On Mon, May 14, 2007 at 10:02:59PM +0200, Gert Brinkmann wrote: > Gert Brinkmann wrote: > > > hard disc is connected to an USB2 controller. The Problem: data transfer > > is very slow. It makes approx. 1 MByte/s only, but it should be more > > than 20 MByte/s. The hard disc is formatted as ext3fs and is mounted as
IDE drives connected through a USB2/IDE translator may have problems. Gert's question encouraged me to to my own experiments. I have been using IDE hotswap with a customized 2.4.22 linux kernel. IDE hotswap is no longer in the kernel, so I have been experimenting with USB2 hotswap on a 2.6.18 kernel (Scientific Linux 5, an RHEL5 clone). My experiment does multiple passes of filling and emptying a 422GB ext3 partition on a 500GB Seagate Barracuda 7200.9 PATA-100 drive. The computer is a 1.7GHz P4 with 1GB of RAM, using a no-name-chinese 3 port USB controller with a VIA Technologies VT6202 (date code 0301) USB2 interface chip. I wrote a little C program to write 100MB files, which sits in a shell script that does this 4300 times, reporting timing. I tried a bunch of different USB2 to IDE translators. Here are the results, from awful to OK: --------------------------------------------------------------------- 0) "Control" - direct IDE connection to Promise Ultra133TX2 PCI controller with PDC20269 controller (date code 0409). Results: Wrote 430GB at 30.6MB/sec (4 hrs), as fast as it gets. 1) No-name-chinese, USB to IDE smart cable. 2005 swap meet. Claimed Linux compatability. Genesys GL811E bridge chip . Results: Doesn't even register with "lsusb". Doorstop, probably a defective individual unit. 2) SanMax/inClose USB2DOCK swap cage . 2003 Fry's Electronics. Cypress C768013 chip, 0304 date code. With a 2.4.22 kernel this locked up after an hour or so. 2.6.18 Results: locks up immediately 3) No-name-chinese, USB to IDE smart cable. May 2007 PCCLUB. Looks like the picture of a SABRENT device at Tiger Direct. Cypress AT2LP Demo RC17 chip according to lsusb -vv . Results: Worked for a while, moved 60GB in about an hour (16.7MB/s), then hung and locked up the kernel. 4) ViPower VP-1028LSF swap cage. 2003.03.17 design. 2004 purch. Genesys GL811USB chip, there are multiple versions :-( Results: Wrote 233GB at 11.0MB/sec (6 hrs), slow. 5) UltraSum TZ350B2 external enclosure. 2004 Local computer store. Myson Century CS88136-103 chip, 0410 date code. Bypassed wimpy power supply. Results: Wrote 430GB at 17.0MB/sec (7 hrs), tolerable. 6) ViPower VP-1028LSF swap cage. 2003.07.04 design. 2006 purch. Cypress C768300A chip 0404, there are multiple versions :-( Results: Wrote 430GB at 19.6MB/sec (6 hrs), tolerable. -------------------------------------------------------------------- As you can see, a random sampling of USB2 drives and enclosures revealed scattered results, from broken to flaky to slow to tolerable. All of the drives are slow, compared to the 48MB/sec one might expect for a 480MB USB2 bus or thw 30MB/sec of a direct IDE connection. Perhaps handshaking and such slows USB to IDE connections down a lot. This will be on the wiki: http://wiki.dirvish.org/index.cgi?USB2drives Feel free to add to it. I am especially interested in USB2 to IDE smart cables, cheap/fast/good . Keith -- Keith Lofstrom [EMAIL PROTECTED] Voice (503)-520-1993 KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon" Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs _______________________________________________ Dirvish mailing list [email protected] http://www.dirvish.org/mailman/listinfo/dirvish
