>Ok, so not as much as at 7:00 this morning... HD media has a higher
>coercivity, thus requires more write current to put a bit on the
>disk. If you use that much write current with LD media (lower
>coercivity) you will get a larger bit. The larger bit will partially
>overwrite adjacent bits, leading to low amplitude, and read errors.
The "bit" size has more to do with the gap and physical construction of
the head, as I remember from my magnetics courses. Yes, the current
is obviously interrelated, but the primary factor is the head gap.
>Ok, I wasn't aware of any 96tpi drives except the HD ones... Were
>they ever used in the PC marketplace, or was it mostly a DEC thing?
Yes, there were a few not-quite-100%-PC-compatible clones that used
DD media at 96 TPI. There were even 100 TPI drives, just to be incompatible
with nearly everybody! (Well, they also eked out a bit more capacity
from the same media, which was a selling point when few had hard drives.)
>After re-reading my uVAX manual about the RX50, I agree it is a
>96tpi single sided drive, though the manual says: "Use only formatted
>RX50 diskettes, available from DIGITAL or its licensed distributors"
>
>So there are four drives using the same media:
>SSDD 180K,48tpi,40tracks/side
>DSDD 360K,48tpi,40tracks/side
>RX50 360K,96tpi,80tracks/side
>???? 720K,96tpi,80tracks/side - What was (is) this called? DSQD?
Some aftermarket third-party DEC-compatible controllers have a
double-sided RX50 mode that they call "RX52".
--
Tim Shoppa Email: shoppa_at_trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927
Received on Tue Oct 12 1999 - 20:11:29 BST