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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
2013:
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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."
2286:
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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.
40:
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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.
2141:
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
1899:
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
1789:
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
1785:
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
1752:
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,
1635:
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
1589:
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"
1895:
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
2568:
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
2232:
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
2161:
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
1623:
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
2581:
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.
1903:
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
1812:
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
1780:
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
1582:– is selected by powering one X and one Y wire to half of the required power, such that only the single core at the intersection is written. Depending on the direction of the currents, the core will pick up a clockwise or counterclockwise magnetic field, storing a 1 or 0.
1911:
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.
2246:
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
3006:
2242:
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.
2228:
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
2598:
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
2137:
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
2573:" in which the half-select currents were modified along with the time at which the sense line was tested ("strobed"). The data plot of this test seemed to resemble a cartoon character called "
2008:
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.
1668:
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
1776:—was used, but proved temperamental and unreliable. Several researchers in the late 1940s conceived the idea of using magnetic cores for computer memory, but MIT computer engineer
2536:
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
1699:
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
2258:
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).
2194:
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.
3020:
2065:
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.
1757:'s Computation Laboratory at the time, and the university was not interested in promoting inventions created in their labs. Wang was able to patent the system on his own.
1632:(DRAM) in the early 1970s. Initially around the same price as core, DRAM was smaller and simpler to use. Core was driven from the market gradually between 1973 and 1978.
1981:
1860:
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
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.
636:
2370:
1801:. A prolific inventor, Rajchman designed a unique core system using ferrite bands wrapped around thin metal tubes, building his first examples using a converted
3763:
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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 "
2150:
field forces the selected core's magnetic flux to circulate in one direction or the other (clockwise or counterclockwise). One direction is a stored
1624:
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
1590:
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
3921:
1672:, which allowed amplification and switch-like performance when built using certain materials. The stable switching behavior was well known in the
1715:
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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2201:
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.
1597:
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
2423:
The performance of early core memories can be characterized in today's terms as being very roughly comparable to a clock rate of 1
1844:
developed one of the first commercial applications of coincident-current core memory storage in the "Tormat" memory of its new range of
3861:
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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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651:
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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
4014:
3426:
Creighton D. Barnes, et al., Magnetic core storage device having a single winding for both the sensing and inhibit function,
3245:
2675:
1066:
3914:
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
2162:
was necessitated by the diagonal sense wires. With the elimination of these diagonal wires, tighter packing was possible.
47:) of data. The small black rings at the intersections of the grid wires, organised in four squares, are the ferrite cores.
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227:
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reduces the net current flowing through the respective core to half the select current, inhibiting change of polarity.
1848:, starting with the V200 developed in 1953 and released in 1955. Numerous uses in computing, telephony and industrial
272:
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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
1014:
957:
277:
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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
2224:
To write a bit of core memory, the circuitry assumes there has been a read operation and the bit is in the 0 state.
1748:
system. Each bit was stored using a pair of transformers, one that held the value and a second used for control. A
125:
2398:(ROM) form of core memory. In this case, the cores, which had more linear magnetic materials, were simply used as
2037:
so that less energy is required to change the magnetization direction. The core can take two states, encoding one
1972:
An example of the scale, economics, and technology of core memory in the 1960s was the 256K 36-bit word (1.2
1908:
to the wires, the needle and wire diameters were the same, and efforts were made to eliminate the use of needles.
3907:
2216:: Any operation that reads the contents of a core erases those contents, and they must immediately be recreated.
1340:
1000:
944:
2517:) to adjust the current levels correctly for temperature changes. An example of this is the core memory used by
1931:
as memory. The cost of core memory declined sharply over the lifetime of the technology: costs began at roughly
3767:
3735:
3633:
3175:
1026:
695:
507:
103:
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
2526:
2518:
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 "
1375:
17:
1953:
memories in the 1970s, though remained in use for mission-critical and high-reliability applications in the
4052:
2130:
in an array of words was spread over a "stack" of planes. Each plane would manipulate one bit of a word in
2127:
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726:
621:
522:
31:
2289:
A 10.8 × 10.8 cm plane of magnetic core memory with 64 × 64 bits (4 Kb), as used in a
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.
1653:
683:
3077:
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.
1594:, and requires additional circuitry to reset the core to its original value if the process flipped it.
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and radiation. These were important advantages for some applications like first-generation industrial
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814:
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2212:
Following any such read, the bit contains a 0. This illustrates why a core memory access is called a
2147:
2102:), with wires woven through the holes in the cores' centers. In early systems there were four wires:
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577:
512:
407:
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Internally, the Moby Memory had 40 bits per word, but they were not exposed to the PDP-10 processor.
3817:(Rate Training Manual). Naval Education and Training Command. 1978. pp. 95–. NAVEDTRA 10088-B.
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2403:
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859:
145:
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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".
3298:
3119:
2439:, which had fallen to 1.2 μs by the early 1970s, and by the mid-70s it was down to 600
1900:
thread the straight X and Y select lines from 25 hours to 12 minutes on a 128 by 128 core array.
1818:
1805:
press in 1949. Rajchman later developed versions of the
Williams tube and led development of the
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327:
162:
140:
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73:
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Norman, P. Glenn (1987), "The new AP101S General-Purpose
Computer (GPC) for the Space Shuttle",
3342:
3327:
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1992:, equivalent to 32 kB) core memory board that fitted into a DEC Q-bus computer was around
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beginning in 1947. A fully developed core system was patented in 1947, and later purchased by
604:
4057:
3353:
Walter P. Shaw and Roderick W. Link, Method and Apparatus for Threading Perforated Articles,
2541:
2465:
1511:
758:
676:
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267:
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93:
58:
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computer; this strategy continued through all of the follow-on core memory systems built by
2464:—it can retain its contents indefinitely without power. It is also relatively unaffected by
3972:
3499:
2975:
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
2461:
2073:
One of three inter-connected modules that make up an Omnibus-based PDP-8 core memory plane.
1947:
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150:
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By the early 1960s, the cost of core fell to the point that it became nearly universal as
8:
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989:
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1954:
1550:. It predominated for roughly 20 years between 1955 and 1975, and is often just called
3672:
3593:
3559:
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lines; this clears the selected cores and any that flip induce voltage pulses in their
2170:
2131:
1950:
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482:
427:
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387:
312:
2312:. This form of core memory typically wove three wires through each core on the plane,
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3549:
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3241:
3208:
3171:
3146:
2909:
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core memory was often used to provide register memory. Other names for this type are
2041:. The core memory contents are retained even when the memory system is powered down (
1869:
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1741:
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1021:
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177:
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3592:(Report). Massachusetts Institute of Technology. p. 18. 681342. Archived from
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2004:
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802:
487:
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207:
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88:
78:
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2738:
Eckert, J. Presper (October 1953). "A Survey of Digital Computer Memory Systems".
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83:
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2841:, George C. Devol, "Magnetic storage devices", published 15 May 1962
2126:(0 or 1). One bit in each plane could be accessed in one cycle, so each machine
3996:
3942:
3545:
3276:
3262:
2950:, Wang, An, "Pulse Transfer Controlling Device", issued 17 May 2020
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135:
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2716:
2081:, used for the main memory of a computer, consists of a large number of small
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.
4036:
4008:
3948:
3836:
3621:
2759:
2650:
2577:," and the name stuck. In many occasions, errors could be resolved by gently
2489:
2481:
2098:) held together in a grid structure (organized as a "stack" of layers called
2085:
2026:
1958:
1777:
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836:
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232:
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3030:. Massachusetts: The Computer Museum: 13. Winter 1983 – via Microsoft.
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
1985:
kilobits/cubic foot = 6.7 kilobits/litre). Its cycle time was 2.75 μs.
2432:
1905:
1696:
1685:
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field, and its application in computer systems was immediate. For example,
1437:
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1397:
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1204:
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847:
809:
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467:
367:
302:
257:
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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
2012:
4002:
3954:
3899:
3706:
3637:
3260:
Clarence Schultz and George Boesen, Selectors for Automatic Phonographs,
2691:
2570:
2480:, and led to core being used for a number of years after availability of
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2022:
1924:
1920:
1916:
1708:
1704:
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1496:
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882:
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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).
2612:
2514:
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If the bit was already 0, the physical state of the core is unaffected.
2175:
2034:
1928:
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671:
437:
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307:
172:
98:
3197:
Proceedings of the 1952 ACM national meeting (Pittsburgh) on - ACM '52
2987:
2443:(0.6 μs). Some designs had substantially higher performance: the
2285:
2655:
2595:
2324:. To read or clear words, the full current is applied to one or more
2030:
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978:
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609:
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297:
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2061:
3990:
2553:
2549:
2545:
2537:
2444:
2428:
2374:
2364:
lines could be selected. This offered a performance advantage over
2290:
1989:
1943:
1719:
1407:
1350:
1285:
1240:
1225:
995:
964:
937:
912:
770:
656:
382:
292:
187:
182:
3041:
Evans, Christopher (July 1983). "Conversation: Jay W. Forrester".
2724:
2088:
1845:
1830:
1826:
1802:
1729:
1305:
1295:
1290:
1250:
1152:
1147:
1127:
932:
907:
897:
688:
3752:. Control Data Corporation. June 1965. Document number 60147400.
3408:
Ronald A. Beck and Dennis L. Breu, Core Patch Stringing Method,
1793:
A third developer involved in the early development of core was
1786:
microseconds) thus increasing the speed of computer operation."
39:
3444:
Victor L. Sell and Syed Alvi, High Density Core Memory Matrix,
2875:
2485:
2449:
2082:
1562:
1300:
1260:
1142:
1031:
829:
372:
2799:
2780:
3369:
Bashe, Charles J.; Johnson, Lyle R.; Palmer, John H. (1986).
2856:
2574:
2522:
2504:
s disintegration and subsequent plunge into the sea in 1986.
2435:). Early core memory systems had cycle times of about 6
2266:
2134:, allowing the full word to be read or written in one cycle.
1977:
1822:
1703:. Frederick Viehe applied for various patents on the use of
1689:
1684:
had done some development work on the concept in 1945 at the
1235:
1172:
1167:
1162:
824:
781:
775:
661:
641:
626:
3236:
Pugh, Emerson W.; Johnson, Lyle R.; Palmer, John H. (1991).
2436:
2250:
Increasing Sense wires also requires more decode circuitry.
2407:
1966:
1962:
1613:
1230:
517:
167:
44:
3859:
1829:
delivered in July 1955, and later in the 702 itself. The
2901:
Milestones in computer science and information technology
2424:
2123:
2118:, but later cores combined the latter two wires into one
2038:
1973:
1861:
1798:
1712:
1574:
1270:
1157:
927:
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.
2253:
43:
A 32 × 32 core memory plane storing 1024 bits (or 128
3168:
Project Whirlwind - The History of a Pioneer Computer
1718:
Substantial work in the field was carried out by the
3587:
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
3368:
30:"Core memory" redirects here. For other uses, see
3338:
3323:
3235:
4034:
3489:
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"
2837:
2818:
2352:line for a bit to be set. In some designs, the
3531:
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).
2280:
2237:
1919:, replacing both inexpensive low-performance
1519:
3440:
3438:
3422:
3420:
3165:
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
2413:
2348:lines, and half current is applied to each
1764:computer required a fast memory system for
3929:
3922:
3908:
3728:Hackers: Heroes of the Computer Revolution
2507:
2377:, which was up to 2 million 60-bit words.
1923:and costly high-performance systems using
1526:
1512:
3435:
3417:
3373:. Cambridge, MA: MIT Press. p. 268.
3277:"An Wang Sells Core Memory Patent to IBM"
3117:
3000:
2965:
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
3190:
2284:
2169:
2068:
2060:
2052:
2048:
2021:The term "core" comes from conventional
2011:
2003:
1868:. Wang used the funds to greatly expand
1652:
1628:chips in the late 1960s, and especially
38:
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"
3075:
1879:
14:
4035:
3862:"A 110-Nanosecond Ferrite Core Memory"
3159:
3143:Computer Architecture and Organization
2897:
2888:
2737:
2165:
1982:MIT Artificial Intelligence Laboratory
1664:The basic concept of using the square
3903:
3140:
3078:"Jay Forrester's Shock to the System"
3040:
2676:Magnetoresistive random-access memory
2077:The most common form of core memory,
1067:Vision Electronic Recording Apparatus
3704:
2946:
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.
2380:
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
24:
3102:Jan A. Rajchman, Magnetic System,
3043:Annals of the History of Computing
2340:lines could be selected while the
1855:
1837:(1957) used magnetic-core memory.
228:Data validation and reconciliation
25:
4069:
3778:
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)
3756:
3741:
3720:
3698:
3647:
3611:
3579:
3570:
3525:
3483:
3453:
3402:
3387:
3362:
3347:
3339:Pugh, Johnson & Palmer 1991
3332:
3324:Pugh, Johnson & Palmer 1991
3317:
3291:
3269:
3254:
3238:IBM's 360 and Early 370 Systems
3229:
3184:
3134:
3111:
3096:
3069:
3034:
3013:
2994:
2959:
2940:
2922:
1935:per bit and dropped to roughly
945:Programmable metallization cell
4043:Magnetic-core memory computers
3659:. US. 4 August 1967. 102731715
2869:
2850:
2831:
2812:
2793:
2774:
2731:
2709:
2533:line of air-cooled computers.
2455:
2373:(ECS) auxiliary memory in the
2154:, while the other is a stored
1999:
508:Persistence (computer science)
13:
1:
4048:History of computing hardware
3279:. US: Computer History Museum
2702:
2627:Magnetic-core memory close-up
2563:
2519:Digital Equipment Corporation
2122:line. Each toroid stored one
1648:
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)
7:
3626:The New Hacker's Dictionary
3118:Hittinger, William (1992).
2746:(10). US: IEEE: 1393–1406.
2644:
2366:X/Y line coincident-current
2079:X/Y line coincident-current
10:
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
2219:
2189:
2025:whose windings surround a
1643:
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
2418:
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
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:
3900:
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:
50:
21:
4073:
4072:
4068:
4067:
4066:
4064:
4063:
4062:
4033:
4032:
4031:
4026:
3934:
3928:
3887:
3864:
3809:
3794:
3792:
3784:
3781:
3776:
3775:
3762:
3761:
3757:
3747:
3746:
3742:
3725:
3721:
3711:
3709:
3703:
3699:
3689:
3680:
3679:
3670:
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:
3530:
3526:
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:
3367:
3363:
3354:
3352:
3348:
3337:
3333:
3322:
3318:
3308:
3306:
3297:
3296:
3292:
3282:
3280:
3275:
3274:
3270:
3261:
3259:
3255:
3248:
3234:
3230:
3215:
3189:
3185:
3178:
3164:
3160:
3153:
3139:
3135:
3116:
3112:
3103:
3101:
3097:
3087:
3085:
3074:
3070:
3039:
3035:
3023:
3019:
3018:
3014:
3007:
2999:
2995:
2964:
2960:
2953:
2945:
2941:
2928:
2927:
2923:
2916:
2896:
2889:
2882:
2874:
2870:
2863:
2855:
2851:
2844:
2836:
2832:
2825:
2817:
2813:
2806:
2798:
2794:
2787:
2779:
2775:
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:
4061:
4060:
4055:
4050:
4045:
4028:
4027:
4025:
4024:
4018:
4012:
4006:
4000:
3994:
3988:
3982:
3976:
3970:
3964:
3958:
3952:
3946:
3939:
3936:
3935:
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:
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:
3769:
3765:
3759:
3751:
3748:"Section 4".
3744:
3737:
3733:
3729:
3726:Steven Levy,
3723:
3708:
3707:"Moby Memory"
3701:
3693:
3686:
3674:
3658:
3657:
3650:
3643:
3639:
3635:
3631:
3627:
3623:
3622:Guy L. Steele
3619:
3614:
3599:on 8 May 2021
3595:
3588:
3582:
3573:
3565:
3561:
3557:
3555:0-7803-1893-5
3551:
3547:
3543:
3539:
3535:
3528:
3521:
3517:
3513:
3509:
3505:
3501:
3497:
3493:
3486:
3470:
3466:
3462:
3456:
3448:
3441:
3439:
3430:
3423:
3421:
3412:
3405:
3397:
3390:
3382:
3380:0-262-52393-0
3376:
3372:
3365:
3357:
3350:
3344:
3340:
3335:
3329:
3325:
3320:
3304:
3300:
3294:
3278:
3272:
3264:
3257:
3249:
3243:
3239:
3232:
3224:
3220:
3216:
3214:9781450373623
3210:
3206:
3202:
3198:
3194:
3187:
3179:
3173:
3169:
3162:
3154:
3152:0-07-027363-4
3148:
3144:
3137:
3129:
3125:
3121:
3114:
3106:
3099:
3083:
3079:
3072:
3064:
3060:
3056:
3052:
3048:
3044:
3037:
3029:
3022:
3016:
3003:
2997:
2989:
2985:
2981:
2977:
2973:
2969:
2962:
2949:
2943:
2935:
2931:
2925:
2917:
2915:1-57356-521-0
2911:
2907:
2903:
2902:
2894:
2892:
2878:
2872:
2859:
2853:
2840:
2834:
2821:
2815:
2802:
2796:
2783:
2777:
2769:
2765:
2761:
2757:
2753:
2749:
2745:
2741:
2734:
2726:
2722:
2718:
2712:
2708:
2698:
2695:
2693:
2690:
2688:
2685:
2682:
2679:
2677:
2674:
2672:
2669:
2667:
2664:
2662:
2659:
2657:
2654:
2652:
2651:Bubble memory
2649:
2648:
2635:
2630:
2623:
2618:
2614:
2607:
2602:
2597:
2590:
2585:
2584:
2583:
2580:
2576:
2572:
2561:
2559:
2555:
2551:
2547:
2543:
2539:
2534:
2532:
2528:
2524:
2520:
2516:
2505:
2500:
2499:
2494:
2491:
2490:Space Shuttle
2487:
2483:
2482:semiconductor
2479:
2476:, as well as
2475:
2471:
2467:
2463:
2453:
2451:
2446:
2442:
2438:
2434:
2430:
2426:
2411:
2409:
2406:used for the
2405:
2401:
2397:
2393:
2388:
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:
2278:
2268:
2263:
2261:
2251:
2248:
2244:
2231:
2227:
2226:
2225:
2217:
2215:
2210:
2208:
2200:
2197:
2196:
2195:
2187:
2185:
2177:
2172:
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:
2046:
2044:
2040:
2036:
2032:
2028:
2027:magnetic core
2024:
2014:
2006:
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:
1877:
1873:
1871:
1863:
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:
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:
792:
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:
587:
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:
53:
52:
46:
41:
37:
33:
19:
18:Core memories
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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