Date   : Sat, 16 Jul 2011 20:03:36 +0100
From   : jgh@... (J.G.Harston)
Subject: GoMMC as a harddisc?

Rick Murray wrote:
> Ah, that could be an interesting compromise - floppy disc images and a
> big harddisc image...
> ...can GoMMC support multiple virtual drives, i.e. to copy from disc
> image to harddisc? Or would an intermediate be required?

No, GoMMC's replacement filing systems replace the entire media,
not just any applicable hard drive. For instance, GoMMC-DFS
replaces all drive access (ie all floppies) with the GoMMC's
disk images. GoMMC-ADFS replaces all drive access (ie all
floppies and all hard drives) with the GoMMC's disk images.
You can't, for instance, do copy :0.file :(mmc).file, with
the GoMMC drive 0 **is** the GoMMC.

You transfer the contents of floppies disks into the GoMMC, and
then use the GoMMC as a replacement for floppy disks. The only
way to use GoMMC storage *and* non-GoMMC storage at the same
time is to use two different filing systems, one a non-GoMMC
filing system and one a GoMMC filing system.

For example, unpatched DFS and GoMMC patched ADFS will let you
access DFS floppies and ADFS GoMMC disk images at the same time.

Rick Murray wrote:
>> See http://mdfs.net/hadfs
> Ummm... So I would need:
>   HADFS
>   HADFS support ROM
>   DNFS (for my setup)
>   GoMMC

No, HADFS 5.29 or later have integrated GoMMC drivers, so:
   HADFS
   DNFS (for my setup)
   GoMMC
leaving one slot for BASIC in an unexpanded BBC.

> PS: Thinks: If I take out the floppies, replace with GoMMC, is there an
>     ADFS+NFS for the Beeb? And does it support Tube?

ADFS takes 16K, so there's no room to combine it with anything else
in the same ROM. You could use a flying lead to put a 32K ROM in
a single slot, http://mdfs.net/Info/Comp/BBC/SROMs/32K (I have DNFS
and VIEW in one 32K ROM).

All properly-written compiant filing systems support Tube. The only
non-Tube compliant filing systems I've ever encounterd have been
strange esoteric development things.

-- 
J.G.Harston - jgh@...