General information about construction of computer and its parts
We begin description of constituent parts of computer with constructive part, which is not necessary for computing system, but, however, it is the first leap to the eye,- tower. Computer’s tower is not the only “packing box”, but functional element, that protects components of computer from influence of environment and serves as base for further widening of system.
Kinds of towers:
SLIMLINE Desktop Tower
· Mini - Tower
· Midi - Tower
· Big - Tower
Main task of Power Supply is to convert network tension 220-240 V into power tension of computer’s constructive elements: 12V and 5V. Weight of modern Power Supplies is about 900 grams.
Cooler is also a part of Power Supply. There are two kinds of coolers: cooler with constant speed of rotation and temperature-control cooler.
Motherboard is the main part of every computer. It is not only the “heart” of computer, but independent element, that controls internal connections and interacts with other devices through interruptions.
In this case Motherboard is computer’s element that influences total throughput of computer.
Motherboard is also called Mainboard or Systemboard.
Memory elements are bases of any computing functioning system, because information is kept and can be used again with the help of them.
Operative memory or RAM is the fastest memory of computer. It’s important that information can be recorded and read from it.
RAM has advantages and disadvantages of its own:
· Thanks to little access time speed of processing increases. If information was read (recorded) only from other devices, user would spend a lot of time waiting for completion of operations.
· RAM is temporary memory and that’s its disadvantage. When power is turned off RAM is completely cleared and all the information will be lost forever.
Every memory element is defined by its address. Memory elements are joined inside of scheme and schemes are set on printed boards. These boards are situated in special slots of motherboard which are called banks. For different boards there is different order of banks. For RAM functioning bank must be always filled with memory elements. If it’s not, the system doesn’t work, because there is memory test when computer is turned on. Error messages are sent to motherboard as acoustic signals.
Different kinds of memory elements are used for different motherboards.
Disk drives (Floppy Disk Drive, in abbreviated form FDD) are the oldest devices of computer.
FDD consists of many mechanical elements and a few electronic ones. There are four main elements in FDD:
· work engine
· work heads
· step engines
· control electronics
Is it a device for a long keeping of information. Winchesters have two main advantages and one little disadvantage:
· Big capacity in comparison to Floppy Disks
· Access time is shorter than Fdisks have
· Winchesters are not used for information exchange, but used for stationary set inside of computer
In general hard disks are similar to Floppy disks. Information is recorded on magnetic layer of disk too. However, this disk is made of hard material, more often of aluminium. Such elements of winchester as control engine, information bearer, reading/recording heads and electronics are joined in aluminium tower.
Floppy disk consists of only one disk, and winchester consists of the same several disks which are situated one above other.
It’s a device for reading from compact disks.
· In comparison to winchesters CD is more reliable in transportation
· CD-Rom has great capacity
· Practically CD-ROM isn’t worn out
· General disadvantage is connected with methods of information processing. CD-ROM is intended for information reading. Information cannot be recorded.
Monitor is a device for visual reflection of information. Signals, received by monitor (numbers, symbols, graphic information and synchronization signals) are formed by Video Card.
At present time standard VGA-card is a standard in sphere of computers. There is big variety of video cards of VGA-standard. VGA-standard is base standard for such standards as Super VGA and HiRes.
VGA is an abbreviation for Video Graphics Array. Standard VGA-card provides 640-480 pixels with 15 colours. However, that are not full information. Actually VGA-card can support 256 colours but this depends on available capacity of video-memory.
Programs oriented on graphic, work better and faster if information density of monitor is high. It’s necessary to raise density for this. Standard one is 800*600 pixels for this mode.
For full-blooded usage of multimedia powerful soundcard is necessary.
Sound Card works in following way:
at first, sound is received as analog signal. Computer can work only with digital information, that’s why analog sound signal must be transformed to digits. Analog-digital converter serves for this. In the analog-digital converter after standardization on amplitude, analog signal is quanted on level and coded. That means that every moment of measuring on time scale is in accordance with digital value of instant signal amplitude. Thus, analog sound signal is a sequence of digits.
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