floppy controller IC (was Re: Fixing a PET?)

From: Glenatacme_at_aol.com <(Glenatacme_at_aol.com)>
Date: Tue Sep 28 21:32:25 1999

In a message dated 09/28/1999 5:53:47 PM Eastern Daylight Time,
ard_at_p850ug1.demon.co.uk writes:

> In general the older full-height 5.25" drives are pretty slow at
> stepping, and may even require 30ms between pulses (some older controller
> cards/OSes always used this timing 'to be safe'). Half-height drives, or
> 3.5" ones tend to support faster step rates. The only way to be sure,
> though, is to check the specs of the drives that you are using.

Thanks again! This is valuable information for me. I've got bins full of
half-height 5.25" drives here, so if worse came to worse and I had to replace
the 1770 with a 1772 I'm certain I could come up with a compatible drive.

Interestingly, with this system when a disk is formatted it is required that
the number of TPI be input. This is then stored on the disk so I might have
one 5.25 DSDD disk with 40 TPI, and another with 50. The maker of the system
says that it will support drives up to 255 tracks per side, "if the drives
themselves ever do."

Anyway, thanks as always --

Glen Goodwin
Received on Tue Sep 28 1999 - 21:32:25 BST

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