From: kilgallen@eisner.decus.org (Larry Kilgallen)
Subject: Re: CRC in Ada?
Date: 1997/03/05
Date: 1997-03-05T00:00:00+00:00 [thread overview]
Message-ID: <1997Mar5.083233.1@eisner> (raw)
In-Reply-To: 331d3cf9.1190126@news.logica.co.uk
In article <331d3cf9.1190126@news.logica.co.uk>, garriga@logica.com (Stephen Garriga) writes:
> I was using a DEC Alpha, DEC Ada (83) and OS/F 3.2c!
> I didn't the time to investigate too closely, but it looked to me
> that, in my case, the I/O was actually implemented as many layers of
> generics on top of the low level OS call then specific instantiations.
> This remained in place at run time so instead of generating a single
> stack frame/procedure call, dozens were done per read!
> Efficiency was weighted over design purity and several such problems
> were addressed with small C procedures interfaced to our Ada.
If I were looking for maximum speed in Assembly Language, I would
minimize the total number of reads done, to a single read if possible.
This should be true for any language.
On VMS, the fact that C programs imported from Unix tend to do a
lot of single character I/O has forced the DEC C team to build in
many little tricks to support an inherently inefficient programming
technique.
For Ada, I would guess that implementors have not counted on
people using C-like programming constructs (vs. doing large
buffer reads as suggested earlier in this thread).
It is certainly possible to build an Ada environment optimized for
single-character reads, but that would not seem to be a priority
for most Ada compiler customers.
Larry Kilgallen
next prev parent reply other threads:[~1997-03-05 0:00 UTC|newest]
Thread overview: 143+ messages / expand[flat|nested] mbox.gz Atom feed top
1997-03-02 0:00 CRC in Ada? Dr. John B. Matthews
1997-03-03 0:00 ` Tom Moran
1997-03-03 0:00 ` David Brown
1997-03-04 0:00 ` David L Brown
1997-03-04 0:00 ` Robert Dewar
1997-03-05 0:00 ` Stephen Garriga
1997-03-05 0:00 ` Larry Kilgallen [this message]
1997-03-05 0:00 ` Robert A Duff
1997-03-05 0:00 ` Larry Kilgallen
1997-03-06 0:00 ` Fergus Henderson
1997-03-06 0:00 ` Robert Dewar
1997-03-06 0:00 ` Larry Kilgallen
1997-03-06 0:00 ` Robert A Duff
1997-03-07 0:00 ` Larry Kilgallen
1997-03-07 0:00 ` Tom Moran
[not found] ` <1997Mar7.202252.1@eisner>
1997-03-08 0:00 ` Robert Dewar
1997-03-09 0:00 ` Geert Bosch
1997-03-11 0:00 ` Robert Dewar
1997-03-12 0:00 ` Mats Weber
1997-03-12 0:00 ` Robert Dewar
1997-03-10 0:00 ` Robert Dewar
1997-03-10 0:00 ` Tom Moran
1997-03-12 0:00 ` Robert Dewar
1997-03-10 0:00 ` Dr. John B. Matthews
1997-03-07 0:00 ` Robert A Duff
1997-03-10 0:00 ` Jim Balter
1997-03-07 0:00 ` Robert Dewar
1997-03-10 0:00 ` Jim Balter
1997-03-06 0:00 ` Robert A Duff
1997-03-06 0:00 ` Larry Kilgallen
1997-03-06 0:00 ` Robert Dewar
1997-03-06 0:00 ` Robert Dewar
1997-03-09 0:00 ` Dr. John B. Matthews
1997-03-06 0:00 ` Robert Dewar
1997-03-10 0:00 ` Tarjei Jensen
1997-03-10 0:00 ` Robert Dewar
1997-03-10 0:00 ` Robert Dewar
1997-03-10 0:00 ` Graham Hughes
1997-03-11 0:00 ` Robert Dewar
1997-03-11 0:00 ` Graham Hughes
1997-03-12 0:00 ` Robert Dewar
1997-03-10 0:00 ` David Brown
1997-03-12 0:00 ` Robert Dewar
1997-03-11 0:00 ` Mark & Zurima McKinney
1997-03-12 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-12 0:00 ` Robert I. Eachus
1997-03-13 0:00 ` Jon S Anthony
1997-03-13 0:00 ` Robert Dewar
1997-03-14 0:00 ` Jim Balter
1997-03-14 0:00 ` Jon S Anthony
1997-03-15 0:00 ` Robert Dewar
1997-03-15 0:00 ` Dr. John B. Matthews
1997-03-17 0:00 ` Jon S Anthony
1997-03-06 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-07 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-07 0:00 ` Robert Dewar
1997-03-08 0:00 ` Robert A Duff
1997-03-10 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-11 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-12 0:00 ` Jim Balter
1997-03-14 0:00 ` Richard A. O'Keefe
1997-03-14 0:00 ` Jim Balter
1997-03-06 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-06 0:00 ` Graham Hughes
1997-03-06 0:00 ` Robert Dewar
1997-03-06 0:00 ` Larry Kilgallen
1997-03-09 0:00 ` Robert Dewar
1997-03-07 0:00 ` David Brown
1997-03-07 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-07 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-07 0:00 ` Robert Dewar
1997-03-08 0:00 ` Fergus Henderson
1997-03-10 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-11 0:00 ` Jim Balter
1997-03-12 0:00 ` Robert Dewar
1997-03-12 0:00 ` Jim Balter
1997-03-14 0:00 ` Samuel Mize
1997-03-11 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-12 0:00 ` Jim Balter
1997-03-10 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-10 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-10 0:00 ` Robert Dewar
1997-03-10 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-11 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-12 0:00 ` Jim Balter
1997-03-11 0:00 ` Fergus Henderson
1997-03-11 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-12 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-12 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-12 0:00 ` Jim Balter
1997-03-04 0:00 ` Stephen Garriga
1997-03-04 0:00 ` Robert Dewar
1997-03-05 0:00 ` Stephen Garriga
1997-03-15 0:00 ` Michael & Amy Hartsough
1997-03-16 0:00 ` Robert Dewar
1997-03-16 0:00 ` Michael & Amy Hartsough
1997-03-16 0:00 ` Robert Dewar
1997-03-18 0:00 ` Michael & Amy Hartsough
1997-03-19 0:00 ` Robert Dewar
1997-03-20 0:00 ` Michael & Amy Hartsough
1997-03-22 0:00 ` Mark & Zurima McKinney
1997-03-22 0:00 ` Robert Dewar
1997-03-22 0:00 ` Robert Dewar
1997-03-24 0:00 ` Sequential IO on OpenVMS (was: CRC in Ada?) Ken Garlington
1997-03-24 0:00 ` Larry Kilgallen
1997-03-21 0:00 ` CRC in Ada? Tom Moran
1997-03-23 0:00 ` Robert Dewar
1997-03-23 0:00 ` Tom Moran
1997-03-24 0:00 ` Portable Code (was: CRC in Ada?) Larry Kilgallen
1997-03-24 0:00 ` CRC in Ada? Robert A Duff
1997-03-24 0:00 ` Robert Dewar
1997-03-24 0:00 ` Robert A Duff
1997-03-24 0:00 ` Larry Kilgallen
1997-03-24 0:00 ` Robert A Duff
1997-03-25 0:00 ` Robert I. Eachus
1997-04-01 0:00 ` David Emery
1997-03-04 0:00 ` Tom Moran
1997-03-04 0:00 ` Stephen Garriga
1997-03-04 0:00 ` Matthew Heaney
1997-03-07 0:00 ` John Apa
1997-03-04 0:00 ` Jon S Anthony
1997-03-05 0:00 ` Robert Dewar
1997-03-05 0:00 ` Laurent Pautet
1997-03-05 0:00 ` David C. Hoos, Sr.
1997-03-06 0:00 ` Jon S Anthony
2013-11-14 17:39 ` david
2013-11-14 18:55 ` Adam Beneschan
2013-11-14 19:35 ` tmoran
2013-11-14 20:09 ` Dmitry A. Kazakov
2013-11-14 20:40 ` John B. Matthews
-- strict thread matches above, loose matches on Subject: below --
1997-03-13 0:00 tmoran
1997-03-13 0:00 ` Robert Dewar
1997-03-14 0:00 ` Tom Moran
1997-03-14 0:00 ` Joakim Olsson
1997-03-15 0:00 ` Tom Moran
1997-03-14 0:00 ` Richard A. O'Keefe
1997-03-14 0:00 ` Jon S Anthony
replies disabled
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox