22 May
2003
22 May
'03
8:13 a.m.
2) Even now,
HD drives have a switch to detect the hole in the HD disk,
and one thing this switch does is to change the head write current to
cater for the different coercivity of the DD and HD media.
Have you got _proof_ (either from schematics, or by actually measuring
the write current in an opertation drive) that the write current is the
same for both DD and HD disks in a correctly-functioning name-brand
drive? Becasue I am darn sure it isn't!
No, but "DD" drives initially, for obvious reasons, did not have a switch.
And, I can easily show you "HD" drives that
do not have a switch! IBM did
not put a switch in their original "1.44" drives in PS/2's. Some users of
How did they work? Did they use the HD write current for all disks? Or
did they use the density select line from the controller, like the 5.25"
1.2M drives do? I would hope the latter.
those claim that DD diskettes work correctly. (and
then later complain
about the COMPUTER being "unreliable")
At no point has the price differential been so extreme as to justify using
the wrong diskette on a regular basis. Admittedly, there can be
FWIW, the street price in the UK at the moment is at least a factor of 2
(with the DD being double the price of the HD). This still has not
convinced me to risk my data :-)
"emergencies", where the correct diskette is
unavailable that might result
in a need to make do with a wrong one.
-tony