On Mon, 5 Mar 2007, Jamie Lists wrote:

Date: Mon, 5 Mar 2007 11:21:35 -0800 From: Jamie Lists jamielist@gmail.com Reply-To: CentOS mailing list centos@centos.org To: centos@centos.org Subject: [CentOS] USB 2 card

Were looking to hook up a Lacie 2TB external drive to be our little rdiff-backup volume and we need a usb 2 interface.

Can anyone make a suggestion to a good USB2 PCI card for centos?

I tried to add usb 2.0 card to my old, PIII, i440BX system. [which is Fedora Core 6 rather then Centos, but I do not think this could make any difference here. If you want, I could test with Centos 4.4 Live CD, or install Centos 4.4] My first try was an EDIMAX card with VIA6212L chip. I wasn't able to get it to work as USB 2.0 acceptably with any sane meaning of 'acceptable' on my system.

With the VIA based card I could work only with USB 1.1, using USB 2.0 produced immediately lots of messages like that

reset high speed USB device USB disconnect sd 0:0:0:0: SCSI error: return code = YYYYYY end_request: I/O error, dev sda, sector ZZZZZ Buffer I/O error on device sda, logical block XXXX

and of course card was useless.

Then I searched Google, and saw some comments that one should avoid Via and Ali chips, and use NEC-based cards.

I bought i-tec USB card, and it worked flawlessly (at least with separate IRQ for EHCI, I disabled Parallel port in BIOS, which I did not need, so that EHCI got IRQ 7; I did that when trying to get via card with VIA chipset working)

The card is described (in Polish) at http://www.i-tec.pl/index.php?lang=pl&pid=2&kid=9&id=PCUSB20 and (in Czech) at http://www.i-tec.cz/index.php?lang=cz&pid=2&kid=9&id=PCUSB20

According to the description the chip is NEC D720100 or D720101.

I have moved several hundreds of GB with that card using external USB/ATAPI converter and ATAPI hard disk (and a few GB with external USB DVD/RW drive) and had no problems.

The transfer rate for hard disk I got was 15-20 MB/s, while identical internal disk with ATA/100 interface get 25-30 MB/s.

I read that 20 MB/s is close to maximal data rate one can get in USB/2 (that 480 Mbit/s seems to be a rather misleading advertising ).

You need to assess, whether about 20MB/s will be enough for your needs.

You could get some faster datarates with FireWire, but I have no experiences with that.

[NOTE. It is quite possible, that VIA card would work better on system with more current PCI implementation; dmesg on my systems says PCI: PCI BIOS revision 2.10 entry at 0xfb520, last bus=1

which, I can guess, would mean it is PCI 2.1 rather then 2.2 ]

Thanks, James

Could you possibly share with us your experiences?

Good luck,

Wojtek