8 May
2007
8 May
'07
4:48 a.m.
On 08/05/2007 11:44, Philip Pemberton wrote:
Quick question - does the write protect sensor on
floppy drives also
lock out the write circuitry, or does the drive depend on the controller
not trying to do silly things like writing to protected floppies?
Normally the write protect does indeed disable the write circuitry, at
least on 5.25" drives and all the 8" ones I've come across.
> That's going from hazy memory of discussions
on here... I'm rather new
> to the 8" drive game. I gather there's an interface line which gets
> toggled on at least some 8" drives and tells the drive to do write
> precomp; I think this line was replaced with another signal when
> things moved to 5.25" drives though, so it's not available separately
> on the standard 34-way header.
More to do with write current rather than precomp. It does exist on
early 5.25" drives, on pin 2.
You're not as new as I am - I don't even HAVE
an 8" drive. I want to get
a 5.25" DD (both 40 and 80 track variants) first, though, as mine's a HD
and I can't tell how to jumper it for 300RPM. It's a YE Data YD-380B,
just on the offchance anyone has a jumper list knocking about...
Otherwise I might dismantle the motor board and trace the speed control
pin back to its source...
Pin 2 on 5.25" HD drives is actually supposed to control the write
current (ie it's the density select), but is very often jumpered or even
hardwired to change the speed as well. On some really old 5.25" drives,
pin 2 was actually TG43 (Track Greater than 43), the same signal as
found on 8" drives to control the write current.
--
Pete Peter Turnbull
Network Manager
University of York