Needtoholdmuch largervaluesthanwhatabytecanhold0

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Unformatted text preview: byte is a combination of 8 bits or 2 nibbles. As a single bit can have 21 = 2 possible representations i.e. 0 and 1, therefore a byte (a combination of 8 bits) can have 28 = 256 possible representations of data in the form of 0s and 1s. Ali Raza Computer System Some commercial units of data storage that are composed of bytes are: Kilobyte: A kilobyte (abbreviated K or KB) is equivalent to 1024 bytes. 210 bytes. Megabyte: A megabyte (abbreviated M or MB) is about 1 million bytes. 2 20 bytes. Gigabyte: A gigabyte (G or GB) is about I billion bytes. 2 30 bytes. Terabyte: A terabyte (T or TB) is about I trillion bytes. 2 40 bytes. Ali Raza Computer System Computers and storage mechanisms (CD­ ROMs, hard drives, USB flash drives, DVD­ROMs, etc.) need to hold much larger values than what a byte can hold (0­ 255). Thus, the terms kilobyte, megabyte, gigabyte, and terabyte were created to represent such large amounts of information. Ali Raza Computer System although computer data and file size is normally measured in binary code using the binary number system (counted by factors of two 1, 2, 4, 8, 16, 32, 64, etc), the prefixes for the multiples are based on the metric system! The nearest binary number to 1,000 is 2^10 or 1,024; thus 1,024 bytes was named a Kilobyte. So, although a metric "kilo" equals 1,000 Ali Raza Computer System (e.g. one kilogram = 1,000 grams), a binary "Kilo" equals 1,024 (e.g. one Kilobyte = 1,024 bytes). bit = 1 bit byte = 8bits Kilobyte = 1024 bytes Megabyte = 1024 kilobytes Gigabyte = 1024 megabytes Terabyte = 1024 gigabytes Petabyte = 1,048,576 gigabytes Exabyte = 1,073,741,824 gigabytes Zettabyte = 1,099,511,627,776 gigabytes The prefix comes from Greek i.e. mega, giga, etc Ali Raza Processor This part of the system unit is also called CPU, which stands for Central Processing Unit. System Unit is a complete box containing Processor or CPU, mother/main board, main memory, hard disk drive, floppy disk drive and buses. The system unit also contains buses on its rear side for connecting to the external Input/Output devices. Ali Raza Processor A CPU is generally a single microprocessor made from a *semi conducting material, usually silicon, with millions of electrical components on its surface. A CPU itself is a combination of different components. Its main parts include ALU (Arithmetic and Logic Unit), CU (Control Unit), and a combination of different general purpose and special purpose storage locations called Registers. A material, such as silicon, which allows electricity to move through it more easily, when its temperature increases. Semi­conductors are used for...
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