Magnetic-core memory - Knowledge (XXG)

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then the total energy would cause a pulse to be injected into the next transformer pair. Those that did not contain a value simply faded out. Stored values were thus moved bit by bit down the chain with every pulse. Values were read out at the end, and fed back into the start of the chain to keep the values continually cycling through the system. Such systems have the disadvantage of not being random-access, to read any particular value one has to wait for it to cycle through the chain. Wang and Woo were working at

2402:; no information was actually stored magnetically within the individual cores. Each bit of the word had one core. Reading the contents of a given memory address generated a pulse of current in a wire corresponding to that address. Each address wire was threaded either through a core to signify a binary , or around the outside of that core, to signify a binary . As expected, the cores were much larger physically than those of read-write core memory. This type of memory was exceptionally reliable. An example was the 2171: 2634: 2622: 2005: 2070: 2054: 1790:

bit forward. To the extent that I may have focused on it, the approach was not suitable for our purposes." He describes the invention and associated events, in 1975. Forrester has since observed, "It took us about seven years to convince the industry that random-access magnetic-core memory was the solution to a missing link in computer technology. Then we spent the following seven years in the patent courts convincing them that they had not all thought of it first."

1821:. The second, Forrester's, was the coincident-current system, which enabled a small number of wires to control a large number of cores enabling 3D memory arrays of several million bits. The first use of magnetic core was in the Whirlwind computer, and Project Whirlwind's "most famous contribution was the random-access, magnetic core storage feature." Commercialization followed quickly. Magnetic core was used in peripherals of the 2277:) instructions incremented (or decremented) the value between the read phase and the write phase of a single memory cycle (perhaps signaling the memory controller to pause briefly in the middle of the cycle). This might be twice as fast as the process of obtaining the value with a read-write cycle, incrementing (or decrementing) the value in some processor register, and then writing the new value with another read-write cycle. 2013: 2286: 2062: 40: 2588: 2447:

had a memory cycle time of 1.0 μs in 1964, using cores that required a half-select current of 200 mA. Everything possible was done in order to decrease access times and increase data rates (bandwidth), including the simultaneous use of multiple grids of core, each storing one bit of a data word.

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greater than a certain intensity ("select") can cause the core to change its magnetic polarity. To select a memory location, one of the X and one of the Y lines are driven with half the current ("half-select") required to cause this change. Only the combined magnetic field generated where the X and Y

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In 1956, a group at IBM filed for a patent on a machine to automatically thread the first few wires through each core. This machine held the full plane of cores in a "nest" and then pushed an array of hollow needles through the cores to guide the wires. Use of this machine reduced the time taken to

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In April 2011, Forrester recalled, "the Wang use of cores did not have any influence on my development of random-access memory. The Wang memory was expensive and complicated. As I recall, which may not be entirely correct, it used two cores per binary bit and was essentially a delay line that moved a

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was installed on Whirlwind in the summer of 1953. Papian stated: "Magnetic-Core Storage has two big advantages: (1) greater reliability with a consequent reduction in maintenance time devoted to storage; (2) shorter access time (core access time is 9 microseconds: tube access time is approximately 25

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produced a series of pulses which were sent into the control transformers at half the energy needed to flip the polarity. The pulses were timed so the field in the transformers had not faded away before the next pulse arrived. If the storage transformer's field matched the field created by the pulse,

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Although core memory is obsolete, computer memory is still sometimes called "core" even though it is made of semiconductors, particularly by people who had worked with machines having actual core memory. The files that result from saving the entire contents of memory to disk for inspection, which is

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into nearby wires. If the new pulse being applied in the X-Y wires is the same as the last applied to that core, the existing field will do nothing, and no induction will result. If the new pulse is in the opposite direction, a pulse will be generated. This is normally picked up in a separate "sense"

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The cost of complete core memory systems was dominated by the cost of stringing the wires through the cores. Forrester's coincident-current system required one of the wires to be run at 45 degrees to the cores, which proved difficult to wire by machine, so that core arrays had to be assembled under

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Diagnosing hardware problems in core memory required time-consuming diagnostic programs to be run. While a quick test checked if every bit could contain a one and a zero, these diagnostics tested the core memory with worst-case patterns and had to run for several hours. As most computers had just a

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To write a 0 bit, two methods can be applied. The first one is the same as reading process with current in the original direction. The second has reversed logic. Write 0 bit, in other words, is to inhibit the writing of a 1 bit. The same amount of current is also sent through the Inhibit line. This

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The toroidal shape of a core is preferred since the magnetic path is closed, there are no magnetic poles and thus very little external flux. This allows the cores to be packed closely together without their magnetic fields interacting. The alternating 45-degree positioning used in early core arrays

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of core slowly increased. By the late 1960s a density of about 32 kilobits per cubic foot (about 0.9 kilobits per litre) was typical. The cost declined over this period from about $ 1 per bit to about 1 cent per bit. Reaching this density requires extremely careful manufacturing, which was almost

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the printed circuit board with the core array on a table. This slightly changed the positions of the cores along the wires running through them, and could fix the problem. The procedure was seldom needed, as core memory proved to be very reliable compared to other computer components of the day.

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Smaller cores made the use of hollow needles impractical, but there were numerous advances in semi-automatic core threading. Support nests with guide channels were developed. Cores were permanently bonded to a backing sheet "patch" that supported them during manufacture and later use. Threading

1892:. Core sizes shrank over the same period from around 0.1 inches (2.5 mm) diameter in the 1950s to 0.013 inches (0.33 mm) in 1966. The power required to flip the magnetization of one core is proportional to the volume, so this represents a drop in power consumption by a factor of 125. 1984:

by 1967. This was considered "unimaginably huge" at the time, and nicknamed the "Moby Memory". It cost $ 380,000 ($ 0.04/bit) and its width, height and depth was 175 cm × 127 cm × 64 cm (69 in × 50 in × 25 in) with its supporting circuitry (189

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Two key inventions led to the development of magnetic core memory in 1951. The first, An Wang's, was the write-after-read cycle, which solved the problem of how to use a storage medium in which the act of reading erased the data read, enabling the construction of a serial, one-dimensional

2029:. In core memory, the wires pass once through any given core—they are single-turn devices. The properties of materials used for memory cores are dramatically different from those used in power transformers. The magnetic material for a core memory requires a high degree of magnetic 2512:

Another characteristic of early core was that the coercive force was very temperature-sensitive; the proper half-select current at one temperature is not the proper half-select current at another temperature. So a memory controller would include a temperature sensor (typically a

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received the principal patent for his invention of the coincident-current core memory that enabled the 3D storage of information. William Papian of Project Whirlwind cited one of these efforts, Harvard's "Static Magnetic Delay Line", in an internal memo. The first core memory of

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The most important change, from the point of view of automation, was the combination of the sense and inhibit wires, eliminating the need for a circuitous diagonal sense wire. With small changes in layout, this also allowed much tighter packing of the cores in each patch.

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However, when Sense wire crosses too many cores, the half select current can also induce a considerable voltage across the whole line due to the superposition of the voltage at each single core. This potential risk of "misread" limits the minimum number of Sense wires.

1996:. At that time, core array and supporting electronics can fit on a single printed circuit board about 25 cm × 20 cm (10 in × 8 in) in size, the core array was mounted a few mm above the PCB and was protected with a metal or plastic plate. 2016:

Close-up of a core plane. The distance between the rings is roughly 1 mm (0.04 in). The green horizontal wires are X; the Y wires are dull brown and vertical, toward the back. The sense wires are diagonal, colored orange, and the inhibit wires are vertical twisted

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in that multiple words could be cleared or written with the same value in a single cycle. A typical machine's register set usually used only one small plane of this form of core memory. Some very large memories were built with this technology, for example the

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The Sense wire is used only during the read, and the Inhibit wire is used only during the write. For this reason, later core systems combined the two into a single wire, and used circuitry in the memory controller to switch the function of the wire.

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of information. Two or more wires pass through each core, forming an X-Y array of cores. When an electrical current above a certain threshold is applied to the wires, the core will become magnetized. The core to be assigned a value – or

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MIT wanted to charge IBM $ 0.02 per bit royalty on core memory. In 1964, after years of legal wrangling, IBM paid MIT $ 13 million for rights to Forrester's patent—the largest patent settlement to that date.

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To write a 1 bit, the selected X and Y lines are driven, with current in the opposite direction as for the read operation. As with the read, the core at the intersection of the X and Y lines changes magnetic

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card holds 8 billion bytes (8 GB). It rests on a section of magnetic-core memory that uses 64 cores to hold eight bytes. The microSDHC card holds over one billion times more bytes in much less physical

2146:) is sufficient to change the state; other cores will see only half the needed field ("half-selected"), or none at all. By driving the current through the wires in a particular direction, the resulting 2205:

The detection of such a pulse means that the bit had most recently contained a 1. Absence of the pulse means that the bit had contained a 0. The delay in sensing the voltage pulse is called the

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Core relies on the square hysteresis loop properties of the ferrite material used to make the toroids. An electric current in a wire that passes through a core creates a magnetic field. Only a

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Diagram of a 4×4 plane of magnetic core memory in an X/Y line coincident-current setup. X and Y are drive lines, S is sense, Z is inhibit. Arrows indicate the direction of current for writing.

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loop of certain magnetic materials as a storage or switching device was known from the earliest days of computer development. Much of this knowledge had developed due to an understanding of

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Another method of handling the temperature sensitivity was to enclose the magnetic core "stack" in a temperature controlled oven. Examples of this are the heated-air core memory of the

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filed a patent for the first static (non-moving) magnetic memory on 3 April 1946. Devol's magnetic memory was further refined via 5 additional patents and ultimately used in the first

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Core memory controllers were designed so that every read was followed immediately by a write (because the read forced all bits to 0, and because the write assumed this had happened).

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To read a bit of core memory, the circuitry tries to flip the bit to the polarity assigned to the 0 state, by driving the selected X and Y lines that intersect at that core.

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One of three inter-connected modules that make up an Omnibus-based PDP-8 core memory plane. This is the middle of the three and contains the array of actual ferrite cores.

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Wang's patent was not granted until 1955, and by that time magnetic-core memory was already in use. This started a long series of lawsuits, which eventually ended when

3921: 2045:). However, when the core is read, it is reset to a "zero" value. Circuits in the computer memory system then restore the information in an immediate re-write cycle. 2178:

curve for a magnetic memory core during a read operation. Sense line current pulse is high ("1") or low ("0") depending on original magnetization state of the core.

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single core-memory board, these diagnostics also moved themselves around in memory, making it possible to test every bit. An advanced test was called a "

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field forces the selected core's magnetic flux to circulate in one direction or the other (clockwise or counterclockwise). One direction is a stored

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always carried out by hand in spite of repeated major efforts to automate the process. Core was almost universal until the introduction of the first

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wire, allowing the system to know whether that core held a 1 or 0. As this readout process requires the core to be written, this process is known as

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in 1956. This development was little-known, however, and the mainstream development of core is normally associated with three independent teams.

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If the bit was previously 1, then the core changes magnetic polarity. This change, after a delay, induces a voltage pulse into the Sense line.

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When not being read or written, the cores maintain the last value they had, even if the power is turned off. Therefore, they are a type of

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The performance of early core memories can be characterized in today's terms as being very roughly comparable to a clock rate of 1

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developed one of the first commercial applications of coincident-current core memory storage in the "Tormat" memory of its new range of

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temperature, and it was easier (and cheaper) to maintain a constant temperature well above room temperature than one at or below it.

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each. As manufacturing volume increased, by 1970 IBM was producing 20 billion cores per year, and the price per core fell to

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Creighton D. Barnes, et al., Magnetic core storage device having a single winding for both the sensing and inhibit function,

3175: 1026: 695: 507: 2803:, George C. Devol & Erik B. Hansell, "Magnetic storage and sensing device", published 10 April 1956 2784:, George C. Devol & Erik B. Hansell, "Magnetic storage and sensing device", published 10 April 1956 2526: 2518: 2162:

was necessitated by the diagonal sense wires. With the elimination of these diagonal wires, tighter packing was possible.

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reduces the net current flowing through the respective core to half the select current, inhibiting change of polarity.

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lines were combined into a single wire, resulting in a memory array with just two wires per bit. For write, multiple

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For example, a value in memory could be read and modified almost as quickly as it could be read and written. In the

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To write a bit of core memory, the circuitry assumes there has been a read operation and the bit is in the 0 state.

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system. Each bit was stored using a pair of transformers, one that held the value and a second used for control. A

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so that less energy is required to change the magnetization direction. The core can take two states, encoding one

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An example of the scale, economics, and technology of core memory in the 1960s was the 256K 36-bit word (1.2

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to the wires, the needle and wire diameters were the same, and efforts were made to eliminate the use of needles.

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as memory. The cost of core memory declined sharply over the lifetime of the technology: costs began at roughly

3767: 2497: 2469: 2403: 1609: 1387: 1370: 859: 145: 3004:, Forrester, Jay W., "Multicoordinate digital information storage device", issued 28 February 1956 2879:, George C. Devol & Maurice J. Dunne, "Ferroresonant devices", published 12 April 1966 1817:(of 50 bits), using two cores to store a bit. A Wang core shift register is in the Revolution exhibit at the 1636:

nowadays commonly performed automatically when a major error occurs in a computer program, are still called "

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memories in the 1970s, though remained in use for mission-critical and high-reliability applications in the

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in an array of words was spread over a "stack" of planes. Each plane would manipulate one bit of a word in

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A 10.8 × 10.8 cm plane of magnetic core memory with 64 × 64 bits (4 Kb), as used in a

2170: 1673: 1566: 1255: 472: 342: 282: 2860:, George C. Devol & Erik B. Hansel, "Coincidence detectors", published 9 Jan 1962 2057:

One of three inter-connected modules that make up an Omnibus-based (PDP 8/e/f/m) PDP-8 core memory plane.

4057: 3077: 2541: 2465: 1511: 758: 676: 462: 272: 267: 247: 237: 103: 93: 58: 3850:– Shows close-ups of the magnetic core memory in this desktop electronic calculator from the mid-1960s. 2452:

word in each one, and the controller could access the entire 32-bit word in a single read/write cycle.

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and radiation. These were important advantages for some applications like first-generation industrial

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Following any such read, the bit contains a 0. This illustrates why a core memory access is called a

2102:), with wires woven through the holes in the cores' centers. In early systems there were four wires: 1947: 1625: 1547: 1322: 1101: 1061: 984: 597: 502: 392: 287: 150: 130: 113: 108: 3576:

Internally, the Moby Memory had 40 bits per word, but they were not exposed to the PDP-10 processor.

2004: 3817:(Rate Training Manual). Naval Education and Training Command. 1978. pp. 95–. NAVEDTRA 10088-B. 2143: 2042: 1841: 1765: 1665: 1598: 1360: 1051: 989: 974: 841: 793: 646: 457: 155: 3853: 3766:. US: National High Magnetic Field Laboratory: Museum of Electricity and Magnetism. Archived from 2966:

Forrester, Jay W. (1951). "Digital Information Storage In Three Dimensions Using Magnetic Cores".

1733: 3672: 3559: 3515: 3298: 3218: 3119: 3058: 2763: 2680: 2439:, which had fallen to 1.2 μs by the early 1970s, and by the mid-70s it was down to 600 2131: 1950: 1900:

thread the straight X and Y select lines from 25 hours to 12 minutes on a 128 by 128 core array.

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press in 1949. Rajchman later developed versions of the Williams tube and led development of the

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Norman, P. Glenn (1987), "The new AP101S General-Purpose Computer (GPC) for the Space Shuttle",

3342: 3327: 2947: 2905: 2899: 1992:, equivalent to 32 kB) core memory board that fitted into a DEC Q-bus computer was around 3731: 3629: 3549: 3374: 3241: 3208: 3171: 3146: 2909: 2755: 2670: 2665: 1869: 1773: 1761: 1741: 1711:

beginning in 1947. A fully developed core system was patented in 1947, and later purchased by

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Walter P. Shaw and Roderick W. Link, Method and Apparatus for Threading Perforated Articles,

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computer; this strategy continued through all of the follow-on core memory systems built by

2473: 2464:—it can retain its contents indefinitely without power. It is also relatively unaffected by 2395: 2391: 2386: 2091: 1834: 1749: 1700: 1605: 1570: 1472: 1466: 1392: 1355: 1345: 1310: 1122: 1076: 1044: 819: 814: 802: 487: 447: 207: 192: 88: 78: 2822:, George C. Devol, "Sensing device for magnetic record", published 1 March 1960 2495:

flight computers used core memory, which preserved the contents of memory even through the

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One of three inter-connected modules that make up an Omnibus-based PDP-8 core memory plane.

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By the early 1960s, the cost of core fell to the point that it became nearly universal as

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lines; this clears the selected cores and any that flip induce voltage pulses in their

2138: 1814: 1806: 1745: 1620: 1484: 1402: 1275: 1245: 902: 764: 700: 572: 557: 537: 532: 477: 442: 397: 347: 337: 332: 317: 212: 202: 135: 2312:. This form of core memory typically wove three wires through each core on the plane, 4036: 4008: 3948: 3836: 3621: 3563: 2650: 2489: 2481: 2304:

core memory was often used to provide register memory. Other names for this type are

2085: 2041:. The core memory contents are retained even when the memory system is powered down ( 2026: 1958: 1777: 1769: 1723: 1490: 1117: 1112: 1081: 836: 746: 562: 552: 547: 527: 362: 352: 232: 217: 3519: 3222: 3062: 3592:(Report). Massachusetts Institute of Technology. p. 18. 681342. Archived from 3192: 2767: 2432: 2285: 1905: 1696: 1685: 1437: 1431: 1397: 1265: 1220: 1204: 1096: 892: 887: 847: 809: 492: 467: 367: 302: 257: 242: 17: 3826: 2738:

Eckert, J. Presper (October 1953). "A Survey of Digital Computer Memory Systems".

3832: 3803: 4002: 3954: 3821: 3637: 2841:, George C. Devol, "Magnetic storage devices", published 15 May 1962 2691: 2570: 2399: 2126:(0 or 1). One bit in each plane could be accessed in one cycle, so each machine 2061: 2022: 1924: 1920: 1916: 1708: 1704: 1669: 1496: 1448: 882: 577: 417: 357: 262: 3545: 3276: 3262: 2950:, Wang, An, "Pulse Transfer Controlling Device", issued 17 May 2020 2751: 3446: 3428: 3410: 3395: 3355: 3104: 2716: 2612: 2514: 2477: 2440: 2175: 2081:, used for the main memory of a computer, consists of a large number of small 2034: 1928: 1740:

in 1949. The patent described a type of memory that would today be known as a

1601:. Depending on how it was wired, core memory could be exceptionally reliable. 1091: 917: 671: 437: 432: 307: 172: 98: 2759: 2577:," and the name stuck. In many occasions, errors could be resolved by gently 2098:) held together in a grid structure (organized as a "stack" of layers called 3511: 3054: 3030:. Massachusetts: The Computer Museum: 13. Winter 1983 – via Microsoft. 2655: 2595: 2544:, about 106 °F (41 °C) and the heated-oil-bath core memory of the 2448:

For instance, a machine might use 32 grids of core with a single bit of the

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kilobits/cubic foot = 6.7 kilobits/litre). Its cycle time was 2.75 μs.

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field, and its application in computer systems was immediate. For example,

39: 3468: 3204: 2556:. Core was heated instead of cooled because the primary requirement was a 2344:

lines ignored. To write words, the half current is applied to one or more

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Clarence Schultz and George Boesen, Selectors for Automatic Phonographs,

2553: 2549: 2545: 2537: 2480:, and led to core being used for a number of years after availability of 2444: 2428: 2374: 2290: 1989: 1943: 1719: 1407: 1350: 1285: 1240: 1225: 995: 964: 937: 912: 770: 656: 382: 292: 187: 182: 3880: 3538:

Proceedings of National Aerospace and Electronics Conference (NAECON'94)

1872:, which he had co-founded with Dr. Ge-Yao Chu, a schoolmate from China. 3860:

Werner, G.E.; Whalen, R.M.; Lockhart, N.F.; Flaker, R.C. (March 1967).

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If the bit was already 0, the physical state of the core is unaffected.

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Proceedings of the 1952 ACM national meeting (Pittsburgh) on - ACM '52

2987: 2443:(0.6 μs). Some designs had substantially higher performance: the 2485: 2449: 2324:. To read or clear words, the full current is applied to one or more 2082: 1562: 1300: 1260: 1142: 1031: 829: 372: 3533: 2364:

lines could be selected. This offered a performance advantage over

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Evans, Christopher (July 1983). "Conversation: Jay W. Forrester".

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Ronald A. Beck and Dennis L. Breu, Core Patch Stringing Method,

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A third developer involved in the early development of core was

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microseconds) thus increasing the speed of computer operation."

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Victor L. Sell and Syed Alvi, High Density Core Memory Matrix,

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Bashe, Charles J.; Johnson, Lyle R.; Palmer, John H. (1986).

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s disintegration and subsequent plunge into the sea in 1986.

2435:). Early core memory systems had cycle times of about 6 2134:, allowing the full word to be read or written in one cycle. 1703:. Frederick Viehe applied for various patents on the use of 1684:

had done some development work on the concept in 1945 at the

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Pugh, Emerson W.; Johnson, Lyle R.; Palmer, John H. (1991).

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Increasing Sense wires also requires more decode circuitry.

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delivered in July 1955, and later in the 702 itself. The

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Milestones in computer science and information technology

2118:, but later cores combined the latter two wires into one 2936:. US: Technical Publishing Company: 161–163. March 1976. 2930:"Wang Interview, An Wang's Early Work in Core Memories" 3393:

Robert L. Judge, Wire Threading Method and Apparatus,

3145:. McGraw-Hill International Book Company. p. 21. 43:

A 32 × 32 core memory plane storing 1024 bits (or 128

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Project Whirlwind - The History of a Pioneer Computer

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Substantial work in the field was carried out by the

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Project MAC. Progress Report IV. July 1966-July 1967

2427:(equivalent to early 1980s home computers, like the 2033:, the ability to stay highly magnetized, and a low 1585:This writing process also causes electricity to be 30:"Core memory" redirects here. For other uses, see 3338: 3323: 2336:line would be selected; but for clear, multiple 2182:The access time plus the time to rewrite is the 1896:microscopes by workers with fine motor control. 1707:for building digital logic circuits in place of 1608:, for example, was used on the mission-critical 3856:in multiple devices in a German computer museum 3534:"Risk management for the B-1B computer upgrade" 3193:"A static magnetic memory system for the ENIAC" 2352:line for a bit to be set. In some designs, the 3170:. Bedford, Mass.: Digital Press. p. 215. 1884:In 1953, tested but not-yet-strung cores cost 27:Type of computer memory used from 1955 to 1975 3915: 3786:"Interactive Tutorial - Magnetic Core Memory" 3532:Stormont, D.P.; Welgan, R. (23–27 May 1994). 1919:, replacing both inexpensive low-performance 1519: 8: 3440: 3438: 3422: 3420: 2540:(which could take up to 30 minutes to reach 3166:Redmond, Kent C.; Smith, Thomas M. (1980). 3130:. US: National Academy of Engineering: 229. 2472:, military installations and vehicles like 2348:lines, and half current is applied to each 1764:computer required a fast memory system for 3922: 3908: 3900: 3728:Hackers: Heroes of the Computer Revolution 2377:, which was up to 2 million 60-bit words. 1923:and costly high-performance systems using 1526: 1512: 50: 3373:. Cambridge, MA: MIT Press. p. 268. 3277:"An Wang Sells Core Memory Patent to IBM" 2904:. Westport, CT: Greenwood Press. p. 2893: 2891: 2611:Magnetic-core memory, 18×24 bits, with a 2262:were designed to take advantage of this. 1961:until an upgrade in early 1990s, and the 1864:bought the patent outright from Wang for 1768:aircraft tracking. At first, an array of 3833:Coincident Current Ferrite Core Memories 3827:Core memory and other early memory types 2021:The term "core" comes from conventional 1868:. Wang used the funds to greatly expand 1628:chips in the late 1960s, and especially 3895:Background on core memory for computers 3869:IBM Journal of Research and Development 3790:National High Magnetic Field Laboratory 3690:CS1 maint: location missing publisher ( 3461:"Project History: Magnetic Core Memory" 2708: 2584: 792: 587: 53: 3862:"A 110-Nanosecond Ferrite Core Memory" 3680: 3670: 3143:Computer Architecture and Organization 1982:MIT Artificial Intelligence Laboratory 1664:The basic concept of using the square 3078:"Jay Forrester's Shock to the System" 2676:Magnetoresistive random-access memory 2077:The most common form of core memory, 1067:Vision Electronic Recording Apparatus 7: 1988:In 1980, the price of a 16 kW ( 1976:) core memory unit installed on the 3730:, 2010 (25th anniversary edition), 3540:. Vol. 2. pp. 1143–1149. 2332:lines. For read, normally only one 2297:architecture with two wires per bit 2254:Combined read and write with modify 1840:It was during the early 1950s that 1619:Using smaller cores and wires, the 3102:Jan A. Rajchman, Magnetic System, 3043:Annals of the History of Computing 2340:lines could be selected while the 1837:(1957) used magnetic-core memory. 228:Data validation and reconciliation 25: 3750:Control Data 6600 Training Manual 3656:FABRI-TEK Mass Core 'Moby' Memory 3191:Auerbach, Isaac L. (2 May 1952). 1772:—a storage system based on 1738:pulse transfer controlling device 278:Distributed file system for cloud 3076:Kleiner, Art (4 February 2009). 2632: 2620: 2604: 2587: 126:Areal density (computer storage) 3339:Pugh, Johnson & Palmer 1991 3324:Pugh, Johnson & Palmer 1991 3238:IBM's 360 and Early 370 Systems 1935:per bit and dropped to roughly 945:Programmable metallization cell 4043:Magnetic-core memory computers 3659:. US. 4 August 1967. 102731715 2533:line of air-cooled computers. 2373:(ECS) auxiliary memory in the 2154:, while the other is a stored 508:Persistence (computer science) 1: 4048:History of computing hardware 3279:. US: Computer History Museum 2627:Magnetic-core memory close-up 2519:Digital Equipment Corporation 2122:line. Each toroid stored one 1616:'s successful Moon landings. 1376:Electronic quantum holography 1630:dynamic random-access memory 727:Video RAM (dual-ported DRAM) 523:Non-RAID drive architectures 32:Core memory (disambiguation) 3626:The New Hacker's Dictionary 3118:Hittinger, William (1992). 2746:(10). US: IEEE: 1393–1406. 2366:X/Y line coincident-current 2079:X/Y line coincident-current 4074: 3546:10.1109/NAECON.1994.332913 3028:The Computer Museum Report 2968:Journal of Applied Physics 2752:10.1109/JRPROC.1953.274316 2384: 2281:Other forms of core memory 2238:Combined sense and inhibit 2025:whose windings surround a 1316:Holographic Versatile Disc 1215:Compact Disc Digital Audio 1087:Magnetic-tape data storage 706:Content-addressable memory 29: 3938: 3822:Core Memory on the PDP-11 3305:. Computer History Museum 3240:. MIT Press. p. 32. 2898:Reilly, Edwin D. (2003). 513:Persistent data structure 408:Digital rights management 3450:, granted Jan. 16, 1973. 3414:, granted Mar. 25, 1975. 3399:, granted Apr. 18, 1967. 2470:programmable controllers 2414:Physical characteristics 2404:Apollo Guidance Computer 1610:Apollo Guidance Computer 1573:). Each core stores one 1388:DNA digital data storage 1371:Holographic data storage 860:Solid-state hybrid drive 146:Network-attached storage 3815:Digital Computer Basics 3512:10.1109/PROC.1987.13738 3359:, granted Nov. 1, 1960. 3266:, granted Feb. 2, 1960. 3141:Hayes, John P. (1978). 3055:10.1109/mahc.1983.10081 2508:Temperature sensitivity 1819:Computer History Museum 1383:5D optical data storage 1200:3D optical data storage 923:Universal Flash Storage 328:Replication (computing) 273:Distributed file system 163:Single-instance storage 141:Direct-attached storage 121:Continuous availability 3854:Still used core memory 3829:accessed 15 April 2006 3806:at Columbia University 3764:"Magnetic Core Memory" 3705:Krakauer, Lawrence J. 3432:, granted 4 July 1967. 3299:"Magnetic Core Memory" 3108:, granted 14 May 1957. 2740:Proceedings of the IRE 2298: 2179: 2074: 2066: 2058: 2018: 2009: 1955:IBM System/4 Pi AP-101 1674:electrical engineering 1661: 1567:hard magnetic material 1256:Nintendo optical discs 473:Storage virtualization 343:Information repository 283:Distributed data store 48: 3628:, 3rd edition, 1996, 3447:U.S. patent 3,711,839 3429:U.S. patent 3,329,940 3411:U.S. patent 3,872,581 3396:U.S. patent 3,314,131 3371:IBM's Early Computers 3356:U.S. patent 2,958,126 3205:10.1145/609784.609813 3105:U.S. patent 2,792,563 2717:"Computer for Apollo" 2542:operating temperature 2484:MOS memory (see also 2371:Extended Core Storage 2288: 2173: 2072: 2064: 2056: 2049:How core memory works 2015: 2007: 1942:Core memory was made 1927:, and later discrete 1656: 759:Mellon optical memory 747:Williams–Kilburn tube 463:Locality of reference 268:Clustered file system 94:Memory access pattern 59:computer data storage 42: 3890:on 26 February 2009. 3263:U.S. patent 2923553A 3199:. pp. 213–222. 3082:The MIT Sloan Review 2721:MIT Science Reporter 2488:). For example, the 2462:non-volatile storage 2209:of the core memory. 1880:Production economics 1626:semiconductor memory 1548:random-access memory 1544:magnetic-core memory 1455:Magnetic-core memory 1102:Digital Data Storage 1062:Quadruplex videotape 503:In-memory processing 393:Information transfer 288:Distributed database 151:Storage area network 131:Block (data storage) 4053:Non-volatile memory 3881:10.1147/rd.112.0153 3504:1987IEEEP..75..308N 2980:1951JAP....22...44F 2166:Reading and writing 2144:logical conjunction 2043:non-volatile memory 1842:Seeburg Corporation 1599:non-volatile memory 1592:destructive readout 1052:Phonograph cylinder 990:Electrochemical RAM 842:Solid-state storage 458:Memory segmentation 156:Block-level storage 18:Ferrite core memory 2681:Read-mostly memory 2299: 2180: 2075: 2067: 2059: 2019: 2010: 1951:integrated circuit 1755:Harvard University 1736:, who created the 1662: 1554:, or, informally, 1461:Plated-wire memory 1426:Paper data storage 1072:Magnetic recording 498:In-memory database 483:Memory-mapped file 428:Volume boot record 423:Master boot record 413:Volume (computing) 388:Data communication 313:Data deduplication 49: 4030: 4029: 3247:978-0-262-51720-1 3124:Memorial Tributes 3120:"Jan A. Rajchman" 2988:10.1063/1.1699817 2671:Ferroelectric RAM 2666:Delay-line memory 2184:memory cycle time 2142:lines cross (the 1870:Wang Laboratories 1783:32 × 32 × 16 bits 1774:cathode ray tubes 1762:Project Whirlwind 1695:Robotics pioneer 1682:Jeffrey Chuan Chu 1678:J. Presper Eckert 1658:Project Whirlwind 1571:semi-hard ferrite 1561:Core memory uses 1536: 1535: 1133:8 mm video format 1057:Phonograph record 876:Flash Core Module 854:Solid-state drive 753:Delay-line memory 712:Computational RAM 615:Scratchpad memory 453:Disk partitioning 178:Unstructured data 104:Secondary storage 16:(Redirected from 4065: 3931:Magnetic storage 3924: 3917: 3910: 3901: 3891: 3889: 3883:. Archived from 3866: 3818: 3811:"Magnetic Cores" 3800: 3798: 3796: 3772: 3771: 3770:on 10 June 2010. 3760: 3754: 3753: 3745: 3739: 3724: 3718: 3717: 3715: 3713: 3702: 3696: 3695: 3688: 3682: 3678: 3676: 3668: 3666: 3664: 3651: 3645: 3615: 3609: 3608: 3606: 3604: 3598: 3591: 3583: 3577: 3574: 3568: 3567: 3529: 3523: 3522: 3492:IEEE Proceedings 3487: 3481: 3480: 3478: 3476: 3467:. Archived from 3457: 3451: 3449: 3442: 3433: 3431: 3424: 3415: 3413: 3406: 3400: 3398: 3391: 3385: 3384: 3366: 3360: 3358: 3351: 3345: 3336: 3330: 3321: 3315: 3314: 3312: 3310: 3295: 3289: 3288: 3286: 3284: 3273: 3267: 3265: 3258: 3252: 3251: 3233: 3227: 3226: 3188: 3182: 3181: 3163: 3157: 3156: 3138: 3132: 3131: 3115: 3109: 3107: 3100: 3094: 3093: 3091: 3089: 3073: 3067: 3066: 3038: 3032: 3031: 3025: 3017: 3011: 3010: 3009: 3005: 2998: 2992: 2991: 2963: 2957: 2956: 2955: 2951: 2944: 2938: 2937: 2926: 2920: 2919: 2895: 2886: 2885: 2884: 2880: 2873: 2867: 2866: 2865: 2861: 2854: 2848: 2847: 2846: 2842: 2835: 2829: 2828: 2827: 2823: 2816: 2810: 2809: 2808: 2804: 2797: 2791: 2790: 2789: 2785: 2778: 2772: 2771: 2735: 2729: 2728: 2713: 2687:Thin-film memory 2661:Core rope memory 2636: 2624: 2608: 2591: 2503: 2474:fighter aircraft 2396:read-only memory 2392:Core rope memory 2387:Core rope memory 2381:Core rope memory 2276: 2272: 2260:Instruction sets 2214:destructive read 1995: 1938: 1934: 1891: 1887: 1867: 1835:Ferranti Mercury 1784: 1750:signal generator 1701:industrial robot 1606:core rope memory 1528: 1521: 1514: 1473:Thin-film memory 1467:Core rope memory 1393:Universal memory 1356:Millipede memory 1346:Racetrack memory 1311:Ultra HD Blu-ray 1123:Linear Tape-Open 1077:Magnetic storage 1045:Analog recording 488:Software entropy 448:Disk aggregation 208:Data degradation 193:Data compression 89:Memory hierarchy 79:Memory coherence 51: 21: 4073: 4072: 4068: 4067: 4066: 4064: 4063: 4062: 4033: 4032: 4031: 4026: 3934: 3928: 3887: 3864: 3859: 3809: 3794: 3792: 3784: 3781: 3776: 3775: 3762: 3761: 3757: 3747: 3746: 3742: 3725: 3721: 3711: 3709: 3704: 3703: 3699: 3689: 3679: 3669: 3662: 3660: 3653: 3652: 3648: 3636:, based on the 3618:Eric S. Raymond 3616: 3612: 3602: 3600: 3596: 3589: 3585: 3584: 3580: 3575: 3571: 3556: 3531: 3530: 3526: 3489: 3488: 3484: 3474: 3472: 3471:on 14 July 2023 3459: 3458: 3454: 3445: 3443: 3436: 3427: 3425: 3418: 3409: 3407: 3403: 3394: 3392: 3388: 3381: 3368: 3367: 3363: 3354: 3352: 3348: 3337: 3333: 3322: 3318: 3308: 3306: 3297: 3296: 3292: 3282: 3280: 3275: 3274: 3270: 3261: 3259: 3255: 3248: 3235: 3234: 3230: 3215: 3190: 3189: 3185: 3178: 3165: 3164: 3160: 3153: 3140: 3139: 3135: 3117: 3116: 3112: 3103: 3101: 3097: 3087: 3085: 3075: 3074: 3070: 3040: 3039: 3035: 3023: 3019: 3018: 3014: 3007: 3000: 2999: 2995: 2965: 2964: 2960: 2953: 2946: 2945: 2941: 2928: 2927: 2923: 2916: 2897: 2896: 2889: 2882: 2875: 2874: 2870: 2863: 2856: 2855: 2851: 2844: 2837: 2836: 2832: 2825: 2818: 2817: 2813: 2806: 2799: 2798: 2794: 2787: 2780: 2779: 2775: 2737: 2736: 2732: 2715: 2714: 2710: 2705: 2647: 2640: 2637: 2628: 2625: 2616: 2609: 2600: 2592: 2566: 2510: 2501: 2460:Core memory is 2458: 2421: 2416: 2410:Moon landings. 2389: 2383: 2350:bit sense/write 2342:bit sense/write 2330:bit sense/write 2322:bit sense/write 2283: 2274: 2270: 2256: 2240: 2222: 2192: 2174:Diagram of the 2168: 2051: 2002: 1993: 1936: 1932: 1889: 1885: 1882: 1865: 1858: 1856:Patent disputes 1850:process control 1833:(1954) and the 1795:Jan A. Rajchman 1782: 1651: 1646: 1532: 1503: 1502: 1421: 1413: 1412: 1366:Patterned media 1336: 1328: 1327: 1195: 1185: 1184: 1180:Hard disk drive 1047: 1037: 1036: 1017: 1006: 1005: 960: 950: 949: 871:IBM FlashSystem 866:USB flash drive 805: 788: 787: 742: 734: 733: 722:Dual-ported RAM 600: 583: 582: 543:Cloud computing 403:Copy protection 323:Data redundancy 253:Shared resource 223:Data validation 198:Data corruption 173:Structured data 84:Cache coherence 69: 55:Computer memory 35: 28: 23: 22: 15: 12: 11: 5: 4071: 4069: 4061: 4060: 4055: 4050: 4045: 4035: 4034: 4028: 4027: 4025: 4024: 4018: 4012: 4006: 4000: 3994: 3988: 3982: 3976: 3970: 3964: 3958: 3952: 3946: 3939: 3936: 3935: 3929: 3927: 3926: 3919: 3912: 3904: 3898: 3897: 3892: 3875:(2): 153–161. 3857: 3851: 3841: 3830: 3824: 3819: 3807: 3801: 3780: 3779:External links 3777: 3774: 3773: 3755: 3740: 3719: 3697: 3681:|website= 3646: 3644:'moby', p. 307 3610: 3578: 3569: 3554: 3524: 3498:(3): 308–319, 3482: 3452: 3434: 3416: 3401: 3386: 3379: 3361: 3346: 3331: 3316: 3303:CHM Revolution 3290: 3268: 3253: 3246: 3228: 3213: 3183: 3176: 3158: 3151: 3133: 3110: 3095: 3068: 3049:(3): 297–301. 3033: 3012: 2993: 2958: 2939: 2921: 2914: 2887: 2868: 2849: 2830: 2811: 2792: 2773: 2730: 2707: 2706: 2704: 2701: 2700: 2699: 2697:Twistor memory 2694: 2689: 2684: 2678: 2673: 2668: 2663: 2658: 2653: 2646: 2643: 2642: 2641: 2638: 2631: 2629: 2626: 2619: 2617: 2610: 2603: 2601: 2593: 2586: 2565: 2562: 2509: 2506: 2457: 2454: 2420: 2417: 2415: 2412: 2385:Main article: 2382: 2379: 2293:. Inset shows 2282: 2279: 2255: 2252: 2239: 2236: 2235: 2234: 2230: 2221: 2218: 2203: 2202: 2199: 2191: 2188: 2167: 2164: 2139:magnetic field 2050: 2047: 2001: 1998: 1881: 1878: 1857: 1854: 1815:shift register 1770:Williams tubes 1746:shift-register 1650: 1647: 1645: 1642: 1621:memory density 1534: 1533: 1531: 1530: 1523: 1516: 1508: 1505: 1504: 1501: 1500: 1494: 1488: 1485:Twistor memory 1482: 1476: 1470: 1464: 1458: 1452: 1446: 1441: 1435: 1429: 1422: 1419: 1418: 1415: 1414: 1411: 1410: 1405: 1403:Quantum memory 1400: 1395: 1390: 1385: 1380: 1379: 1378: 1368: 1363: 1358: 1353: 1348: 1343: 1337: 1335:In development 1334: 1333: 1330: 1329: 1326: 1325: 1320: 1319: 1318: 1313: 1308: 1303: 1298: 1293: 1288: 1283: 1278: 1273: 1268: 1263: 1258: 1253: 1248: 1246:Super Video CD 1243: 1238: 1233: 1228: 1223: 1218: 1212: 1207: 1196: 1191: 1190: 1187: 1186: 1183: 1182: 1177: 1176: 1175: 1170: 1165: 1160: 1155: 1150: 1145: 1140: 1135: 1130: 1125: 1120: 1115: 1110: 1105: 1099: 1094: 1089: 1084: 1079: 1069: 1064: 1059: 1054: 1048: 1043: 1042: 1039: 1038: 1035: 1034: 1029: 1024: 1018: 1012: 1011: 1008: 1007: 1004: 1003: 998: 993: 987: 982: 972: 967: 961: 956: 955: 952: 951: 948: 947: 942: 941: 940: 935: 930: 925: 920: 915: 910: 905: 903:MultiMediaCard 900: 895: 890: 880: 879: 878: 873: 868: 863: 857: 851: 839: 834: 833: 832: 827: 817: 812: 806: 801: 800: 797: 796: 790: 789: 786: 785: 779: 773: 768: 765:Selectron tube 762: 756: 750: 743: 740: 739: 736: 735: 732: 731: 730: 729: 719: 714: 709: 703: 698: 693: 692: 691: 681: 680: 679: 674: 669: 664: 659: 654: 649: 644: 639: 634: 629: 619: 618: 617: 612: 605:Hardware cache 601: 596: 595: 592: 591: 585: 584: 581: 580: 575: 570: 565: 560: 558:Edge computing 555: 550: 545: 540: 538:Grid computing 535: 533:Bank switching 530: 525: 520: 515: 510: 505: 500: 495: 490: 485: 480: 478:Virtual memory 475: 470: 465: 460: 455: 450: 445: 443:Disk mirroring 440: 435: 430: 425: 420: 415: 410: 405: 400: 398:Temporary file 395: 390: 385: 380: 375: 370: 365: 360: 355: 350: 348:Knowledge base 345: 340: 338:Storage record 335: 333:Memory refresh 330: 325: 320: 318:Data structure 315: 310: 305: 300: 295: 290: 285: 280: 275: 270: 265: 260: 255: 250: 245: 240: 235: 230: 225: 220: 215: 213:Data integrity 210: 205: 203:Data cleansing 200: 195: 190: 185: 180: 175: 170: 165: 160: 159: 158: 153: 143: 138: 136:Object storage 133: 128: 123: 118: 117: 116: 106: 101: 96: 91: 86: 81: 76: 70: 67: 66: 63: 62: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 4070: 4059: 4056: 4054: 4051: 4049: 4046: 4044: 4041: 4040: 4038: 4022: 4019: 4016: 4013: 4010: 4007: 4004: 4001: 3998: 3995: 3992: 3989: 3986: 3983: 3980: 3977: 3974: 3971: 3968: 3965: 3962: 3959: 3956: 3953: 3950: 3947: 3944: 3941: 3940: 3937: 3932: 3925: 3920: 3918: 3913: 3911: 3906: 3905: 3902: 3896: 3893: 3886: 3882: 3878: 3874: 3870: 3863: 3858: 3855: 3852: 3849: 3847: 3842: 3839: 3838: 3837:Byte magazine 3834: 3831: 3828: 3825: 3823: 3820: 3816: 3812: 3808: 3805: 3802: 3791: 3787: 3783: 3782: 3778: 3769: 3765: 3759: 3756: 3751: 3748:"Section 4". 3744: 3741: 3737: 3733: 3729: 3726:Steven Levy, 3723: 3720: 3708: 3707:"Moby Memory" 3701: 3698: 3693: 3686: 3674: 3658: 3657: 3650: 3647: 3643: 3639: 3635: 3631: 3627: 3623: 3622:Guy L. Steele 3619: 3614: 3611: 3599:on 8 May 2021 3595: 3588: 3582: 3579: 3573: 3570: 3565: 3561: 3557: 3555:0-7803-1893-5 3551: 3547: 3543: 3539: 3535: 3528: 3525: 3521: 3517: 3513: 3509: 3505: 3501: 3497: 3493: 3486: 3483: 3470: 3466: 3462: 3456: 3453: 3448: 3441: 3439: 3435: 3430: 3423: 3421: 3417: 3412: 3405: 3402: 3397: 3390: 3387: 3382: 3380:0-262-52393-0 3376: 3372: 3365: 3362: 3357: 3350: 3347: 3344: 3340: 3335: 3332: 3329: 3325: 3320: 3317: 3304: 3300: 3294: 3291: 3278: 3272: 3269: 3264: 3257: 3254: 3249: 3243: 3239: 3232: 3229: 3224: 3220: 3216: 3214:9781450373623 3210: 3206: 3202: 3198: 3194: 3187: 3184: 3179: 3173: 3169: 3162: 3159: 3154: 3152:0-07-027363-4 3148: 3144: 3137: 3134: 3129: 3125: 3121: 3114: 3111: 3106: 3099: 3096: 3083: 3079: 3072: 3069: 3064: 3060: 3056: 3052: 3048: 3044: 3037: 3034: 3029: 3022: 3016: 3013: 3003: 2997: 2994: 2989: 2985: 2981: 2977: 2973: 2969: 2962: 2959: 2949: 2943: 2940: 2935: 2931: 2925: 2922: 2917: 2915:1-57356-521-0 2911: 2907: 2903: 2902: 2894: 2892: 2888: 2878: 2872: 2869: 2859: 2853: 2850: 2840: 2834: 2831: 2821: 2815: 2812: 2802: 2796: 2793: 2783: 2777: 2774: 2769: 2765: 2761: 2757: 2753: 2749: 2745: 2741: 2734: 2731: 2726: 2722: 2718: 2712: 2709: 2702: 2698: 2695: 2693: 2690: 2688: 2685: 2682: 2679: 2677: 2674: 2672: 2669: 2667: 2664: 2662: 2659: 2657: 2654: 2652: 2651:Bubble memory 2649: 2648: 2644: 2635: 2630: 2623: 2618: 2614: 2607: 2602: 2597: 2590: 2585: 2583: 2580: 2576: 2572: 2563: 2561: 2559: 2555: 2551: 2547: 2543: 2539: 2534: 2532: 2528: 2524: 2520: 2516: 2507: 2505: 2500: 2499: 2494: 2491: 2490:Space Shuttle 2487: 2483: 2482:semiconductor 2479: 2476:, as well as 2475: 2471: 2467: 2463: 2455: 2453: 2451: 2446: 2442: 2438: 2434: 2430: 2426: 2418: 2413: 2411: 2409: 2406:used for the 2405: 2401: 2397: 2393: 2388: 2380: 2378: 2376: 2372: 2367: 2363: 2359: 2355: 2351: 2347: 2343: 2339: 2335: 2331: 2327: 2323: 2319: 2315: 2311: 2307: 2306:linear select 2303: 2296: 2292: 2287: 2280: 2278: 2268: 2263: 2261: 2253: 2251: 2248: 2244: 2237: 2231: 2227: 2226: 2225: 2219: 2217: 2215: 2210: 2208: 2200: 2197: 2196: 2195: 2189: 2187: 2185: 2177: 2172: 2165: 2163: 2159: 2157: 2153: 2149: 2145: 2140: 2135: 2133: 2129: 2125: 2121: 2120:Sense/Inhibit 2117: 2113: 2109: 2105: 2101: 2097: 2093: 2090: 2087: 2086:ferrimagnetic 2084: 2080: 2071: 2063: 2055: 2048: 2046: 2044: 2040: 2036: 2032: 2028: 2027:magnetic core 2024: 2014: 2006: 1999: 1997: 1991: 1986: 1983: 1979: 1975: 1970: 1968: 1964: 1960: 1959:Space Shuttle 1957:(used in the 1956: 1952: 1949: 1948:semiconductor 1945: 1940: 1930: 1926: 1922: 1918: 1913: 1909: 1907: 1904:needles were 1901: 1897: 1893: 1879: 1877: 1873: 1871: 1863: 1855: 1853: 1851: 1847: 1843: 1838: 1836: 1832: 1828: 1825:in 1953, the 1824: 1820: 1816: 1810: 1808: 1804: 1800: 1796: 1791: 1787: 1779: 1778:Jay Forrester 1775: 1771: 1767: 1763: 1758: 1756: 1751: 1747: 1743: 1739: 1735: 1731: 1728: 1725: 1721: 1716: 1714: 1710: 1706: 1702: 1698: 1693: 1691: 1687: 1683: 1679: 1675: 1671: 1667: 1659: 1655: 1648: 1643: 1641: 1639: 1633: 1631: 1627: 1622: 1617: 1615: 1612:essential to 1611: 1607: 1604: 1600: 1595: 1593: 1588: 1583: 1581: 1576: 1572: 1568: 1565:(rings) of a 1564: 1559: 1557: 1553: 1549: 1546:is a form of 1545: 1541: 1529: 1524: 1522: 1517: 1515: 1510: 1509: 1507: 1506: 1498: 1495: 1492: 1491:Bubble memory 1489: 1486: 1483: 1480: 1477: 1474: 1471: 1468: 1465: 1462: 1459: 1456: 1453: 1450: 1447: 1445: 1442: 1439: 1436: 1433: 1430: 1427: 1424: 1423: 1417: 1416: 1409: 1406: 1404: 1401: 1399: 1396: 1394: 1391: 1389: 1386: 1384: 1381: 1377: 1374: 1373: 1372: 1369: 1367: 1364: 1362: 1359: 1357: 1354: 1352: 1349: 1347: 1344: 1342: 1339: 1338: 1332: 1331: 1324: 1321: 1317: 1314: 1312: 1309: 1307: 1304: 1302: 1299: 1297: 1294: 1292: 1289: 1287: 1284: 1282: 1279: 1277: 1274: 1272: 1269: 1267: 1264: 1262: 1259: 1257: 1254: 1252: 1249: 1247: 1244: 1242: 1239: 1237: 1234: 1232: 1229: 1227: 1224: 1222: 1219: 1216: 1213: 1211: 1208: 1206: 1203: 1202: 1201: 1198: 1197: 1194: 1189: 1188: 1181: 1178: 1174: 1171: 1169: 1166: 1164: 1161: 1159: 1156: 1154: 1151: 1149: 1146: 1144: 1141: 1139: 1136: 1134: 1131: 1129: 1126: 1124: 1121: 1119: 1118:Cassette tape 1116: 1114: 1113:Videocassette 1111: 1109: 1106: 1103: 1100: 1098: 1095: 1093: 1090: 1088: 1085: 1083: 1082:Magnetic tape 1080: 1078: 1075: 1074: 1073: 1070: 1068: 1065: 1063: 1060: 1058: 1055: 1053: 1050: 1049: 1046: 1041: 1040: 1033: 1030: 1028: 1025: 1023: 1020: 1019: 1016: 1010: 1009: 1002: 999: 997: 994: 991: 988: 986: 983: 980: 976: 973: 971: 968: 966: 963: 962: 959: 954: 953: 946: 943: 939: 936: 934: 931: 929: 926: 924: 921: 919: 916: 914: 911: 909: 906: 904: 901: 899: 896: 894: 891: 889: 886: 885: 884: 881: 877: 874: 872: 869: 867: 864: 861: 858: 855: 852: 849: 846: 845: 843: 840: 838: 837:ROM cartridge 835: 831: 828: 826: 823: 822: 821: 818: 816: 813: 811: 808: 807: 804: 799: 798: 795: 791: 783: 780: 777: 774: 772: 769: 766: 763: 760: 757: 754: 751: 748: 745: 744: 738: 737: 728: 725: 724: 723: 720: 718: 715: 713: 710: 707: 704: 702: 699: 697: 694: 690: 687: 686: 685: 682: 678: 675: 673: 670: 668: 665: 663: 660: 658: 655: 653: 650: 648: 645: 643: 640: 638: 635: 633: 630: 628: 625: 624: 623: 620: 616: 613: 611: 608: 607: 606: 603: 602: 599: 594: 593: 590: 586: 579: 576: 574: 571: 569: 566: 564: 563:Dew computing 561: 559: 556: 554: 553:Fog computing 551: 549: 548:Cloud storage 546: 544: 541: 539: 536: 534: 531: 529: 528:Memory paging 526: 524: 521: 519: 516: 514: 511: 509: 506: 504: 501: 499: 496: 494: 491: 489: 486: 484: 481: 479: 476: 474: 471: 469: 466: 464: 461: 459: 456: 454: 451: 449: 446: 444: 441: 439: 436: 434: 431: 429: 426: 424: 421: 419: 416: 414: 411: 409: 406: 404: 401: 399: 396: 394: 391: 389: 386: 384: 381: 379: 376: 374: 371: 369: 366: 364: 363:File deletion 361: 359: 356: 354: 353:Computer file 351: 349: 346: 344: 341: 339: 336: 334: 331: 329: 326: 324: 321: 319: 316: 314: 311: 309: 306: 304: 301: 299: 296: 294: 291: 289: 286: 284: 281: 279: 276: 274: 271: 269: 266: 264: 261: 259: 256: 254: 251: 249: 246: 244: 241: 239: 236: 234: 233:Data recovery 231: 229: 226: 224: 221: 219: 218:Data security 216: 214: 211: 209: 206: 204: 201: 199: 196: 194: 191: 189: 186: 184: 181: 179: 176: 174: 171: 169: 166: 164: 161: 157: 154: 152: 149: 148: 147: 144: 142: 139: 137: 134: 132: 129: 127: 124: 122: 119: 115: 114:floating-gate 112: 111: 110: 107: 105: 102: 100: 97: 95: 92: 90: 87: 85: 82: 80: 77: 75: 72: 71: 65: 64: 60: 56: 52: 46: 41: 37: 33: 19: 4058:Types of RAM 3961:Ferrite core 3960: 3885:the original 3872: 3868: 3845: 3835: 3814: 3793:. Retrieved 3768:the original 3758: 3749: 3743: 3727: 3722: 3710:. Retrieved 3700: 3661:. Retrieved 3655: 3649: 3641: 3625: 3613: 3601:. Retrieved 3594:the original 3581: 3572: 3537: 3527: 3495: 3491: 3485: 3473:. Retrieved 3469:the original 3464: 3455: 3404: 3389: 3370: 3364: 3349: 3334: 3319: 3307:. Retrieved 3302: 3293: 3281:. Retrieved 3271: 3256: 3237: 3231: 3196: 3186: 3167: 3161: 3142: 3136: 3127: 3123: 3113: 3098: 3086:. Retrieved 3081: 3071: 3046: 3042: 3036: 3027: 3015: 2996: 2974:(1): 44–48. 2971: 2967: 2961: 2942: 2933: 2924: 2900: 2871: 2852: 2833: 2814: 2795: 2776: 2743: 2739: 2733: 2720: 2711: 2567: 2557: 2535: 2511: 2496: 2459: 2433:Commodore 64 2422: 2400:transformers 2390: 2365: 2361: 2357: 2353: 2349: 2345: 2341: 2337: 2333: 2329: 2325: 2321: 2317: 2313: 2309: 2305: 2301: 2300: 2294: 2264: 2257: 2249: 2245: 2241: 2223: 2213: 2211: 2206: 2204: 2193: 2183: 2181: 2160: 2155: 2151: 2136: 2119: 2115: 2111: 2107: 2103: 2099: 2095: 2078: 2076: 2023:transformers 2020: 1987: 1971: 1941: 1925:vacuum tubes 1914: 1910: 1902: 1898: 1894: 1883: 1874: 1859: 1839: 1811: 1792: 1788: 1759: 1737: 1734:Way-Dong Woo 1717: 1705:transformers 1697:George Devol 1694: 1686:Moore School 1670:transformers 1663: 1634: 1618: 1596: 1591: 1584: 1579: 1560: 1555: 1551: 1543: 1537: 1454: 1438:Punched tape 1432:Punched card 1398:Time crystal 1266:Hyper CD-ROM 1205:Optical disc 1097:Tape library 1032:FeFET memory 1013:Early-stage 893:CompactFlash 888:Memory Stick 848:Flash memory 810:Diode matrix 794:Non-volatile 578:Kryder's law 568:Amdahl's law 493:Software rot 468:Logical disk 368:File copying 303:Data storage 258:File sharing 243:Data cluster 36: 4003:Floppy disk 3973:Stripe card 3840:, July 1976 3804:Core Memory 3795:27 November 3638:Jargon File 3465:web.mit.edu 3341:, pp. 3021:"Whirlwind" 2692:Transfluxor 2639:At an angle 2493:IBM AP-101B 2456:Reliability 2207:access time 2000:Description 1929:transistors 1921:drum memory 1917:main memory 1906:butt welded 1866:US$ 500,000 1709:relay logic 1688:during the 1660:core memory 1569:(usually a 1552:core memory 1497:Floppy disk 1449:Drum memory 883:Memory card 850:is used in: 784:(2002–2010) 749:(1946–1947) 573:Moore's law 418:Boot sector 358:Object file 263:File system 74:Memory cell 4037:Categories 3848:calculator 3736:1449393748 3712:7 December 3663:7 December 3634:0262680920 3603:7 December 3326:, p. 3177:0932376096 3002:US 2736880 2948:US 2708722 2934:Datamation 2877:US 3246219 2858:US 3016465 2839:US 3035253 2820:US 2926844 2801:US 2741757 2782:US 2590091 2703:References 2613:US quarter 2571:Shmoo test 2564:Diagnosing 2558:consistent 2529:for their 2521:for their 2515:thermistor 2498:Challenger 2478:spacecraft 2362:word write 2358:word write 2346:word write 2318:word write 2176:hysteresis 2035:coercivity 1969:bombers). 1890:US$ 0.0003 1852:followed. 1742:delay-line 1727:physicists 1666:hysteresis 1649:Developers 1638:core dumps 1420:Historical 1092:Tape drive 918:SmartMedia 741:Historical 438:Disk image 433:Disk array 308:Data store 109:MOS memory 99:Memory map 4021:Racetrack 3985:Thin film 3967:Hard disk 3683:ignored ( 3673:cite book 3564:109575632 2760:0096-8390 2656:Core dump 2615:for scale 2596:microSDHC 2550:IBM 7094s 2354:word read 2338:word read 2334:word read 2326:word read 2314:word read 2302:Word line 2295:word line 2229:polarity. 2031:remanence 1994:US$ 3,000 1939:per bit. 1846:jukeboxes 1807:Selectron 1766:real-time 1692:efforts. 1603:Read-only 1540:computing 1479:Disk pack 1444:Plugboard 1281:DVD-Video 1210:LaserDisc 1108:Videotape 979:3D XPoint 970:Memristor 610:CPU cache 378:Core dump 298:Data bank 248:Directory 3520:19179436 3283:12 April 3223:17518946 3063:25146240 2723:. 1965. 2645:See also 2554:IBM 7030 2548:, early 2546:IBM 7090 2538:IBM 1620 2445:CDC 6600 2429:Apple II 2375:CDC 6600 2291:CDC 6600 2132:parallel 2092:ferrites 2083:toroidal 1990:kiloword 1944:obsolete 1937:US$ 0.01 1933:US$ 1.00 1886:US$ 0.33 1760:The MIT 1724:American 1720:Shanghai 1408:UltraRAM 1286:DVD card 1241:Video CD 1226:CD Video 996:Nano-RAM 965:Memistor 938:XQD card 913:SIM card 771:Dekatron 657:XDR DRAM 652:EDO DRAM 589:Volatile 383:Hex dump 293:Database 188:Metadata 183:Big data 4011:(~1970) 3999:(~1968) 3997:Twistor 3846:AL-1000 3738:, p. 98 3500:Bibcode 3475:14 July 3309:1 April 3088:1 April 2976:Bibcode 2768:8564797 2579:tapping 2220:Writing 2190:Reading 2148:induced 2116:Inhibit 2089:ceramic 1980:at the 1831:IBM 704 1827:IBM 702 1803:aspirin 1730:An Wang 1644:History 1587:induced 1580:written 1563:toroids 1493:(~1970) 1487:(~1968) 1469:(1960s) 1306:Blu-ray 1296:MiniDVD 1291:DVD-RAM 1251:Mini CD 1193:Optical 1153:U-matic 1148:MicroMV 1128:Betamax 992:(ECRAM) 933:MicroP2 908:SD card 898:PC Card 689:1T-SRAM 647:QDRSRAM 238:Storage 68:General 4023:(2008) 4017:(1995) 4009:Bubble 4005:(1969) 3993:(1962) 3987:(1962) 3981:(1956) 3975:(1956) 3969:(1956) 3963:(1949) 3957:(1932) 3951:(1928) 3945:(1898) 3844:Casio 3734: 3632: 3562: 3552: 3518: 3377: 3244: 3221: 3211: 3174: 3149: 3061: 3008: 2954: 2912: 2883: 2864: 2845: 2826: 2807: 2788: 2766: 2758: 2599:space. 2552:, and 2486:MOSFET 2450:32-bit 2320:, and 2269:, the 2114:, and 2100:planes 2017:pairs. 1722:-born 1499:(1971) 1481:(1962) 1475:(1962) 1463:(1957) 1457:(1949) 1451:(1932) 1440:(1725) 1434:(1725) 1428:(1725) 1301:HD DVD 1261:CD-ROM 1217:(CDDA) 1143:MiniDV 862:(SSHD) 844:(SSS) 830:EEPROM 778:(2009) 767:(1952) 761:(1951) 755:(1947) 373:Backup 3933:media 3888:(PDF) 3865:(PDF) 3597:(PDF) 3590:(PDF) 3560:S2CID 3516:S2CID 3343:204–6 3219:S2CID 3059:S2CID 3024:(PDF) 2764:S2CID 2683:(RMM) 2594:This 2575:Shmoo 2523:PDP-1 2502:' 2419:Speed 2394:is a 2267:PDP-6 2112:Sense 2096:cores 1978:PDP-6 1823:ENIAC 1690:ENIAC 1361:ECRAM 1341:CBRAM 1276:DVD+R 1236:CD-RW 1173:D-VHS 1168:VHS-C 1163:S-VHS 1104:(DDS) 1027:ReRAM 1022:FeRAM 1015:NVRAM 1001:CBRAM 958:NVRAM 856:(SSD) 825:EPROM 782:Z-RAM 776:T-RAM 708:(CAM) 696:ReRAM 662:RDRAM 642:LPDDR 637:SGRAM 632:SDRAM 627:eDRAM 61:types 45:bytes 4015:MRAM 3991:CRAM 3979:MICR 3955:Drum 3949:Tape 3943:Wire 3797:2023 3732:ISBN 3714:2020 3692:link 3685:help 3665:2020 3642:s.v. 3630:ISBN 3605:2020 3550:ISBN 3477:2023 3375:ISBN 3311:2018 3285:2010 3242:ISBN 3209:ISBN 3172:ISBN 3147:ISBN 3090:2018 3084:. US 2910:ISBN 2756:ISSN 2725:WGBH 2431:and 2408:NASA 2356:and 2308:and 2275:SOS* 2273:(or 2271:AOS* 2128:word 1967:B-1B 1965:and 1963:B-52 1732:and 1680:and 1614:NASA 1556:core 1351:NRAM 1323:WORM 1231:CD-R 985:MRAM 820:PROM 815:MROM 717:VRAM 701:QRAM 684:SRAM 672:GDDR 622:DRAM 518:RAID 168:Data 57:and 3877:doi 3542:doi 3508:doi 3328:182 3201:doi 3051:doi 2984:doi 2906:164 2748:doi 2531:PDP 2527:DEC 2466:EMP 2425:MHz 2310:2-D 2124:bit 2039:bit 1974:MiB 1946:by 1862:IBM 1799:RCA 1797:at 1744:or 1713:IBM 1640:". 1575:bit 1538:In 1271:DVD 1158:VHS 975:PCM 928:SxS 803:ROM 677:HBM 667:DDR 598:RAM 4039:: 3873:11 3871:. 3867:. 3813:. 3788:. 3677:: 3675:}} 3671:{{ 3640:, 3624:, 3620:, 3558:. 3548:. 3536:. 3514:, 3506:, 3496:75 3494:, 3463:. 3437:^ 3419:^ 3301:. 3217:. 3207:. 3195:. 3126:. 3122:. 3080:. 3057:. 3045:. 3026:. 2982:. 2972:22 2970:. 2932:. 2908:. 2890:^ 2762:. 2754:. 2744:41 2742:. 2719:. 2441:ns 2437:μs 2316:, 2186:. 2158:. 2110:, 2106:, 1809:. 1558:. 1542:, 1221:CD 1138:DV 3923:e 3916:t 3909:v 3879:: 3799:. 3716:. 3694:) 3687:) 3667:. 3607:. 3566:. 3544:: 3510:: 3502:: 3479:. 3383:. 3313:. 3287:. 3250:. 3225:. 3203:: 3180:. 3155:. 3128:5 3092:. 3065:. 3053:: 3047:5 2990:. 2986:: 2978:: 2918:. 2770:. 2750:: 2727:. 2156:0 2152:1 2108:Y 2104:X 2094:( 1527:e 1520:t 1513:v 981:) 977:( 34:. 20:)

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Index