A redundant array of independent memory (RAIM) is a design feature found in certain
computer
A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as C ...
s' main
random access memory
Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A Random access, random-access memory device allows data items to b ...
.
RAIM utilizes additional memory modules and
striping
In computer data storage, data striping is the technique of segmenting logically sequential data, such as a file, so that consecutive segments are stored on different physical storage devices.
Striping is useful when a processing device request ...
algorithms
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing c ...
to protect against the failure of any particular module and keep the memory system operating continuously. RAIM is similar in concept to a
redundant array of independent disks
Raid, RAID or Raids may refer to:
Attack
* Raid (military), a sudden attack behind the enemy's lines without the intention of holding ground
* Corporate raid, a type of hostile takeover in business
* Panty raid, a prankish raid by male college ...
(RAID), which protects against the failure of a
disk drive
Disk storage (also sometimes called drive storage) is a general category of storage mechanisms where data is recorded by various electronic, magnetic, optical, or mechanical changes to a surface layer of one or more rotating disks. A disk drive is ...
, but in the case of memory it supports several DRAM device
chipkill __NOTOC__
Chipkill is IBM's trademark for a form of advanced error checking and correcting (ECC) computer memory technology that protects computer memory systems from any single memory chip failure as well as multi-bit errors from any portion of a ...
s and entire memory channel failures. RAIM is much more robust than
parity checking
A parity bit, or check bit, is a bit added to a string of binary code. Parity bits are a simple form of error detecting code. Parity bits are generally applied to the smallest units of a communication protocol, typically 8-bit octets (bytes), ...
and
ECC memory
Error correction code memory (ECC memory) is a type of computer data storage that uses an error correction code (ECC) to detect and correct n-bit data corruption which occurs in memory. ECC memory is used in most computers where data corruption c ...
technologies which cannot protect against many varieties of memory failures.
On July 22, 2010,
IBM introduced the first high end computer server featuring RAIM, the
zEnterprise 196
IBM Z is a family name used by IBM for all of its z/Architecture mainframe computers.
In July 2017, with another generation of products, the official family was changed to IBM Z from IBM z Systems; the IBM Z family now includes the newest mo ...
. Each z196 machine contains up to 3 TB (usable) of RAIM-protected main memory. In 2011 the business class model z114 was introduced also supporting RAIM. The formal announcement letter offered some additional information regarding the implementation:
See also
*
IBM mainframe
IBM mainframes are large computer systems produced by IBM since 1952. During the 1960s and 1970s, IBM dominated the large computer market. Current mainframe computers in IBM's line of business computers are developments of the basic design of th ...
References
{{Reflist, 2
Computer memory
Error detection and correction
Fault-tolerant computer systems