Interesting stats Kay. I have a feeling that not all USB memory sticks are equal either. The no-name ones we give out to students (8 GB) are relatively cheap and definitely don't perform as well as a couple of name brand sticks I have lying around.
I don't think we even get close to 11 MB/s out of these cheapies. Terry... On 26/04/2012, at 6:59 PM, "Kay C Lan" <lan.kc.macm...@gmail.com> wrote: > Hi Terry, > > Strange you should raise this as I was just wondering myself why SD cards > are so slow when they have no mechanical parts. You don't mention if the HD > you were using was internal or external, but on my own system I get the > following benchmarks: > > Internal HD - 99 MB/s > External eSATA (via cardbus adapter) - 81 MB/s > External FW800 - 58 MB/s > Exernal FW400 - 32 MB/s * > External USB 2.0 - 26 MB/s * > SD Card (via card bus adaptor) - 11 MB/s > > * same HD, same enclosure, dual port. > > I've seen a youTube video (so it must be true;-) which showed a benchtest > between a USB stick and an SD card and the USB stick was about 1 MB/s > slower. I don't have a usb stick to benchtest, but because of the video, > when I bought my last SD card it was the fasted I could find - they have a > speed rating which I can't recall right now. > > The above is not accurate because to be a true test of bus interface speed > the HD should be the same, and in this case I've used 3 different HDs, 1 x > Internal, 1 x eSATA & FW800, and the last one in a dual port enclosure. > > I believe though that it gives a ball park figure of what you can expect, > and so anacdotally a USB stick is about 10 times slower than an internal > HD. This doesn't fully explain your performance drop, but I believe it > explains a good portion of it. > > It also explains why downloading photos off the SD card takes soooooo > loooooonnnnggggggggg...... > > I still don't understand why though.... there are no moving parts? > > On Thu, Apr 26, 2012 at 9:57 AM, Terry Judd <terry.j...@unimelb.edu.au>wrote: > >> We're finding that it's very slow to write even small amounts of data from >> Livecode to a sqlite file when the Livecode app and the db file are on a >> usb stick (the db stores a local copy of the user's messages as they are >> downloaded from a server). It seems to be something that is peculiar to the >> usb setup as it works very quickly when run from a hard drive (less that 1 >> second for 40 messages vs 20-30 seconds on the usb stick). Has anyone >> experienced anything similar and/or does anyone have any suggestions as to >> how we might speed the process up? >> >> I'm currently downloading the messages (as xml), converting them to an >> array (from, to, subject, body, attachments etc.) and then writing each to >> the sqlite db within a repeat loop and then closing the db connection. >> >> Terry... >> >> _______________________________________________ >> use-livecode mailing list >> use-livecode@lists.runrev.com >> Please visit this url to subscribe, unsubscribe and manage your >> subscription preferences: >> http://lists.runrev.com/mailman/listinfo/use-livecode >> > _______________________________________________ > use-livecode mailing list > use-livecode@lists.runrev.com > Please visit this url to subscribe, unsubscribe and manage your subscription > preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode > _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
