Floppy Densities

[usctech]

Hi - I realize this is a really basic question, but I am asking anyway!!
I read the section in the PC Guide about Floppys and I saw 3 std 3.5" densities listed: 720Kb, 1.44MB, 2.88MB.

When I log on to buy floppys at a place such as CDW, I see the typical 1.44MB but no 720Kb or 2.88MB. Also, I see 1.0MB and 2.0MB.

Are 720Kb obsolete and 2.88MB rarely used? Are 1.0 and 2.0MB just additional sizes that can be used in a typical HD drive?

I figured I try to understand this for a change instead of just ordering the 1.44MB like usual.
Thanks for any help you will give!
Shelly

[tjaymadison]

720's aren't exactly 'obsolete', but they are getting rare.
2.88's are what is also referred to 'Japanese mode 3', I think.

The 1.0MB and 2.0MB may be references to the unformatted capacities of 720 and 1.44.

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[This message has been edited by tjaymadison (edited 06-15-2001).]

[usctech]

Originally posted by tjaymadison:
720's aren't exactly 'obsolete', but they are getting rare.
2.88's are what is also referred to 'Japanese mode 3', I think.

The 1.0MB and 2.0MB may be references to the unformatted capacities of 720 and 1.44.

Thanks for your help. I read some more and you are right about the 1.0 MB and 2.0 MB. The 2.88s are LS-120 'Superdisk' drives that never really caught on. It is nice to get feedback just to help the brain get jump started at least! Shelly

[Paleo Pete]

tjay was also right about the 2.88MB size, that's the Japanese Mode 3 disk size. LS-120 drives might be able to use it, but I'm not sure. They usually use 120MB disks, which are a completely different animal. They can also use standard floppy sizes, and usually can be used as a standard bootable floppy drive.

1.0MB and 2.0MB are the unformatted sizes, 720MB were used in some 286/386 machines, that size never really caught on much, since the 1.44MB format was produced soon afterward, and it became the standard. Some IBM PS/2 machines used 2.88MB drives, but they are very uncommon these days. You can use a standard 1.44MB disk as a 720 by putting tape over the hole opposite the write-protect hole. The drives have a tab that drops into that hole, telling it you have a 1.44MB disk. Cover the hole and it thinks it's a 720.

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[usctech]

Thanks for the additional info. I don't know where I got 2.88 w/ LS-120. Maybe I was trying to read too many things at once. :-)
shelly