Types of Computer Memory

Types of Computer Memory - The data being processed by the processor will be temporarily stored in physical memory. As long as the physical memory is electrified, the data will continue to be stored and will be lost when the power is turned off or reset. Memory on a computer is divided into two, namely ROM and RAM, but there is also another memory called cache memory.

ROM (Read Only Memory)

ROM (Read only Memory) is hardware in the form of a semiconductor memory chip whose contents can only be read. ROM data can only be read and cannot be written over and over again. This ROM is a non-volatile type, which means that the stored data does not easily disappear even if the power source is turned off. For this reason, this ROM is used to store the main program of a system so that data is safe and is not lost in the middle of the process.

Until now there are several types of ROM that have been used on computers, namely:

1. PROM (Programmable Read-Only Memory)

PROM is sold empty. In contrast to ROMs whose contents are determined by the vendor, PROMs can be loaded with programs by the user. Once filled, the contents of the PROM can no longer be deleted.

2. EPROM (Erasable Programmable Read-Only Memory)

Unlike PROM whose contents cannot be erased, the contents of an EPROM can be erased once programmed. Removal of the contents of the EPROM is carried out using ultraviolet light.

3. EEPROM (Electrically Erasable Programmable Read-Only Memory)

EEPROM can be used to store data permanently and its contents can be electrically erased using a program. Examples of EEPROM are flash memory used in digital cameras, video game consoles and BIOS chips.

RAM (Random Access Memory)

RAM is hardware (hardware) in the form of a semiconductor memory chip with memory properties that can be read and written. In this RAM, the stored data can disappear in the middle of the process because this memory is a volatile memory type where the stored data will be lost if the power source is turned off.

When viewed from the way it works, RAM consists of two types, namely dynamic RAM and static RAM. Dynamic RAM (DRAM) is composed of cells that store data as electrical charges in capacitors. Dynamic RAM (DRAM) is categorized into several types, namely:

• Fast Page Mode DRAM (FPM DRAM)
• Extended Data Output DRAM (EDO DRAM)
• Synchronous DRAM (SDRAM)
• Rambus DRAM (RDRAM)
• Double Data Rate SDRAM (DDR SDRAM)

In addition to this RAM, there is RAM that has special functions for video, namely:

• Video RAM (VRAM)
• Windows RAM (WRAM)
• Synchronous Graphics RAM (SGRAM)

Static RAM (SRAM) stores data by storing binary values ​​of information using flip-flop logic gates. Judging from the module, static RAM (SRAM) is divided into:

• Single Inline Memory Module (SIMM)
• Double Inline Memory Module (DIMM)
• Rambus Inline Memory Module (RIMM)

Cache Memory

Cache memory is memory that has a limited capacity at a very high speed. This memory cache is more expensive than the main memory. Cache memory is located between CPU registers and main memory. This cache memory serves so that the CPU does not directly refer to the main memory but to cache memory which has a higher access speed so that system performance can be improved.

High-speed buffers used to store data are accessed at the same time as adjacent data in main memory. The access time required for cache memory is 5 to 10 times faster than main memory.

In the past, cache memory was stored outside the processor and could be added, whereas now cache memory is embedded in the processor with the aim of increasing performance.