open reel

open reel

Open reel refers to magnetic tape coiled in a reel. The drives have two spindles; one for the supply reel and another for take-up. Open reels gave way to self-threading tape cartridges, which contain both reels (see magnetic tape).

Starting in the 1950s
The first computers used open reel half-inch digital tapes with seven parallel tracks that stored a 6-bit character plus parity. Starting in the 1960s, 9-track tapes supported the 8-bit byte and parity. Also in the 1950s, consumers began using quarter-inch open reel tapes for recording analog audio. See half-inch tape, magnetic tape and byte.

Manual Threading
The supply reel is manually mounted on one spindle, and the loose end of the supply tape is threaded around a magnetic head and onto the empty take-up reel on the other spindle.

Manual Threading
The supply reel is manually mounted on one spindle, and the loose end of the supply tape is threaded around a magnetic head and onto the empty take-up reel on the other spindle.

There Were Millions of Them
For more than 50 years, open reel tapes were used for data storage. For a short time after the turn of the century, half-inch open reel tape drives were still manufactured. Widely used computer standards hang around longer than one might think. (Bottom image courtesy of The Computer History Museum, www.computerhistory.org)

There Were Millions of Them
For more than 50 years, open reel tapes were used for data storage. For a short time after the turn of the century, half-inch open reel tape drives were still manufactured. Widely used computer standards hang around longer than one might think. (Bottom image courtesy of The Computer History Museum, www.computerhistory.org)