Random Access Memory (RAM)
RAM (pronounced ramm) is an acronym for random access memory, a type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers.
Main Types of RAM
There are two main types of RAM:
DRAM (Dynamic Random Access Memory)
SRAM (Static Random Access Memory).
The two types of RAM differ in the technology they use to hold data, with DRAM being the more common type. In terms of speed, SRAM is faster. DRAM needs to be refreshed thousands of times per second while SRAM does not need to be refreshed, which is what makes it faster than DRAM.
DRAM supports access times of about 60 nanoseconds, SRAM can give access times as low as 10 nanoseconds. Despite SRAM being faster, it’s not as commonly used as DRAM because it’s more expensive. Both types of RAM are volatile, meaning that they lose their contents when the power is turned off.
RAM, Main Memory and ROM Explained
In common usage, the term RAM is synonymous with main memory, the memory available to programs. For example, a computer with 8MB RAM has approximately 8 million bytes of memory that programs can use. In contrast, ROM (read-only memory) refers to special memory used to store programs that boot the computer and perform diagnostics. Most personal computers have a small amount of ROM (a few thousand bytes). In fact, both types of memory (ROM and RAM) allow random access. To be precise, therefore, RAM should be referred to as read/write RAM and ROM as read-only RAM.
Read Also:
- RAM cache
(1) Same as L2 cache. (2) On Apple Macintosh computers, the term RAM cache refers to a disk cache.
- RAMDAC
Short for Random Access Memory Digital-to-Analog Converter, a single chip on video adapter cards. The RAMDAC’s role is to convert digitally encoded images into analog signals that can be displayed by a monitor. A RAMDAC actually consists of four different components – SRAM to store the color map and three digital-to-analog converters (DACs), one for […]
- RAM disk
Refers to RAM that has been configured to simulate a disk drive. You can access files on a RAM disk as you would access files on a real disk. RAM disks, however, are approximately a thousand times faster than hard disk drives. They are particularly useful, therefore, for applications that require frequent disk accesses. Because […]
- RAM latency
A delay in transmitting data between a computer’s RAM and its processor. Since RAM is not necessarily fast compared to the computer’s processor, RAM latency can occur, causing a delay between the time a computer’s hardware recognizes the need for a RAM access (initiates a request for data) and the time the data or instruction […]
- RAMbo drive
A DVD-RAM drive that can read and write CD-R and CD-RW media.