Glossary
SIMATIC Rack PC 840 V2
Glossary-6
Operating Instructions, Edition 05/2006, A5E00248055-04
Operating system
Summarizing term describing all functions for program execution, allocation of system
resources to the various user programs, and for controlling and monitoring consistency of the
operating mode in cooperation with the hardware (e.g. Windows XP Professional).
Packet writing
The CD-RW is used as a diskette medium. The CD can then be read only by packet–writing
compatible software or has to be finalized. Finalization of a CD closes the CD within an
ISO9660 shell. You can still write to the CD-RW several times in spite of finalization. Not all
CD drives can read packet-written CDs . There are restrictions to using this method in
general data transfer.
PATA
An interface for hard disk drives and optical drives with parallel data transfer of up to 100
Mbps.
PC card
Trademark of the Personal Computer Memory Card International Association (PCMCIA).
Designation for auxiliary cards that conform with PCMCIA specifications. A PC card that has
roughly the size of a credit card can be plugged into a PCMCIA slot. Version 1 specifies
cards of Type I with a thickness of 3.3 millimeters, which is conceived mainly for use as
external memory. Version 2 of the PCMCIA specification also defines a card Type II with a
thickness of 5 mm and a card of the Type III with a thickness of 10.5 mm. Type II cards can
realize devices such as modems, fax and network interface cards. Type III cards are
equipped with devices that require more space, for example wireless communication
modules or rotary storage media (hard disks, for example).
PC/104 / PC/104-Plus
Two bus architectures are especially fashionable today in the industrial world. PC/104 and
PC/104-
Plus. Both are standard in single-board computers of the PC class. The electrical
and logical layout of the two bus systems is identical with ISA (PC/104) and PCI (PC/104-
Plus). Software cannot usually detect a difference between them and normal desktop bus
systems. Their advantage is the compact design and the resulting space they save.
PCMCIA
Association consisting of approx. 450 member companies of the computer industry. Their
focus is set on providing worldwide standards for miniaturization and flexible use of PC
expansion cards, and thus to provide a basic technology to the market.
Pentium M
Intel processor type: The architecture of the processor is designed for mobile computing; the
processor features superior performance characteristics for computer applications and
enhanced power-saving functions
