From: ok@goanna.cs.rmit.edu.au (Richard A. O'Keefe)
Subject: Re: Ariane 5 failure
Date: 1996/10/03
Date: 1996-10-03T00:00:00+00:00 [thread overview]
Message-ID: <52vaj6$nh@goanna.cs.rmit.edu.au> (raw)
In-Reply-To: 52p49m$kug@beyond-software.com
"Wayne L. Beavers" <wayneb@beyond-software.com> writes:
>I have been reading this thread awhile and one topic that I have not
>seen mentioned is protecting the code area from damage.
I imagine that everyone else has taken this for granted.
UNIX compilers have been doing it for years, and so I believe have VMS ones.
>When I code in PL/I or any other reentrant language I always make sure
>that the executable code is executing from read-only storage.
(a) This is not something that the programmer should normally have to be
concerned with, it just happens.
(b) It cannot always be done. Run-time code generation is a practical and
important technique. (Making a page read-only after new code has been
written to it is a good idea, of course.)
>There is no way to put the data areas in read-only storage (obviously)
It may be obvious, but in important cases it isn't true.
UNIX (and I believe VMS) compilers have for years had the ability to put
_selected_ data in read-only storage. And of course it is perfectly
feasible in many operating systems (certainly UNIX and VMS) to write data
into a page and then ask the operating system to make that page read-only.
>but I can't think of any reason to put the executable code in writeable
>storage.
Run-time binary translation. Some approaches to relocation. How many
reasons do you want?
>I one had to port 8,000 subroutines in PL/I, 24 megabytes of executable
>code from one system to another.
In a language where the last revision of the standard was 1976?
You have my deepest sympathy.
--
Australian citizen since 14 August 1996. *Now* I can vote the xxxs out!
Richard A. O'Keefe; http://www.cs.rmit.edu.au/%7Eok; RMIT Comp.Sci.
next prev parent reply other threads:[~1996-10-03 0:00 UTC|newest]
Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <agrapsDy4oJH.29G@netcom.com>
1996-09-25 0:00 ` Ariane 5 failure @@ robin
1996-09-25 0:00 ` Michel OLAGNON
1996-09-25 0:00 ` Chris Morgan
1996-09-25 0:00 ` Byron Kauffman
1996-09-25 0:00 ` A. Grant
1996-09-25 0:00 ` Ken Garlington
1996-09-26 0:00 ` Byron Kauffman
1996-09-27 0:00 ` A. Grant
1996-09-26 0:00 ` Sandy McPherson
1996-09-25 0:00 ` Bob Kitzberger
1996-09-26 0:00 ` Ronald Kunne
1996-09-26 0:00 ` Matthew Heaney
1996-09-27 0:00 ` Wayne Hayes
1996-09-27 0:00 ` Richard Pattis
1996-09-29 0:00 ` Chris McKnight
1996-09-29 0:00 ` Real-world education (was: Ariane 5 failure) Michael Feldman
1996-09-29 0:00 ` Ariane 5 failure Dann Corbit
1996-09-29 0:00 ` Alan Brain
1996-10-01 0:00 ` Ken Garlington
1996-09-27 0:00 ` Ronald Kunne
1996-09-27 0:00 ` Lawrence Foard
1996-10-04 0:00 ` @@ robin
1996-09-28 0:00 ` Ken Garlington
1996-09-28 0:00 ` Ken Garlington
1996-09-29 0:00 ` Alan Brain
1996-09-29 0:00 ` Robert A Duff
1996-09-30 0:00 ` Wayne L. Beavers
1996-10-01 0:00 ` Ken Garlington
1996-10-01 0:00 ` Wayne L. Beavers
1996-10-01 0:00 ` Ken Garlington
1996-10-02 0:00 ` Sandy McPherson
1996-10-03 0:00 ` Richard A. O'Keefe [this message]
1996-10-01 0:00 ` Ken Garlington
1996-09-28 0:00 ` Ken Garlington
1996-09-27 0:00 ` Ken Garlington
1996-09-27 0:00 ` Alan Brain
1996-09-28 0:00 ` Ken Garlington
1996-09-29 0:00 ` Louis K. Scheffer
1996-09-27 0:00 ` John McCabe
1996-10-01 0:00 ` Michael Dworetsky
1996-10-04 0:00 ` Steve Bell
1996-10-07 0:00 ` Ken Garlington
1996-10-09 0:00 ` @@ robin
1996-10-09 0:00 ` Steve O'Neill
1996-10-12 0:00 ` Alan Brain
1996-10-04 0:00 ` @@ robin
1996-10-04 0:00 ` Joseph C Williams
1996-10-06 0:00 ` Wayne Hayes
1996-10-04 0:00 ` Michel OLAGNON
1996-10-09 0:00 ` @@ robin
1996-10-17 0:00 ` Ralf Tilch
1996-10-17 0:00 ` Ravi Sundaram
1996-10-22 0:00 ` shmuel
1996-10-22 0:00 ` Jim Carr
1996-10-24 0:00 ` hayim
1996-10-25 0:00 ` Ken Garlington
1996-10-25 0:00 ` Michel OLAGNON
1996-10-01 0:00 Marin David Condic, 407.796.8997, M/S 731-93
1996-10-02 0:00 ` Matthew Heaney
1996-10-04 0:00 ` Ken Garlington
1996-10-05 0:00 ` Robert Dewar
1996-10-06 0:00 ` Keith Thompson
1996-10-10 0:00 ` Ken Garlington
1996-10-14 0:00 ` Matthew Heaney
1996-10-15 0:00 ` Robert Dewar
1996-10-16 0:00 ` Ken Garlington
1996-10-18 0:00 ` Keith Thompson
1996-10-18 0:00 ` Ken Garlington
1996-10-18 0:00 ` Samuel T. Harris
1996-10-21 0:00 ` Ken Garlington
1996-10-23 0:00 ` robin
1996-10-02 0:00 ` Robert I. Eachus
1996-10-02 0:00 ` Ken Garlington
-- strict thread matches above, loose matches on Subject: below --
1996-10-01 0:00 Marin David Condic, 407.796.8997, M/S 731-93
1996-10-02 0:00 ` Ken Garlington
1996-10-01 0:00 Marin David Condic, 407.796.8997, M/S 731-93
1996-10-02 0:00 ` Alan Brain
1996-10-02 0:00 ` Ken Garlington
1996-10-02 0:00 ` Matthew Heaney
1996-10-04 0:00 ` Robert S. White
1996-10-05 0:00 ` Alan Brain
1996-10-06 0:00 ` Robert S. White
1996-10-05 0:00 ` Robert Dewar
1996-10-03 0:00 ` Alan Brain
1996-10-04 0:00 ` Ken Garlington
1996-10-03 0:00 Marin David Condic, 407.796.8997, M/S 731-93
1996-10-03 0:00 Marin David Condic, 407.796.8997, M/S 731-93
1996-10-03 0:00 Marin David Condic, 407.796.8997, M/S 731-93
1996-10-14 0:00 Marin David Condic, 407.796.8997, M/S 731-93
1996-10-15 0:00 ` Robert I. Eachus
1996-10-15 0:00 ` Robert Dewar
1996-10-16 0:00 ` Michael F Brenner
1996-10-16 0:00 ` Robert Dewar
1996-10-23 0:00 ` robin
1996-10-16 0:00 Marin David Condic, 407.796.8997, M/S 731-93
1996-10-18 0:00 ` Ken Garlington
1996-10-19 0:00 ` Frank Manning
1996-10-21 0:00 ` Norman H. Cohen
1996-10-21 0:00 Marin David Condic, 407.796.8997, M/S 731-93
1996-10-22 0:00 ` Adam Beneschan
1996-10-28 0:00 Marin David Condic, 561.796.8997, M/S 731-93
1996-10-28 0:00 Marin David Condic, 561.796.8997, M/S 731-93
1996-10-29 0:00 ` Ken Garlington
1996-11-08 0:00 ` robin
1996-10-31 0:00 Marin David Condic, 561.796.8997, M/S 731-93
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