Basic Computer Memory Types Explained
Random Access Memory (RAM)
RAM is a location within the computer system which is responsible for stacking away data on a temporary basis, so that it can be promptly accessed by the processor. The information stored in RAM is typically loaded from the computer's hard disk, and includes data related to the operating system and certain applications. When the system is switched off, RAM loses all the stored information. The data remains stored and can be retained only when the system is running.
When the RAM gets full, the computer system is more likely to operate at a slow speed. The data can be retrieved in any random order. Generally, there are two types of RAM; namely Static RAM (SRAM) and Dynamic RAM (DRAM). When many programs are running on the computer simultaneously, the virtual memory allows the computer to search in RAM for memory portions which haven't been utilized lately and copy them onto the hard drive. This action frees up RAM space and enables the system to load different programs.
Read Only Memory (ROM)
This type of memory is active, regardless of whether the system is turned on or is switched off. It is a kind of permanent non-volatile storage memory. As the name 'read only' suggests, the contents in it cannot be changed or modified. It is an integrated circuit which is pre-programmed with important data that should necessarily be present for the computer to carry out its normal functionalities.
Cache is a kind of RAM which a computer system can access more responsively than it can in regular RAM. The central processing unit looks up in the cache memory before searching in the central memory storage area to determine the information it requires. This rules out the need for the system to search for information in larger and bigger memory storage areas, which in turn leads to a faster extraction of data.
Computer Hard Drive
These devices are important data storage components that are installed in the CPU. Their memory ranges widely, and a user may choose the memory depending on the data needed to be stored and accessed. Nowadays, hard drives having a memory capacity of 120 gigabytes to 500 gigabytes are normally used.
This is a non-volatile kind of memory which is intended to contribute to portable storage and a convenient transfer of data from one computer to another. The data in it can be erased and re-programmed as per the user's requirements. It only has a specific number of erase and write cycles that it can withstand, after which it creates a tendency to lose out on the stored information. Memory cards and USB flash drives are some modes of this type of memory storage.
These are just the common and main computer memory types which facilitate memory and data storage. However, there are many subtypes which are sorted out according to the memory-related functionalities they perform and the requirements they serve.