3 Feb
2023
3 Feb
'23
4:44 p.m.
On Fri, Feb 3, 2023 at 4:40 PM Chris Zach via cctalk
<cctalk(a)classiccmp.org> wrote:
Question: I just used a strong magnet to wipe an old Maxtor MFM drive
(magnet on outside of case). Now the drive will not even seek properly
on start up, just endlessly moves the heads..
Is the drive now toast? Do MFM drives have embedded servo information on
the platter formatted by the factory?
I assume by 'MFM' you mean a drive with an interface similar to the ST412.
Embedded servo is rare (unheard-of) on ST412 interfaced drives simply
because the manufacturer has no idea how it will be low-level
formatted and thus where the sector headers will be. So no safe place
for the servo bursts on the data surfaces
But a dedicated servo surface is very common on larger such drives.
That's why you often see an odd number of data heads. There is a head
on each side of each disk, but one is used for the servo.
Sounds like you've wiped that. No sensible way to recover I'm afraid
-tony