Subj : Re: Am I the only one dumpster diving ?
To   : Spectre
From : boraxman
Date : Sat May 28 2022 21:12:06

 Sp>  bo> You can use a 1.44M disk drive with disks formatted as 720K disks.  I
 Sp>  bo> it with my XT mainboard and a newer IO card and by gum, it worked!
 Sp> 
 Sp> If you then put it in a HD Drive you won't be able to read it though,
 Sp> unless you cover the detection hole...for a short time before its
 Sp> retirement I was drilling holes in the corner of the high densitys so
 Sp> they would look like 720's on the IIgs
 Sp> 
 Sp> Spec

It's the other way around.  The hole indicates it is a HD disk.  The presense/absense of the hole indicates what disk type but you can choose when you format it, to use the DD format not the HD one.

The holes had to be drilled to make a DD format as a HD one, which was always a little risky.

Interestingly, the floppy drive on the Amstrad PC2386 would always just format a DD disk as a HD one, even without the hole.  Perhaps it didn't check, or that particular drive I had, had a fault.  But I had man 720K disks formatted as 1.44M without a hole drilled.  Oddly, they were quite reliable, even more reliable than new floppies purchased at the end of the 90's, early 2000s.  I did have to drill holes laters to read them on another floppy drive.

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