RANDOM ACCESS MEMORY

RANDOM ACCESS MEMORY

RAM is a memory in which each element of information has its own address (location) and from which any element can be retrieved easily and quickly by using that address. It is a temporary memory of a computer used to store the data and instructions of the user when the computer is on. It is also called as Read-And-Write Memory (RAM) since the computer can store (write) data at any selected location (address) and at any subsequent time, retrive (read) the data. The contents arelost when the power to the computer is shut off. Thus RAM is active only when computer is one and is also referred as a volatile memory because the data stored in it disappears whenever the computer is switched off. However he RAM has the advantage of much better access time, higher transfer rate and simple interfacing. Generally RAM is meausred in K bytes or M bytes. Large RAM size provides larger amount of information which a computer can hold for processing and hence increases the processing speed. Random access memory plays an integral part in the internal operating of a processor. These three random access memory as well as read only memory, the control unit and arithmetic and logic unit work together.

READ ONLY MEMORY

The other type of memory contained in the computers is the read only Memory (ROM). This is a permanent memory of the computer designed by the manufacturers of the the computers. This is used to store the instructions required to control the basic input-output operations of the computer when it is first tured on. It is a semiconductor chip programmes stored in ROM are called firmware. ROM is a nonvolatile i.e. the contents of this type of memory are not lost when the computer is turned off.

SECONDARY MEMORY

Secondary storage or secondary memory also referred as backing storage is used to supplement the capacity of main storage. This memory stored a bulk of information. It is also called auxiliary storage or mass storage. The information stored in this memory is used by the CPU by first bringing it to main memory. Examples of secondary memory are magnetic disks, magnetic tape and mass cartridage systems. Secondary storage is two types: Sequential and Direct access.

SEQUENTIAL ACCESS

Access through sequential acces storage is non-addressable that is an operator cannot refer directly to the contents of a particular storage location such as that used with meagnetic tape. This involves examining sequentially all recorded data. This form of storage necessitates tape searching by starting at the beginning of the tqpe and continuing to search through all records until the desired information area is found.

DIRECT ACCESS STORAGE

Direct access storage is addressable that is a given item can be selected from anywhere in storage by simply specifying the address where it is located Direct access devices such as magnetic disks provide immediate access to individul records and do not require reading from the beginning of a file to find a particular record.

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