> On Mar 11, 2015, at 6:53 PM, Paul Davis <[email protected]> wrote: > > robin reports back that your dd-tester gives: > > 41.1806 MB/sec write > 42.6064 MB/sec read > > (Western Digital 6400AAV - we can't find specs online) > > He also tried it formatted as FAT32, with essentially no change in the > results. >
Ok, this is enough information to calculate if your drive is performing within spec. Looking at the first example (block size 65536) From your test: $ ./run-readtest.sh -f 10 -d /Volumes/OSXext/disktest/ 65536 131072 4096000 # Building files for test... # Blocksize 65536 # Min: 8.9910 MB/sec Avg: 9.4645 MB/sec || Max: 0.890 sec # Max Track count: 51 @ 48000SPS # Sus Track count: 49 @ 48000SPS 65536 8.9910 9.4645 0.8898 0.00912 So: file size: 10485760 num files: 128 total bytes: 1342177280 seeks = 1342177280 / 65536 seeks: 20480 total_time: 270.484 Drive reports: 42.6064 MB/sec read (44676048 bytes/sec) Time required to stream 1342177280 bytes -> 30.04 seconds Blocksize 65536 Number of seeks 20480 Time taken: 270.484 seconds Time available for seeks: 270.484 - 30.04 = 240.444 seconds 240.444 / 20480 -> 11.74 ms seek time Out of 270 seconds it took to read the 1.25GB, the drive had to spend 240 seconds performing 20480 seeks, with an average seek time of 11.74 milliseconds. This drive seems to be performing well. Regards, Hamilton _______________________________________________ Do not post admin requests to the list. They will be ignored. Coreaudio-api mailing list ([email protected]) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/coreaudio-api/archive%40mail-archive.com This email sent to [email protected]
