Date   : Sat, 20 Aug 2011 15:28:26
From   : jgh@... (J.G.Harston)
Subject: [BeebSoc] Re: Amstrad emailer / DataCentre

Rick Murray wrote:
> If JGH replies, I would be interested to know... the GoMMC instructions say:
> "To install a blank HADFS filesystem on the GoMMC disk, use, for example:
>    *HADFS
>    *INSTALL M $ <diskname> D16383K "
> That 16383 is 16Mb. Is this a limitation for GoMMC, or can I use any
> arbitrary value?

It's an HADFS limitation, not a GoMMC limitation. The disk size is
a 16-bit number, 16383K is &FFFC00 which results in a disk size of
&FFFC. If you uses "16384K" that would be seen as a disk size of
&0000 ;)

The HADFS *INSTALL command doesn't talk to GoMMC in any way other
than just reading and writing data to the virtual disk sectors.
That's why you have to tell GoMMC to set up an HADFS parition
before installing the filesystem on it. Effectively, running
MMCHADFS is the equivalent of placing a disk in a drive, whereas
*INSTALL formats that disk.

When BigDisk support works properly, disks up to 4G will be
installable; a disk size up to 16384K (ie &00xxxx) will be
installed as a SmallDisk with SmallDirs, disks sizes over 16384K
(ie &**xxxx where **<>00) will be installed as a BigDisk with
BigDirs.

You can already access HADFS disk images with BigDisks and BigDirs
with HADFSFiler on RISC OS.

-- 
J.G.Harston - jgh@...      - mdfs.net/jgh
/* Real programmers don't use comments. */