Synonyms containing ecc memory
We've found 2,007 synonyms:
In DOS memory management, extended memory refers to memory above the first megabyte of address space in an IBM PC or compatible with an 80286 or later processor. The term is mainly used under the DOS and Windows operating systems. DOS programs, running in real mode or virtual x86 mode, cannot directly access this memory, but are able to do so through an application programming interface called the eXtended Memory Specification. This API is implemented by a driver or the operating system, which takes care of memory management and copying memory between conventional and extended memory, by temporarily switching the processor into protected mode. In this context the term "extended memory" may refer to either the whole of the extended memory or only the portion available through this API. Extended memory can also be accessed directly by DOS programs running in protected mode using VCPI or DPMI, two methods of using protected mode under DOS. Extended memory should not be confused with expanded memory, an earlier method for expanding the IBM PC's memory capacity beyond 640 kb using an expansion card with bank switched memory modules. Because of the available support for expanded memory in popular applications, device drivers were developed that emulated expanded memory using extended memory. Later two additional methods were developed allowing direct access to a small portion of extended memory from real mode. These memory areas are referred to as the high memory area and the upper memory area.
|Dynamic random-access memory|
Dynamic random-access memory
Dynamic random-access memory (DRAM) is a type of random access semiconductor memory that stores each bit of data in a memory cell consisting of a tiny capacitor and a transistor, both typically based on metal-oxide-semiconductor (MOS) technology. The capacitor can either be charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. The electric charge on the capacitors slowly leaks off, so without intervention the data on the chip would soon be lost. To prevent this, DRAM requires an external memory refresh circuit which periodically rewrites the data in the capacitors, restoring them to their original charge. This refresh process is the defining characteristic of dynamic random-access memory, in contrast to static random-access memory (SRAM) which does not require data to be refreshed. Unlike flash memory, DRAM is volatile memory (vs. non-volatile memory), since it loses its data quickly when power is removed. However, DRAM does exhibit limited data remanence. DRAM typically takes the form of an integrated circuit chip, which can consist of dozens to billions of DRAM memory cells. DRAM chips are widely used in digital electronics where low-cost and high-capacity computer memory is required. One of the largest applications for DRAM is the main memory (colloquially called the "RAM") in modern computers and graphics cards (where the "main memory" is called the graphics memory). It is also used in many portable devices and video game consoles. In contrast, SRAM, which is faster and more expensive than DRAM, is typically used where speed is of greater concern than cost and size, such as the cache memories in processors. Due to its need of a system to perform refreshing, DRAM has more complicated circuitry and timing requirements than SRAM, but it is much more widely used. The advantage of DRAM is the structural simplicity of its memory cells: only one transistor and a capacitor are required per bit, compared to four or six transistors in SRAM. This allows DRAM to reach very high densities, making DRAM much cheaper per bit. The transistors and capacitors used are extremely small; billions can fit on a single memory chip. Due to the dynamic nature of its memory cells, DRAM consumes relatively large amounts of power, with different ways for managing the power consumption.DRAM had a 47% increase in the price-per-bit in 2017, the largest jump in 30 years since the 45% jump in 1988, while in recent years the price has been going down.
In computing, memory refers to 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. The term primary memory is used for the information in physical systems which function at high-speed, as a distinction from secondary memory, which are physical devices for program and data storage which are slow to access but offer higher memory capacity. Primary memory stored on secondary memory is called "virtual memory". An archaic synonym for memory is store. The term "memory", meaning primary memory is often associated with addressable semiconductor memory, i.e. integrated circuits consisting of silicon-based transistors, used for example as primary memory but also other purposes in computers and other digital electronic devices. There are two main types of semiconductor memory: volatile and non-volatile. Examples of non-volatile memory are flash memory and ROM/PROM/EPROM/EEPROM memory. Examples of volatile memory are primary memory, and fast CPU cache memory .
Error-correcting code memory is a type of computer data storage that can detect and correct the most common kinds of internal data corruption. ECC memory is used in most computers where data corruption cannot be tolerated under any circumstances, such as for scientific or financial computing. ECC memory maintains a memory system immune to single-bit errors: the data that is read from each word is always the same as the data that had been written to it, even if a single bit actually stored, or more in some cases, has been flipped to the wrong state. Some non-ECC memory with parity support allows errors to be detected, but not corrected; otherwise errors are not detected.
In DOS memory management, expanded memory is a system of bank switching that provided additional memory to DOS programs beyond the limit of conventional memory (640 KiB). Expanded memory is an umbrella term for several incompatible technology variants. The most widely used variant was the Expanded Memory Specification (EMS), which was developed jointly by Lotus Software, Intel, and Microsoft, so that this specification was sometimes referred to as "LIM EMS". LIM EMS had several versions. The first widely implemented version was EMS 3.2, which supported up to 8 MiB of expanded memory and uses parts of the address space normally dedicated to communication with peripherals (upper memory) to map portions of the expanded memory. EEMS, an expanded-memory management standard competing with LIM EMS 3.x, was developed by AST Research, Quadram and Ashton-Tate ("AQA"); it could map any area of the lower 1 MiB. EEMS ultimately was incorporated in LIM EMS 4.0, which supported up to 32 MiB of expanded memory and provided some support for DOS multitasking as well. IBM, however, created its own expanded-memory standard called XMA. The use of expanded memory became common with games and business programs such as Lotus 1-2-3 in the late 1980s through the mid-1990s, but its use declined as users switched from DOS to protected-mode operating systems such as Linux, IBM OS/2, and Microsoft Windows.
mem′o-ri, n. the power of retaining and reproducing mental or sensory impressions: a having or keeping in the mind: time within which past things can be remembered: that which is remembered: commemoration: remembrance.—n.pl. Memorabil′ia, things worth remembering: noteworthy points.—adj. Mem′orable, deserving to be remembered: remarkable.—adv. Mem′orably.—n. Memoran′dum, something to be remembered: a note to assist the memory: (law) a brief note of some transaction: (diplomacy) a summary of the state of a question:—pl. Memoran′dums, Memoran′da.—adjs. Mem′orātive, pertaining to memory: aiding the memory; Mem#x14D;′rial, bringing to memory: contained in memory.—n. that which serves to keep in remembrance: a monument: a note to help the memory: a written statement forming the ground of a petition, laid before a legislative or other body: (B.) memory.—v.t. Memō′rialise, to present a memorial to: to petition by a memorial.—n. Memō′rialist, one who writes, signs, or presents a memorial.—v.t. Mem′orise, to commit to memory: (Shak.) to cause to be remembered.—adv. Memor′iter, from memory: by heart.
— Chambers 20th Century Dictionary
Prospective memory is a form of memory that involves remembering to perform a planned action or intention at some future point in time. Prospective memory tasks are highly prevalent in daily life and range from relatively simple tasks to extreme life-or-death situations. Examples of simple tasks include remembering to put the toothpaste cap back on, remembering to reply to an email or remembering to return a rented movie. Examples of highly important situations include a patient remembering to take medication or a pilot remembering to perform specific safety procedures during a flight. In contrast to prospective memory, retrospective memory involves memory of people, events and words that have been encountered in the past. Prospective memory and retrospective memory differ in the fact that retrospective memory emphasizes memory for events that have previously occurred, while prospective memory focuses on intended future events and is thus considered a form of memory for the future. Retrospective memory involves the memory of what we know, containing informational content; prospective memory focuses on when to act, without focusing on informational content.
Long-term memory is memory in which associations among items are stored, as part of the theory of a dual-store memory model. The division of long term and short term memory has been supported by several double dissociation experiments. According to the theory, long-term memory differs structurally and functionally from sensory memory, working memory, short-term memory, and intermediate-term memory. While short-term and working memories persist for only about 20 to 30 seconds, information can remain in intermediate-term memory for 5 to 8 hours, and in long-term memory indefinitely. This differs from the theory of the single-store retrieved context model that has no differentiation between short-term and long-term memory. Long term memory is an important aspect of cognition. LTM can be divided into three processes: encoding, storage, and retrieval. Encoding of long-term memory occurs in the medial temporal lobe, and damage to the medial temporal lobe is known to cause anterograde amnesia.
A SIMM, or single in-line memory module, is a type of memory module containing random access memory used in computers from the early 1980s to the late 1990s. It differs from a dual in-line memory module, the most predominant form of memory module today, in that the contacts on a SIMM are redundant on both sides of the module. SIMMs were standardised under the JEDEC JESD-21C standard. Most early PC motherboards used socketed DIP chips. With the introduction of 286-based IBM XT/286, which could use larger amounts of memory, memory modules evolved to save motherboard space and to ease memory expansion. Instead of plugging in eight or nine single DIP DRAM chips, only one additional memory module was needed to increase the memory of the computer. A few 286-based computers used memory modules like SIPP memory. The SIPP's 30 pins often bent or broke during installation, which is why they were quickly replaced by SIMMs which used contact plates rather than pins. SIMMs were invented and patented by Wang Laboratories. Wang invented what was to become the basic memory module, now known as a SIMM in 1983. The original memory modules were built upon ceramic and had pins. Later the pins were removed and the modules were built on standard PCB material.
Memory segmentation is a computer (primary) memory management technique of division of a computer's primary memory into segments or sections. In a computer system using segmentation, a reference to a memory location includes a value that identifies a segment and an offset (memory location) within that segment. Segments or sections are also used in object files of compiled programs when they are linked together into a program image and when the image is loaded into memory. Segments usually correspond to natural divisions of a program such as individual routines or data tables so segmentation is generally more visible to the programmer than paging alone. Different segments may be created for different program modules, or for different classes of memory usage such as code and data segments. Certain segments may be shared between programs.Segmentation was originally invented as a method by which system software could isolate different software processes (tasks) and data they are using. It was intended to increase reliability of the systems running multiple processes simultaneously. In a x86-64 architecture it is considered legacy and most x86-64-based modern system software don't use memory segmentation. Instead they handle programs and their data by utilizing memory-paging which also serves as a way of memory protection. However most x86-64 implementations still support it for backward compatibility reasons. Moreover, segmentation is more of user's end of memory management scheme.
|Forward error correction|
Forward error correction
In telecommunication, information theory, and coding theory, forward error correction (FEC) or channel coding is a technique used for controlling errors in data transmission over unreliable or noisy communication channels. The central idea is the sender encodes the message in a redundant way, most often by using an error-correcting code (ECC). The redundancy allows the receiver to detect a limited number of errors that may occur anywhere in the message, and often to correct these errors without re-transmission. FEC gives the receiver the ability to correct errors without needing a reverse channel to request re-transmission of data, but at the cost of a fixed, higher forward channel bandwidth. FEC is therefore applied in situations where re-transmissions are costly or impossible, such as one-way communication links and when transmitting to multiple receivers in multicast. FEC information is usually added to mass storage (magnetic, optical and solid state/flash based) devices to enable recovery of corrupted data, is widely used in modems, is used on systems where the primary memory is ECC memory and in broadcast situations, where the receiver does not have capabilities to request re-transmission or doing so would induce significant latency. For example, in the case of a satellite orbiting around Uranus, a re-transmission because of decoding errors can create a delay of at least 5 hours. FEC processing in a receiver may be applied to a digital bit stream or in the demodulation of a digitally modulated carrier. For the latter, FEC is an integral part of the initial analog-to-digital conversion in the receiver. The Viterbi decoder implements a soft-decision algorithm to demodulate digital data from an analog signal corrupted by noise. Many FEC coders can also generate a bit-error rate (BER) signal which can be used as feedback to fine-tune the analog receiving electronics. The maximum proportion of errors or missing bits that can be corrected is determined by the design of the ECC, so different forward error correcting codes are suitable for different conditions. In general, a stronger code induces more redundancy that needs to be transmitted using the available bandwidth, which reduces the effective bit-rate while improving the received effective signal-to-noise ratio. The noisy-channel coding theorem of Claude Shannon answers the question of how much bandwidth is left for data communication while using the most efficient code that turns the decoding error probability to zero. This establishes bounds on the theoretical maximum information transfer rate of a channel with some given base noise level. His proof is not constructive, and hence gives no insight of how to build a capacity achieving code. However, after years of research, some advanced FEC systems like polar code achieve the Shannon channel capacity under the hypothesis of an infinite length frame.
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes the main storage available to a process or task, as a contiguous address space which is unique to each running process, or virtualizes the main storage available to all processes or tasks on the system as a contiguous global address space. The operating system manages virtual address spaces and the assignment of real memory to virtual memory. The CPU automatically translates virtual addresses to physical addresses using special memory management hardware, often referred to as a memory management unit. As long as virtual addresses are resolved to real memory locations the process runs uninterrupted. When translation fails, the operating system takes over and moves the desired memory page from backing store to main memory, returning control to the interrupted process. This simplifies the organization of applications, as, if they need to use more code and data than will fit into real memory, they do not have to move code and data between real memory and backing store. In addition, when processes are given separate address spaces, the technique offers protection to applications by isolating memory from other processes.
Non-volatile memory, nonvolatile memory, NVM or non-volatile storage is computer memory that can retrieve stored information even after having been power cycled. Examples of non-volatile memory include read-only memory, flash memory, ferroelectric RAM, most types of magnetic computer storage devices, optical discs, and early computer storage methods such as paper tape and punched cards. Non-volatile memory is typically used for the task of secondary storage, or long-term persistent storage. The most widely used form of primary storage today is a volatile form of random access memory, meaning that when the computer is shut down, anything contained in RAM is lost. However, most forms of non-volatile memory have limitations that make them unsuitable for use as primary storage. Typically, non-volatile memory either costs more or has a poorer performance than volatile random access memory. Several companies are working on developing non-volatile memory systems comparable in speed and capacity to volatile RAM. IBM is currently developing MRAM.
ECC Foreign Language Institute is one of the major private English teaching companies or eikaiwa in Japan. It is part of the ECC group. ECC is based in the Kansai region of Japan and also has many branches in the Chūbu and Kantō regions. As of February 2013 it has 171 schools across Japan. It has over 650 native English speakers as instructors.
Working memory is the system that actively holds multiple pieces of transitory information in the mind, where they can be manipulated. This involves execution of verbal and nonverbal tasks—such as reasoning and comprehension—and makes them available for further information-processing. Working memory can be partly distinguished from short term memory, depending on how these two forms of memory are defined. Working memory includes subsystems that store and manipulate visual images or verbal information, as well as a central executive that coordinates the subsystems. It includes visual representation of the possible moves, and awareness of the flow of information into and out of memory, all stored for a limited amount of time. Working memory tasks require monitoring as part of completing goal-directed actions in the setting of interfering processes and distractions. The cognitive processes needed to achieve this include the executive and attention control of short-term memory, which permit interim integration, processing, disposal, and retrieval of information. These processes are sensitive to age: working memory is associated with cognitive development, and research shows that its capacity tends to decline with old age. Working memory is a theoretical concept central both to cognitive psychology and neuroscience. In addition, neurological studies demonstrate a link between working memory and learning and attention.