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Browse Prior Art Database

Processor Control Checking System

IP.com Disclosure Number: IPCOM000094807D
Original Publication Date: 1965-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Merwin, RE: AUTHOR

Abstract

This computer control checking system makes a probabilistic determination, rather than an exact determination, that the computer has made an error or is making errors.

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Processor Control Checking System

This computer control checking system makes a probabilistic determination, rather than an exact determination, that the computer has made an error or is making errors.

If a device has a plurality of input lines and different combinations of signals are applied to these input lines, each bit has a statistical chance of appearing so many times. If it does not, then this may signify an error. a4 a3 a2 a1 E1 E2 E3

d c b a

0 0 0 0 0 0 0

0 0 0 1 0 0 1

0 0 1 0 0 0 1

0 0 1 1 0 0 0

0 1 0 0 0 0 1

0 1 0 1 0 0 1

0 1 1 0 0 0 1

0 1 1 1 1 1 1

a4 a3 a2 a1 E1 E2 E3

d c b a

1 0 0 1 1 0 1

1 0 1 0 1 0 1

1 0 1 1 1 0 0

1 1 0 0 1 0 1

1 1 0 1 1 0 1

1 1 1 0 1 0 1

1 1 1 1 0 1 1

8 2 12

P0 = E0/16 = 1/2 P1 = E2/16 = 1/8 P3 = E3/16 = 3/4

The table shows that, for any of the sixteen input combinations, the three output bits may appear or not, depending on the input combinations. However, for sixteen different input combinations, E1 appears in eight of the output combinations, E2 appears in two, and E3 appears in twelve. If the statistical averages here hold true for eight input combinations, E1 should appear as an output in response to four of the inputs. E2 should appear as an output in response to one of the inputs. E3 should appear as an output in response to six of the inputs. The deviation of these output bits from the statistical ratios specified may signify an error or at least provide for quality control.

In the drawing, a random number generator emits numbers under control of the processor clock. Each number ao...an ente...