Hi all,
sorry for cross posting, but I found the following info very interesting
when discussing about USB 1.1 vs. USB 2.0 stuff.
Some of us (including me) would like to see a USB 2.0 breakout box which
grants more than 2x2 channels while using a standard USB 2.0 protocol.
Bruce Wahler politely agreed to spread his info to our lists, so all
credits go to Bruce.
ce
---------- ----------
Subject: OT -- USB History
Date: Donnerstag, 16. Februar 2006 18:12
From: Bruce Wahler <desp@email-addr-hidden>
To: access-list@email-addr-hidden
Hi All,
[Warning: This post has little to do with the Virus TI per se. It
might be of interest to some of you, though.]
I was involved in the early USB efforts, working for a major PC
manufacturer. The 3-tier speed approach of USB is a confusing -- and
necessary -- part of the design. Early USB appealed to two groups:
1) manufacturers who wanted to simple, cheap way to untangle the rat's
nest of wires that were growing behind computers; and 2) developers
who wanted a better, more flexible connection than serial and parallel
ports provided. In addition, the creators of USB had this grand
vision of "USB everything": kitchen appliances, phones, televisions,
you name it.
USB attempts to satisfy all of these needs, but the goals of different
markets are sometimes at odds with each other. Devices like mice
can't afford to add even $1.00-2.00USD of product cost, because their
customer base won't accept the price increase. On the other end,
there's no such a thing as "too fast" for disk drives and networks.
USB 1.0 (and 1.1) came out with Low- and Full-Speed specifications to
try to bridge the needs of these two camps. Same connectors, same (or
similar) cables, same hardware at the host (computer) end; all of the
higher-speed functions had to be a layer on top of the basic ones.
At the time of USB 1.0 (1995), the practical limit for cables and such
was considered to be somewhere in the range of 10-15Mbit/sec. This
wasn't a PHYSICAL limitation; it was governed by the cost of hardware
(cables, connectors, ICs, etc.) compared to the amount of data being
sent (<1GB). Unfortunately, USB 1.x took several years to gain
acceptance. (PCs had the USB ports back in 1995, but there were no
real peripherals nor OS support for 3-4 more years. One of my bosses
used to refer to it as the "Useless Serial Bus.") By the USB really
took hold (2000? 2004?), there were enough advances in technology and
manufacturing to up the speed a great deal. Add to that the need to
transfer more data, and the fear that FireWire would eclipse USB, and
"Hi-Speed USB" was born. Hi-Speed USB follows the same rules as USB
1.0: faster protocols must work around the limits of slower ones, so
nothing becomes truly obsolete. This is why a 12Mbit/sec Virus TI is
still "USB 2 compliant."
Some important things to know about Hi-Speed USB:
1. The GUARANTEED cable length is shorter (5m vs. 2m). With a quality
cable, you might run further, but there's no whining if it doesn't
work. This certainly limits the ability to use the Virus TI as both a
recording platform and a performance synth at the same time.
2. Raw bandwidth numbers of Hi-Speed USB are deceptive. (This is also
true of FireWire.) While the cable and ICs can support 480Mbit/sec.,
it takes great drivers, proper interrupt selection, and a relatively
unused computer to use that bandwidth. Otherwise, it's a game of
"hurry-up-and-wait." Sharing USB with slower devices also clouds the
picture.
3. USB 2.0 enhancements focused on data storage. There weren't any
high-speed audio extensions added. If Access had wanted to use
480Mbit USB audio, they would have had to develop and support it from
scratch -- on both the Mac and PC. So, it's not just a case of adding
a little product cost; it's a large development and testing challenge,
too. Why weren't there audio extensions? Probably because the two
"official" audio uses for USB -- Internet phones and digital USB audio
-- didn't need them. The first one is fine with 12Mbit/sec, and the
second one never really caught on.
4. The USB specifications were mostly written by big companies like
Microsoft, IBM, Intel, and Compaq. They sunk a lot of resources into
USB, and so their needs took top priority. None of those companies is
known for professional audio gear -- they're computer companies, and
USB audio was and still is a bit of an afterthought. (Quick: Name me
one 'major' US PC manufacturer who sells a true MPC in their standard
line? Anyone?)
So, why not add the hardware (ICs) now, and write the OS support later?
The approach rarely works, IMHO. Even in the computer industry,
known for technology advances, hardware that is unused at product
launch often remains forever unused. Why? Remember the old adage,
"If it ain't broke, don't fix it" ? Well, updating software or
firmware requires breaking that rule. And anyone who's written
software will tell you that bugs crop up in the strangest places.
While the updates are cool, there's often very little evidence that
the efforts resulted in big sales increases. Thus, a small company
like Access must be choosy when planning product updates.
Regards,
-BW
-- Bruce Wahler Design Consultant Ashby Solutions™ http://consult.ashbysolutions.com 978.386.7389 voice/fax bruce@email-addr-hidden _______________________________________________ access-list mailing list access-list@email-addr-hidden http://www.ampfea.org/mailman/listinfo/access-list <--- SUBSCRIBE/UNSUBSCRIBE DETAILS HERE Patches: http://www.ampfea.org/cool/stuff/access-list -------------------------------------------------------Received on Fri Feb 17 00:15:06 2006
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