Busicom HL-21

Serial No. 324555

Date: 1966-1970

Capacity: 10x11x21

Price paid (including postage): £16.80

Another machine with an educational background, it has a number of decals identifying the machine as the property of Croydon Education Committee.  This is a lovely machine to operate.  It also has the largest capacity of any of the machines in my collection, and is the only machine where the largest possible number in the input register can be squared and will fit in the result register.  A disadvantage of fitting all of these numbers into a relatively compact machine is that the numbers are a bit small – the pinwheels are on a 5mm spacing rather than the 7mm of the Odhners.

This machine would have cost £60 in 1966.

One curious connection between this machine and modern PCs is that Busicom entered into a contract with Intel (then unknown) in order to develop a chip set for a forthcoming electronic calculator.  The product of the collaboration was the 4004 micro-processor from which the entire family of Intel micro-processors can trace their ancestry.

The operator’s guide for this machine can be found here.




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