1.44 Floppy Disk

Started by alanh01, November 23, 2022, 04:00:55 PM

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I have a file size of 1.41MB and for some reason, I can't copy it to a 1.44MB floppy disk. Can anyone tell me why?




It is because there is no such thing as a "1.44MB Floppy disk".

Floppy disk sizes were traditionally measured in KB, which was of course at the time, binary. so A "360K Diskette" was a disk that could hold 368,640 bytes.

The larger capacities for both sizes of disk included 1200KB diskettes (1,228,800 bytes) for the 5-1/4" diskettes and 1440K  (1474560 bytes) for the 3-1/2" disks.

People started to shorten these and called them 1.2MB and 1.44MB. However 1,228,800 bytes is not 1.2MB by any definition, and 1,474,560 bytes is not 1.44MB.

Additionally, A formatted diskette is going to have additional space used by that. A Formatted 3-1/2" diskette will also have a boot sector (512 bytes), 18 sectors for the FAT and Mirror FAT, and 14 sectors for the Root Directory, which means an additional 16,898 bytes bringing the total usable space down to around 1.39MB.

I was trying to dereference Null Pointers before it was cool.


Thanks. I never knew that. So can I do a zip.exe, and if I can, how do I do that?


Quote from: alanh01 on November 24, 2022, 11:28:21 AM
... So can I do a zip.exe, and if I can, how do I do that?

Did you mean pkzip ?

If you did, they yes, if you've got it in your path, then you can use it.   Whether or not it will compress the file enough is another question.   Text files compress quite a bit.  Some other types of files, do not.  Nothing to do but try it, and see what happens.

I haven't used pkzip for many years now.   You've reminded me of something that I have used, though.
There was a command line option to make it span disks.    Of course, then you'd have two disks to keep track of.
You can read a little about it here:

And if I recall correctly, there are also options to vary the amount of compression.   You'll probably have to google for the pkzip manual / command line   for that.   

I hope this helps.