On Fri, Feb 3, 2023 at 4:40 PM Chris Zach via cctalk <cctalk@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
