Random access memory Information - definition of random access memory

Random access memory

RAM redirects here. For other meanings of the word ram see Ram (disambiguation). For the Hindu God see Rama.

Random access memory (sometimes random-access memory), commonly known by its acronym RAM, is a type of computer storage (in practice only computer chips) whose contents can be accessed in any (i.e., random) order. This is in contrast to sequential memory devices such as magnetic tapes, discs and drums, in which the mechanical movement of the storage medium forces the computer info on random access memory to access data in a fixed order.

Look up RAM and random access memory in Wiktionary, the free dictionary.

RAM is typically used for primary storage (main memory) in computers to hold actively used and actively changing information, although some devices use certain types of RAM to provide long-term secondary storage.

Because RAM chips can be both written to and read from, the term RAM is often used to mean read-write memory, and thus taken to be the opposite of read-only memory (ROM). However, RAM refers to the way memory is accessed in a chip so ROM in definition of random access memory the form of a chip is also RAM. Also, DVD-RAM is a misnomer random access memory reviews because a disk like a DVD (or CD or hard disk) can by its nature not use random access.

Overview

This section needs to be cleaned up to conform to a higher standard of article quality. After the section has been cleaned up, you may remove this message. For help, see How to Edit 2114 random access memory a Page and the Style and How-to Directory.

Computers use random access memory types RAM working of random access memory to hold the program code and data during execution. One defining characteristic of RAM is that its accesses to different memory locations are almost random access memory check always completed at about the same speed, in contrast to some other technologies that required a certain delay time for a bit or byte to “come around”.

Early vacuum tube-based systems behaved much like modern RAM, even though the devices failed much more frequently. Core memory, which used wires attached to small ferrite electromagnetic cores, also had roughly equal access time (the term “core” is still used by some programmers to describe the RAM at the heart of a computer). The basic ideas behind tube and core memory are still used in modern RAM implemented with integrated circuits.

Alternative primary storage mechanisms usually involved a non-uniform delay for memory access. Delay line memory used a sequence of sound wave pulses in mercury-filled tubes to hold a series of bits. Drum memory acted much like the modern hard disk, storing data magnetically in continuous circular bands. (See primary storage for a greater discussion of these alternatives and others.)

Many 2 common sizes of random access memory random access memory history types of RAM are volatile, which means that unlike some other forms of computer history of static random access memory storage such as disk storage and tape storage, they lose their data when the computer is powered down. Modern RAM generally stores a bit of data as either a charge in a capacitor, as in dynamic RAM, or the state of a flip-flop, as in static RAM.

Currently, there are several types of non-volatile RAM under development, which will preserve data while powered down. Technologies that are being used include carbon nanotube technology and magnetic tunnel effect.

In the summer of 2003, a 128 Kib Magnetic RAM chip was introduced, which was manufactured with 0.18 µm technology. The core technology of MRAM is based on the magnetic tunnel effect. In June of 2004, Infineon Technologies data sheets for 2114 random access memory unveiled a 16-Mib prototype based on 0.18 µm technology once random access memory progression again.

As for carbon nanotube memory, a high-tech startup Nantero has built a functioning random access memory specs chart prototype 10 GiB array in 2004.

In computers, RAM can sometimes be allocated as a partition, allowing it to effectively act as a hard drive, only much faster. This is usually referred to as a ramdisk.

The memory wall

This section is a stub. You can help by adding to it.

In today's computers, memory access is becoming very slow when compared to CPU cycles since most computers use cheap, but comparatively slow, DRAM for the main memory. It is slow due to the fact that it has only one 64 bit (8 byte) data transfer while other chips have double that. Hence, the memory access, like hard disk access, might become the term that bounds computation speed. This is another important boundary for fast computations.

Shadow RAM

This section is a stub. You can help by adding to it.

Shadow RAM is the part of RAM with its contents copied from ROMs from where it will run much faster [1]. (ROM is in general slower than RAM.) The definition of a random access memory original ROM is disabled and the new location on the RAM is random access memory write protected. the 7 characteristics of random access memory This process is called shadowing.

Types of RAM

Common

Static RAM (SRAM)

Non-Volatile RAM (NV-RAM)

Dynamic RAM (DRAM)

Fast Page Mode DRAM

EDO RAM or Extended Data Out DRAM

XDR DRAM

SDRAM or Synchronous DRAM

DDR SDRAM or Double Data Rate Synchronous DRAM; now being replaced by DDR2

RDRAM or Rambus DRAM

Uncommon

Dual-ported RAM

Video RAM, a dual-port memory with one random access port and one sequential access port. This is becoming more popular as people need more and more video memory. See description under Dynamic RAM.

WRAM

MRAM

feRAM

ZRAM and TTRAM

RAM packaging

Semiconductor RAM is produced as integrated circuits (ICs). RAM ICs are often assembled into plug-in modules. Some standard what is random access memory module types are:

Single in-line Pin Package (SIP)

Dual in-line Package (DIP)

Single in-line memory module (SIMM)

Dual in-line memory module (DIMM)

Rambus modules are actually DIMMs, but are often referred to (by Rambus themselves and others) as RIMMs due to their proprietary slot.

Small outline DIMM (SO-DIMM). Smaller version of the DIMM, used in laptops. Comes in versions with 72 (32 bit), 144 (64 bit), 200 (72 bit) pins

Small outline RIMM (SO-RIMM)

RAM manufacturers

Major manufacturers of semiconductor RAM as of 2005:

Corsair waht is static random access memory Memory – (Official website)

Crucial Technology – (Official website)

Hynix – (Official website)

Infineon Technologies – (Official website)

Micron Technology – (Official website)

OCZ Technology – (Official website)

Rambus – (Official website)

Samsung – (Official website)

External links

A definition of RAM – From searchMobileComputing.com

What is RAM? – From Webopedia

What kind of RAM do I have? – From Darrell's Computer Help and Information

"How RAM Works" – Article by Jeff Tyson and Dave Coustan

Memory eXpansion Technology – At SourceForge

Memory Basics (Macromedia Flash required) – From RAM manufacturer Corsair

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Electronics Topics

The field of electronics is the study and use of systems that operate by controlling the flow of electrons or other electrically charged particles in devices such as thermionic valves and semiconductors. The design and construction of electronic circuits to solve practical problems is part of the fields of electronic engineering, and the hardware design side of computer engineering. The study of new semiconductor devices and their technology is sometimes considered as a branch of physics.

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Random access memory (sometimes random-access memory), commonly known by its acronym RAM, is a type of computer storage (in practice only computer chips) whose contents can be accessed in any (i.e., random) order. This is in contrast to sequential memory devices such as magnetic tapes, discs and drums, in which the mechanical movement of the storage medium forces the computer info on random access memory to access data in a fixed order.

Look up RAM and random access memory in Wiktionary, the free dictionary.

RAM is typically used for primary storage (main memory) in computers to hold actively used and actively changing information, although some devices use certain types of RAM to provide long-term secondary storage.

Because RAM chips can be both written to and read from, the term RAM is often used to mean read-write memory, and thus taken to be the opposite of read-only memory (ROM). However, RAM refers to the way memory is accessed in a chip so ROM in definition of random access memory the form of a chip is also RAM. Also, DVD-RAM is a misnomer random access memory reviews because a disk like a DVD (or CD or hard disk) can by its nature not use random access.

Overview

This section needs to be cleaned up to conform to a higher standard of article quality. After the section has been cleaned up, you may remove this message. For help, see How to Edit 2114 random access memory a Page and the Style and How-to Directory.

Computers use random access memory types RAM working of random access memory to hold the program code and data during execution. One defining characteristic of RAM is that its accesses to different memory locations are almost random access memory check always completed at about the same speed, in contrast to some other technologies that required a certain delay time for a bit or byte to “come around”.

Early vacuum tube-based systems behaved much like modern RAM, even though the devices failed much more frequently. Core memory, which used wires attached to small ferrite electromagnetic cores, also had roughly equal access time (the term “core” is still used by some programmers to describe the RAM at the heart of a computer). The basic ideas behind tube and core memory are still used in modern RAM implemented with integrated circuits.

Alternative primary storage mechanisms usually involved a non-uniform delay for memory access. Delay line memory used a sequence of sound wave pulses in mercury-filled tubes to hold a series of bits. Drum memory acted much like the modern hard disk, storing data magnetically in continuous circular bands. (See primary storage for a greater discussion of these alternatives and others.)

Many 2 common sizes of random access memory random access memory history types of RAM are volatile, which means that unlike some other forms of computer history of static random access memory storage such as disk storage and tape storage, they lose their data when the computer is powered down. Modern RAM generally stores a bit of data as either a charge in a capacitor, as in dynamic RAM, or the state of a flip-flop, as in static RAM.

Currently, there are several types of non-volatile RAM under development, which will preserve data while powered down. Technologies that are being used include carbon nanotube technology and magnetic tunnel effect.

In the summer of 2003, a 128 Kib Magnetic RAM chip was introduced, which was manufactured with 0.18 µm technology. The core technology of MRAM is based on the magnetic tunnel effect. In June of 2004, Infineon Technologies data sheets for 2114 random access memory unveiled a 16-Mib prototype based on 0.18 µm technology once random access memory progression again.

As for carbon nanotube memory, a high-tech startup Nantero has built a functioning random access memory specs chart prototype 10 GiB array in 2004.

In computers, RAM can sometimes be allocated as a partition, allowing it to effectively act as a hard drive, only much faster. This is usually referred to as a ramdisk.

The memory wall

This section is a stub. You can help by adding to it.

In today's computers, memory access is becoming very slow when compared to CPU cycles since most computers use cheap, but comparatively slow, DRAM for the main memory. It is slow due to the fact that it has only one 64 bit (8 byte) data transfer while other chips have double that. Hence, the memory access, like hard disk access, might become the term that bounds computation speed. This is another important boundary for fast computations.

Shadow RAM

This section is a stub. You can help by adding to it.

Shadow RAM is the part of RAM with its contents copied from ROMs from where it will run much faster [1]. (ROM is in general slower than RAM.) The definition of a random access memory original ROM is disabled and the new location on the RAM is random access memory write protected. the 7 characteristics of random access memory This process is called shadowing.

Types of RAM

Common

Uncommon

RAM packaging

Semiconductor RAM is produced as integrated circuits (ICs). RAM ICs are often assembled into plug-in modules. Some standard what is random access memory module types are:

RAM manufacturers

External links

Back to the top of Random access memory.

Provided by wikipedia.org