Re: Firmware/Software for homebrew IDE HDC.

[david@wraith.cs.uow.edu.au (David E A Wilson)]

dempson@swell.actrix.gen.nz (David Empson) writes:
>If you want to implement a partitioning scheme, then it must be
>transparent to ProDOS.  The only way to implement this properly is to
>have RAM on the interface card which holds the partition table from
>the drive.  The partitioning should be read by the boot code.
>Accesses through the ProDOS driver should refer to a particular
>partition, which will start at a given offset into the disk.

If you are prepared to limit yourself to 32MB partitions and a single IDE
drive then you could use something similar to that used by Cirtech. For
example (assuming your card is in slot 5):

Blocks		ProDOS unit	Smartport unit	Drive size
00000..0FFFF	$50		1
10000..1FFFF	$D0		2		>32MB
20000..2FFFF	$20		3		>64MB
30000..3FFFF	$A0		4		>96MB
40000..4FFFF	$?0		5		>128MB (only if using P8 v2.x)
etc

If your card is not in slot 5 and you are not using P8 v2.x then you would
only have units 1 and 2 accessable.

If you want two drives just interleave them (odd units are first drive, even
units are 2nd drive).

Let me know how it works out.