20 Sep
2013
20 Sep
'13
4:06 p.m.
On 09/20/2013 02:27 PM, Dave wrote:
The only readers I have seen that read row binary
were IBM but I said
"some" as I didn't know if they were the only readers that worked that
way. It seems obvious it should be faster that way so I have in the past
wondered if IBM had a patent on reading by the row...
Yup, the card reader on the 704 read cards starting with the nine's row,
storing right and left sides into 26-bit words. Now you know why
FORTRAN reserved the last 8 columns for a sequence number--the 704
couldn't read them! The 1402 reader, read column-wise and I believe
all subsequent IBM readers did also.
A quick check in my library says that the "short" cards were 51 column,
not 40. I haven't the faintest idea of what or why that particular
format came about. Perhaps something like perforated inventory cards,
where a part of the card could be torn off and used as a printed record?
Anyone know for certain what the 51-column card was for?
--Chuck