read04b.md

computer structer

what is computer

an electronic device for storing and processing data, typically in binary form, according to instructions given to it in a variable program. to reduce human effort .

how computer work : computer work in system of number called binary . depand on number like this an mathematics and digital electronics, a binary number is a number expressed in the base-2 numeral system or binary numeral system, which uses only two symbols: typically "0" and "1"

circuit work of computer Computer circuits are binary in concept, having only two possible states. They use on-off switches (transistors) that are electrically opened and closed in nanoseconds and picoseconds (billionths and trillionths of a second). A computer's speed of operation depends on the design of its circuitry.

now we will look for componant of computer

Input unit: - The source program/high level language program/coded information/simply data is fed to a computer through input devices keyboard is a most common type. Whenever a key is pressed, one corresponding word or number is translated into its equivalent binary code over a cable & fed either to memory or processor. Joysticks, trackballs, mouse, scanners etc are other input devices. Memory unit: - Its function into store programs and data. It is basically to two types

1. Primary memory
2. Secondary memory
3. Primary memory: - Is the one exclusively associated with the processor and operates at the electronics speeds programs must be stored in this memory while they are being executed. The memory contains a large number of semiconductors storage cells. Each capable of storing one bit of information. These are processed in a group of fixed site called word. To provide easy access to a word in memory, a distinct address is associated with each word location. Addresses are numbers that identify memory location. Number of bits in each word is called word length of the computer. Programs must reside in the memory during execution. Instructions and data can be written into the memory or read out under the control of processor. Memory in which any location can be reached in a short and fixed amount of time after specifying its address is called random-access memory (RAM). The time required to access one word in called memory access time. Memory which is only readable by the user and contents of which can’t be altered is called read only memory (ROM) it contains operating system. Caches are the small fast RAM units, which are coupled with the processor and are aften contained on the same IC chip to achieve high performance. Although primary storage is essential it tends to be expensive. 2 2 Secondary memory: - Is used where large amounts of data & programs have to be stored, particularly information that is accessed infrequently. Examples: - Magnetic disks & tapes, optical disks (ie CD-ROM’s), floppies etc.

hardwaer and softwaer

check your memory

1. .....................: - Is used where large amounts of data & programs have to be stored .
2. read only memory :............ 3.andom-access memory :.........
3. what is CPU :.................. .
4. ..............number is a number expressed in the base-2 numeral system or binary numeral system, which uses only two symbols: typically "0" and "1"

thank you