RichCini
Veteran Member
Not sure this fits here, but it relates to my Gazelle so I figured the S100 section would be a good start.
I'm continuing on my work with the Gazelle replica I built and now I'm focusing on the hard drive subsystem which uses Morrow HDC-DMA controller. The system came with MS-DOS 2.0 and related source code (so like an early OEM adaptation kit). When looking at the code, it appears that it natively supported two hard drives -- an IMI 5018 (CHS=306/6/17) and a MiniScribe MS-4020 (CHS=480/4/17). What's interesting -- and what prompts my question -- is that the drive geometry in the source code doesn't match the native geometry of the drives. The SPT used in the code is 8 and the native SPT for each drive is 17; the cylinders and heads match.
Now, I *might* be able to locate a working IMI drive for the unit, so is there any issue with low-level formatting the drive with an SPT that doesn't match the native SPT?
As an alternative, I have a working Quantum Q540 drive, which is larger (CHS=512/8/17) than either of the original drives. Would there be any issue low-level formatting it to 480/4/8 to match the MiniScribe geometry? I would guess not, but it's been so long since I've worked with MFM drives and low-level formatting I thought I'd check.
Thanks!
Rich
I'm continuing on my work with the Gazelle replica I built and now I'm focusing on the hard drive subsystem which uses Morrow HDC-DMA controller. The system came with MS-DOS 2.0 and related source code (so like an early OEM adaptation kit). When looking at the code, it appears that it natively supported two hard drives -- an IMI 5018 (CHS=306/6/17) and a MiniScribe MS-4020 (CHS=480/4/17). What's interesting -- and what prompts my question -- is that the drive geometry in the source code doesn't match the native geometry of the drives. The SPT used in the code is 8 and the native SPT for each drive is 17; the cylinders and heads match.
Now, I *might* be able to locate a working IMI drive for the unit, so is there any issue with low-level formatting the drive with an SPT that doesn't match the native SPT?
As an alternative, I have a working Quantum Q540 drive, which is larger (CHS=512/8/17) than either of the original drives. Would there be any issue low-level formatting it to 480/4/8 to match the MiniScribe geometry? I would guess not, but it's been so long since I've worked with MFM drives and low-level formatting I thought I'd check.
Thanks!
Rich