| Universal Serial Bus (USB) is an initiative originally
proposed by Intel, Compaq, and Microsoft back in 1995. The primary purpose of USB was to
make adding devices and peripherals to the PC easier. And to centralized all the I/O
connectors in the back of a typical PC. Currently, there are connectors for keyboard,
mouse, printer, joystick, serial ports, etc. Why not just have one universal
connector in which user can connect all their devices? In addition to standardizing on
one port, the USB design also have the following advantages:
Speed - The maximum bandwidth of USB is 12Mbps, which is faster than most
ethernet cards. Compare this to the maximum speed of a typical serial port, which is
115Kbps.
 | Hot Swap - USB is mainly designed for external devices. Wouldn't it be nice to
add and sremove devices to your system without having to power it off and on? USB allows
user to add a device while the system is turned on; USB will then automatically enumerate
the new device, load the driver, and allow the user to use it. |
| Flexibility - With traditional serial ports, users were limited to the type of
device they can add. With USB, there's almost no limitation. A USB device may be almost
anything: mouse, joystick, modem, printer, scanner, etc. Also, a user can add up to 127
USB devices per system. Of course, practical limitations may reduce this number, but it is
still better than having the standard "two serial ports per system." So
you're thinking, "Hey, this is a great idea! But if USB was introduced in 1995, where
are all those wonderful USB devices today?" USB suffers from the classic
chicken-and-egg problem. Peripheral makers were waiting for system manufacturers to
integrate the USB port into their system, and PC makers were waiting for peripheral
designers to create USB devices first. And to compound the problem, Microsoft didn't
release USB drivers for Windows 95 until late 1997. If you've purchased a new computer
system in late 1997 or now, chances are you'll have two USB ports with the USB drivers
loaded.
USB devices should take off once Windows 98 hits the market. For more information about
USB, see the following links:
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