(SOLVED) Flash Drive observation

[Ferdes Fides]

Observation:

When I run LXDE on a Kingston 16 GB flash drive there is almost
no discernable difference in operation from running  it on my
/dev/sda1 SSD.

When I run LXDE on the same model flash drive but only 8 GB capacity
a definite slowdown is observed.  

Speed tests on both are over 18 MB/second read speed.  

Is there a way to determine the drive cache size ?   Kingston spec sheet
doesn't give that info.   If the 16 GB has a 64k cache and the 8 GB
only has a 8k cache, I'd have to place my bet that's the reason.   I've
read where flash drive caches were small, but I can't find the info today
and I'm trying to find out the reason for this major difference in operation
performance.   The 16 GB's are running fine, even with KDE, but of course,
they cost twice as much.

THX

[djohnston]

lshw is just one possible way.

*-cache:1
             description: L2 cache
             physical id: 6
             slot: L2-Cache
             size: 512KiB
             capacity: 1MiB
             capabilities: pipeline-burst internal varies

[Ferdes Fides]

lshw is just one possible way.

*-cache:1
             description: L2 cache
             physical id: 6
             slot: L2-Cache
             size: 512KiB
             capacity: 1MiB
             capabilities: pipeline-burst internal varies

Hi,

I actually ran that program thru the systeminfo program but
that info wasn't there.   I'll try it again then, maybe I missed it.

THX

[djohnston]

lshw | less

so you can pause the output.

[AS]

lshw is just one possible way.

*-cache:1
             description: L2 cache
             physical id: 6
             slot: L2-Cache
             size: 512KiB
             capacity: 1MiB
             capabilities: pipeline-burst internal varies

lshw is actually listing only CPU(s) cache ... FF is searching info about USB flash drive cache ... 

[Ferdes Fides]

lshw is just one possible way.

*-cache:1
             description: L2 cache
             physical id: 6
             slot: L2-Cache
             size: 512KiB
             capacity: 1MiB
             capabilities: pipeline-burst internal varies

Hi,

I'm reading that info as CPU info.    Nothing in the
lshw output regarding the cache or buffers for USB's that
are attached.

FF

[djohnston]

Sorry. Didn't catch that. Yeah, the disk descriptions for the hard drives don't show the cache size.

[Ferdes Fides]

lshw is actually listing only CPU(s) cache ... FF is searching info about USB flash drive cache ... 

Hi,

What's the exact terminal command then.   I'm not
getting the right output with lshw -FF

Sorry,

Thanks a bunch.

[Just18]

lshw is actually listing only CPU(s) cache ... FF is searching info about USB flash drive cache ... 

Hi,

What's the exact terminal command then.   I'm not
getting the right output with lshw -FF

Sorry,

Thanks a bunch.

FF .......  is you    

...  an interesting observation about the speed of operation ......  looking forward to some indication of what is causing it 

[AS]

lshw is actually listing only CPU(s) cache ... FF is searching info about USB flash drive cache ... 

Hi,

What's the exact terminal command then.   I'm not
getting the right output with lshw -FF

Sorry,

Thanks a bunch.

LOL! 

my post was a direct reply to djohnstonpost, and I have used FF as a shorts of Ferdes Fides.

My apologies!

AS

[djohnston]

hdparm will give you the info. Run it as root or you'll get device permission errors. This is what I did to show the info on one of my drives:

#hdparm -I /dev/sdc | grep cache/buffer
cache/buffer size  = 16384 KBytes

hdparm -I /dev/sdc will show you everyhting on the drive you're checking. Substitute your USB drive's designation.

[AS]

hdparm will give you the info. Run it as root or you'll get device permission errors. This is what I did to show the info on one of my drives:

#hdparm -I /dev/sdc | grep cache/buffer
cache/buffer size  = 16384 KBytes

hdparm -I /dev/sdc will show you everyhting on the drive you're checking. Substitute your USB drive's designation.

Unfortunately hdparm doesn't appear to get the info when using my Kingston-G3 8GB:

# hdparm -I /dev/sdc

/dev/sdc:
SG_IO: bad/missing sense data, sb[]:  70 00 05 00 00 00 00 0a 00 00 00 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

ATA device, with non-removable media
Standards:
        Likely used: 1
Configuration:
        Logical         max     current
        cylinders       0       0
        heads           0       0
        sectors/track   0       0
        --
        Logical/Physical Sector size:           512 bytes
        device size with M = 1024*1024:           0 MBytes
        device size with M = 1000*1000:           0 MBytes
        cache/buffer size  = unknown
Capabilities:
        IORDY not likely
        Cannot perform double-word IO
        R/W multiple sector transfer: not supported
        DMA: not supported
        PIO: pio0

[Just18]

Code:

# hdparm -I /dev/sdm | grep cache/buffer
SG_IO: bad/missing sense data, sb[]:  f0 00 05 00 00 00 00 0a 00 00 00 00 26 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
        cache/buffer size  = unknown

[djohnston]

What a gyp! Just tried my thumb drive with same result. Does a USB flash drive have a cache chip? I'm beginning to wonder.

[Ferdes Fides]

What a gyp! Just tried my thumb drive with same result. Does a USB flash drive have a cache chip? I'm beginning to wonder.

Well I'll just keep drilling and searching a little
bit till I solve this cache question.  Only possible
factor causing the slower speed I can think of.
The larger flash's must have larger caches but
I need to prove it !   See if a google search
has something relevant now.

Thanks for the response(s)


Ferdes Fides