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Storage Devices

Storage Devices:




Computers are used to process large volumes of data and to execute very complex programs. The computers need to have some kinds of storage device to hold these programs and data. such a device should be directly accessible to the cpu and its speed must be compatible with the speed of the cpu. Also a computer must be able to store frequently needed data on some permanent storage.




A capacity gadget alludes to a figuring equipment used to store data forever or briefly. The gadget can be outer or inner to a PC, server, and other processing frameworks. Capacity gadgets are otherwise called stockpiling medias or capacity medium. There are two kinds of capacity gadget: optional capacity gadget and essential stockpiling gadget.








Secondary storage device


An optional stockpiling gadget has a bigger stockpiling limit and can store information for all time. The gadget can be both outside and inward to a PC and incorporates; minimized circle, USB drive, hard plate, and so forth.



Primary storage device



An essential stockpiling gadget is very littler in size and it's intended to catch or hold information for an impermanent period. Most essential stockpiling gadgets are found inside the PC, and they have the quickest access to information. Instances of Primary gadgets incorporate Cache memory and RAM.






* Main Memory:


Digital computers are stored-programs computers that means a program  to be executed is first located in the memory and then instructions are executed one by one. The data and result of calculations are also stored in the memory. In this sense main memory is the working area of the computer. It is very fast but limited.

The main memory of a computer consist of thousands or even millions of the cells, each capable of storing a bit i.e O or I. These cells are logically organized into group of 8 bits (Binary digits) Called a byte.





* RAM (Random access memory):


Ram is the primary storage device and the data and instructions are stored temporarily in it. It takes the same amount of time to access any location in RAM. CPU can perform TWO types of operations on RAM, these are.

. Read

. Write

 During Read operation the contents of the memory location are copied to a CPU register whereas during Writing Operation the contents of a CPU register are copied in the memory location. The CPU cannot perform any other operations on memory locations.





* Floppy disk:


Floppy disks are mostly used for Transferring data between computer and system and for casual backup of data. They have low capacity, and are very slow as compared to other storage devices. They most common size is 3.5 inches diameter. These disks are encased in a rigid envelop. Despite their small size These have a larger storage capacity than the older floppy disk.




*Hard disk:


Most digital computers use atleast one hard-disk drive. Some large scale computers normally contain hundreds of hard-disks. hard disks are used to permanently store digital data so you can say that hard disks give computers the ability to remember things when the power goes out. 





* Campact disks:


One of the most Prominent optical storage system is the Compact disk (CD), Which is compatible with those in the music industry except that computer Cd players spin the Cd faster than the original CD's used in the music industry to obtain higher data transfer rates.

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