From: William Clodius <wclodius@lanl.gov>
Subject: Re: Fortran or Ada?
Date: 1998/09/30
Date: 1998-09-30T00:00:00+00:00 [thread overview]
Message-ID: <361241FC.2847@lanl.gov> (raw)
In-Reply-To: 19980929.214309.386@yktvmv.watson.ibm.com
jbs@yktvmv.watson.ibm.com wrote:
> <snip>
> The accident report indicates that they deliberately
> chose not to do it in this case because they were worried about
> performance. This would seem to indicate that turning off the
> error check is not cheap (in terms of performance).
> James B. Shearer
I repeat:
"For reasons of reliability computer systems on rockets and satellites
are implemented using processors that are several generations behind
commercial processors in performance. Also, there is always a tendency
to add features so that system utilization closely matches maximum
allowed utilization.
As a result every potential and unnecessary increase in processor load
is avoided however small. However, this was only one of several reasons
given for not protecting this value. Protecting this value (for the
Ariane 4) was viewed as unnecessary and dangerous. Quoting the report.
"The reason for the three remaining variables, including the one
denoting horizontal bias, being unprotected was that further reasoning
indicated that they were either physically limited or that there was a
large margin of safety, a reasoning which in the case of the variable BH
turned out to be faulty. It is important to note that the decision to
protect certain variables but not others was taken jointly by project
partners at several contractual levels."
--
William B. Clodius Phone: (505)-665-9370
Los Alamos Nat. Lab., NIS-2 FAX: (505)-667-3815
PO Box 1663, MS-C323 Group office: (505)-667-5776
Los Alamos, NM 87545 Email: wclodius@lanl.gov
next prev parent reply other threads:[~1998-09-30 0:00 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <36068E73.F0398C54@meca.polymtl.ca>
1998-09-22 0:00 ` Fortran or Ada? Gisle S{lensminde
1998-09-22 0:00 ` Jeff Templon
1998-09-22 0:00 ` Larry Kilgallen
1998-09-22 0:00 ` Corey Minyard
1998-09-22 0:00 ` dewarr
1998-09-23 0:00 ` Jeff Templon
1998-09-23 0:00 ` Corey Minyard
1998-09-24 0:00 ` Joel Seidman
1998-09-24 0:00 ` Craig Burley
1998-09-25 0:00 ` dewarr
1998-09-25 0:00 ` Jonathan Guthrie
1998-09-26 0:00 ` Craig Burley
1998-09-26 0:00 ` dewarr
1998-09-26 0:00 ` Robert B. Love
1998-09-26 0:00 ` Craig Burley
1998-09-24 0:00 ` Marc A. Criley
1998-09-24 0:00 ` Jeff Templon
1998-09-25 0:00 ` Dale Stanbrough
1998-09-30 0:00 ` Daniel Barker
1998-09-30 0:00 ` Lawrence Kirby
1998-10-01 0:00 ` Aaron Crane
1998-10-02 0:00 ` Fortran or Ada or gobbledygook? Wes Groleau
1998-10-05 0:00 ` Fortran or Ada? Terry Devine
1998-09-25 0:00 ` dewarr
1998-09-24 0:00 ` dewarr
1998-09-24 0:00 ` Robert I. Eachus
1998-09-24 0:00 ` William Clodius
1998-09-25 0:00 ` dewarr
1998-09-25 0:00 ` dewarr
1998-09-25 0:00 ` Robert I. Eachus
1998-09-25 0:00 ` dewarr
1998-09-25 0:00 ` jbs
1998-09-26 0:00 ` dewarr
1998-09-28 0:00 ` jbs
1998-09-29 0:00 ` Dean F. Sutherland
1998-09-29 0:00 ` William B. Clodius
1998-09-30 0:00 ` jbs
1998-09-30 0:00 ` dewarr
1998-09-30 0:00 ` jbs
1998-09-30 0:00 ` William Clodius
1998-09-30 0:00 ` William Clodius [this message]
1998-10-03 0:00 ` Niklas Holsti
1998-10-03 0:00 ` Toon Moene
1998-10-03 0:00 ` Niklas Holsti
1998-10-03 0:00 ` Toon Moene
1998-10-04 0:00 ` Niklas Holsti
1998-10-05 0:00 ` Michel OLAGNON
1998-10-05 0:00 ` Ian St. John
1998-10-05 0:00 ` dewarr
1998-10-05 0:00 ` Ian St. John
1998-10-06 0:00 ` dewarr
1998-10-06 0:00 ` Toon Moene
1998-10-06 0:00 ` Jonathan Guthrie
1998-10-06 0:00 ` Ian St. John
1998-10-08 0:00 ` Offtopic Airport Diversion (Was: Fortran or Ada?) Harold Stevens ** PLEASE SEE SIG **
1998-10-08 0:00 ` Ian St. John
1998-10-08 0:00 ` Fortran or Ada? Gary L. Scott
1998-10-06 0:00 ` James Giles
1998-10-06 0:00 ` Mark A Biggar
1998-10-06 0:00 ` James Giles
1998-10-07 0:00 ` dewarr
1998-10-07 0:00 ` dewarr
1998-10-05 0:00 ` Richard D Riehle
1998-10-05 0:00 ` dewarr
1998-10-06 0:00 ` Michel OLAGNON
1998-10-07 0:00 ` Ian St. John
1998-09-29 0:00 ` Dean F. Sutherland
1998-09-29 0:00 ` Gautier.DeMontmollin
1998-09-29 0:00 ` Dean F. Sutherland
1998-10-02 0:00 ` Geoff Bull
1998-10-02 0:00 ` Robert I. Eachus
1998-10-02 0:00 ` jbs
1998-10-02 0:00 ` William Clodius
1998-10-03 0:00 ` jbs
1998-10-03 0:00 ` Larry Elmore
1998-10-06 0:00 ` Robert I. Eachus
1998-10-06 0:00 ` Pat Rogers
[not found] ` <6udre0$ha1$1@nnrp1.dejane <6utg60$h6l$1@nnrp1.dejanews.com>
1998-10-01 0:00 ` robin_v
1998-09-22 0:00 ` Rakesh Malhotra
1998-09-23 0:00 ` Frank Ecke
1998-09-23 0:00 ` bglbv
1998-09-23 0:00 ` Robert I. Eachus
1998-09-24 0:00 ` Richard D Riehle
1998-09-23 0:00 Marin David Condic, 561.796.8997, M/S 731-96
1998-09-23 0:00 ` Gisle S{lensminde
1998-09-24 0:00 ` John McCabe
1998-09-24 0:00 ` Gisle S{lensminde
1998-09-24 0:00 ` Dean F. Sutherland
1998-09-24 0:00 ` Samuel T. Harris
-- strict thread matches above, loose matches on Subject: below --
1998-09-23 0:00 Marin David Condic, 561.796.8997, M/S 731-96
1998-09-24 0:00 Walt Brainerd
1998-09-25 0:00 ` dewarr
1998-09-25 0:00 ` Robert I. Eachus
1998-10-05 0:00 Robert I. Eachus
1998-10-05 0:00 robin
1998-10-05 0:00 Condic, Marin D.
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