Glossary - Samsung NP-R20 Series Service Manual

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11. References

3) Glossary

Bad Sector
An area on a hard disk or floppy disk that cannot be used to store data, because of a
manufacturing defect or accidental damage. A floppy or hard disk saves data in units and the
smallest unit of storage on a disk is a sector. A bad sector means a sector that is damaged and
cannot be used to write or read data.
BIOS
An acronym for Basic Input/Output System. A set of instructions stored on a read-only memory
(ROM) chip which handles all input-output functions. The BIOS communicates between the operating
system and the computer's hardware. This is a part of the computer firmware (computer dedicated
software).
The BIOS allows the computer's hardware and the operating system to communicate with application
programs and peripheral devices as well as providing the fundamental services required for the
computer's operation. To view or change the BIOS settings, press the "Del" key when the system is
booting up.
Boot Sector
The very first track (track 0) on a hard drive of an IBM compatible PC. If the power is turned on,
the booting software reads the first block of the boot sector which contains a very short program (in
the order of a few hundred bytes) which will load and start running the operating system properly.
Bus Mastering
Bus mastering is a feature that enables a CPU extension board or software controller connected to
the bus to communicate directly with other devices on the bus without going through the CPU.
Although the CPU generally controls data communication over the bus (which lowers the data rate),
some high-speed devices may communicate with each other without going through the CPU. To
resolve this problem, a microprocessor installed on an extension board or a piece of software must
take control of the data transfer over the bus. By taking over some of the work of the system
microprocessor, the bus master creates a multiprocessing environment and increases the overall
system performance. This technology is called bus mastering.
Cache
A cache is temporary high speed memory designed to speed up access to resources. It is similar to
RAM but is much faster than RAM or a hard disk drive. A cache is used to reduce the wait time
caused by the difference in the data rate between two different types of storages such as the hard
disk and the RAM.
Cache Memory
High-speed memory with a copy of the most recently used memory data. When the CPU's request
for instructions or data can be satisfied from the cache, the CPU can run at full rated speed. Using
a part of the hard disk space as cache memory due to small main memory capacity is called disk
cache.
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