Re: Simple utility to measure disk random access time

[Bill Davidsen]

Linux Portal wrote:
> And a few graphs here: http://linux.inet.hr/how_fast_is_your_disk.html
>
> Comments welcome!

These results:

gaimboi:davidsen> ./da /dev/hdb
Seeker v2.0, 2007-01-15, http://linux.inet.hr/how_fast_is_your_disk.html
Benchmarking /dev/hdb [0MB], wait 30 seconds..............................
Results: 565841 seeks/second, 0.00 ms random access time
gaimboi:davidsen> ./da /dev/hda
Seeker v2.0, 2007-01-15, http://linux.inet.hr/how_fast_is_your_disk.html
Benchmarking /dev/hda [19092MB], wait 30 
seconds..............................
Results: 49 seeks/second, 20.20 ms random access time
gaimboi:davidsen> ./da /dev/hdc
Seeker v2.0, 2007-01-15, http://linux.inet.hr/how_fast_is_your_disk.html
Benchmarking /dev/hdc [57241MB], wait 30 
seconds..............................
Results: 64 seeks/second, 15.56 ms random access time


led to this patch:

RCS file: RCS/disk_access.c,v
retrieving revision 1.1
diff -r1.1 disk_access.c
67a68,72
>       if (numblocks <= 0) {
>               /* pretty small disk found here */
>               printf("Disk too small, size: %d blocks\n", numblocks);
>               exit(EXIT_FAILURE);
>       }
69a75
>

and this warning:

gaimboi:davidsen> ./da /dev/hdb
Seeker v2.0, 2007-01-15, http://linux.inet.hr/how_fast_is_your_disk.html
Disk too small, size: 0 blocks


--
bill davidsen <davidsen@xxxxxxx>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979
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