[clug] OT - USB flash timings

Robert Edwards bob at cs.anu.edu.au
Mon Jun 18 00:05:47 GMT 2007


Hi Steve,

Can you tell us what your actual testing methodology was? Were you using
dd to a raw device, or something else to copy to a filesystem - which
one (assuming DOS/VFAT, but can you confirm)?

Cheers,

Bob Edwards.

steve jenkin wrote:
> I got a question from a cousin about his new USB flash taking an age to
> copy something...
> Thought the group might be interested...
> 
> Seems standard devices are very sensitive to block size on *write* - but
> not on read...
> 
> For some good reference material: Wikipedia and Kingston:-
> 
> <http://www.kingston.com/products/pdf_files/FlashMemGuide.pdf>
> <http://en.wikipedia.org/wiki/Flash_Memory>
> 
> 
> Device used for these tests: 4Gb Kingston 'Data Traveller'.
> 512Mb file used for most timings (1Mb for 1b test).  No FileSystem Cache
> issues.
> 
>> USB Flash - WRITE performance
>>    1b    88,827 bytes/sec
>>    8k 1,035,601 bytes/sec
>>  128k 3,819,827 bytes/sec
>>  512k 4,155,635 bytes/sec
>>
>> USB Flash - READ performance
>>    8k 9,467,708 bytes/sec
>>   16k 9,448,265 bytes/sec
>>   32k 9,386,199 bytes/sec
>>   64k 9,475,763 bytes/sec
>>  128k 9,466,469 bytes/sec
>>  256k 9,453,077 bytes/sec
>>  512k 9,415,421 bytes/sec
>> 1024k 9,482,868 bytes/sec
> Hope this is interesting/helpful.
> 
> regards
> stevej
> 



More information about the linux mailing list