5 Apr
2005
5 Apr
'05
1:16 p.m.
Jim wrote:
Isn't that only a requirement of SCSI drives? I
certainly don't have any
terminators on my MFM/RLL drives...
Yes, you're supposed to have termination on your last floppy drive, and
on your last ST506/ST412 or ESDI drive, and not on any others on the
chains.
I'm not sure about the ST506/ST412 and ESDI drives, but for 3.5" floppy
drives they cheat, and put a higher-value termination on each drive, so
that you can have two drives without removing the terminator from the
one in the middle of the bus. Completely wrong as far as transmission
line theory goes, but the signal edges are slow enough that it works
more-or-less OK.
On ST506/ST412 and ESDI drives, the data signals are on the radial
connector (20 position), and have non-removable termination, but the
the low-speed signals on the 34-position connector are still supposed
to be terminated properly since that connection can be bussed to
multiple drives.
Eric