VOGONS


First post, by ultimate386

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I have recently acquired two Miniscribe model 8212 Type 1 hard disk drives. These are MFM drives - certainly old, but nothing particularly noteworthy about them, I suppose. What made these interesting (to me, at least) is that they are MFM drives mated to a bridge board that converts the interface to IDE! The drives have Compaq logos on them and appear to be meant for the Compaq Portable II. I found this write up while searching for info: https://buildingtents.com/2017/01/01/restorin … aq-portable-ii/.

I am in the early stages of testing them with a generic 386 motherboard and IDE controller. The first drive had a stuck spindle, but a few quick twists got it moving (I haven't tried the second drive yet). I was able to fdisk and format, but got about half the drive as bad sectors. SpinRite and SpeedStor refused to touch the drive. I think I may have had the drive geometry wrong in BIOS though - I'll update this post as the situation evolves.

I am curious: If I were to transfer the drive to standard MFM controller (which would involve a low level format), I suspect I would no longer be able to use it with the MFM to IDE bridge unless that board could perform its own low level format?

Now, pictures!

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AMD386/IIT387DX40, 32MB, ATi Mach64, AWE64
Compaq Prolinea 4/33, 32MB, Tseng ET4000, SB16
AMD X5, 64MB, S3 Virge/Voodoo1, AWE64
AMD K62+550, 256MB, Voodoo3, AWE64 Gold
P3 1.2Ghz, 512MB, Radeon 7500/Voodoo2 SLI, SB Live!

Reply 1 of 2, by derSammler

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There's no real difference between "MFM" and IDE. IDE just means that the electronics from an MFM controller is part of the hard disk. The IDE host adapter itself is just a buffered connection to the ISA bus.

As for MFM drives in general: yes, they only work with the controller they were low-level formatted with. If you change the controller, you need to re-format the drive.

Reply 2 of 2, by dr.ido

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I had the 8425 with IDE bridge board in my portable II. I've never seen an 8212 before - The first 2 in 8212 suggests 2 heads so geometry is probably 615/2/17 which differs from the standard type 1 10Mb (306/4/17?). From memory the bridge board has issues on more recent IDE controllers - it certainly won't auto detect.