Tape drives rented for about $1000 a month ($9000 in current dollars). Tape drives were pretty common because they could hold much more data than cards. However

Tape drives rented for about $1000 a month ($9000 in current dollars). Tape drives were pretty common because they could hold much more data than cards. However, everyone used cards for data input because you couldn't enter data directly onto cards. Sorting was tricky on tape drives; you typically needed 4 drives. Cards were also more reliable since it's pretty hard to destroy a card unless you burn it. (Even if someone rips up a card, you just look at it and punch a new one.) IBM's documentation explains how the cards work in detail. I've put the information for each card online. For instance, the CW card in the article is described here: http://righto.com/sms/CW http://righto.com/sms/CW (Click the arrows on the schematic to get to the text description.) I used the IBM 1401 at the Computer History Museum in Mountain View, California. They have two working 1401s.