Caveat Emptor

[atrax27407]

I was having some intermittent read errors on one of my disk drives (specifically, DSK2 which is a 3.5", 720K drive). I spent several hours swapping out drives, etc. I found that my fingers are too fat to easily manipulate the mounting screws which led to some "X rated" language. I finally came to the conclusion that it wasn't the disk drive but rather the disk itself. It seems that, some time ago, I had purchased a lot of DSDD 3.5" disks off of eBay. Hidden among that lot were a couple of HD disks and they were the ones causing the read errors. So, make certain you examine any eBay purchases thoroughly - it might save you some grief (and colorful language).

Edited February 10, 2021 by atrax27407

[+mizapf]

3.5" HD disks should be easily recognized by their holes. Up right: write protection, up left: HD indicator (always open).

[atrax27407]

The HD disks can be (allegedly) as 720K disks if the high density hole is covered. I forgot that the drive I was using was a 720K drive.

[+mizapf]

2 hours ago, atrax27407 said:

The HD disks can be (allegedly) as 720K disks if the high density hole is covered. I forgot that the drive I was using was a 720K drive.

No, don't do that. The magnetic coating of the disk does not magically change when the hole is covered. And this is the reason why HD disks normally don't work in DD drives.

[atrax27407]

That's why I said "allegedly". The offending disks are now residing in the "refuse repository".