| 1 |
On 2015-01-17, Grant Edwards <grant.b.edwards@×××××.com> wrote: |
| 2 |
|
| 3 |
>> OTOH I suspect most of us here starting computing with punched cards ... |
| 4 |
> |
| 5 |
> Actually, I started with OMR IBM cards where you marked them in |
| 6 |
> pencil. You sent your deck off to the University for scanning and |
| 7 |
> running, and week later you got your results. At least I think they |
| 8 |
> were IBM. They were the same form factor as regular IBM punch cards. |
| 9 |
> IIRC, each logical column had two physical columns for marks. You put |
| 10 |
> two marks in each _logical_ column which selected the symbol _between_ |
| 11 |
> the marks. Something like this: |
| 12 |
> |
| 13 |
> [ ]A[ ] |
| 14 |
> 0 P |
| 15 |
> [ ]B[ ] |
| 16 |
> 1 Q |
| 17 |
> [ ]C[ ] |
| 18 |
|
| 19 |
I think this page from an IBM 3505 card reader manual shows the |
| 20 |
physical spec for the OMR cards I remember, but it doesn't any |
| 21 |
semantics: |
| 22 |
|
| 23 |
http://www.panix.com/~grante/files/IBM-3505-OMRcard.pdf |
| 24 |
|
| 25 |
That shows 40 columns of 12 OMR cells, and at two columns of cells per |
| 26 |
symbol, that would only be 20 logical columns. |
| 27 |
|
| 28 |
If there were symbols only in the spaces between OMR cells, that would |
| 29 |
be 11 + 11 + 12 = 34 symbols. That's not enough to write FORTRAN IV. |
| 30 |
|
| 31 |
So, there must have been symbols _in_ each of the cells that you could |
| 32 |
select by marking a single cell. That would add 24 more symbols for a |
| 33 |
total of 56, _which_ would be enough. |
| 34 |
|
| 35 |
Google found me this picture showing semantics for what looks like the |
| 36 |
same physical IBM OMR card, but I don't think it's the layout I |
| 37 |
remember using: |
| 38 |
|
| 39 |
http://www.panix.com/~grante/files/IBM-OMRcard.jpg |
| 40 |
|
| 41 |
It could be that the layout I remember using was something local to |
| 42 |
the University where we sent the cards to be run... |
| 43 |
|
| 44 |
-- |
| 45 |
Grant |
Archives
