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98-608: It was slightly wider, and the keys are slightly larger than the previous model. The display had more contrast, and the keyboard cover is a (removable) hinged lid (clamshell) instead of plastic slipcase. There were also four additional BASIC commands (Multiline IF ... ENDIF, WHILE ... WEND, REPEAT ... UNTIL, SWITCH ... CASE ... ENDSWITCH) It came with 32 KB of RAM which could be upgraded to 96 KB using memory expansion cards. The monochrome LCD had 240×32 pixels which could display four lines with 40 characters per line as well as graphics. The 256 KB system ROM that contained

196-513: A CR1616 lithium battery for memory backup. The memory configuration was software-switchable from the command-line. The RAM card could be appended to the system memory, replace the system memory or act as a separate space to be used as a RAM drive (F:). The main memory could also be partitioned off to a RAM drive (E:). The PC-E500S had a weight of 340 g (with batteries) and was powered by four AAA batteries . It could, given its power consumption of 0.09  W , be used for about 70 hours on

294-407: A button can perform multi-function working with key combinations . Calculators usually have liquid-crystal displays (LCD) as output in place of historical light-emitting diode (LED) displays and vacuum fluorescent displays (VFD); details are provided in the section Technical improvements . Large-sized figures are often used to improve readability; while using decimal separator (usually

392-399: A calculator could be made using just a few chips of low power consumption, allowing portable models powered from rechargeable batteries. The first handheld calculator was a 1967 prototype called Cal Tech , whose development was led by Jack Kilby at Texas Instruments in a research project to produce a portable calculator. It could add, multiply, subtract, and divide, and its output device

490-503: A charge. RAM Random-access memory ( RAM ; / r æ m / ) is a form of electronic computer memory that can be read and changed in any order, typically used to store working data and machine code . A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory, in contrast with other direct-access data storage media (such as hard disks and magnetic tape ), where

588-684: A development from the "Cal-Tech" project. It had no traditional display; numerical output was on thermal paper tape. Sharp put in great efforts in size and power reduction and introduced in January 1971 the Sharp EL-8 , also marketed as the Facit 1111, which was close to being a pocket calculator. It weighed 1.59 pounds (721 grams), had a vacuum fluorescent display , rechargeable NiCad batteries, and initially sold for US$ 395. However, integrated circuit development efforts culminated in early 1971 with

686-563: A few dozen or few hundred bits of such memory could be provided. The first practical form of random-access memory was the Williams tube . It stored data as electrically charged spots on the face of a cathode-ray tube . Since the electron beam of the CRT could read and write the spots on the tube in any order, memory was random access. The capacity of the Williams tube was a few hundred to around

784-609: A full single chip calculator IC for the Monroe Royal Digital III calculator. Pico was a spinout by five GI design engineers whose vision was to create single chip calculator ICs. Pico and GI went on to have significant success in the burgeoning handheld calculator market. The first truly pocket-sized electronic calculator was the Busicom LE-120A "HANDY", which was marketed early in 1971. Made in Japan, this

882-470: A hard drive. This entire pool of memory may be referred to as "RAM" by many developers, even though the various subsystems can have very different access times , violating the original concept behind the random access term in RAM. Even within a hierarchy level such as DRAM, the specific row, column, bank, rank , channel, or interleave organization of the components make the access time variable, although not to

980-424: A memory capacity that is a power of two. Usually several memory cells share the same address. For example, a 4 bit "wide" RAM chip has four memory cells for each address. Often the width of the memory and that of the microprocessor are different, for a 32 bit microprocessor, eight 4 bit RAM chips would be needed. Often more addresses are needed than can be provided by a device. In that case, external multiplexors to

1078-485: A pocket calculator. Launched in early 1972, it was unlike the other basic four-function pocket calculators then available in that it was the first pocket calculator with scientific functions that could replace a slide rule . The $ 395 HP-35 , along with nearly all later HP engineering calculators, uses reverse Polish notation (RPN), also called postfix notation. A calculation like "8 plus 5" is, using RPN, performed by pressing 8 , Enter↑ , 5 , and + ; instead of

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1176-428: A point rather than a comma ) instead of or in addition to vulgar fractions . Various symbols for function commands may also be shown on the display. Fractions such as 1 ⁄ 3 are displayed as decimal approximations , for example rounded to 0.33333333 . Also, some fractions (such as 1 ⁄ 7 , which is 0.14285714285714 ; to 14 significant figures ) can be difficult to recognize in decimal form; as

1274-404: A portion of a computer's RAM, allowing it to act as a much faster hard drive that is called a RAM disk . A RAM disk loses the stored data when the computer is shut down, unless memory is arranged to have a standby battery source, or changes to the RAM disk are written out to a nonvolatile disk. The RAM disk is reloaded from the physical disk upon RAM disk initialization. Sometimes, the contents of

1372-555: A relatively slow ROM chip are copied to read/write memory to allow for shorter access times. The ROM chip is then disabled while the initialized memory locations are switched in on the same block of addresses (often write-protected). This process, sometimes called shadowing , is fairly common in both computers and embedded systems . As a common example, the BIOS in typical personal computers often has an option called "use shadow BIOS" or similar. When enabled, functions that rely on data from

1470-437: A result, many scientific calculators are able to work in vulgar fractions or mixed numbers . Calculators also have the ability to save numbers into computer memory . Basic calculators usually store only one number at a time; more specific types are able to store many numbers represented in variables . Usually these variables are named ans or ans(0). The variables can also be used for constructing formulas . Some models have

1568-420: A series of separate identical seven-segment displays to build a metering circuit, for example. If the numeric quantity were stored and manipulated as pure binary, interfacing to such a display would require complex circuitry. Therefore, in cases where the calculations are relatively simple, working throughout with BCD can lead to a simpler overall system than converting to and from binary. (For example, CDs keep

1666-542: A single MOS transistor per capacitor. The first commercial DRAM IC chip, the 1K Intel 1103 , was introduced in October 1970. Synchronous dynamic random-access memory (SDRAM) was reintroduced with the Samsung KM48SL2000 chip in 1992. Early computers used relays , mechanical counters or delay lines for main memory functions. Ultrasonic delay lines were serial devices which could only reproduce data in

1764-491: A switch that lets the control circuitry on the chip read the capacitor's state of charge or change it. As this form of memory is less expensive to produce than static RAM, it is the predominant form of computer memory used in modern computers. Both static and dynamic RAM are considered volatile , as their state is lost or reset when power is removed from the system. By contrast, read-only memory (ROM) stores data by permanently enabling or disabling selected transistors, such that

1862-611: A thousand bits, but it was much smaller, faster, and more power-efficient than using individual vacuum tube latches. Developed at the University of Manchester in England, the Williams tube provided the medium on which the first electronically stored program was implemented in the Manchester Baby computer, which first successfully ran a program on 21 June, 1948. In fact, rather than the Williams tube memory being designed for

1960-615: Is a type of flip-flop circuit, usually implemented using FETs . This means that SRAM requires very low power when not being accessed, but it is expensive and has low storage density. A second type, DRAM, is based around a capacitor. Charging and discharging this capacitor can store a "1" or a "0" in the cell. However, the charge in this capacitor slowly leaks away, and must be refreshed periodically. Because of this refresh process, DRAM uses more power, but it can achieve greater storage densities and lower unit costs compared to SRAM. To be useful, memory cells must be readable and writable. Within

2058-419: Is common in electronic systems where a numeric value is to be displayed, especially in systems consisting solely of digital logic, and not containing a microprocessor. By employing BCD, the manipulation of numerical data for display can be greatly simplified by treating each digit as a separate single sub-circuit. This matches much more closely the physical reality of display hardware—a designer might choose to use

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2156-403: Is far more expensive than the dynamic RAM used for larger memories. Static RAM also consumes far more power. CPU speed improvements slowed significantly partly due to major physical barriers and partly because current CPU designs have already hit the memory wall in some sense. Intel summarized these causes in a 2005 document. First of all, as chip geometries shrink and clock frequencies rise,

2254-513: Is lost if power is removed. The two main types of volatile random-access semiconductor memory are static random-access memory (SRAM) and dynamic random-access memory (DRAM). Non-volatile RAM has also been developed and other types of non-volatile memories allow random access for read operations, but either do not allow write operations or have other kinds of limitations. These include most types of ROM and NOR flash memory . The use of semiconductor RAM dates back to 1965 when IBM introduced

2352-468: Is more expensive to produce, but is generally faster and requires less dynamic power than DRAM. In modern computers, SRAM is often used as cache memory for the CPU . DRAM stores a bit of data using a transistor and capacitor pair (typically a MOSFET and MOS capacitor , respectively), which together comprise a DRAM cell. The capacitor holds a high or low charge (1 or 0, respectively), and the transistor acts as

2450-473: Is needed to fit all the desired functions in the limited memory space available in the calculator chip , with acceptable calculation time. The first known tools used to aid arithmetic calculations were: bones (used to tally items), pebbles, and counting boards , and the abacus , known to have been used by Sumerians and Egyptians before 2000 BC. Except for the Antikythera mechanism (an "out of

2548-405: Is notably different from the layout of telephone Touch-Tone keypads which have the 1 - 2 - 3 keys on top and 7 - 8 - 9 keys on the third row. In general, a basic electronic calculator consists of the following components: Clock rate of a processor chip refers to the frequency at which the central processing unit (CPU) is running. It is used as an indicator of

2646-489: Is reduced by the size of the shadowed ROMs. The ' memory wall is the growing disparity of speed between CPU and the response time of memory (known as memory latency ) outside the CPU chip. An important reason for this disparity is the limited communication bandwidth beyond chip boundaries, which is also referred to as bandwidth wall . From 1986 to 2000, CPU speed improved at an annual rate of 55% while off-chip memory response time only improved at 10%. Given these trends, it

2744-610: Is the first calculator in the world which includes the square root function. Later that same year were released the ELKA 22 (with a luminescent display) and the ELKA 25, with an built-in printer. Several other models were developed until the first pocket model, the ELKA 101 , was released in 1974. The writing on it was in Roman script , and it was exported to western countries. The first desktop programmable calculators were produced in

2842-423: Is the processor-memory performance gap, which can be addressed by 3D integrated circuits that reduce the distance between the logic and memory aspects that are further apart in a 2D chip. Memory subsystem design requires a focus on the gap, which is widening over time. The main method of bridging the gap is the use of caches ; small amounts of high-speed memory that houses recent operations and instructions nearby

2940-664: Is typically a portable electronic device used to perform calculations , ranging from basic arithmetic to complex mathematics . The first solid-state electronic calculator was created in the early 1960s. Pocket-sized devices became available in the 1970s, especially after the Intel 4004 , the first microprocessor , was developed by Intel for the Japanese calculator company Busicom . Modern electronic calculators vary from cheap, give-away, credit-card-sized models to sturdy desktop models with built-in printers. They became popular in

3038-578: The Atanasoff–Berry Computer , the Williams tube and the Selectron tube . In 1966, Robert Dennard invented modern DRAM architecture for which there is a single MOS transistor per capacitor. While examining the characteristics of MOS technology, he found it was capable of building capacitors , and that storing a charge or no charge on the MOS capacitor could represent the 1 and 0 of a bit, while

Sharp PC-E500S - Misplaced Pages Continue

3136-583: The BIOS , a diagnostic suite, and the BASIC interpreter used to program the device. An algebraic calculation system was included. The Algebraic Expression Reserve (AER) memory: Frequently used formulas or constants could be stored in memory and recalled for repeated use. The PC-E500 series also performed as a scientific calculator when switched into 'CAL' mode. It also included an X<>Y exchange key for working with complex numbers and polar to rectangular conversions. In addition things like amino acids and

3234-413: The periodic table of elements were available. These built-in programs were accessed through a menu system and special function keys. There was also a built-in menu editor to add new software to the menus or indeed replace some built-in software or formulas. The Sharp PC-E500 series could store data and programs on memory expansion cards as well as the main RAM. Six cards were available: These cards used

3332-432: The 1960s with bipolar memory, which used bipolar transistors . Although it was faster, it could not compete with the lower price of magnetic core memory. In 1957, Frosch and Derick manufactured the first silicon dioxide field-effect transistors at Bell Labs, the first transistors in which drain and source were adjacent at the surface. Subsequently, in 1960, a team demonstrated a working MOSFET at Bell Labs. This led to

3430-515: The ANITA was superseded in June 1963 by the U.S. manufactured Friden EC-130, which had an all-transistor design, a stack of four 13-digit numbers displayed on a 5-inch (13 cm) cathode-ray tube (CRT), and introduced Reverse Polish Notation (RPN) to the calculator market for a price of $ 2200, which was about three times the cost of an electromechanical calculator of the time. Like Bell Punch, Friden

3528-598: The Autumn of 1971, with four functions and an eight-digit red LED display, for US$ 240 , while in August 1972 the four-function Sinclair Executive became the first slimline pocket calculator measuring 5.4 by 2.2 by 0.35 inches (137.2 mm × 55.9 mm × 8.9 mm) and weighing 2.5 ounces (71 g). It retailed for around £79 ( US$ 194 at the time). By the end of the decade, similar calculators were priced less than £5 ($ 6.85). Following protracted development over

3626-505: The BIOS's ROM instead use DRAM locations (most can also toggle shadowing of video card ROM or other ROM sections). Depending on the system, this may not result in increased performance, and may cause incompatibilities. For example, some hardware may be inaccessible to the operating system if shadow RAM is used. On some systems the benefit may be hypothetical because the BIOS is not used after booting in favor of direct hardware access. Free memory

3724-544: The Baby, the Baby was a testbed to demonstrate the reliability of the memory. Magnetic-core memory was invented in 1947 and developed up until the mid-1970s. It became a widespread form of random-access memory, relying on an array of magnetized rings. By changing the sense of each ring's magnetization, data could be stored with one bit stored per ring. Since every ring had a combination of address wires to select and read or write it, access to any memory location in any sequence

3822-402: The MOS transistor could control writing the charge to the capacitor. This led to his development of a single-transistor DRAM memory cell. In 1967, Dennard filed a patent under IBM for a single-transistor DRAM memory cell, based on MOS technology. The first commercial DRAM IC chip was the Intel 1103 , which was manufactured on an 8   μm MOS process with a capacity of 1   kbit , and

3920-696: The Mk VII for continental Europe and the Mk VIII for Britain and the rest of the world, both for delivery from early 1962. The Mk VII was a slightly earlier design with a more complicated mode of multiplication, and was soon dropped in favour of the simpler Mark VIII. The ANITA had a full keyboard, similar to mechanical comptometers of the time, a feature that was unique to it and the later Sharp CS-10A among electronic calculators. The ANITA weighed roughly 33 pounds (15 kg) due to its large tube system. Bell Punch had been producing key-driven mechanical calculators of

4018-489: The RAM comes in an easily upgraded form of modules called memory modules or DRAM modules about the size of a few sticks of chewing gum. These can be quickly replaced should they become damaged or when changing needs demand more storage capacity. As suggested above, smaller amounts of RAM (mostly SRAM) are also integrated in the CPU and other ICs on the motherboard , as well as in hard-drives, CD-ROMs , and several other parts of

Sharp PC-E500S - Misplaced Pages Continue

4116-444: The RAM device, multiplexing and demultiplexing circuitry is used to select memory cells. Typically, a RAM device has a set of address lines A 0 , A 1 , . . . A n {\displaystyle A_{0},A_{1},...A_{n}} , and for each combination of bits that may be applied to these lines, a set of memory cells are activated. Due to this addressing, RAM devices virtually always have

4214-587: The SP95 memory chip for the System/360 Model 95 . Dynamic random-access memory (DRAM) allowed replacement of a 4 or 6-transistor latch circuit by a single transistor for each memory bit, greatly increasing memory density at the cost of volatility. Data was stored in the tiny capacitance of each transistor, and had to be periodically refreshed every few milliseconds before the charge could leak away. Toshiba 's Toscal BC-1411 electronic calculator , which

4312-611: The ability to do computer algebra . Graphing calculators can be used to graph functions defined on the real line, or higher-dimensional Euclidean space . As of 2016 , basic calculators cost little, but scientific and graphing models tend to cost more. Computer operating systems as far back as early Unix have included interactive calculator programs such as dc and hoc , and interactive BASIC could be used to do calculations on most 1970s and 1980s home computers. Calculator functions are included in most smartphones , tablets , and personal digital assistant (PDA) type devices. With

4410-493: The ability to extend memory capacity to store more numbers; the extended memory address is termed an array index. Power sources of calculators are batteries , solar cells or mains electricity (for old models), turning on with a switch or button. Some models even have no turn-off button but they provide some way to put off (for example, leaving no operation for a moment, covering solar cell exposure, or closing their lid ). Crank -powered calculators were also common in

4508-413: The adding machine as a means of completing this operation. There is a debate about whether Pascal or Shickard should be credited as the known inventor of a calculating machine due to the differences (like the different aims) of both inventions. Schickard and Pascal were followed by Gottfried Leibniz who spent forty years designing a four-operation mechanical calculator, the stepped reckoner , inventing in

4606-560: The algebraic infix notation : 8 , + , 5 , = . It had 35 buttons and was based on Mostek Mk6020 chip. The first Soviet scientific pocket-sized calculator the "B3-18" was completed by the end of 1975. In 1973, Texas Instruments (TI) introduced the SR-10 , ( SR signifying slide rule ) an algebraic entry pocket calculator using scientific notation for $ 150. Shortly after the SR-11 featured an added key for entering pi (π). It

4704-415: The comptometer type under the names "Plus" and "Sumlock", and had realised in the mid-1950s that the future of calculators lay in electronics. They employed the young graduate Norbert Kitz, who had worked on the early British Pilot ACE computer project, to lead the development. The ANITA sold well since it was the only electronic desktop calculator available, and was silent and quick. The tube technology of

4802-405: The computer system. In addition to serving as temporary storage and working space for the operating system and applications, RAM is used in numerous other ways. Most modern operating systems employ a method of extending RAM capacity, known as "virtual memory". A portion of the computer's hard drive is set aside for a paging file or a scratch partition , and the combination of physical RAM and

4900-538: The course of two years including a botched partnership with Texas Instruments, Eldorado Electrodata released five pocket calculators in 1972. One called the Touch Magic was "no bigger than a pack of cigarettes" according to Administrative Management . The first Soviet Union made pocket-sized calculator, the Elektronika B3-04 was developed by the end of 1973 and sold at the start of 1974. One of

4998-448: The development of metal–oxide–semiconductor (MOS) memory by John Schmidt at Fairchild Semiconductor in 1964. In addition to higher speeds, MOS semiconductor memory was cheaper and consumed less power than magnetic core memory. The development of silicon-gate MOS integrated circuit (MOS IC) technology by Federico Faggin at Fairchild in 1968 enabled the production of MOS memory chips . MOS memory overtook magnetic core memory as

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5096-408: The device are used to activate the correct device that is being accessed. RAM is often byte addressable, although it is also possible to make RAM that is word-addressable. One can read and over-write data in RAM. Many computer systems have a memory hierarchy consisting of processor registers , on- die SRAM caches, external caches , DRAM , paging systems and virtual memory or swap space on

5194-437: The dominant memory technology in the early 1970s. Integrated bipolar static random-access memory (SRAM) was invented by Robert H. Norman at Fairchild Semiconductor in 1963. It was followed by the development of MOS SRAM by John Schmidt at Fairchild in 1964. SRAM became an alternative to magnetic-core memory, but required six MOS transistors for each bit of data. Commercial use of SRAM began in 1965, when IBM introduced

5292-428: The early computer era. The following keys are common to most pocket calculators. While the arrangement of the digits is standard, the positions of other keys vary from model to model; the illustration is an example. The arrangement of digits on calculator and other numeric keypads with the 7 - 8 - 9 keys two rows above the 1 - 2 - 3 keys is derived from calculators and cash registers . It

5390-493: The eve of the industrial revolution made large scale production of more compact and modern units possible. The Arithmometer , invented in 1820 as a four-operation mechanical calculator, was released to production in 1851 as an adding machine and became the first commercially successful unit; forty years later, by 1890, about 2,500 arithmometers had been sold plus a few hundreds more from two arithmometer clone makers (Burkhardt, Germany, 1878 and Layton, UK, 1883) and Felt and Tarrant,

5488-410: The extent that access time to rotating storage media or a tape is variable. The overall goal of using a memory hierarchy is to obtain the fastest possible average access time while minimizing the total cost of the entire memory system (generally, the memory hierarchy follows the access time with the fast CPU registers at the top and the slow hard drive at the bottom). In many modern personal computers,

5586-467: The first Japanese one) was the Casio (AL-1000) produced in 1967. It featured a nixie tubes display and had transistor electronics and ferrite core memory. The Monroe Epic programmable calculator came on the market in 1967. A large, printing, desk-top unit, with an attached floor-standing logic tower, it could be programmed to perform many computer-like functions. However, the only branch instruction

5684-492: The first direct multiplication machine in 1834: this was also the second key-driven machine in the world, following that of James White (1822). It was not until the 19th century and the Industrial Revolution that real developments began to occur. Although machines capable of performing all four arithmetic functions existed prior to the 19th century, the refinement of manufacturing and fabrication processes during

5782-560: The first low-cost calculators was the Sinclair Cambridge , launched in August 1973. It retailed for £29.95 ($ 41.03), or £5 ($ 6.85) less in kit form, and later models included some scientific functions. The Sinclair calculators were successful because they were far cheaper than the competition; however, their design led to slow and less accurate computations of transcendental functions (maximum three decimal places of accuracy). Meanwhile, Hewlett-Packard (HP) had been developing

5880-412: The fundamental building block of computer memory . The memory cell is an electronic circuit that stores one bit of binary information and it must be set to store a logic 1 (high voltage level) and reset to store a logic 0 (low voltage level). Its value is maintained/stored until it is changed by the set/reset process. The value in the memory cell can be accessed by reading it. In SRAM, the memory cell

5978-537: The gap between RAM and hard disk speeds, although RAM continues to be an order of magnitude faster, with single-lane DDR5 8000MHz capable of 128 GB/s, and modern GDDR even faster. Fast, cheap, non-volatile solid state drives have replaced some functions formerly performed by RAM, such as holding certain data for immediate availability in server farms - 1 terabyte of SSD storage can be had for $ 200, while 1 TB of RAM would cost thousands of dollars. Electronic calculator An electronic calculator

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6076-610: The introduction of the first "calculator on a chip", the MK6010 by Mostek , followed by Texas Instruments later in the year. Although these early hand-held calculators were very costly, these advances in electronics, together with developments in display technology (such as the vacuum fluorescent display , LED , and LCD ), led within a few years to the cheap pocket calculator available to all. In 1971, Pico Electronics and General Instrument also introduced their first collaboration in ICs,

6174-555: The logic circuits, appeared in the 1940s and 1950s. Electronic circuits developed for computers also had application to electronic calculators. The Casio Computer Company, in Japan , released the Model 14-A calculator in 1957, which was the world's first all-electric (relatively) compact calculator. It did not use electronic logic but was based on relay technology, and was built into a desk. The IBM 608 plugboard programmable calculator

6272-545: The means of producing inductance within solid state devices, resistance-capacitance (RC) delays in signal transmission are growing as feature sizes shrink, imposing an additional bottleneck that frequency increases don't address. The RC delays in signal transmission were also noted in "Clock Rate versus IPC: The End of the Road for Conventional Microarchitectures" which projected a maximum of 12.5% average annual CPU performance improvement between 2000 and 2014. A different concept

6370-436: The memory cannot be altered. Writable variants of ROM (such as EEPROM and NOR flash ) share properties of both ROM and RAM, enabling data to persist without power and to be updated without requiring special equipment. ECC memory (which can be either SRAM or DRAM) includes special circuitry to detect and/or correct random faults (memory errors) in the stored data, using parity bits or error correction codes . In general,

6468-637: The mid-1960s. They included the Mathatronics Mathatron (1964) and the Olivetti Programma 101 (late 1965) which were solid-state, desktop, printing, floating point, algebraic entry, programmable, stored-program electronic calculators. Both could be programmed by the end user and print out their results. The Programma 101 saw much wider distribution and had the added feature of offline storage of programs via magnetic cards. Another early programmable desktop calculator (and maybe

6566-461: The mid-1970s as the incorporation of integrated circuits reduced their size and cost. By the end of that decade, prices had dropped to the point where a basic calculator was affordable to most and they became common in schools. In addition to general purpose calculators, there are those designed for specific markets. For example, there are scientific calculators , which include trigonometric and statistical calculations. Some calculators even have

6664-467: The monolithic (single-chip) 16-bit SP95 SRAM chip for their System/360 Model 95 computer, and Toshiba used bipolar DRAM memory cells for its 180-bit Toscal BC-1411 electronic calculator , both based on bipolar transistors . While it offered higher speeds than magnetic-core memory , bipolar DRAM could not compete with the lower price of the then-dominant magnetic-core memory. In 1966, Dr. Robert Dennard invented modern DRAM architecture in which there's

6762-711: The only other competitor in true commercial production, had sold 100 comptometers . It wasn't until 1902 that the familiar push-button user interface was developed, with the introduction of the Dalton Adding Machine, developed by James L. Dalton in the United States . In 1921, Edith Clarke invented the "Clarke calculator", a simple graph-based calculator for solving line equations involving hyperbolic functions. This allowed electrical engineers to simplify calculations for inductance and capacitance in power transmission lines . The Curta calculator

6860-443: The order it was written. Drum memory could be expanded at relatively low cost but efficient retrieval of memory items requires knowledge of the physical layout of the drum to optimize speed. Latches built out of triode vacuum tubes , and later, out of discrete transistors , were used for smaller and faster memories such as registers . Such registers were relatively large and too costly to use for large amounts of data; generally only

6958-571: The paging file form the system's total memory. (For example, if a computer has 2 GB (1024 B) of RAM and a 1 GB page file, the operating system has 3 GB total memory available to it.) When the system runs low on physical memory, it can " swap " portions of RAM to the paging file to make room for new data, as well as to read previously swapped information back into RAM. Excessive use of this mechanism results in thrashing and generally hampers overall system performance, mainly because hard drives are far slower than RAM. Software can "partition"

7056-422: The power grid, was released at the start of the 1970s. The electronic calculators of the mid-1960s were large and heavy desktop machines due to their use of hundreds of transistors on several circuit boards with a large power consumption that required an AC power supply. There were great efforts to put the logic required for a calculator into fewer and fewer integrated circuits (chips) and calculator electronics

7154-421: The process his leibniz wheel , but who couldn't design a fully operational machine. There were also five unsuccessful attempts to design a calculating clock in the 17th century. The 18th century saw the arrival of some notable improvements, first by Poleni with the first fully functional calculating clock and four-operation machine, but these machines were almost always one of a kind . Luigi Torchi invented

7252-631: The processor's speed, and is measured in clock cycles per second or hertz (Hz) . For basic calculators, the speed can vary from a few hundred hertz to the kilohertz range. A basic explanation as to how calculations are performed in a simple four-function calculator: To perform the calculation 25 + 9 , one presses keys in the following sequence on most calculators: 2   5   +   9   = . Other functions are usually performed using repeated additions or subtractions. Most pocket calculators do all their calculations in binary-coded decimal (BCD) rather than binary. BCD

7350-577: The processor, speeding up the execution of those operations or instructions in cases where they are called upon frequently. Multiple levels of caching have been developed to deal with the widening gap, and the performance of high-speed modern computers relies on evolving caching techniques. There can be up to a 53% difference between the growth in speed of processor and the lagging speed of main memory access. Solid-state hard drives have continued to increase in speed, from ~400 Mbit/s via SATA3 in 2012 up to ~7 GB/s via NVMe / PCIe in 2024, closing

7448-603: The same time). The Victor 3900 was the first to use integrated circuits in place of individual transistors , but production problems delayed sales until 1966. There followed a series of electronic calculator models from these and other manufacturers, including Canon , Mathatronics , Olivetti , SCM (Smith-Corona-Marchant), Sony , Toshiba , and Wang . The early calculators used hundreds of germanium transistors , which were cheaper than silicon transistors , on multiple circuit boards. Display types used were CRT, cold-cathode Nixie tubes , and filament lamps . Memory technology

7546-435: The same type, simply because it takes longer for signals to traverse a larger circuit. Constructing a memory unit of many gibibytes with a response time of one clock cycle is difficult or impossible. Today's CPUs often still have a mebibyte of 0 wait state cache memory, but it resides on the same chip as the CPU cores due to the bandwidth limitations of chip-to-chip communication. It must also be constructed from static RAM, which

7644-400: The term RAM refers solely to solid-state memory devices (either DRAM or SRAM), and more specifically the main memory in most computers. In optical storage, the term DVD-RAM is somewhat of a misnomer since, it is not random access; it behaves much like a hard disc drive if somewhat slower. Aside, unlike CD-RW or DVD-RW , DVD-RAM does not need to be erased before reuse. The memory cell is

7742-443: The time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement. In today's technology, random-access memory takes the form of integrated circuit (IC) chips with MOS (metal–oxide–semiconductor) memory cells . RAM is normally associated with volatile types of memory where stored information

7840-403: The time" astronomical device), development of computing tools arrived near the start of the 17th century: the geometric-military compass (by Galileo ), logarithms and Napier bones (by Napier ), and the slide rule (by Edmund Gunter ). The Renaissance saw the invention of the mechanical calculator by Wilhelm Schickard in 1623, and later by Blaise Pascal in 1642. A device that

7938-738: The track number in BCD, limiting them to 99 tracks.) The same argument applies when hardware of this type uses an embedded microcontroller or other small processor. Often, smaller code results when representing numbers internally in BCD format, since a conversion from or to binary representation can be expensive on such limited processors. For these applications, some small processors feature BCD arithmetic modes, which assist when writing routines that manipulate BCD quantities. Where calculators have added functions (such as square root, or trigonometric functions ), software algorithms are required to produce high precision results. Sometimes significant design effort

8036-558: The transistor leakage current increases, leading to excess power consumption and heat... Secondly, the advantages of higher clock speeds are in part negated by memory latency, since memory access times have not been able to keep pace with increasing clock frequencies. Third, for certain applications, traditional serial architectures are becoming less efficient as processors get faster (due to the so-called von Neumann bottleneck ), further undercutting any gains that frequency increases might otherwise buy. In addition, partly due to limitations in

8134-643: The very wide availability of smartphones and the like, dedicated hardware calculators, while still widely used, are less common than they once were. In 1986, calculators still represented an estimated 41% of the world's general-purpose hardware capacity to compute information. By 2007, this had diminished to less than 0.05%. Electronic calculators contain a keyboard with buttons for digits and arithmetical operations; some even contain "00" and "000" buttons to make larger or smaller numbers easier to enter. Most basic calculators assign only one digit or operation on each button; however, in more specific calculators,

8232-624: Was IBM's first all-transistor product, released in 1957; this was a console type system, with input and output on punched cards, and replaced the earlier, larger, vacuum-tube IBM 603 . In October 1961, the world's first all-electronic desktop calculator, the British Bell Punch /Sumlock Comptometer ANITA ( A N ew I nspiration T o A rithmetic/ A ccounting) was announced. This machine used vacuum tubes , cold-cathode tubes and Dekatrons in its circuits, with 12 cold-cathode "Nixie" tubes for its display. Two models were displayed,

8330-447: Was Samsung's 64   Mbit DDR SDRAM chip, released in June 1998. GDDR (graphics DDR) is a form of DDR SGRAM (synchronous graphics RAM), which was first released by Samsung as a 16   Mbit memory chip in 1998. The two widely used forms of modern RAM are static RAM (SRAM) and dynamic RAM (DRAM). In SRAM, a bit of data is stored using the state of a six- transistor memory cell , typically using six MOSFETs. This form of RAM

8428-578: Was a manufacturer of mechanical calculators that had decided that the future lay in electronics. In 1964 more all-transistor electronic calculators were introduced: Sharp introduced the CS-10A , which weighed 25 kilograms (55 lb) and cost 500,000 yen ($ 4555.81), and Industria Macchine Elettroniche of Italy introduced the IME 84, to which several extra keyboard and display units could be connected so that several people could make use of it (but apparently not at

8526-589: Was a paper tape. As a result of the "Cal-Tech" project, Texas Instruments was granted master patents on portable calculators. The first commercially produced portable calculators appeared in Japan in 1970, and were soon marketed around the world. These included the Sanyo ICC-0081 "Mini Calculator", the Canon Pocketronic, and the Sharp QT-8B "micro Compet". The Canon Pocketronic was

8624-553: Was also the first calculator to use an LED display, the first hand-held calculator to use a single integrated circuit (then proclaimed as a "calculator on a chip"), the Mostek MK6010, and the first electronic calculator to run off replaceable batteries. Using four AA-size cells the LE-120A measures 4.9 by 2.8 by 0.9 inches (124 mm × 71 mm × 23 mm). The first European-made pocket-sized calculator, DB 800

8722-419: Was an implied unconditional branch (GOTO) at the end of the operation stack, returning the program to its starting instruction. Thus, it was not possible to include any conditional branch (IF-THEN-ELSE) logic. During this era, the absence of the conditional branch was sometimes used to distinguish a programmable calculator from a computer. The first Soviet programmable desktop calculator ISKRA 123 , powered by

8820-436: Was at times somewhat over-promoted as being able to perform all four arithmetic operations with minimal human intervention. Pascal's calculator could add and subtract two numbers directly and thus, if the tedium could be borne, multiply and divide by repetition. Schickard's machine, constructed several decades earlier, used a clever set of mechanised multiplication tables to ease the process of multiplication and division with

8918-474: Was developed in 1948 and, although costly, became popular for its portability. This purely mechanical hand-held device could do addition, subtraction, multiplication and division. By the early 1970s electronic pocket calculators ended manufacture of mechanical calculators, although the Curta remains a popular collectable item. The first mainframe computers, initially using vacuum tubes and later transistors in

9016-493: Was expected that memory latency would become an overwhelming bottleneck in computer performance. Another reason for the disparity is the enormous increase in the size of memory since the start of the PC revolution in the 1980s. Originally, PCs contained less than 1 mebibyte of RAM, which often had a response time of 1 CPU clock cycle, meaning that it required 0 wait states. Larger memory units are inherently slower than smaller ones of

9114-410: Was introduced in 1965, used a form of capacitor-bipolar DRAM, storing 180-bit data on discrete memory cells , consisting of germanium bipolar transistors and capacitors. While it offered higher speeds than magnetic-core memory, bipolar DRAM could not compete with the lower price of the then dominant magnetic-core memory. Capacitors had also been used for earlier memory schemes, such as the drum of

9212-592: Was made in May 1971 by Digitron in Buje , Croatia (former Yugoslavia ) with four functions and an eight-digit display and special characters for a negative number and a warning that the calculation has too many digits to display. The first American-made pocket-sized calculator, the Bowmar 901B (popularly termed The Bowmar Brain ), measuring 5.2 by 3.0 by 1.5 inches (132 mm × 76 mm × 38 mm), came out in

9310-608: Was one of the leading edges of semiconductor development. U.S. semiconductor manufacturers led the world in large scale integration (LSI) semiconductor development, squeezing more and more functions into individual integrated circuits. This led to alliances between Japanese calculator manufacturers and U.S. semiconductor companies: Canon Inc. with Texas Instruments , Hayakawa Electric (later renamed Sharp Corporation ) with North-American Rockwell Microelectronics (later renamed Rockwell International ), Busicom with Mostek and Intel , and General Instrument with Sanyo . By 1970,

9408-460: Was possible. Magnetic core memory was the standard form of computer memory until displaced by semiconductor memory in integrated circuits (ICs) during the early 1970s. Prior to the development of integrated read-only memory (ROM) circuits, permanent (or read-only ) random-access memory was often constructed using diode matrices driven by address decoders , or specially wound core rope memory planes. Semiconductor memory appeared in

9506-433: Was released in 1970. The earliest DRAMs were often synchronized with the CPU clock (clocked) and were used with early microprocessors. In the mid-1970s, DRAMs moved to the asynchronous design, but in the 1990s returned to synchronous operation. In 1992 Samsung released KM48SL2000, which had a capacity of 16   Mbit . and mass-produced in 1993. The first commercial DDR SDRAM ( double data rate SDRAM) memory chip

9604-767: Was usually based on the delay-line memory or the magnetic-core memory , though the Toshiba "Toscal" BC-1411 appears to have used an early form of dynamic RAM built from discrete components. Already there was a desire for smaller and less power-hungry machines. Bulgaria's ELKA 6521 , introduced in 1965, was developed by the Central Institute for Calculation Technologies and built at the Elektronika factory in Sofia . The name derives from EL ektronen KA lkulator , and it weighed around 8 kg (18 lb). It

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