Different Type Of Memories
Any storage unit of a computer system is ranked according to the following criteria. They are :
1. Access time
2. Storage capacity
3. Cost per bit of storage
➤Access time: This is the time required to locate and retrieve storage data from the storage unit in response unit response to a program instruction. A fast access time is preferred.
➤Storage capacity: It is the amount of data that can be stored in the storage unit.
➤Storage capacity: It is the amount of data that can be stored in the storage unit.
➤Cost per bit of storage : An obvious goal is to minimize the cost.
According to the above criteria storage units are basically two types. They are:
A primary (or) Internal storage section is basic to all computers. it is made up of several small storage areas called locations or cell. A special type of memory is known as cache memory. primary memory decided into the following.
RAM: Primary storage is usually referred to as Random access memory. Because it is possible to randomly select and use any location of memory to directly store and retrieve data and instructions.
RAM is usually referred to as read/write memory because information can be read form RAM chip and can Also be written into it. When the power supply is switched off the information stored inside in RAM will be loss.
Ram Can classified into 2 types They are
1. SRam (Static Random Access Memory)
2. DRam (Dynamic Random Access Memory)
ROM is further divided into PROM, EPROM, EEPROM.
PROM: A variation of ROM chip is programmable read only memory. ROM chips are supplied by the computer system manufacturer and it is not possible for a customer to modify the programs stored in the ROM chip.
PROMs are programmed to record information using a special facility known as a prom-programmer. However, once the chip has been programmed the recorded information cannot be changed.
EPROM: Once the information is stored in the ROM chip (or)a PROM chip can't be changed (or) altered. However, there is another type of memory chip called erasable programmable read only memory that over comes this problem.
EPROM chip can be reprogrammed by using special prom-programmable facility. EPROMs are mainly used by R&D personnel because they frequently change the micro-programs to test the efficiency of the computer system with new programs.
EEPROM: EEPROM is known as erasable programmable read only memory. it is the advanced one of EPROM.
Cache memory
A special very high speed memory is sometimes used to increase the speed of processing by making current programs and data available to the CPU at a rapid time. In many situations performance of the processors are limited due to the slow speed of the main memory.
A technique is used to compensate for the mismatch in operating speeds is to employ an extremely fast, small memory between CPU and main memory whose access time is close to the processing speed of the CPU. This type of memory is called high speed buffer (or) cache memory.
The most important effect of cache memory is in improving the memory transfer rates and thus raising the processor speed.
- Primary storage section.
- Secondary storage section.
A primary (or) Internal storage section is basic to all computers. it is made up of several small storage areas called locations or cell. A special type of memory is known as cache memory. primary memory decided into the following.
RAM: Primary storage is usually referred to as Random access memory. Because it is possible to randomly select and use any location of memory to directly store and retrieve data and instructions.
RAM is usually referred to as read/write memory because information can be read form RAM chip and can Also be written into it. When the power supply is switched off the information stored inside in RAM will be loss.
Ram Can classified into 2 types They are
1. SRam (Static Random Access Memory)
2. DRam (Dynamic Random Access Memory)
- DDR
- DDR2
- DDR3
- DDR4
- DDR5
ROM is further divided into PROM, EPROM, EEPROM.
PROM: A variation of ROM chip is programmable read only memory. ROM chips are supplied by the computer system manufacturer and it is not possible for a customer to modify the programs stored in the ROM chip.
PROMs are programmed to record information using a special facility known as a prom-programmer. However, once the chip has been programmed the recorded information cannot be changed.
EPROM: Once the information is stored in the ROM chip (or)a PROM chip can't be changed (or) altered. However, there is another type of memory chip called erasable programmable read only memory that over comes this problem.
EPROM chip can be reprogrammed by using special prom-programmable facility. EPROMs are mainly used by R&D personnel because they frequently change the micro-programs to test the efficiency of the computer system with new programs.
EEPROM: EEPROM is known as erasable programmable read only memory. it is the advanced one of EPROM.
Cache memory
A special very high speed memory is sometimes used to increase the speed of processing by making current programs and data available to the CPU at a rapid time. In many situations performance of the processors are limited due to the slow speed of the main memory.
A technique is used to compensate for the mismatch in operating speeds is to employ an extremely fast, small memory between CPU and main memory whose access time is close to the processing speed of the CPU. This type of memory is called high speed buffer (or) cache memory.
The most important effect of cache memory is in improving the memory transfer rates and thus raising the processor speed.
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