I'm working through some old MFM HDDs (backing up, erasing, etc.) but I'm noticing that the reported geometry from tools I'm using (e.g. Active@ KillDisk) are reporting one cylinder less than the stated hard drive spec. For example, I'm currently working on an IBM Type 13 20MB HDD with a Xebec fixed disk controller, which should have the CHS values of: 306 Cylinders, 8 Heads, 17 Sectors. With the tools I'm using however only 305 cylinders are being reported as thus the maximum accessible sector is 41480 (C*H*S) when the actual sectors for a 306C disk should be 41616, so I'm concerned there's data being missed out and not erased. I'm using a 486 machine, as the Xebec fixed disk controller appears incompatible with later BIOSes (it hangs on POST). On a socket 7 machine I used for another MFM drive, this issue was also present. PC-Config 9.33 reports the correct geometry.
I'd wondered whether it's to do with formatted vs unformatted capacities but according to this information I don't think that's the case.
Are sectors being missed out here? Obviously really important if they are! Thanks
I'd wondered whether it's to do with formatted vs unformatted capacities but according to this information I don't think that's the case.
Are sectors being missed out here? Obviously really important if they are! Thanks