Date   : Mon, 08 Feb 1999 13:12:47 -0000 
From   : "Fraser, Colin J" <Colin.Fraser@...>
Subject: Re: BBC hard drives

> -----Original Message-----
> From: Mark Usher [mailto:marku@...]
> Sent: 08 February 1999 12:55
> To: 'BBC MICRO Mailing List POSTINGS'
> Subject: RE: [BBC-Micro] BBC hard drives
> 
> > I tested this board out connected to my Master as a host
> > adapter, and a
> > Model B on the other end with a bit of code to let me see
> > what the Master is
> > sending on the SASI bus. I got as far as seeing how the ADFS
> > determines it
> > has a functional host adapter connected to the 1MHz bus, and
> > how it then
> > looks to see if it can find any devices.
> Wouldn't it have been easier to diassemble the ADFS rom to 
> see how it checks
> the 1MHz bus  ?

I did some disassembly of ADFS and knew what to expect as far as the adapter
detect went.
I wanted to build the hardware anyway - the interface board will develop
into the IDE board, so I didn't continue disassembly to find the command
passing routines. 

> Definately a project that would benefit many. On the IDE side 
> of things, I'm
> not actually sure if it is possible to low level format an 
> IDE drive to use
> 256bytes per sector.

I don't believe it is.
I'll either be doing address translation - mapping two 256 byte SCSI sectors
to one 512 byte IDE sector, or just losing half the disk.
I have an old 140Mb IDE drive to use, and I can't imagine I'll find 70Mb of
data to fill it.
The two drives supported by the ADFS should map nicely to a master/slave IDE
pair too.
Anyway - I'll post further developments to the list as they happen.


Colin f