27 Mar
2000
27 Mar
'00
4:02 a.m.
On Sun, 26 Mar 2000, Richard Erlacher wrote:
I'm in agreement, pretty much with what's been
said here. Please see
embedded comments below.
Yes, but, given that the goal is to write a 48TPI 360K diskette, the
coercivity will be the same, since the media are the same. It's worth
Are you saying that a 300 Oerstedt diskette is the SAME as a 600 Oerstedt
diskette?? Is TRI-X camera film the same as Pan-X, also?
target medium is the 300-Oerstedt 48TPI 5.25"
diskette. The issue was that
the old 48TPI disk drive had trouble reading the 48TPI diskette written on a
1.2MB 96TPI drive. The reason is not the media, it's the drive. Why?
It's because the medium is the same physical diskette. It cancels out of
the equation.
The symptoms described (inability to read a diskette written in a 1.2M
drive, supposedly as a 360K) match TWO possibilities:
1) failure to bulk-erase and format in the 1.2M, when the diskette had
residual 1/3mm wide tracks.
2) use of a 600 Oerstedt diskette when trying to create a 360K.
Either (OR BOTH!) of those mistakes would give the symptoms described.
I fail to see how the media could be "cancels out of the equation". The
magnetic coercivity of the diskette would not magically be altered into
the correct one by any action of the drive. Setting the ASA dial on the
camera to 400 does NOT convert Pan-X film into TRI-X.
There are folks who enjoy claiming that their risky
way of doing things is
better than paying the 10% extra for the correct product.
Agreed
Let's try to keep the 3.5" diskettes out of
the picture for now. The 720K
Mentioned simply because:
the gap in coercivity of the different 5.25" diskettes is SIGNIFICANT.
The gap in coercivity of the different 3.5" diskettes is much less.
Therefore any success in using wrong diskettes in 3.5" should not be
extrapolated to apply to 5.25"
Some of the controllers switched the data rate and in
other cases the drive
switched speed.
Because it is on topic for collectors: The original IBM AT switched data
transfer rate. Many later went for dual spindle speed. Both methods
seemed to work OK. The Weltec 250Kbps/180RPM 1.2M was trying to stretch
things a little too far.
--
Grumpy Ol' Fred cisin(a)xenosoft.com