Zoë Blade's notebook

IBM Card

IBM Card tech specs

  • Released: 1928[1]
  • Company: IBM
  • Type: Punched card
  • Capacity: 80 12-bit words (120 bytes)

The IBM Card was a 7⅜×3¼″ punched card format by IBM. The original version introduced in 1928 consisted of 80 columns × 10 rows of punchable cells per sheet of card. In 1930, this was updated to 80 columns × 12 rows.[1] Each cell represented one bit of information, so the card as a whole could store eighty 12-bit words.

The IBM 704, 709, and 7090 mainframe computers could only read 72 columns (defaulting to the first 72 in particular, which few clients saw a need to change). The card reader would read in each of the twelve rows as two 36-bit words.[2] The computer could then translate these into their actual 72 columns of 12-bit values. The unreadable last 8 columns could be repurposed to order the cards.

The later System/360 could read all 80 columns.

The de facto standard of 72 or 80 characters per line persists to this day.

Notably, IBM rented punched card technology to the Nazis, and printed custom cards for them, to help them commit genocide against Jewish people and other minority groups.[3] While the technology itself isn't inherently good or evil, it can certainly be put to horrific uses.

References

  1. "The IBM Punched Card" IBM Heritage
  2. "IBM 7090 owner's manual" IBM, Mar 1962, pp. 96—98
  3. IBM and the Holocaust Edwin Black, 2001, ISBN 0-609-60799-5

Data storage media: CD | Cassette tape | Cassette tape as a data storage medium | DAT | Floppy disk | IBM Card | MiniDisc | microSD card

IBM: IBM Card