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Rod Memory
Rod memory is one of the many variations on magnetic core memory that attempts to lower costs by automating its manufacturing. It was introduced by NCR in 1964 as part of the NCR 315 RMC computer, RMC for "rod memory computer". It was also used in their Century line. Like many similar concepts, notably twistor memory and thin film memory, rod memory was competing for the role of taking over from core when the first semiconductor memory systems wiped out the entire market in 1970. Description Instead of magnetic rings, the ''cores'', and rod memory uses magnetic bars surrounded by a metal coil. Instead of the electrical current running linearly and the magnetic field around the core, in rod memory the current runs around the solenoid and the magnetic field is linear in the rod. The end result is essentially the same, however, with the bits being represented by the direction of the magnetic field in the rod. To do this, the rods are placed in the middle of tiny solenoids, which prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Core Memory
In computing, magnetic-core memory is a form of random-access memory. It predominated for roughly 20 years between 1955 and 1975, and is often just called core memory, or, informally, core. Core memory uses toroids (rings) of a hard magnetic material (usually a Ferrite (magnet)#Semi-hard ferrites, semi-hard ferrite). Each core stores one bit 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 ''written'' – is selected by powering one X and one Y wire to half of the required current, 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. This writing process also causes electricity to be electromagnetic induction, induced into nearby wires. If t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NCR Corporation
NCR Voyix Corporation, previously known as NCR Corporation and National Cash Register, is a global software, consulting and technology company providing several professional services and Electronics, electronic products. It manufactured Self-checkout, self-service kiosks, point of sale, point-of-sale terminals, automated teller machines, cheque, check processing systems, and barcode reader, barcode scanners. NCR was founded in Dayton, Ohio, in 1884. It grew to become a dominant market leader in cash registers, then decryption machinery, then computing machinery, and computers over the subsequent 100 years. By 1991, it was still the fifth-largest manufacturer of computers. That year, it was acquired by AT&T Corporation, AT&T. A restructuring of AT&T in 1996 led to NCR's re-establishment on January 1, 1997, as a separate company and involved the Corporate spin-off, spin-off of Lucent Technologies from AT&T. In June 2009, the company sold most of the Dayton properties and moved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NCR 315
The NCR 315 Data Processing System, released in January 1962 by NCR, is a second-generation computer. All printed circuit boards use resistor–transistor logic (RTL) to create the various logic elements. It uses 12-bit ''slab'' memory structure using magnetic-core memory. The instructions can use a memory slab as either two 6-bit alphanumeric characters or as three 4-bit BCD digits. Basic memory is 5000 "slabs" (10,000 characters or 15,000 decimal digits) of handmade core memory, which is expandable to a maximum of 40,000 slabs (80,000 characters or 120,000 decimal digits) in four refrigerator-size cabinets. The main processor includes three cabinets and a console section that houses the power supply, keyboard, output writer (an IBM electric typewriter), and a panel with lights that indicate the current status of the program counter, registers, arithmetic accumulator, and system errors. Input/Output is by direct parallel connections to each type of peripheral through a tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NCR Century 100
The NCR Century 100 was NCR's first all integrated circuit computer built in 1968. All logic gates were created by wire-wrapping NAND gates together to form flip-flops and other complex circuits. The console of the system had only 18 lights and switches and allowed entry of a boot routine, or changes to loaded programs or data in memory. A typewriter console was also available. Peripherals The 615-100 Series integrated a complete data processing system that had 16KB or 32KB of short rod memory, an 80-column punched card reader or paper tape reader, two 5MB removable disk drives, and a 600-line-per-minute line printer. The system could be provided with a punched paper tape reader, or an external card reader/punch, and also allowed for the attachment of multiple 9-track, 1/2-inch, reel-to-reel magnetic tape drives. Two more disk drives could be attached to the system. The Century series used an instruction set with two instruction lengths: 4 bytes (32 bits) and 8 bytes (64 bit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twistor Memory
Twistor memory is a form of computer memory formed by wrapping magnetic tape around a current-carrying wire. Operationally, twistor was very similar to core memory. Twistor could also be used to make ROM memories, including a re-programmable form known as piggyback twistor. Both forms were able to be manufactured using automated processes, which was expected to lead to much lower production costs than core-based systems. Introduced by Bell Labs in 1957, the first commercial use was in their 1ESS switch which went into operation in 1965. Twistor was used only briefly in the late 1960s and early 1970s, when semiconductor memory devices replaced almost all earlier memory systems. The basic ideas behind twistor also led to the development of bubble memory, although this had a similarly short commercial lifespan. Core memory Construction In core memory, small ring-shaped magnets - the cores - are threaded by two crossed wires, ''X'' and ''Y'', to make a matrix known as a ''pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thin Film Memory
Thin-film memory is a high-speed alternative to magnetic-core memory developed by Sperry Rand in a government-funded research project. Instead of threading individual ferrite cores on wires, thin-film memory consisted of 4-micrometer thick dots of permalloy, an iron–nickel alloy, deposited on small glass plates by vacuum evaporation techniques and a mask. The drive and sense lines were then added using printed circuit wiring over the alloy dots. This provided very fast access times in the range of 670 nanoseconds, but was very expensive to produce. In 1962, the UNIVAC 1107, intended for the civilian marketplace, used thin-film memory only for its 128-word general register stack. Military computers, where cost was less of a concern, used larger amounts of thin-film memory. Thin film was also used in a number of high-speed computer projects, including the high-end of the IBM System/360 The IBM System/360 (S/360) is a family of mainframe computer systems announced by IBM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor Memory
Semiconductor memory is a digital electronic semiconductor device used for digital data storage, such as computer memory. It typically refers to devices in which data is stored within metal–oxide–semiconductor (MOS) memory cells on a silicon integrated circuit memory chip. There are numerous different types using different semiconductor technologies. The two main types of random-access memory (RAM) are static RAM (SRAM), which uses several transistors per memory cell, and dynamic RAM (DRAM), which uses a transistor and a MOS capacitor per cell. Non-volatile memory (such as EPROM, EEPROM and flash memory) uses floating-gate memory cells, which consist of a single floating-gate transistor per cell. Most types of semiconductor memory have the property of random access, which means that it takes the same amount of time to access any memory location, so data can be efficiently accessed in any random order. This contrasts with data storage media such as CDs which re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
