[LAU] USB, realtime, practical considerations

Hi Folks

Whilst my 2.6.24.7-rt17 kernel and disabling all hardware and services
unneeded for audio seems to have gotten rid of those nasty xruns, I live
in fear that they will return. My main worry is how I organise my USB
devices.

My laptop (ThinkPad Z61m) has 3 USB ports. I have several devices that
need to be connected to them, meaning that I need to use USB hubs.

Here are some assumptions (or guesses) that I have made, on which I
would appreciate comment:

* It would be best to balance the devices across the 3 ports.

* My soundcard is a Behringer UCA202, capable of sampling at a maximum
of 48kHz @ 16bits x 2 channels. I'm guessing that this will have the
greatest data rate of all attached devices.
  - Should it have its own port?
  - Can USB 2.0 take more than this (like another device?)
  - Anyone know how to set the sampling rate on this device through
    Linux? Just specify in Jack setup?

* Now that I know that I can run USB to MIDI devices through a powered
hub (thanks David), I was thinking of of hooking the following into a
7-port hub:
  - iPod cable (no iPod on the end, so no burden.)
  - cellphone cable (as per iPod cable.)
  - external USB QWERTY keyboard (don't have desk space for this
    when doing audio work, so hope it won't be transmitting any
    data.)
  - trackball (only transmitting when wiggled (I hope) - which should
    not occur when recording is going on.)
  - USB floppy drive (not in use when recording.)
  - USB to MIDI interface
  - Another USB to MIDI interface - is it too much to have 2 of
    these on the same hub? If not, would it take a third?

Cheers

M

-- 
Matthew Smith
Smiffytech - Technology Consulting & Web Application Development
Business: http://www.smiffytech.com/
Personal: http://www.smiffysplace.com/
LinkedIn: http://www.linkedin.com/in/smiffy
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user