[LAU] External USB 2 HD for real-time recording

[Ralf Mardorf]

On Sat, 2013-03-09 at 09:00 -0800, Len Ovens wrote:
> On Sat, March 9, 2013 4:30 am, Ralf Mardorf wrote:
> > This drive should be used as a backup media only, but I'm thinking to
> > buy an additional external hard drive for recording, to be able to visit
> > a Windows user (Mac became seldom here :), but to boot Linux from the
> > drive and to record on the drive.
> 
> Sounds like fun :)  now the amount of ram in an unknown system comes into
> play. Assuming you are taking a USB audio IF, then USB irqs have to be
> looked at before deciding where to put the IF, USB stick and drive (DVD
> might in this case be better than USB stick, though the USB sticks seem to
> be more reliable). I personally have not had any problems a USB drive
> being in a USB port that shares irqs while recording, but I can not say
> for sure that a write or read was forced while I was recording.

Yes, there are several weak points. I e.g. would set up an install using
the vesa driver. RAM today usually isn't an issue, but the sound card
will be a serious issue. I'm thinking of some musicians who don't use
the computer for music them self. Modern PCs with Windows 8 with some
integrated audio device.

I only want to be able to play at least a stereo track (a temporary mix
of a production with much more tracks) and to record some tracks with
microphones for drums. Perhaps it's needed to use a mixer and to record
a stereo mix, I guess onboard surround devices can't record more than
stereo, especially in duplex mode.

It would be easy to at least visit one friend living close to me,
perhaps 1 km away, disconnecting and carrying the tower would be too
much work, but taking an USB drive, it would be an easy and short walk
only.

For my mobo I noticed that the default USB slots don't share IRQs. When
I bought the USB drive I also bought a sheet with two USB slots, since
there are 3 double-sockets for 6 additional USB slots. I bought a sheet
with 2 single jacks, instead of one double-jack. When I tested all the 6
additional ports, I noticed that 2 are free and 4 do share IRQs, 4 ports
I usually unbind. Perhaps vendors of mobos take care that the ports that
are available by default, seldom cause IRQ issues? FWIW, the 2
additional ports I can use are provided by one double-socket, so there
was no need to buy the sheet with 2 individual jacks (missing the
polarity protection a double-jack has got).

There's the possibility to use 4 + 6 USB ports, but to avoid a shared
IRQ with the RME card, I only have 4 + 2 ports.
If vendors are smart, they always put the ports that share an IRQ to the
by default unused ports on the mobos.

Regards,
Ralf