3736Re: correction - hard drive analysis
- Jul 3, 2006--- In email@example.com, "B. Degnan" <billdeg@...> wrote:
> For the IBM XT you need to use the reference disk to format the hard
> if it's from an alien system. I should have thought of that beingan ex
> IBMer...but it's been a while. In the process of formatting a drivenow.
> BillBill, as I remember XT's and MFM controllers, many of those
controllers had a "low level format" routine in their BIOS ROM. That
routine was accessed by using DEBUG and starting at a ROM address,
something like C300:0005. A Web search on those terms should find this
info. POWER THE DRIVE FOR SEVERAL MINUTES before doing this, so it's
A low level format will rewrite all tracks and sectors. I recommend it
so that any marginal tracks can be recovered. However this may also
wipe out any info about "bad" tracks found by previous use.
Consequently a reasonable next step is to use a program to test and
mark bad tracks, perhaps the program you mentioned.
The problem is that relative to drives today, the old MFM drives had
limited self-diagnostics. Also becuase of their advanced age, they
will be marginal and have physical errors, probably. For any serious
use of such drives, they should be reformatted and tested THROUGHLY.
Can you format under MS-DOS and use on DEC or other OS's? Low level
formats are not OS dependent; they CAN be controller-dependent. High
level format which determines drive partitioning IS OS dependent.
Features like "bad blocks" may or may not be OS dependent. Best
practice is to low level format and partition on the destination OS
and controller - but testing on a more demanding controller and OS is
a good idea!
Other MARCH associates know more about MFM drives than me and can
probably advise you, or more likely remind you of tricks you learned
Herbert R. Johnson, New Jersey USA
<a href="http://retrotechnology.com/herbs_stuff/"> web site</a>
<a href="http://retrotechnology.net/herbs_stuff/"> domain mirror</a>
my email address: hjohnson AAT retrotechnology DOTT com
if no reply, try in a few days: herbjohnson ATT comcast DOTT net
"Herb's Stuff": old Mac, SGI, 8-inch floppy drives
S-100 IMSAI Altair computers, docs, by "Dr. S-100"
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