Date : Mon, 01 Oct 2007 14:35:46 +0100
From : adsb@... (Andrew Benham)
Subject: Acorn SCSI access / serial transfer
Jules Richardson wrote:
> Meanwhile someone else - Andrew B I think - had some code to dump the contents
> of a hard disk over the serial port, xfer-style, but I think this was tied to
> an ADFS filesystem rather than using raw sectors (Andrew / whoever, correct me
> if I'm wrong there).
One of Mike Tubby's utilities enabled one to backup the Winchester to ADFS
floppies. It used OSWORD &72 to read/write raw sectors. In order to only
backup the "active" part of the disk, it examined the ADFS free space map to
find the start of the final chunk of free space, and stopped at that point.
Over the years I've modified the utility in a number of ways - e.g. using a
bigger buffer on a Master by using a shadow screen mode, coping with unreadable
sectors, etc.
The most recent modification was, rather than writing to floppies, writing to
the serial port with XMODEM protocol. This enabled me to get a copy of the
hard disk on one of my Linux boxes, where I can use my ADFS Fuse filesystem
to read it.
It reads raw sectors. The only "ADFSish" part is the code that decides when
to stop, and that's easy to remove.
[ In fact, when backing up my hard disk to XMODEM, I manually set the start
and stop sectors and did the transfer in about 3 chunks ].
> I want to look into how complex it'll be to concoct something to grab raw
> sectors from the drive and spit them down a serial line at 9600 baud (19200 at
> a push!) - probably quite trivial for someone who knows 6502 assembler or BBC
> BASIC, but that ain't me! ;)
You need my program then!
The other option is to connect the Adaptec bridge board to a SCSI controller
under Linux and 'dd' the data off the drive, but I've (still!) not tried this
and I wouldn't put money on being able to get this sorted inside 6 weeks.
--
Andrew Benham adsb@...
Southgate, London N14, United Kingdom
The gates in my computer are AND OR and NOT, not "Bill".