Question and Answers on Floppies

HOW DISKS DIFFER:

Q: What's the difference between 5.25-inch and a 3.5-inch disks?

A: Beyond the obvious size, which precludes using one type of disk in the
   other type of drive -- There are two major distinctions between the 5.25 
   and the 3.5 disks: The amount of information that can be stored and the 
   protective covering.  The smaller disk can hold more infomation, oddly
   enough, and has a sturdier cover.

Q: What's the difference between single-sided and double-sided disks?
   Which one should you buy?

A: There's no fundamental difference in the way single and double sided 
   disks are made, except that the manufacturers have tested and will
   therefore guarantee only one side of a single sided disk. ( The single 
   sided disks where popular due to earlier drives only had one read/write 
   head.)  Most of todays drives have heads above and below the disk and 
   read and write on both sides automatically. Where as a double sided disk
   would be tested on both sides of the disk.

Q: Can a single sided disk be used in place of double sided disks?

A: Yes,  But it is not advisable to do so. If the manufacturer recommends 
   double sided disks, use them.  Since only one side of the single sided
   disk has been tested, you can't be certain that both sides will work 
   correctly.  Jeopardizing imprtant data on the disk in order to save a few
   dollars could be costly in the long run.
   However, if you are using the disk soley for your working copy of the
   program and you have a orignal program disk handy, you can use single 
   sided disks to run your programs without fear of losing anything.

Q: What about using double sided disks instead of single sided ones?

A: Go ahead,  If you don't mind wasting money.  A double sided disk of the 
   correct size and density should always work in a drive designed for a 
   single sided disk.  However, the drive will read and write data only to
   one side of the disk only, leaving the other side unused.

Q: What do I need to know about single, double, and high density disks?

A: Density refers to how much data can be reliably stored on a disk.
   If you don't know already, first find out which type your computer uses.
   
   Single density floppies are no longer common; today nearly all computers
   require at least double density disks.  High density ( somtimes called 
   quad-density ) 5.25 disks are needed for 1.2 MB drives on AT-class
   compatibles; and 1.44MB drives like those on the IBM models etc..

Q: Can double density disks replace high density disks?

A: No. Double density disks can't store the same amount of information as a
   high density disk can, so you're asking for trouble if you format a 
   double density disk in a IBM high density drive. (Mac high desity drives
   can format any 3.5 inch disk).  However, most IBM type high density drives
   will write to a double density disk.  Even so, this is not a good idea
   because too often the disk can't read subsequently on a double density
   drive.  Yet if you need only read data from a double density disk in a 
   high density drive and not to write to it, you shouldn't have any problems.

Q: How many pages of text can be stored on a disk?

A: A rule of thumb is that it takes about 2K to store one double spaced page.
   Therefore you can save approximately 180 pages on a 5.25... 360K disk;
   600 pages on a 5.25... 1.2MB disk;  360 pages on the 3.5... 720K disk;
   and 720 pages on a 3.5... 1.44MB disk.

Q: What makes a good disk good?

A: A high quality disk will format the first time with no errors, as will
   every other disk in the box.  A good disk will also let you read and 
   write data repeatedly over a months or even years, without losing any
   information.  Finally, well made disks can be reformatted many times with
   no error messages.