https://en.wikipedia.org/wiki/Floppy_disk#3.C … nch_floppy_disk

If it has the HD hole, it is 1440KB floppy. If it only has write protect slider hole, it is 720KB floppy.

Or buy a hole puncher and make them ALL high density! Ah good times...

Thanks. That also answers my question on all these 1.0MB floppies. They are functionally 720KB. The 1.0MB is unformatted (marketing) capacity.

Yes 1 mb unformated, since you could use them on different computers. If you would format a 720kb disk in a amiga it would become a 880kb disk. If used on a one of the first msx1 diskdrives it would become a 360kb disk.
Back in the day i punshed a lot of dd disks to be able to format them as a hd. You could also use vgacopy and format a 1.44mb disk as 1.7mb using a memory resistant program.

Makes me feel old seeing, i presume younger persones, don't know how to tell the difference between a dd or a hd disk.

seob wrote:

Yes 1 mb unformated, since you could use them on different computers. If you would format a 720kb disk in a amiga it would become a 880kb disk. If used on a one of the first msx1 diskdrives it would become a 360kb disk.
Back in the day i punshed a lot of dd disks to be able to format them as a hd. You could also use vgacopy and format a 1.44mb disk as 1.7mb using a memory resistant program.

Makes me feel old seeing, i presume younger persones, don't know how to tell the difference between a dd or a hd disk.

I'm not that young (I'm 46), but I am rusty with retaining some of this knowledge from back then (I just got back into retro PCs at the end of 2015). I do remember on my Apple II (which I used exclusively from 1983 to 1990) using a hole puncher to make 5.25" disks double-sided, then using masking tape to write-protect them. When I transitioned from the Apple II to the PC, it was around 1990. By then the 3.5" floppies I encountered were already pretty much all 1.44MB. So there is definitely a gap in my experience with DD 3.5 floppies since I was on the Apple II during their hey day.

I see. For me i never had a 5 1/4" diskdrive. We went from tape storage on a cpc464 to 3.5" disks on our 286.

I generally do the opposite - cover up the hole and convert HD floppies to DD. They're more reliable that way, so I only format as HD if I'm using the disk for something that actually needs that much space.
If you run into any HD floppies that crap out on you, try reformatting as DD before you toss them out. Most likely they'll start working again as DD.

shamino wrote:

I generally do the opposite - cover up the hole and convert HD floppies to DD. They're more reliable that way, so I only format as HD if I'm using the disk for something that actually needs that much space.
If you run into any HD floppies that crap out on you, try reformatting as DD before you toss them out. Most likely they'll start working again as DD.

Nice tip...thanks 😀