A frightening little bit of technology
cclist at sydex.com
Fri Sep 7 19:35:08 CDT 2007
On 7 Sep 2007 at 23:18, Tony Duell wrote:
> And yes, I am clueful enough not be be complaining they didn't work as HD
> disks on a PC/AT. What I a talking about is formatting them as 80
> cylinder disks on BBC micros, TRS80s, etc.
> I assume it was something like an increased background noise level. I cna
> think of no other explanation.
Dunno, but when we were selling our own-branded Dysan 100 tpi
diskettes, I was told by the Dysan sales tech that the formulation
was exactly the same as the 48 tpi versions; that only the
verification process was different. Maybe the UK got all of the
floor sweepings; I don't know.
I do know that the certifiers used for DSDD diskettes were programmed
to toss a cookie that verified fine on one side but not the other
into the "about to become SSDD" media pile.
That's not to say that the occasional branded-and-certified-as-100-
tpi diskette failed to format either. There was a reason that
everyone had a flawing mechanism of some sort built into most
operating systems. And our application was a bit tougher than most
as we were packing something like 950K in a 77cyl * 2sides *12sect *
512bytes format using GCR and an elevated clock rate. This was a
couple of years before Osborne was putting, what, 90K on a 5.25"
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