19 Jun
2007
19 Jun
'07
4:16 p.m.
On 19 Jun 2007 at 18:47, Ethan Dicks wrote:
Commodore did vary the bit clock to create 4 zones of
sectors on 5.25"
floppies (2040/3040/4040/2031/1541/1571 for the PET, VIC-20, and
C-64).
Yup, you're correct. I was thinking of the C128/C64 GCR "zoned"
drives. But let's consdier the Amiga format and compare it to XDF.
The 250Kb/sec capacity for a DS2D diskette is 6250 bytes. So, 11*512
= 5632 bytes, giving a track utilization of about 90%. So XDF at 94%
still beats the Amiga with all of its fancy hardware--and XDF uses
standard gaps and address headers--and even puts an IAM on the track.
The Amiga could have done the same thing with nothing more than a
plain old 28-pin WD1770.
Cheers,
Chuck