Date   : Mon, 05 Jul 2004 18:57:22 +0100
From   : "Ken Lowe" <kglowe@...>
Subject: Re: Acorn Winchester unit

> Op 2-jul-04 om 15:03 heeft Richard Gellman het volgende geschreven:
>
> > Jules Richardson wrote:
> >
> >> I found an Acorn Winchester unit yesterday. Still has the Acorn
> >> Winchester board lurking below the Adaptec ST506-SCSI bridge board,
> >> and
> >> a Rodime drive present. However, there's no case lid! If anyone
ever
> >> finds a shell of one of these in a skip, let me know :)
> >>
> >> I almost missed picking it up (I was sifting through a lot of junk
at
> >> the time) as I could see the Adaptec bridge board and figured I
didn't
> >> need another one of those - I have a few already. Without the case
> >> lid I
> >> couldn't tell it was an Acorn unit, but luckily someone else pulled
it
> >> off the shelf and I saw Acorn written on the back...
> >>
> >> Q: what ROM(s) do I need present in the host system to drive this?
> >> Does
> >> ADFS already contain code to talk to the Winchester board if
present
> >> on
> >> the 1MHZ bus, or do I need ADFS + some software, or is there a
> >> different
> >> ROM altogether that I need?
> >>
> >> ta
> >>
> >> Jules
> >>
> > Yes, the ADFS ROM contains the code to access the drive over the
1Mhz
> > Bus. I'm led to believe there are some bizarre DFSes out there that
> > can handle hard drives too, but I wouldn't know which. ADFS works
> > better anyways.
> >
> > Note that you can't just nick the ADFS ROM code from a Master 128 if
> > you intend to use a BBC B. Firstly the ADFS ROM in the M128 uses
> > 65C12-specific opcodes, and the B's 6502 will just vomit at those,
> > secondly, if you try to use the ADFS with floppy disks it will b0rk,
> > even if you have a 177x controller fitted, as the B puts the FDC at
a
> > different location to the Master.
> >
> > By the way, if anyone has an Acorn Winchester Host Adapter board
(1Mhz
> > Bus -> SCSI board) they'd like to flog me, let me know. I'd like to
> > play with getting my 500Mb SCSI drive hooked up.
> >
> > -- Richard
> >
> >
> Recently, I build a Winchester Host Adapter board because I would like
> to use some old scsi harddrive to store all my Master stuff on. As far
> as I could find, a standard 8-bit scsi drive should work just fine. I
> have a whole stack of them, ranging from 40Mb till 4 Gb.
> Using the small programs in the Service Manual, I was able to debug my
> board as I build it on Vero-board with wires for every connection.
Yes,
> it was two days work just to solder everything on. And another day to
> get the small glitches out.
> But now I ran into a very stupid problem: All harddrives I have seem
to
> be formated with 512bytes/sector or more. Most of the bit newer drives
> can be formatted with 1024 bytes/sector or more, but as the Master
uses
> 256 bytes/sector, I am not able to format them correctly.
> Does this sound familiar, or did I overlook something.

Yes, this sounds very familiar. I have a Viglen Host Adapter connected
to a Fujitsu M2681 240MB (I think) SCSI drive. This drive was originally
formatted with 512 byte sectors, and I needed to convert it to 256 byte
sectors.

> I used HDForm first to format, them I found Superform somewhere on the
> net. These programs don't seem to care that my drive is using
> 512bytes/sector but as soon as I start to save data on the drives, I
run into
> problemes that invalid data is read from the disk.
> Does anybody know a way arround this? Or is anybody able to sell me a
> harddisk with 256bytes/sector for very little money? Any help would be
> appreciated.

I wrote a program (based on the format program which came with my
original Viglen Winchester) to change my Fujitsu drive from 512 byte
sectors to 256 byte sectors (block length). I found a document on the
Fujitsu website (still there after all this time)...

http://www.fujitsu-europe.com/archive/archive/01000009.htm

describing how to change block length from 512 to 256 using MODE SELECT
0x15 (I'm not sure if this is specific to the Fijitsu drive). It was
then necessary to issue a FORMAT UNIT 0x04 command using this same
program, which reformatted with the specified block length. Once the low
level format was complete, I initiated a high level format to the SCSI
disk again. This created the Free Space Map (sectors 0 & 1) and root
directory (sectors 2 thru 6) on the HDD, and I now have a 120MB drive
(it may still be 240MB - I'm not sure if I lost half the space by
changing block length from 512 to 256, but I defined the drive as 120MB
in the free space map, to be on the safe side). The HDD worked great
after that. I think I should still have the format programs on my HDD
somewhere if anybody is interested. I haven't booted it up in a few
years though.

Ken.