Bi-quinary coded decimal: Difference between revisions

Revision as of 05:26, 4 June 2024

Revision as of 13:27, 19 July 2024

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* [[George Stibitz|Stibitz]]<ref name="Stibitz_1957"/><!-- In this book Stibitz claims that he invented this code some years after inventing Excess-3 --> relay calculators at Bell Labs from [[Bell Labs#Calculators|Model II]] onwards

* [[FACOM 128]] relay calculators at [[Fujitsu]]

===IBM 650===

{{anchor|IBM650code}}<!--link from IBM 650 article-->

The [[IBM 650]] uses seven bits: Twotwo ''bi'' bits: (0 and 5) and five ''quinary'' bits: (0, 1, 2, 3, 4), with error checking.

* [[IBM 650]] – seven bits

: Two ''bi'' bits: (0 and 5) and five ''quinary'' bits: (0, 1, 2, 3, 4), with error checking.

: Exactly one ''bi'' bit and one ''quinary'' bit is set in a valid digit. In the pictures of the front panel below and in close-up, theThe bi-quinary encoding of the internal workings of the machine are evident in the arrangement of theits lights – the ''bi'' bits form the top of a T for each digit, and the ''quinary'' bits form the vertical stem.

: (the machine was running when the photograph was taken and the active bits are visible in the close-up and just discernible in the full panel picture)

{| cellpadding="5" class="wikitable"

|-

| Value || 05-01234 bits<ref name="Ledley_1960"/>

| rowspan="11" | [[File:IBM-650-panel.jpg|thumb|center|IBM 650 front panel while running, with active bits just discernible]]

[[File:IBM 650 panel close-up of bi-quinary indicators.jpg|thumb|center|Close-up of IBM 650 indicators while running, with active bits visible]]

|-

| 0 || 10-10000

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| 9 || 01-00001

|}

* [[===Remington Rand 409]] - five bits===

:One ''quinary'' bit (tube) for each of 1, 3, 5, and 7 - only one of these would be on at the time.

The [[Remington Rand 409]] has five bits: one ''quinary'' bit (tube) for each of 1, 3, 5, and 7 - only one of these would be on at the time. The fifth ''bi'' bit represented 9 if none of the others were on; otherwise it added 1 to the value represented by the other ''quinary'' bit. The machine was sold in the two models [[UNIVAC 60]] and [[UNIVAC 120]].

:(sold in the two models [[UNIVAC 60]] and [[UNIVAC 120]])

{| cellpadding="5" class="wikitable"

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| 9 || 0000-1

|}

* [[===UNIVAC Solid State]] – four bits===

The [[UNIVAC Solid State]] uses four bits:One one ''bi'' bit: (5), three binary coded ''quinary'' bits: (4 2 1)<ref name="Steinbuch_1962"/><ref name="Steinbuch-Wagner_1967"/><ref name="Steinbuch-Weber-Heinemann_1974"/><ref name="Dokter_1973"/><ref name="Dokter_1975"/><ref name="Savard_2018_Decimal"/> and one [[parity bit|parity check bit]]

{| cellpadding="5" class="wikitable"

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| 9 || 1-1-100

|}

===UNIVAC LARC===

* [[UNIVAC LARC]] – four bits<ref name="Savard_2018_Decimal"/>

The [[UNIVAC LARC]] has four bits<ref name="Savard_2018_Decimal"/>:One one ''bi'' bit: (5), three [[Johnson counter]]-coded ''quinary'' bits and one parity check bit.

{| cellpadding="5" class="wikitable"