The IBM card punch

The IBM card punch is my all-time favourite machine! Its purpose was to punch holes in cards that would subsequently be read by a computer and interpreted as either instructions or data. There was a lovely clunky feel to the keyboard and a sequence of clicking sounds as the current card was ejected and another one brought down ready to be punched.

The cards, known as Hollerith cards, had 80 columns and 12 rows, allowing 80 characters (letters, numbers, symbols) to be encoded using the 12 rows. A computer program would typically consist of thousands of these cards, each one containing a line of computer code.

Elastic bands were used to keep the cards together, or a tray or box would be used for larger programs. One always had to be careful not to drop the cards since they would be useless if fed to the computer out of sequence!

You can obtain used punch cards, (out of interest rather than for any practical use), from the Centre for Computing History in Cambridge. At a mere £3 for 5,  here’s the link http://www.computinghistory.org.uk/det/9355/Punch-Cards/

Have your say!

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Create a website or blog at WordPress.com

Up ↑

%d bloggers like this: