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Unformatted text preview: ed via serial are generally much
slower than those connected by parallel.
• Serial is convenient, relatively inexpensive and getting faster all of the time.
• The current serial standard for peripherals is called USB 2.0 USB 2.0
• Max transfer speed of 400Mbps (Megabits per second), 40 times faster than the predecessor USB 1.1
• Supports up to 127 devices connected to the same controller chip!
• A USB cable can be 5 meters long without causing any performance problems
• USB has become the ubiquitous serial connection standard for practically every external PC peripheral IEEE 1394, aka Firewire
• Another high speed serial bus in wide use is the Firewire bus, first introduced by Apple
• Similar in performance to USB 2.0
• Designed primarily for video devices such as camcorders, digital TVs, DVD devices and VCRs
• Many PCs today also include Firewire for use with Video authoring software and downloading
video onto your computer USB 3.0!
• Standard introduced in 2008
• Up to 5 Gigabits per second!
• 10 times faster than USB 2.0 Clocking Data
• Both serial and parallel busses transfer data using a clock signal that ensures that data is
sent and received at certain times based on
the clock speed.
• Without the clock, data transfers would be less reliable given the variation in cable length and
other environmental factors Wireless I/O
• Wifi: Wireless local area network (LAN) technology that uses Internet Protocol to transfer
data between devices. Latest generation (n)
operates at >100 megabits/second and has an
indoor range of about 150 ft.
• Bluetooth: Personal area network (PAN) Very low power with range of <20 ft in most
applications and speeds of 80 kilobits/second I/O Example using a car
climate control system
n On/Off Switch, Temperature,
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- Fall '08
- Operating Systems