B&R 5PC600.SE00-00, Руководство пользователя, Страница: 557 / 594

Appendix A • Glossary
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A
557 Automation PC 620 with 945GME N270 CPU board User's Manual V 1.10
Ethernet
An IEEE 802.3 standard for networks. Ethernet uses bus or star topology and controls the traffic
on communication lines using the access procedure CSMA/CD (Carrier Sense Multiple Access
with Collision Detection). Network nodes are connected using coaxial cables, fiber optic cables
or twisted pair cabling. Data transfer on an Ethernet network takes place in frames of variable
lengths that consist of supply and controller information as well as 1500 bytes of data. The
Ethernet standard provides base band transfers at 10 megabit and 100 megabit per second.
ETX
Abbreviation for " E mbedded T echnology e X tended" This established standard offers complete
PC functionality on a very compact form factor of just 114 mm x 100 mm (´4.5" x 4"). The
flexibility offered by ETX® in the development of system specific main boards allows easy
requirement fulfillment in a number of different applications.
FDD
Abbreviation for " F loppy D isk D rive". Reading device for removable magnetic memory from the
early days of PC technology. Due to their sensitivity and moving components, FDDs have been
almost completely replaced by CompactFlash memory in modern automation solutions.
Fiber optics
Fiber optic cable
FIFO
An abbreviation for " F irst I n F irst O ut". A queuing organization method whereby elements are
removed in the same order as they were inserted. The first element inserted is the first one
removed. Such an organization method is typical for a list of documents that are waiting to be
printed.
Firmware
Programs stored permanently in read-only memory. Firmware is software used to operate
computer-controlled devices that generally stays in the device throughout its lifespan or over a
long period of time. Such software includes operating systems for CPUs and application
programs for industrial PCs as well as programmable logic controllers (e.g. the software in a
washing machine controller). This software is written in read-only memory (ROM, PROM,
EPROM) and cannot be easily replaced.
Floppy
Also known as a diskette. A round plastic disk with an iron oxide coating that can store a
magnetic field. When the floppy disk is inserted in a disk drive, it rotates so that the different
areas (or sectors) of the disk's surface are moved under the read/write head. This allows the
magnetic orientation of the particle to be modified and recorded. Orientation in one direction
represents binary 1, while the reverse orientation represents binary 0.
F