Computer Memory
Jun 09, 2015
Computer Memory
Learning Objective
Computer Memory Primary Memory Secondary Memory RAM ROM Cache Storage
Computer Memory
Computer memory are the physical devices used to store programs or data on a temporary or permanent basis for use in a computer or other digital electronic device.
Two basic categories of computer memory:
Primary storage and Secondary storage
Primary Memory Primary storage or main memory stores 3 types of
information for very brief periods of time:
-Data to be processed by the CPU;
-Instructions for the CPU as to how to process the data;
-Operating system programs that manage various aspects of the computer’s operation.
Primary storage takes place in chips mounted on the computer’s main circuit board, called the motherboard.
Four main types of primary storage: register, Random Access Memory, Read Only Memory and Cache Storage
Random Access Memory
Holds its data as long as the computer is switched on
All data in RAM is lost when the computer is switched off
Described as being volatile It is direct access as it can be both
written to or read from in any order Its purpose is to temporarily hold
programs and data for processing. In modern computers it also holds the operating systems
Types of RAM
Dynamic Random Access Memory Synchronous Dynamic Random
Access Memory Direct Rambus Dynamic Random
Access Memory Static Random Access Memory Video Random Access Memory
Read Only Memory
ROM holds programs and data permanently even when computer is switched off
Data can be read by the CPU in any order so ROM is also direct access.
The contents of ROM are fixed at the time of manufacture
Stores a program called the bootstrap loader that helps start up the computer
Access time of between 10 and 50 nanoseconds
Types of ROM
Programmable Read Only Memory Erasable Programmable Read Only
Memory Electrically Erasable
Programmable Read Only Memory Flash ROM ROM catridges
Cache Memory
A smaller, high speed storage device used to increase the speed of processing by making current programs and data available to the CPU at a rapid rate.The basic characteristic of cache memory is its fast access time
Secondary Memory
Secondary memory refers to storage devices, such as hard drives and solid state drives. It may also refer to removable storage media, such as USB flash drives, CDs, and DVDs.
Unlike primary memory, secondary memory is not accessed directly by the CPU.
Instead, data accessed from secondary memory is first loaded into RAM and is then sent to the processor.
CD – Compact DISKDVD – Digital VERSATILE DISC – DIGITAL VIDEO DISC
Types of Cache Level 1 cache is built within the CPU(internal)
Level 2 cache may be on chip or nearby(external)
Made by
Nithila Adlin Thangaraj Niyati Raj Rachel Angelica Pereira Pearl Soares