8-bit IDE

From: allisonp <allisonp_at_world.std.com>
Date: Sun Apr 16 19:44:36 2000

>Frankly, the reason I'm exploring this is because with the 8-bit mode, I
>don't have to buffer the data at all beyond the on-board data-in and data

>out buffers at the bus interface. The board I'm using to host the thing
is


handy but that feature is not there.

>From what I read in the standard, this is a normally selectable operating
>mode for the interface. What's more, only the smallest of drives would be
>appropriate for CP/M on the S-100, since CP/M supports, at most, 120 MB,

Actually it supports 16 drives of 8mb each for CP/M 2.2 and 32Mb for CP/M3.
P2dos, Novados, SuprBDOS all support files to 32mb and drives to 1gb.

BUT, the logical drive to physical drive map does not have to be static.
For example you could only have drives C/D/E/F as mapped to 8mb logical
drives. Drive C: could be partition 1 and a fixed mapping. Drives D/E/F
could be mapped to floating partitions anywhere on a very large drive.
I supported two 71mb MFM drives this way back in 87 under CP/M2.2.

>handle that much. Back when I used CP/M every day, I owned the largest
hard
>disk system on CP/M that I'd ever seen, at 44MB.


Obviously you've never seen many of the systems I ran or have aquired.
Likely
the 44mb limit was based on inavailability of really large drives. Even my
AmproLB has a 45mb SCSI on it and I plan to bump that up to a 160mb. The
current system I'm building I'm planning will have IDE 250mb drive. Space
is
handy as I can have a 8mb partition for pascal and another for C or
whatever.

>notebook drives should cost about $5-10, which is acceptable. Clearly,


There are plenty for under 25$. Though you have to decide on 9.5mm, 12mm
or 17mm thick models.

Allison
Received on Sun Apr 16 2000 - 19:44:36 BST