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HP-67
The HP-67 is a magnetic card-programmable handheld calculator, introduced by Hewlett-Packard in 1976 at an MSRP of $450. A desktop version with built-in thermal printer was sold as the HP-97 at a price of $750. Marketed as improved successors to the HP-65, the HP-67/97 were based on the technology of the "20-series" of calculators (HP-25, HP-19C etc.) introduced a year earlier. The two models are functionally equivalent, and programs on magnetic cards can be interchanged between them. Features The 67/97 provide a complete set of scientific, statistical and engineering operations, including trigonometric, logarithmic and exponential functions, coordinate conversions, average/standard deviation etc. The HP-67/97 series featured a program memory of 224 eight-bit words. The two extra bits per word compared to the HP-65's six allowed the designers to store any program instruction in a single memory cell ("fully merged keycodes") even if it required multiple keystrokes to enter. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hp-97 Front-2
The HP-67 is a magnetic card-programmable handheld calculator, introduced by Hewlett-Packard in 1976 at an MSRP of $450. A desktop version with built-in thermal printer was sold as the HP-97 at a price of $750. Marketed as improved successors to the HP-65, the HP-67/97 were based on the technology of the "20-series" of calculators (HP-25, HP-19C etc.) introduced a year earlier. The two models are functionally equivalent, and programs on magnetic cards can be interchanged between them. Features The 67/97 provide a complete set of scientific, statistical and engineering operations, including trigonometric, logarithmic and exponential functions, coordinate conversions, average/standard deviation etc. The HP-67/97 series featured a program memory of 224 eight-bit words. The two extra bits per word compared to the HP-65's six allowed the designers to store any program instruction in a single memory cell ("fully merged keycodes") even if it required multiple keystrokes to enter. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HP-41C
The HP-41C series are programmable, expandable, continuous memory handheld RPN calculators made by Hewlett-Packard from 1979 to 1990. The original model, HP-41C, was the first of its kind to offer alphanumeric display capabilities. Later came the HP-41CV and HP-41CX, offering more memory and functionality. The alphanumeric "revolution" The alphanumeric LCD screen of the HP-41C revolutionized the way a pocket calculator could be used, providing user friendliness (for its time) and expandability (keyboard-unassigned functions could be spelled out alphabetically). By using an alphanumeric display, the calculator could tell the user what was going on: it could display error messages, such as showing ("DATA ERROR") upon attempting to divide by zero instead of simply displaying a blinking zero; it could also specifically prompt the user for arguments ("ENTER RADIUS") instead of just displaying a question mark. Earlier calculators needed a key, or key combination, for every a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TI-59 / TI-58
The TI-59 is an early programmable calculator, that was manufactured by Texas Instruments from 1977. It is the successor to the TI SR-52, quadrupling the number of "program steps" of storage, and adding "ROM Program Modules" (an insertable ROM chip, capable of holding 5000 program steps). Just like the SR-52, it has a magnetic card reader for external storage. One quarter of the memory is stored on each side of one card. The TI-58 (May 1977), and later TI-58C (1979), are cut-down versions of the TI-59, lacking the magnetic card reader and having half the memory, but otherwise identical. Although the TI-58C uses a different chip than the TI-58, the technical data remain identical. The "C" in a TI (or Hewlett-Packard) model name indicates that the calculator has a ''constant'' memory (or continuous memory, respectively) allowing retention of programs and data when turned off. These calculators use a parenthesized infix calculation system called "Algebraic Operating System" (AOS) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tape Head
A tape head is a type of transducer used in tape recorders to convert electrical signals to magnetic fluctuations and vice versa. They can also be used to read credit/debit/gift cards because the strip of magnetic tape on the back of a credit card stores data the same way that other magnetic tapes do. Cassettes, reel-to-reel tapes, 8-tracks, VHS tapes, and even floppy disks and early hard drive disks all use the same principle of physics to store and read back information. The medium is magnetized in a pattern. It then moves at a constant speed over an electromagnet. Since the moving tape is carrying a changing magnetic field with it, it induces a varying voltage across the head. That voltage can then be amplified and connected to speakers in the case of audio, or measured and sorted into ones and zeroes in the case of digital data. Principles of operation The electromagnetic arrangement of a tape head is generally similar for all types, though the physical design varie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programmable Calculator
Programmable calculators are calculators that can automatically carry out a sequence of operations under control of a stored computer programming, program. Most are Turing complete, and, as such, are theoretically general-purpose computers. However, their user interfaces and programming environments are specifically tailored to make performing small-scale numerical computations convenient, rather than general-purpose use. The first programmable calculators such as the IBM CPC used punched cards or other media for program storage. Hand-held electronic calculators store programs on magnetic strips, removable read-only memory cartridges, flash memory, or in battery-backed read/write memory. Since the early 1990s, most of these flexible handheld units belong to the class of graphing calculators. Before the mass-manufacture of inexpensive dot-matrix LCDs, however, programmable calculators usually featured a one-line numeric or alphanumeric display. The Big Four manufacturers of pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HP-65
The HP-65 is the first magnetic card-programmable handheld calculator. Introduced by Hewlett-Packard in 1974 at an MSRP of $795 (), it featured nine storage registers and room for 100 keystroke instructions. It also included a magnetic card reader/writer to save and load programs. Like all Hewlett-Packard calculators of the era and most since, the HP-65 used Reverse Polish Notation (RPN) and a four-level automatic operand stack. Bill Hewlett's design requirement was that the calculator should fit in his shirt pocket. That is one reason for the tapered depth of the calculator. The magnetic program cards are fed in at the thick end of the calculator under the LED display. The documentation for the programs in the calculator is very complete, including algorithms for hundreds of applications, including the solutions of differential equations, stock price estimation, statistics, and so forth. Features The HP-65 introduced the "tall", trapezoid-shaped keys that would become iconic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motherboard
A motherboard (also called mainboard, main circuit board, mb, mboard, backplane board, base board, system board, logic board (only in Apple computers) or mobo) is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It holds and allows communication between many of the crucial electronic components of a system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals. Unlike a backplane, a motherboard usually contains significant sub-systems, such as the central processor, the chipset's input/output and memory controllers, interface connectors, and other components integrated for general use. ''Motherboard'' means specifically a PCB with expansion capabilities. As the name suggests, this board is often referred to as the "mother" of all components attached to it, which often include peripherals, interface cards, and daughterboards: sound cards, video cards, network cards, host bus adapters, TV t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PPC Journal
''PPC Journal'' was an early hobbyist computer magazine, originally targeted at users of HP's first programmable calculator, the HP-65. It originated as ''65 Notes'' and the first issue was published in 1974. It later changed names in 1978 to ''PPC Journal'' and in 1980 to ''PPC Calculator Journal''. With Volume 12 published in 1984 the magazine was renamed ''PPC Journal''. The magazine ended publication in July 1987 (Volume 14). The founder of the ''PPC'' (Personal Programming Center) and editor of the journal was Richard J. Nelson. This hobbyist group worked around the journal and was known because Nelson discovered hidden instructions on the HP-65 calculator. Later the club and the journal got maximum notoriety when several club members discovered the " synthetic instructions" of the HP-41C. Competition A similar journal since 1976 was '' 52-Notes'' for the Texas Instruments SR-52 user community. It was edited by Richard C. Vanderburgh. Both journals deliberately established a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HP-25
The HP-25 was a hand-held programmable scientific/engineering calculator made by Hewlett-Packard between early January 1975 and 1978. The HP-25 was introduced as a cheaper (US$195 MSRP) alternative to the ground-breaking HP-65. To reduce cost, the HP-25 omitted the HP-65's magnetic card reader, so it could only be programmed using the keyboard. After switching off, the program was lost and had to be typed in again. The model HP-25C, introduced in 1976, addressed that shortcoming through the first use of battery-backed CMOS memory in a calculator, termed ''continuous memory'' by HP. Like all early HP calculators, the 25 used the Reverse Polish Notation (RPN) for entering calculations, working on a four-level stack (x,y,z,t). Nearly all buttons had two alternative functions, accessed by a blue and yellow prefix key. A small sliding switch was used to change between "run" and "program" mode. The HP-25 used a 10-digit red LED display and was the first calculator to introduce the " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HP-19C
The HP-19C and HP-29C were scientific/engineering pocket calculators made by Hewlett-Packard between 1977 and 1979. They were the most advanced and last models of the "20" family (compare HP-25) and included ''Continuous Memory'' (battery-backed CMOS memory) as a standard feature. The HP-19C included a small thermal printer, one of the very few hand-held scientific calculators to offer such a feature (HP-91, HP-92 and HP-97 were desktop units and later models like the HP-41C only supported external printers). Due to the printer's power requirements, the 19C used a battery pack of four AA-sized NiCd cells, adding to the weight of the calculator and printer mechanism. All other capabilities were the same in both models – RPN expression logic, 98 program memory locations, statistical functions, and 30 registers. Users could develop software for the HP-29C/19C, such as a prime number generator. The calculators expanded the HP-25's program capabilities by adding subrou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calculator Input Methods
There are various ways in which calculators interpret keystrokes. These can be categorized into two main types: * On a single-step or immediate-execution calculator, the user presses a key for each operation, calculating all the intermediate results, before the final value is shown. * On an expression or formula calculator, one types in an expression and then presses a key, such as "=" or "Enter", to evaluate the expression. There are various systems for typing in an expression, as described below. Immediate execution The immediate execution mode of operation (also known as single-step, algebraic entry system (AES) or chain calculation mode) is commonly employed on most general-purpose calculators. In most simple four-function calculators, such as the Windows Calculator, Windows calculator in Standard mode and those included with most early operating systems, each binary operation is executed as soon as the next operator is pressed, and therefore the order of operations in a math ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suggested Retail Price
The list price, also known as the manufacturer's suggested retail price (MSRP), or the recommended retail price (RRP), or the suggested retail price (SRP) of a product is the price at which its manufacturer notionally recommends that a retailer sell the product. Suggested pricing methods may conflict with competition theory, as they allow prices to be set higher than would be established by supply and demand. Resale price maintenance—fixing prices—goes further than suggesting prices, and is illegal in many countries. Retailers may charge less than the suggested retail price, depending upon the actual wholesale cost of each item, usually purchased in bulk from the manufacturer, or in smaller quantities through a distributor. The suggested price is sometimes unrealistically high, so the seller can appear to be offering a discount. List price often cannot be compared directly internationally as products may differ in detail, sometimes due to different regulations, and list pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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