SSDD and DSDD floppies

[chicago]

Hello. I'm concerned about SSDD and DSDD 5.25 floppies. I didn't use comuter much at that time(early 80s), so I don't really remember those old 5-1/4 floppies well. Could SSDD 5.25 floppy drives read DSDD floppies? Furthermore, can 1.2mb floppy drives(which I used most often)
read and write SSDD&DSDD floppies?

 

[Chuck(G)]

A single-sided floppy drive can obviously read only one side of a floppy, be it double or single-sided. However a double-sided drive can read both single- and double-sided floppies.

And yes, since a "1.2M" drive is double-sided, it can read both.

Apple users can remember "notching" floppies to turn them into "flippies" in single-sided drives--a trick learned from the 8" world, where 8" "flippies" were commercially marketed.

 

[Stone]

And yes, since a "1.2M" drive is double-sided, it can read both.

And it can write both.

 

[krebizfan]

And it can write both.

HD drive will write to the DD disk, true, but double density drives might have a hard time reading the disk. The problem of HD drives writing a narrow track doesn't go away if using only a single side of the disk. I expect most single sided drives to be more likely to be slightly out of alignment and therefore be less likely to catch the narrow track. The single sided drive is just that much older and before some design improvements.

 

[Chuck(G)]

...and now you know why I said "read".

Writing to a 360K/320K/180K/160K 5.25" floppy that was created on a "360K" drive using a 1.2M 5.25" drive will work, but the result can only be read back by another 1.2M drive--"360K" drives will see garbage. It's a one-way-street.