10. CPU: (Central Processing Unit) The computing part of a computer.
11. DMA: (Direct Memory Access) A peripheral has to go through the CPU to
access the main memory. To speed up memory access, the DMA forms a
second data channel between the peripherals and main memory through
which a peripheral can directly access the main memory without the
help of the CPU and read or write data. DMA data transfer is very
fast, occurring at 33MHz instead of the usual 13MHz.
12. Expansion Slot: Circuit. boards of the graphics adapter and other
peripheral interfaces plug into dual contact strips called ports,
or slots, on the mainboard which connect them to the computer's
bus. An expansion, or bus, slot contains the electric contacts for
all necessary control, data, and address signals.
13. External Clock: The input clock of the CPU that regulates the electrical
frequency supplied to the CPU. Also known as the external CPU clock
or bus clock.
14. Fast Page Mode, EDO Mode: Two types of DRAM information transfer
standards with different access speed capabilities.
15. FDD (Floppy Disk Drive): A computer's main memory is erased when the
power is turned off, making it unsuitable for long term information
storage. Magnetic memories maintain their content without
electrical input. Both hard and floppy disks consist of tiny
magnetic rings through which run read and write wires, making up a
magnetic core memory. Floppy disk drives read circular floppy disks
that are coated with a magnetic material and housed in a square
protective case.
16. Graphics Adapter: The electronic circuitry for displaying graphics,
constructed as a plug-in card for a bus slot, which drives the
monitor and displays text and graphics. An adapter's hub is a
graphics control chip.
17. HDD (Hard Disk Drive): A drive for data recording which uses a stiff
data carrier in the form of a fast rotating disk. Hard disks,
unlike floppies, do not have variable data volume it is fixed in
the drive. A hard disk holds many times more information than a
single floppy.
18, HDD Boot Sector: The boot sector always occupies the first sector of a
floppy disk or partition on a hard disk. Without knowing the
specific content of the rest of the disk, BIOS can locate and
access the boot sector and read information necessary to boot the
computer.
19. HDD Partition Table: The hard drive controller hardware and the BIOS can
only manage a limited number of drives. Furthermore, DOS OS/2 and
Unix/Xenix, the most common operating systems for microcomputers,
have completely incompatible data structures. When formatting a
hard disk drive, if you want to support multiple operating systems,
you must allocate each operating system its own section of the hard
disk. Each section is called a partition. When you power up, the
BIOS checks the hard disk for an operating system. Information
about the location ofindividual partitions in the hard disk
drive is stored on a partition table, located at a designated spot
on the hard disk.
20. IDE: (Integrated/Intelligent Drive Electronics) There are two types of
intelligent hard disk controllers - IDE and SCSI. IDE is a standard
for connecting intelligent hard disks with an internal controller
to the AT bus, and is sometimes referred to as an AT bus or ATA
interface. IDE ready mainboards do not need an additional hard disk
controller - they have a 40-pin Header that connects from the IDE
controller mounted standard on the mainboard directly to an
