these RTL or what?

Tim Shoppa shoppa_classiccmp at trailing-edge.com
Sun Oct 7 18:28:35 CDT 2007


woodelf <bfranchuk at jetnet.ab.ca> wrote:
> Allison wrote:
>
> > Does it really makes that much differnce the number of bits for a char?
> > Really, Six bits was kinda tight for work where upper or lower case
> > was used but it didn't affect calculating Pi to a 100 places.
> > Wasn't the basic chunk 9 bits for PDP10 and it happened (DEC 
> > software) used 6 bit char notation as a carry over from earlier 
> > life with friden flexowriter and TTYs on earlier machines?
>
> Floppy disk is 8 bit I/O. That made all the difference when standard
> floppy disk controlers came out. Ben.

There's nothing intrinsically 8-bit about a floppy disk. A serial
bitstream to be sliced/diced however you want.

Several word processors, using 8" hard-sectored floppies, had 7-bit
and 9-bit formats.

Now, IBM 3740 floppy format (from which almost all modern floppy
formats have descended) has a lot of 8-bitness in it. But it
was still used by 12-bit machines (with various packing/repacking).
There's a whole lot of crap in the IBM 3740 floppy format that 
nobody has used for decades but is still carried around, too. (e.g.
"deleted data" marks).

Tim.



More information about the cctech mailing list