What's meant by double sided floppy discs ?

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What's meant by double sided floppy discs ?

OK, so it might seem a stupid question, but I'm more used to using 3 1/2 inch style floppies than the 5 1/4's.

I've got loads of Double Sided, Double Density 5 1/4's, but does the double sided mean the drive reads both sides with the disk in the drive, or that you can turn the disc over and read the other side, or am I barking up the wrong tree ?

:? :? :?

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Double sided means that both

Double sided means that both sides of the magnetic media are "certified" to work at double density. In the very earliest days of 5-1/4" floppy disk production, only one side might have been coated - or maybe only one side had the proper magnetic characteristics to work reliably. So those were sold as single sided. Not much later, as quality and quality control levels rose, it was just as easy to make sure both sides worked as required. So often even batches labeled as single sided worked fine on both sides.

Now, as to the way they get read in drives: the Apple drive (and lots of other early mechanisms) only had one read head, and it read from the bottom of the disk. In order to use both sides, you would need to flip the disk over and, generally, cut out the write protect notch to be able to write on it. Sometimes these were called "flippy" disks by users.

There are some superstitions about flipping disks over - including shifting the deposits of dust and grime, etc. but in general, high quality disks in high quality storage conditions suffer no ill effects.

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Cheers for clearing things up

Cheers for clearing things up, next question is are they standard capacity or can they vary quite alot ?

I have quite a few disk that don't state the capacity, is there anyway to tell what they are ? I've formatted a couple using ADTPro and they come up as 280 blocks free.

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Re: Cheers for clearing things up

Cheers for clearing things up, next question is are they standard capacity or can they vary quite alot ?

I have quite a few disk that don't state the capacity, is there anyway to tell what they are ? I've formatted a couple using ADTPro and they come up as 280 blocks free.

On an Apple II computer a 5.25 disk can only be formatted for 280 blocks/140K. Also it won't do you any good to use a High Density disk, which is what some old IBM formatted 5.25 disks are (they could be formatted for up to 1.4MB), because the Apple 5.25 disk drives can't read those reliably. So your best bet is to use either Single Sided Double Density or Double Sided Double Density if you want to be able to use both sides of the disk.

Dean
Apple II Forever!

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5.25" floppy HDD on Apple II drives

The HDD just means that the grain size of the magnetic media got smaller. Apple II's have no problems with them. There have been rumors that if you try to reformat an IBM formatted disk (in both 5.25" and 3.5" floppies) that will confuse the drive and you have to reboot. I've had this problem with a 3.5" disk, but not the 5.25" disks.

In any event, you can wipe out the format on any magnetic disk by rubbing a magnet against it's surface ( don't touch the inner, actual disk! just rub the housing with the magnet), and then format it how you like.

Mutant_Pie

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