Artifact Details

Title

JOHNNIAC Elapsed Hour Meter Panel

Catalog Number

X1560.98

Type

Physical object

Date

1953 ca.

Manufacturer

RAND Corporation

Place Manufactured

Santa Monica, CA, US

Identifying Numbers

Model number Johnniac
Serial number 1

Dimensions

11 x 30 1/2 x 11 (HWD) in.

Description

Donation via Mort Bernstein. Many early computers used elpased-hour meters as a means of planning for maintenance and for billing purposes. This meter is the original Johnniac elapsed-hour meter and shows a slightly-larger "heater voltage" reading than "B+" reading, reflecting the common practice with vacuum tube computers of leaving the tube filaments powered on all the time. This practice, originally discovered by the ENIAC deisgners (1946), caught on with other machines and resulted in greatly extended machine life. This item is a plaque- mounted control panel with two elapsed hour indicators, one for B+ (51, 349 hours) , the other for heater (54, 720 hours) voltages. It indicated the total running time of the Johnniac at time of decommissioning.

Category

I/O: other

Subject

JOHNNIAC

Credit

Gift of the Rand Corporation

Lot Number

X1560.98

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