Re: Did the Apple II use single-density 5.25" drives?

[Michael Black <et472@ncf.ca>]

On Thu, 6 Jun 2013, ivan@ivanexpert.com wrote:

> Was GCR chosen because MFM encoding wasn't a viable or economical option 
> at the time, and it was a higher-density method than FM? And why not 40 
> tracks (which would have yielded 160K per side with DOS 3.3) instead of 
> 35? Same reason?
Early drives, as I said in another post, were 35 tracks.  Even when I got 
a Radio Shack Color Computer in 1984, the standard disk controller was set 
for 35 tracks, though I guess by then most drives were 40 track.  YOu had 
to patch the ROM to get the use of 40 tracks.

So I'm pretty sure that there wasn't the option of 40 tracks when Apple 
first came out with their floppy disk system.  I have no idea why there 
wsa no later upgrade, other than perhaps they didn't want two standards 
floating around.  Or maybe, since standard Apple II drives were custom 
made, Apple never changed the specs.

As for GCR, we were talking about that some weeks back.  Woz cooked up a 
scheme that used little hardware (the board on the drive is much simpler, 
the controller board in the Apple II is pretty simple, not needing some 
big and expensive IC at the time) that resulted in a much lower cost for 
Apple at the time.  At the time, even the dedicated floppy controller ICs 
required lots of extra parts, making them expensive and bulky.

  Michael