Re: Vulcan GS/OS Driver

[Rusty <rdekema@gmail.com>]

> > At a minimum it probably supports multi-sector transfers on a single IO
> > call. IIRC, the P8 compatible ROM-based drivers were typically
> > sector-at-a-time.
>
> IIRC, the Vulcan drive(s) were all geometrically addressed, rather than
> logically, so the driver had to do some divides to convert the block
> addresses to CHS.  A 65816 could do that much faster in 16-bit mode
> than in 8-bit mode.  This would also be a prime target for consecutive
> block optimizations.
>
> I don't recall how the data registers of the card are laid out, but if
> they were consecutive addresses, then a 16-bit load could have speeded
> the data move loop as well.  In 8-bit mode, the move "loops" were
> significantly unrolled for speed.
>
> Being able to allocate system RAM for caching and for the partition
> table, instead of using the bank-switched on-card SRAM, would also
> have allowed some speedups in 65816 mode.
>
> I wonder if Bob S-C did the GSOS driver as well as the firmware?
>
> > Directory caching is a possibility as well.
>
> Caching of any kind would be a big win--index blocks come to mind.


This all makes a lot of sense; thanks for the info. Another member of
this group has offered to send me the driver in the mail on a floppy
disk. I wonder, would it be considered improprietous to host the file
on the web once I receive it? I would imagine that the intellectual
property involved is protected by copyright, although I don't really
imagine the distribution of their driver could do any harm to whatever
is left of Applied Engineering...

Rusty