Loboyko Steve wrote:
>
> The SBC6120 (PDP-8 board) uses an IDE drive in LBA
> mode, simply stating, "on address X read or write
> these 256 16(12) bit words". Because this obviously
> requires a great deal of intelligence on the drive's
> part, (certainly more than the computer itself has) I
> suppose that philosophically speaking, this is
> "cheating"....
Bigger YES! Cheating no!
Other than stupid floppies and the old HD's on the PC where you just get
raw data from the drive, almost all the interfaces for disks have been -
set track / sector / head and buffer address then a read/write a block
to memory command. With a machine as small as pdp-8 you had very dense
I/O routines compared to today's machines that need 64kb?? of bios for
basic I/O. The last page (128 bytes??) was often all the room you had
for a disk driver that often swapped the entire 4k of memory to and from
disk. As for the cpu on the HD it is more powerful than a pdp-8 but then
HD's are a hell of a lot faster than in the 1960's that were often only
FM formatted hard sectored machines.
--
Ben Franchuk - Dawn * 12/24 bit cpu *
www.jetnet.ab.ca/users/bfranchuk/index.html
Received on Sat Apr 06 2002 - 21:43:16 BST