|Computer memory types|
The Williams tube or the Williams-Kilburn tube (after inventors Freddie Williams and Tom Kilburn), developed about 1946 or 1947, was a cathode ray tube used to electronically store binary data. DDR SDRAM ( double data rate synchronous dynamic random access memory) is a class of memory Integrated circuit used in Computers It achieves nearly twice Static random access memory (SRAM is a type of Semiconductor memory where the word static indicates that unlike ''dynamic'' RAM (DRAM, it does not Z-RAM, short for " zero capacitor RAM " is a new type of Computer memory in development by Innovative Silicon Inc Twin Transistor RAM ( TTRAM) is a new type of Computer memory in development by Renesas Genesis in radar The basic concept of the delay line originated with World War II Radar research as a system to reduce clutter from reflections from the ground Non-volatile memory, nonvolatile memory, NVM or non-volatile storage, is Computer memory that can retain the stored information A programmable read-only memory ( PROM) or field programmable read-only memory ( FPROM) is a form of digital memory where the setting of each bit is EEPROM (also written E2PROM and pronounced e-e-prom or simply e-squared which stands for E lectrically E rasable P rogrammable An EPROM, or E rasable P rogrammable '''''R'''ead-'''O'''nly '''M'''emory'', is a type of memory chip that retains its EEPROM (also written E2PROM and pronounced e-e-prom or simply e-squared which stands for E lectrically E rasable P rogrammable Flash memory is non-volatile computer memory that can be electrically erased and reprogrammed Ferroelectric RAM ( FeRAM or FRAM) is a Random access memory similar in construction to DRAM but uses a Ferroelectric layer instead Magnetoresistive Random Access Memory ( MRAM) is a non-volatile computer memory ( NVRAM) technology which has been under development since The programmable metallization cell, or PMC, is a new form of non-volatile Computer memory being developed at Arizona State University and Phase-change memory (also known as PCM, PRAM, PCRAM, Ovonic Unified Memory, Chalcogenide RAM and C-RAM) is a type This article is about the music device manufacturer For the computer memory system see SONOS. Resistive random-access memory ( RRAM) is a new Non-volatile memory type being developed by Fujitsu, Sharp, Samsung, Micron IBM Racetrack Memory is an experimental Non-volatile memory device under development at IBM 's Almaden Research Center by a team led by Stuart Nano-RAM is a proprietary Computer memory technology from the company Nantero. Drum memory is a magnetic Data storage device and was an early form of Computer memory widely used in the 1950s and into the 1960s invented by Gustav Tauschek Magnetic core memory, or ferrite-core memory, is an early form of Random access Computer memory. Prehistory twistor memory Bubble memory is largely the brainchild of a single person Andrew Bobeck. Twistor is a form of Computer memory, similar to Core memory, formed by wrapping or closing Magnetic tape around a current-carrying wire Sir Frederic Calland Williams ( June 26, 1911. Stockport &ndash August 11 1977. Tom Kilburn ( August 11, 1921 - January 17, 2001) was an English Engineer. Year 1946 ( MCMXLVI) was a Common year starting on Tuesday (link will display full 1946 calendar of the Gregorian calendar. Year 1947 ( MCMXLVII) was a Common year starting on Wednesday (link will display full 1947 calendar of the Gregorian calendar. The cathode ray tube (CRT is a Vacuum tube containing an Electron gun (a source of electrons and a Fluorescent screen with internal or
When a dot is drawn on a cathode ray tube, the visible spot lasts for a time (called "persistence") that depends on the type of phosphor used in the tube. A phosphor is a substance that exhibits the phenomenon of Phosphorescence (sustained glowing after exposure to energized particles such as Electrons The operation of the Williams tube is due to a completely unrelated effect (in fact some Williams tubes were made with no phosphor), caused by secondary emission, such that the area of this dot becomes slightly positively charged and the area immediately around this dot becomes slightly negatively charged (creating a charge well). Secondary emission is a phenomenon where additional electrons called Secondary electrons, are emitted from the surface of a material when an incident particle (often charged Also a positively charged dot is erased (filling the charge well) by drawing a second dot immediately adjacent to the one to be erased (most systems did this by drawing a short dash starting at the dot position, the extension of the dash erased the charge initially stored at the starting point). By later drawing a dot at that spot and measuring the charge, by means of a metal plate placed over the outside of the front of the tube, you have a simple form of memory that lasts for a time depending on the electrical resistance of the inside surface of the face of the tube. Electrical resistance is a ratio of the degree to which an object opposes an Electric current through it measured in Ohms Its reciprocal quantity is Reading a memory location destroyed its contents (creating a charge well), so any read had to be followed by a write (most systems did this by drawing a short dash starting at the dot position if the positive charge created needed to be erased). Also, because the charge gradually leaked off, it was necessary to scan the tube periodically and rewrite every dot (similar to the memory refresh cycles of DRAM in modern systems). Memory refresh is the process of periodically reading information from an area of Computer memory, and immediately rewriting the read information to the same area with no modifications
Williams tubes stored roughly 500 to 1,000 bits of data.
Developed at the University of Manchester in England, it provided the medium on which the first ever electronically stored-memory program was written in the Manchester Mark I computer. The Victoria University of Manchester (commonly known as the University of Manchester) was a University in Manchester, England. England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland This article is about the early British computer. The term "Manchester Mark I" can also refer to the Avro Manchester heavy bomber in RAF service during Tom Kilburn wrote a 17-line program to calculate the highest factor of a number. Tradition at Manchester University has it that this was the only program Tom Kilburn ever wrote.
The Williams tube tended to become unreliable with age, and most working installations had to be "tuned" by hand. By contrast, mercury delay line memory was slower and also needed hand tuning, but it did not age as badly and enjoyed some success in early digital electronic computing despite its speed, weight, cost, thermal and toxicity problems. Genesis in radar The basic concept of the delay line originated with World War II Radar research as a system to reduce clutter from reflections from the ground However, the Manchester Mark I was successfully commercialised as the Ferranti Mark I and some early computers in the USA also used the Williams tube, including the IAS machine, originally designed for Selectron tube (picture) memory, and the UNIVAC 1103, IBM 701 and IBM 702. The Ferranti Mark I was the world's first successful commercially available general-purpose Electronic Computer, with the first machine being delivered in February The IAS machine was the first electronic digital Computer built by the Institute for Advanced Study (IAS, Princeton NJ, USA. The Selectron was an early form of digital Computer memory developed by Jan A The UNIVAC 1103 or ERA 1103 a successor to the UNIVAC 1101, was a computer system designed by Engineering Research Associates and built by the Remington The IBM 701, known as the Defense Calculator while in development was announced to the public on April 29, The IBM 702 ( photos was announced September 25, 1953 and withdrawn October 1, 1954, but the first production model was not installed until Williams tubes were also used in the Soviet computer, Strela-1. Strela computer (ЭВМ "Стрела" English "Arrow" was the first Mainframe computer manufactured serially in the Soviet Union since 1953
The first major computer in California, the Standards Western Automatic Computer (SWAC) used Williams tubes (picture) as well. SWAC was located at the National Bureau of Standards, in Los Angeles. It was designed by Harry Huskey, who had worked on ENIAC in 1945 and later on the Pilot ACE at the British National Physics Laboratory, during 1949-1951. When the Los Angeles NBS office was closed (due to pressure from Senator McCarthy) SWAC was moved to UCLA around 1953. Computation on SWAC was charged out at $40. - per hour. It remained in use to 1962, eventually for conversion of data for the new IBM 7090 being acquired by WDPC (Western Data Processing Center) at UCLA.