29 Jun
2020
29 Jun
'20
12:41 p.m.
From: Chuck Guzis
Sent: Sunday, June 28, 2020 4:51 PM
It's noteworthy that on the Univac 1100 series, a
"byte" could be 6, 9
or 12 bits, but not 8. (36 bit words). The PDP-10 had similar issues,
such as the "packed" string format of 5 7-bit characters per word, with
one bit unused.
Of course, on the PDP-10, bytes can be anywhere from 1 to 36 bits long;
the size is defined in the pointer, not the hardware.
And in the 7-bit ASCII text format, bit 35 (the word is big-endian) *is*
used by the default editor: In order to allow line numbering in source
files for languages which do not allow it, the line numbers are ASCII
strings with bit 35 set, and the monitor (=kernel=operating system) strips
them out before handing them to compilers' input streams.
Rich
Rich Alderson
ex-Sr. Systems Engineer/Curator emeritus
Living Computers: Museum + Labs
2245 1st Ave S
Seattle, WA 98134
Cell: (206) 465-2916
Desk: (206) 342-2239
http://www.LivingComputers.org/
NB: This e-mail address will cease working after 1 July 2020. Use lcml at
alderson.users.panix.com for future communications.