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

[Jonathan Stickel <jjstickel@myrealMAPSbox.com>]

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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