Re: floppy capacity question

[shoppa@alph02.triumf.ca (Tim Shoppa)]

In article <4ptgpb$45e@news.pacifier.com>,
jimbell <jimbell@pacifier.com> wrote:
>A question has been raised in another area about the capacity of an original
>Apple II floppy.  I am aware that they went to 140 kilobytes, but I was under
>the impression that they started out at 90 kilobytes.  Could somebody confirm or
>deny this?

The "140 kb" figure you mention is almost certainly the DOS3.3 capacity,
16 sectors * 35 tracks * 256 bytes/sector = 143360 bytes.  DOS3.2
was only 13 sectors, resulting in a capacity of 116480 bytes.  There
were Apple II DOS's before 3.2, but I never used them.

The "90 kb" figure you remember was probably for a FM-encoded single-density
5.25" floppy.  Woz's Apple GCR recording scheme was superior to FM
and got the higher storage figures I mentioned above.  The 90kb figure
you remember applied to several non-Apple uses of SSSD 5.25" floppies.

Tim. (shoppa@triumf.ca)

  (copy me by email, please.)
>