Ex parte TAYLOR et al.

Board of Patent Appeals and Interferences

Feb 18, 1998

08271238 (B.P.A.I. Feb. 18, 1998)

Application for patent filed July 6, 1994. According to1
appellants, the application is a continuation of Application
07/709,919 filed May 31, 1991.
1
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today
(1) was not written for publication in a law journal and
(2) is not binding precedent of the Board.
Paper No. 27
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte MARK A. TAYLOR, DAVID J. GARCIA,
AND PAUL A. DUFFY
_____________
Appeal No. 96-4106
Application 08/271,2381
______________
ON BRIEF
_______________
Before HAIRSTON, KRASS, and BARRETT, Administrative Patent
Judges.
HAIRSTON, Administrative Patent Judge.
Appeal No. 96-4106
Application No. 08/271,238
2
DECISION ON APPEAL
This is an appeal from the final rejection of claims 4,
5, 11, 12, 26 through 28, 31 through 33 and 35 through 37. In
the final rejection, claims 1 through 3, 19 through 25 and 34
were indicated as being allowable, and claims 13, 29 and 30
were listed as being dependent upon a rejected base claim, but
would be allowable if rewritten in independent form including
all of the limitations of the base claim and any intervening
claims. In an Amendment After Final (paper number 18), claims
38 through 40 were added to the application. In an Advisory
Action (paper number 20), claims 38 through 40 were added to
the list of allowable claims. As a result of the withdrawal
of the rejection of claims 4, 5, 11, 12 and 37 (Answer, page
3), and the allowance of these claims (Answer, page 1), claims
26 through 28, 31 through 33, 35 and 36 are the only claims
that remain before us on appeal.
The disclosed invention relates to a method and apparatus
that checks the proper operation of a processor unit by
operating a copy of the processor unit, and by comparing the
output signals from the two processor units. The operation of
Appeal No. 96-4106
Application No. 08/271,238
3
the copy processor unit lags the operation of the checked
processor unit by at least one clock period.
Claims 26 and 35 are illustrative of the claimed
invention, and they read as follows:
26. A self-checking processor system, comprising:
first and second processor units each operating in
response to instructions to produce address and data signals;
memory means for supplying the instructions to the first
processor unit in response to address signals from the first
processor unit;
first bus means coupling the memory means to the first
processor unit for communicating address and data signals
therebetween;
first circuit means, including second bus means, coupling
the first bus means to the second processor unit for
communicating to the second processor unit data signals from
the first bus means in a manner emulating the memory means to
the second processor unit; and
second circuit means coupled to first circuit means to
receive and compare address and data signals produced by the
first processor unit to address and data signals produced by
the second processor unit to assert an error signal when a
miscompare is detected.

35. A method of operating first and second substantially
identical digital circuits to use the first digital circuit as
a check for proper operation of the second digital circuit,
the second digital circuit operating in response to a periodic
clock signal to receive data and to supply therefrom second
data in execution cycles measured by the periodic clock
signal, the method comprising the steps of:
Appeal No. 96-4106
Application No. 08/271,238
4
providing the data to the first digital circuit at least
one clock period after the data is supplied the second digital
circuit, whereby the first digital circuit operates to produce
first data from the data;
holding the second data from the second digital circuit;
and
then, comparing at least selected portions of the first
and second data to issue an error signal if the comparing is
not correct.
The references relied on by the examiner are:
Zieve et al. (Zieve) 3,810,119 May 7,
1974
McDonald et al. (McDonald) 4,358,823 Nov. 9,
1982
Claims 26 through 28 and 31 through 33 stand rejected
under 35 U.S.C. § 103 as being unpatentable over McDonald.
Claims 35 and 36 stand rejected under 35 U.S.C. § 103 as
being unpatentable over McDonald in view of Zieve.
Reference is made to the brief and the answer for the
respective positions of the appellants and the examiner.
OPINION
We have carefully considered the entire record before us,
and we will sustain the obviousness rejection of claims 26
through 28, and reverse the obviousness rejection of claims 31
through 33, 35 and 36.
Appeal No. 96-4106
Application No. 08/271,238
5
McDonald discloses a double redundant processor (Figure
1) that includes first and second master processors 50 and 64.
When the first master processor is in an active state for
processing signals, the second master processor is in a
standby state. Each of the master processors includes first
and second subprocessors 4 and 5 for simultaneously processing
data, control and address signals, and a comparator 6 for
comparing the output signals from the two subprocessors 4 and
5 (column 3, lines 7 through 22).
Appellants argue (Brief, page 8) that:
Claim 26, specifies a “first circuit means,
including second bus means, coupling the first bus
means to the second processor unit for communicating
to the second processor unit data signals from the
first bus means in a manner emulating the memory
means to the second processor uit.” (Claim 26,
lines 11-15). Applicants are unable to find
anything in McDonald et al. suggesting that data is
supplied to one of the CPUs 4, 5 (Fig. 1) or the
subprocessors 26, 29 (Fig. 4) indirectly, i.e., “in
a manner emulating” a memory. To the contrary, Fig.
1 shows the CPUs 4, 5 connected in parallel to the
memory 24 so that both CPUs 4, 5 receive the same
data at the same time. Subprocessors 26, 29 are
similarly corrected [sic, connected] and, this
direct connection of the CPUs 4, 5 used by McDonald
et al. is required, in light of the fact the CPUs 4,
5 are operated in “lock step.” (See McDonald et
al., column 1, lines 63-65.) In addition, claim 26
includes “second circuit means coupled to the first
circuit means to receive and compare address and
Appeal No. 96-4106
Application No. 08/271,238
6
data signals produced by the first processor unit to
address and data signals produced by the second
processor unit to assert an error signal when a
miscompare is detected.” (Claim 26, lines 16-20).
Again, the structure of the “second circuit means”
is not found in the lock-step design taught by
McDonald et al. ‘823.
Nothing in claim 26 requires data to be “indirectly”
supplied to the second processor means, or precludes “direct”
connection of the second processor to the memory.
Figure 4 of McDonald shows a first bus 7 coupling the
memory means 24 to the first subprocessor unit 26 for
communicating address and data signals therebetween, a first
circuit means in the form of a driver/receiver 30, including
second bus 15-1, coupling the first bus 7 to the second
subprocessor unit 29 for communicating to the second
subprocessor unit 29 data signals from the first bus means in
a manner emulating the memory means to the second subprocessor
unit. Appellants’ contentions to the contrary
notwithstanding, the “emulating” or imitation of one system
with another system does not require that the operation of the
imitating system lag the operation of the imitated system.
Appeal No. 96-4106
Application No. 08/271,238
Emulation is defined in the attached excerpts from the2
Encyclopedia of Computer Science, Ralston (Editor), pages 535,
925, 927 and 928 (New York, Van Nostrand Reinhold Company,
1976).
7
The act of emulation can occur in real time as in McDonald,2
or in lag time. In Figure 4 of McDonald, the second circuit
means includes the driver 44 and bus 10-4 (coupled to the
first circuit means via the first subprocessor unit 26),
address comparator 6-4 which receives the address signals on
bus 10-4, bus 11-4 which transfers address signals from the
second subprocessor unit 29 to the address comparator 6-4, bus
10-1 (coupled to the first circuit means via bus 15-1) to
transfer data signals from the first subprocessor unit 26 to a
data comparator 6-1, and a bus 11-1 which transfers data
signals from the second subprocessor unit 29 to the data
comparator 6-1. Any “miscompare” from the comparators 6-1 and
6-4 will cause error signals to be generated on outputs 51 and
58, respectively.
The obviousness rejection of claim 26 is sustained
because the contested limitations (i.e., the first and second
Appeal No. 96-4106
Application No. 08/271,238
Appellants have not relied on the 6th paragraph of 3
35 U.S.C. § 112 to distinguish the claimed invention over
McDonald, and have not rebutted the examiner’s finding of
equivalence (Answer, pages 8 and 9) between the claimed means
for “emulating” and the structure found in McDonald.
8
circuit means ) are found in the teachings of McDonald. In3
view of the grouping of the claims (Brief, pages 4 and 5), the
obviousness rejection of claims 27 and 28 is likewise
sustained.
Turning to claim 31, the lock-step operation in McDonald
precludes “temporarily holding each instruction of the
instruction stream before communicated to the second processor
unit.” Thus, the obviousness rejection of claims 31 through
33 is reversed because we agree with the appellants that
“McDonald et al. specifically teaches lock step operation of
pairs of CPUs,” and that “[t]his is not what claim 31
specifies” (Brief, page 9).
Claims 35 and 36 require that the data or instruction
words be provided to one digital circuit, and that the data or
instruction words be provided to another digital circuit “at
least one clock period after” or during “subsequent” clock
periods. The claimed lagging operation is opposite to the
Appeal No. 96-4106
Application No. 08/271,238
9
lock-step operation of the subprocessors in McDonald. Zieve
was cited by the examiner to show two processors “operating in
response to their independent clocks” (Answer, page 6).
Although Zieve is capable of inserting a special function “at
selected intervals to delay the lead processor until the other
catches up” (column 1, lines 58 through 62), this special
function is merely incidental to the simultaneous operation of
the two processors (column 1, lines 55 through 58). The
obviousness rejection of claims 35 and 36 is, therefore,
reversed because Zieve can not cure the shortcomings in the
teachings of McDonald.
DECISION
The decision of the examiner rejecting claims 26 through
28, 31 through 33, 35 and 36 under 35 U.S.C. § 103 is affirmed
as to claims 26 through 28, and is reversed as to claims 31
through 33, 35 and 36. Accordingly, the decision of the
examiner is affirmed-in-part.
Appeal No. 96-4106
Application No. 08/271,238
10
No time period for taking any subsequent action in
connection with this appeal may be extended under 37 CFR
§ 1.136(a).
AFFIRMED-IN-PART
KENNETH W. HAIRSTON )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
ERROL A. KRASS ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
LEE E. BARRETT )
Administrative Patent Judge )
Appeal No. 96-4106
Application No. 08/271,238
11
Townsend and Townsend and Crew
Two Embarcadero Center
Eighth Floor
San Francisco, CA 94111