Memory Unit:

Memory units are the storage areas in a computer. The team “Memory” usually refers to the main Memory of the computer, whereas, the word “storage” is used for the Memory that exits on disks, CDs, floppies or taps. The main Memory is usually called a physical Memory which refers to the ‘chip’ (Integrated circuit) capable of holding data and instructions.

There are different types of Memory. They are Randam Access Memory(RAM), Read Only Memory(ROM), Programmable Read-Only Memory(PROM), Erasable Programmable Read-Only Memory(EPROM), Electrically Erasable Programmable Read-Only Memory(EEPROM).

🌟Random Access Memory – RAM🌟

RAM is the most common type of Memory found in the modern computers. This is really the main store and is the place where the program gets stored. When the CPU runs a program, it fetches the program instructions from the RAM and carries them out. If the CPU needs to store the result of the calculations it can store them in RAM. When we switch of the computer, whatever is stored in the RAM gets erased. It is a volatile form of memory.

🌟Read Only Memory – ROM🌟

In ROM, the information is burned( pre- recorded) into the ROM chip at manufacturing time. Once data has been written into the ROM chip, it cannot be erased. But you can read it. When we switch of the computer, the contents of the ROM are not erased but remains store permanently. ROM is non-volatile Memory. ROM stored critical programs such as the programme that boots the computer.

🌟Programmable Read Only Memory – PROM🌟

PROM is a Memory on which data can be written only once. A variation of the PROM chip is that it is not burnt at the manufacturing time but can be programmed using PROM programmer are a PROM burner. PROM is also nan volatile Memory.

🌟Erasable Programmable Read-Only Memory – EPROM🌟

In EPROM ,the information can be erased and program using a special PROM-programmer. EPROM is non volatile Memory. A EPROM differs from a PROM in that a PROM can be written to only once and cannot be erased. But an ultra volatile light is used to erase the contents of the EPROM.

🌟Electrically Erasable Programmable Read-Only Memory – EEPROM🌟

EEPROM is a recently developed type of Memory. This is equalent to EPROM, but does not required ultraviolet light to erase its content. It can be erased by exposing it to an electrical charge. It is also non -volatile in nature. EEPROM is not as fast as RAM are the type of the ROM. A flash memory is a special type of EPROM that can be erased and reprogrammed.

The main Memory must store many data items and have some way of ŕretrinving them when they are needed. The Memory can be compared to the boxes at a post office. Each box- holder as a box with a unique number which is called is address. This address serves to identify the box. The Memory as a number of location in its store. Each location in a Memory as a unique number called its Memory address. This serves to identify it for storage and retrieval.

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