Date   : Sat, 11 Mar 2006 19:00:47 +0000
From   : jgh@... (Jonathan Graham Harston)
Subject: Re: 1MHZ SCSI/ATA board.

Fragula <fragula@...> wrote:
> Now what about ADFS and partitions? filesystem limits? Any ideas for
 
ADFS uses 24-bit sector numbers, with the top 3 bits used for the
drive number. Consequently, the largest ADFS drive is 2^(21+8)
bytes, 512M.
 
> How about a hardware partitioning? an extra register on the 1MHz bus
> that (if possible using any SCSI device no./LUN info ADFS may offer)
> adds an offset of so many "max-adfs-filesystem-sizes"(+a searchable for
> marker block perhaps) to the blocknumbers going through. it could be a
> bit of software (would have to be on each partition if you wanted to
> switch back!) or better still.
 
I think the best way of implmenting this might be the GoMMC
method, where a specific command is used to "mount" a "drive"
which is then seen by ADFS, think of it as inserting a 512M
removable disk.
 
> The ROM where all the little do-dahas that do not deserve a whole ROM,
> yet are inconvenient on disk for whatever reason.
> 
> Do we have one of those?
 
Various options.
 
'Intern' supplied with HADFS builds an HADFS ROMDisk, where the contents
can also be run as *commands. See http://mdfs.net/Software/HADFS
 
The Micron Plus EPROM programmer included code to build a ROM image where
the contents could be run as *commands. I wrote a BASIC version of the
code, 'CmdROM', and a command *RList to list the contents of any such
ROMs. See http://mdfs.net/System/ROMs/Programmer/MicronPlus 
The code needs cleaning up as it tramples on language workspace. Doing
*HELP from VIEW causes... interesting... effects.
 
-- 
J.G.Harston - jgh@...                - mdfs.net/User/JGH
BBC BASIC for Windows and Internationalisation
  See http://mdfs.net/Software/BBCBasic/Windows/ProgTips