12 Jan
1999
12 Jan
'99
9:01 a.m.
I wrote:
For instance, the IBM 1401, which typically was booted
from cards, but
had only 64 distinct characters.
Hans replied:
Shure ? the 1401 is a bit before my time, but
didn't they
already use 12 row cards with EBCDIC coding (like 12,1 to
12,9; 11,1 to 11,9 and 0,2 to 0,9 for A-i; J-R and S-Z) ?
The 1401 most definitely did not use EBCDIC. It only had six
bit characters, with a seventh bit to serve as a word mark,
and an eighth (non-programmer-accessible) parity bit. The
word mark was used to denote the (leftmost?) end of a field,
for variable-field-length instructions.
However, since EBCDIC was by design (and by name) an extended
version of existing codes, the 1401's card code is similar.
Eric