these RTL or what?
cclist at sydex.com
Sun Oct 7 10:55:41 CDT 2007
On 7 Oct 2007 at 8:49, woodelf wrote:
> Floppy disk is 8 bit I/O. That made all the difference when standard
> floppy disk controlers came out. Ben.
It's not the 8-bittedness of floppy disk I/O that's the problem for
non-8 bit systems; it's the length of a sector as a power of two 8-
bit characters. Witness the strange packing used for WPS I, etc. on
the 12-bit DECstation.
If it were just character size, it would be a non-issue, since we're
usually talking about characters that are a multiple of 3 or 4. So 2
12-bit characters = 3 8 bit characters; 3 16 bit characters = 4 12
bit characters, etc.
There was a 2311-lookalike for the CDC systems that had a fixed
sector size at something like 256 8 bit bytes. If you're working
with 60-bit words or 12 bit words, that's not very friendly. IIRC, a
great hunk of the capacity went unused, rather than working out some
sort of packing algorithm to make things come out right.
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