MS-DOS FAT file system ripped off? (from WHOM?)

From: Fred Cisin <>
Date: Tue Jan 12 19:00:10 1999

On Tue, 12 Jan 1999, Doug Yowza wrote:
> > Microsoft produced some "Stand-Alone BASIC" systems. They had file IO,
> > and used a a directory structure that was, in principle, similar to that
> > of MS-DOS, although they subscribed to the seek center fallacy of putting
> > the directory on a track approximately halfway towards the center.
> Remind me again about why this was a fallacy. I thought the idea was to
> reduce the average seek time slightly by minimizing the average distance
> the head traveled by factor of 2 versus a directory on a track at one end
> of the disk.

When going to the directory on a system without a track 0 stop or track
0 switch, it DOES substantially reduce the average access.

But, if there IS a track 0 stop, or track 0 switch, then it is normally
possible to get to track 0 at full maximum velocity, rather than stepping
one track at a time, pausing (and maybe reading) before taking the next step.
That usually makes even the maximum seek to track 0 take even less than
half the time that track by track stepping would.

AND, on systems with a track 0 switch, track 0 is the one place where you
always know where you are. Therefore, whenever there is an unknown or a
seek error, the system will normally send the head out to track 0 and
count back in again.

Fred Cisin            
2210 Sixth St.                  (510) 644-9366
Berkeley, CA 94710-2219
Received on Tue Jan 12 1999 - 19:00:10 GMT

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