Re: GS/OS for xgs emulator?

[mjmahon@aol.com (MJMahon)]

Dan wrote:

> But a standard *did* exist.  It was called (I think) IBM 3740 format. 
It
> existed before Apples and PCs.  It is a *digital* medium.  Apple's is
> *analog*, and hence the incompatibility will never be overcome.

I shudder to join this battle, but there are a few facts that I think need
recounting:

1) Dan, stop saying *analog* about Apple disks--there is absolutely
   no basis in fact.  GCR is just as _digital_ as MFM, but is more
   efficient than the FM "single-density" recording that was "standard"
   until the early 80's.  That's why Woz chose GCR--better density.

2) Woz and Apple in general did have a tendency to do things their
   own way, even when another way was more straightforward.

   In the case of the Disk ][ controller, I think the result was elegant--
   a work of genius.  In the case of the Apple 400K 3.5" floppy (and
   all subsequent Apple 3.5" drives until they adopted the 1.4MB
   media/recording standard), they chose to vary the speed of the
   motor to achieve more uniform bit packing on the media, rather
   than do the obviously easier thing--leaving the speed constant
   and letting the data separator chip do its work.  This trick gained
   them 10% in density (800K rather than 720K), but remained a
   more costly, specialized hack--and when seeking from one zone
   to another, the controller had to wait for the speed to re-stabilize!

The computer world is changing rapidly, and there's no time to
wallow in "coulda', woulda', shoulda'"--just enjoy the passing clouds
and get on with it.  ;-)

-michael

 Email:  mjmahon@aol.com
 Home page:  http://members.aol.com/MJMahon/