Date   : Mon, 04 May 2009 13:15:20 +0100
From   : zeem.uk@... (Alex Taylor)
Subject: ADFS 1.53 patch

2009/5/4 Mike Tomlinson <mike@...>:

> I originally wrote "Obviously, you lost half the capacity in 8-bit
> mode", but the above suggests that the designed capacity (42MB) is still
> fully available in 8-bit mode, so perhaps the drive controller used a
> double-transfer technique to make use of the full capacity.

I'm not sure if they need to do that, XTA after all is an 8-bit bus by
definition, so drives designed for it are designed entirely for 8-bit
data and commands. I wouldn't have thought there would be any need for
a double-transfer, such as is required for getting 16-bit data in and
out of a drive using an 8-bit bus.

> The Connor drive I referred to earlier has a jumper to select ATA or IDE
> mode. ?I thought that might be a 16-bit/8-bit selector, hence the
> possible interest to people using IDE interfaces on 8b-bit systems, but
> some more googling suggests that this jumper had a different purpose.

It appears to be to do with selecting different types of Master/Slave
selection - something I'd almost forgotten about. I remember faffing
about with Conner drives trying to get a slave CDROM drive recognised.

>> I've got a couple of
>>Western Digital 30MB FileCards with duff XTA drives on them, pulled
>>out of Amstrad PC1640s.
>
> Are they dead? ?Have you tried reformatting them? ?You can jump into the
> controller BIOS/formatting program by booting a DOS floppy, running
> debug, then entering g=c800:5 (if that doesn't work, try cc00:5)

I've low-level formatted them loads of times using the Option ROM
formatter, which seems to succeed. The most recent one I got in a
PC1512 will run through the formatter, but running a disk checking
utility afterwards results in multiple read errors on each cylinder.
Trying to format from DOS it results in 'Track 0 bad or media
unusable'. I haven't looked at the other one for ages, but I seem to
remember it doing something very similar.

-- 
Alex Taylor