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Innovation:
USB
The
Follow-on to ADB
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In 1983 Apple used a phone-like (RJ-11) connector for the
keyboard, and a DB-9 (Joystick-like) connector for the
mouse. Both were hot-swappable and it worked pretty
good.
In 1985 Apple had a revolutionary idea -- make a simple,
low-cost, serial cable that can connect many devices to the
Mac -- like Keyboards, Mice, Joysticks, Trackballs and so
on. All this was supposed to be on one daisy-chainable
serial port, with each device dynamically and automatically
figuring out it's own address.
By 1995 Intel had a revolutionary idea -- to take Apple's
idea and design, change the connector slightly, make it a
little faster, and make USB (Universal Serial Bus). What a
brilliant idea -- and only ten years late. Still the
implementation was good, and ADB was growing long in the
tooth (OLD). There were of course additions -- like making
it faster, or putting power on the line so many devices
wouldn't need their own power supplies (like Apple had done
a little with ADB and IEEE-1394 FireWire), and the topology
would change so that it wouldn't have to be a strict
daisy-chain (like Apple had done with IEEE-1394 FireWire).
Of course you could use hubs (splitters) on ADB as well
(like ethernet, ADB, and IEEE-1394 FireWire). USB also
allowed for the neat feature of "hot swappable" -- so that
you could plug in and remove devices while the computer was
on (just like Apple's IEEE-1394 FireWire). Lastly it would
be fast enough that you could use it for some faster devices
(like printers, scanners, and so on) -- just like Apple's
other serial bus (the unnamed and unused one built into Macs
since 1984 but never really used). Don't you love Intel
innovation their motto could be, "just like the others...
only later".
For the record:
Apple wasn't the first company to do a Daisy-Chain to
connect devices.
IEEE-488 GPIB (General Purpose
Interface Bus by Hewlett Packard) was a
1970's technology that worked that way, but was a
parallel bus -- but it worked with a daisy chain and
allowed 7 devices (+ computer). IEEE-488 was a way to
connect test equipment and some faster devices (floppy
drives, printers, plotters), and worked really well.
Commodore used IEEE-488 for their peripherals. Later
when Commodore came out with low-cost computers (VIC-20's
and C-64's) they decided to simplify IEEE-488 to trim
costs, and so they made a serial version the cable, that
was how you added drives to those computers. It worked,
but it was fairly slow -- and didn't connect much of
anything besides the floppy.
On a totally separate note, Commodore also
needed to get the picture quality better than the NTSC
they were using on their computers. So they separated
the the Luminance Component from the Chroma on the
video signal and created a Commodore high quality
video. (NTSC had the two signal on the same line and
they interfered with each other a bit, and ran the two
signal at different qualities. By separating them they
could increase the quality). S-Video connectors came
along and "innovated" this same revolutionary concept
that Commodore had been using for many years.
I imagine there were other "busses" as well as those
mentioned.
Apple took the idea of a peripheral bus, and decided
to design two separate addressable serial busses.
One was the RS-422 serial ports in the first Macs (and
most follow-ons), which also had an "addressable device"
protocol. This was supposed to work with pass-thru serial
ports, be high speed (1 Mb externally clocked) serial bus
for drives, printers, scanners and so on. If you've never
daisy-chained serial devices to your Macs serial port,
you are not alone -- I think there was one device that
actually tried to use this feature of the Macs serial
port (two if you counted an ill-fated hard-drive that
connected to the serial port) -- everyone else just
ignored the feature. It is so ignored that most people
have never heard of it -- and you can only see mention of
it in the oldest developer documentation. The idea was
modified slightly, and then used as AppleTalk (LocalTalk)
to network computers and peripherals-- so it isn't quite
as dead as people might think. But there are some subtle
differences between the two implementations (LocalTalk
and the SerialBus), even if the high level concepts are
similar. Basically the power of AppleTalk was good
enough, and so no one even needed to implement the other
form of that device bus.
The other serial bus was released on Apple
]['s and later Macs (circa 1985/6), and was
ADB (Apple Desktop Bus). It
was a lower speed serial bus for keyboards, mice and
other "inputs". It has been standard on Macs ever since.
Apple openly licensed the technology, and NeXT used it,
and I think Sun even used it on a couple of machines.
Apple was going to make it more of a standard, and there
was even talk about PC manufacturers using it for a while
-- but PC manufacturers wanted cheap, not good, so stuck
with their older proprietary keyboard and mice connectors
for 10+ more years. But when the same idea comes from
Intel, then it is revolutionary. Besides, with the
hardware monopoly stranglehold Intel has on the PC
industry, they just put the connector on their support
chips, all the PC makers were forced to have USB whether
they wanted it or not.
Conclusion
Many ideas evolve. Apple was working on (or had at least
thought of) ADB-2 -- a faster follow-on to ADB with some
nicer features like more than 16-32 devices, and more power,
hot swappable and so on, (and had been working on the very
fast FireWire) -- but Intel copied with their revolutionary
<sarcasm> USB. Apple wisely chose to go USB because it
was going to be a standard.
When standards are available, Apple does use
them -- but that is not always possible when you are on
the leading edge. Apple couldn't be standard in 1985,
because no one was doing what they were doing -- but a
decade later, Intel was finally making a standard, so
Apple used it.
Apple still made a difference to USB. The normal adoption
curve in PC's would imply that by the year 2010 the PC users
would have actually started adopting the USB port -- and
another 10 years later they may drop the old RS-232 and
Parallel ports. (PC's are netoriously slow at adopting
anything). Fortunately as there was starting to be a little
momentum building on the PC side (they finally got OS
support), Apple put USB in all their machines, and
leap-frogged the PC's in adoption. This has helped to drive
many more devices for both Macs and PC's, and helped both
the Mac and the PC market with a faster adoption cycle
(1).
(1) Let's call the threshold for adoption
of a technology the 50% mark (LD50). When 50% of your
machines (either installed base, or new sales) are sold
with a technology (and that technology is used), then it
is adopted.
Guess what -- in most cases the Mac beats the PCs in
adoption by a longshot, even with supposed PC
innovations. An example is USB. It took PC's years to get
it on the motherboards, but most didn't bring the
connectors out to the real world, and almost no one
really used it (other than the QuickCam) -- it wasn't
even fully OS supported until Win98. Apple helped
jump-start the market by putting USB on millions of
iMacs, claiming that USB was the future of low-speed
serial on the Mac (and it was going to be on all new Macs
after that), and by removing other serial ports so that
hardware developers and ISV's knew how serious Apple
was.
All iMacs shipped with USB Keyboards and Mice long
before any PC's did the same. USB became standard on Macs
years (decades) before they will be on PC's. So even if a
small percentage of PC got USB first -- the majority of
Macs got it first, and Macs use it far more than most
PC's do.
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