Whow... After some trouble trying to compile it under libc5 (gave up on that one -
I'm on RH7.2), I ended up doing a static then strip against my libc6. That required
a little rming in tomsrtbt...
Anyway. Performance is now much improved, although not yet enough to keep
the HD busy on the old hardware I'm using. I'm getting about 300k/s, but the HD
could do probably about 3 times that (tried a few old machines). I guess there will
be a break-even point, as processors increase in speed much more than bus/hd -
so it should be OK on newer hardware - but on the stuff I'm running at the
moment, it's still a little slow.
If a faster version springs to mind, let me know. I'll try and see if I can compile
GNU's shred for tomsrtbt in the meantime. But I'm _not_ a C programmer (at all),
so I may not go very far...
Thanks ever so much, help much apreciated.
Yan
---- On 21 May 2002, at 15:32, [EMAIL PROTECTED] wrote: ----
> On Tue, 21 May 2002 [EMAIL PROTECTED] wrote:
>
> > Am I right then in thinking there's really no easy solution with Linux? (short of
> > leaving the dd running overnight, or mounting the HD in another (faster)
>machine...)
>
> There are kerjillions of easy ways of doing it with Linux :).
>
> You could write a simple program that uses standard library random
> function for generating random data. That should be way faster than
> /dev/*random as its should have a rather plainforward implementation.
>
> Then you can direct its output to /dev/hda or use dd if you wish.
>
> More than 5,6 megabytes under 3 seconds with the following:
> --------------------------------------------------------
> #include <stdlib.h>
> #include <stdio.h>
> #include <errno.h>
>
> int main(int argc, char *argv[]){
> int seed;
> if (argc != 2){
> printf ("Usage: %s [seed], "
> "where seed can be any integer.\n", argv[0]);
> exit (1);
> }
> errno=0;
> if ((seed = atol(argv[1])) && !errno)
> srand(seed);
> else {
> printf ("Error: %s: %s\n", argv[1],
> errno ? "Numerical result out of range." : "Not a number.");
> exit (2);
> }
> while (1) printf("%d",rand());
> }
>
> Compile it with
> gcc -o rand rand.c
> and strip symbols with
> strip -s rand
> and you'll get a 3kB binary that should fit into tomsrtbt easily.
>
> Usage:
> rand 12347 | dd of=/dev/hda
> or
> rand 12347 > /dev/hda
>
>
> Drop me a note if you need a smaller or faster version -- printf is
> overhead, using library rand() is also overhead. I guess it can be done
> under 1 kB and considerably faster than with stdlib rand(), as the latter
> uses long integers.
>
> Regards,
> m
>
--
Yan Fitterer
IT Manager, Royal Academy of Music
E-mail : [EMAIL PROTECTED]
Marylebone Rd, London, NW1 5HT
Phone (+44) 20 7873 7365 Fax (+44) 20 7873 7364
