted, but let's think good thots here) Also, power
failures during writes could honk up the drive real easily...
The real trick here however is coming up with the little format enabler
chip and the proper incantation to mumble at it!
There have been stories of people who have opened up their ProFiles and
found the previously mentioned socket occupied by the magic module, but
last time I looked in mine I was not one of the fortunate (?) ones...
The real downer in this, is that we are all likely to be impacted by this
somewhere along the way...
-jim
---
jimw_at_computergarage.org
The Computer Garage - http://www.computergarage.org
Computer Garage Fax - (503) 646-0174
Received on Tue May 18 1999 - 00:52:33 BST