[sdiy] [ot] Ensoniq Mirage

Rainer Buchty rainer at buchty.net
Mon Mar 11 13:05:50 CET 2013


On Sun, 10 Mar 2013, rsdio at sounds.wa.com wrote:

> I wouldn't call it conventional. Ensoniq used 10 sectors, while the 
> ubiquitous IBM-PC DOS used only 9 sectors.

Also with PCs you could've gone higher, both sector and track count. 
There were several tools around which allowed that.

Multiple sector sizes, however, is something which is not supported very 
well on PC floppy controllers (which are NEC 765 descendants by nature) 
but required more intelligent ones like the ubiquitous WD1772.

On the Atari ST there was one particularly aggressive formatter, which 
IIRC went up to track 82 or 83, squeezing out the theoretical 1MB per DD 
disk.

> Where DOS put 720 KB on a DD floppy, Ensoniq managed to fit 800 KB. 
> Not much, but it is 11% more. There is custom software out there to 
> read and write Ensoniq floppies.

Ensoniq even managed to get 880kB onto a disk (80*2*(5*1024+512)) or 
440kB per side, at least on the machines using their MSS format.

That's why the Ensoniqs are equally picky about disk quality as e.g. the 
Commodore Amiga. Disks that fail formatting on those machines often will 
happily work on PCs -- sometimes at reduced capacity, though, for 
marking bad sectors as occupied.

Rainer




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