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Re: [vox-tech] PCMCIA USB2 (was: backing up DVDs)
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Re: [vox-tech] PCMCIA USB2 (was: backing up DVDs)



David Margolis wrote:
Jonathan,

I'd like to know more about this card.  I've seen USB 2.0 PC-Cards at the
various computer stores and always wanted to look into that for my laptop
I have an external CD-burner that works well (but slow) in my ThinkPad's
regular USB port.

If you don't mind and have time:

1. Which PC-Card USB 2.0 adapter did you get?
I got the cheapest one available at Fry's at the time. It is some no-name generic. Literally, I checked and there is no manufacture's name anywhere on the card! Technically, it is a CardBus, not PCMCIA. Also, it requires it's own power via an ac-adapter or PS/2 cable. It came with both, and power from the PS/2 worked just fine. I read that this is typical with these cards.

2. Run me through the basic setup (what module, config, etc.)
I had to download and install the card manager tools available through http://pcmcia-cs.sourceforge.net/ . I think this also checks for, and installs if necessary, the required kernel modules. It comes with decent documentation. With my RH9 install, I then plugged in the card and the USB2 DVDRW, which was automatically detected and assigned to /dev/scd1. If connected on bootup, kudzu even wrote an appropriate line in my fstab for the DVDRW.

3. What was the _work around_ you mentioned?
The problem was when I stopped or ejected the card, although I was able disconnect the USB2 device ok. Doing so caused a complete system hang (MSysRQ to the rescue!) Shutting down essentially stops the card as well, causing the same hang, so I couldn't even reboot with the card still plugged in. The solution was to manually remove the USB kernel drivers first, as I discovered from reading http://www.linux-usb.org/usb2.html . Specifically, I use

$/sbin/rmmod ehci-hcd usb-ohci
$/sbin/cardctl eject

I am using a 2.4.20 kernel. This might be fixed in the 2.5 kernel.

4. Any way to test the throughput that you know of?
Technically, no. But I used a USB2 harddrive in my USB1.1 plug, and it had noticeably slow read/write. With the hd in the USB2 cardbus, it was clearly much faster, seemingly as fast as my internal hd.

Hope this helps.

Jonathan


Dave Margolis

On Tue, 16 Sep 2003, Jonathan Stickel wrote:


I actually used an external DVD+/-RW drive (and an external HD)
connected to my laptop through a PMCMCIA USB2.0 card.  As far as I could
tell, no problems with byte transfer there at all, after I got it all
setup.  My 2.4.20 kernel liked to crash when I ejected the card, though,
but I found a work-a-round.

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