[time-nuts] Prologix GPIB/USB converter help...

[Christopher Hoover]

"Tom Van Baak" <tvb at LeapSecond.com> wrote:
> If a device is USB-only you pretty much have to just plug it
> into a wintel PC, install their OS-dependent software, and
> take what you're given.

There's not much in the way of OS-dependent software, at least not in the
conventional sense of "must install custom driver or it won't work."  

USB serial adapters of the FDTI ilk just work in Windows and Linux.  (Yes, a
manufacturer can assign its own ID, and that will require a custom wrapper
for the standard driver ... but it doesn't happen that much, as it is
ordinarily a bad idea.)

Serial usb devices -- most USB devices in fact -- work quite well on non-x86
hardware, too.   I can tell you from experience, mostly with ARM platforms
(XScale and StrongARM).   (I worked on the OHCI usb host controller driver
for the StrongARM SA1110 for Linux.  Don't get me started on the silicon
bugs in this part.)


"Poul-Henning Kamp" <phk at phk.freebsd.dk> wrote:
> The biggest mistake in USB, was that they didn't define mandatory
> device models, like for instance SCSI.

What are you talking about?   The standard USB Mass Storage model can
directly encapsulate and transport SCSI commands.  In fact that's about all
it can do.  The entire spec is only 7 pages, because it is layered on top of
all the T10 specs.

Furthermore, there are a number of other standard device models: hid, cdc,
audio, et al.   There's an entire working group (DWG) for this.  

Arguably there are few ad hoc device interfaces that ought to be
standardized, but the state isn't dire.   I look at that as the market at
work.

(Compare this situation to that of Bluetooth.  There are several half-baked
and useless device profiles in the specs that were defined too soon in the
specification process, before experience with the devices could be
considered and reflected back into the specs.)

-ch