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Appendix F
Packet
The unit of data that is routed between an origin and a destination on the
Internet or any other packet-switched network. The packet includes a
header containing control information and (usually) user data. Packets
are most often used to refer to network layer units of data.
PCI
see Peripheral Component Interface (PCI)
Peripheral Component Interconnect (PCI)
Peripheral Component Interconnect (PCI) is an interconnection system
between a microprocessor and attached devices in which expansion
slots are spaced closely for high-speed operation. PCI is designed to be
synchronized with the clock speed of the microprocessor, in the range of
20 MHz to 33 Mhz.
PCI transmits 32 bits at a time in a 124-pin connection (the extra pins
are for power supply and grounding) and 64 bits in a 188-pin connection
in an expanded implementation. PCI uses all active paths to transmit
both address and data signals, sending the address on one clock cycle
and data on the next. Burst data can be sent starting with an address on
the first cycle and a sequence of data transmissions on a certain number
of successive cycles.
POP3
see Post Office Protocol (POP3)
Post Office Protocol 3 (POP3)
Post Office Protocol (POP) is a standard protocol for receiving email.
POP is a client/server protocol in which email is received and held for
you by your Internet server. When you read your mail, all of it is
immediately downloaded to your computer and no longer maintained on
the server. POP3 is built into the Netscape Navigator and Microsoft
Internet Explorer browsers.
POP can be thought of as a store-and-forward service. Another protocol,
Internet Message Access Protocol (IMAP), can be thought of as a
remote file server.
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