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HP-75D
The HP-75C and HP-75D were hand-held computers programmable in BASIC, made by Hewlett-Packard from 1982 to 1986. The HP-75 had a single-line liquid crystal display, 48 KiB system ROM and 16 KiB RAM, a comparatively large keyboard (albeit without a separate numeric pad), a manually operated magnetic card reader (2×650 bytes per card), 4 ports for memory expansion (1 for RAM and 3 for ROM modules), and an HP-IL interface that could be used to connect printers, storage and electronic test equipment. The BASIC interpreter also acted as a primitive operating system, providing file handling capabilities for program storage using RAM, cards, or cassettes/diskettes (via HP-IL). Other features included a text editor as well as an appointment reminder with alarms, similar to functions of modern PDAs. The HP-75D (1984–1986) added a port for a bar code wand, often used for inventory control tasks. The HP-75 was comparatively expensive with an MSRP of $995 ($2,014 in 2005) for the 75C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HP-75D
The HP-75C and HP-75D were hand-held computers programmable in BASIC, made by Hewlett-Packard from 1982 to 1986. The HP-75 had a single-line liquid crystal display, 48 KiB system ROM and 16 KiB RAM, a comparatively large keyboard (albeit without a separate numeric pad), a manually operated magnetic card reader (2×650 bytes per card), 4 ports for memory expansion (1 for RAM and 3 for ROM modules), and an HP-IL interface that could be used to connect printers, storage and electronic test equipment. The BASIC interpreter also acted as a primitive operating system, providing file handling capabilities for program storage using RAM, cards, or cassettes/diskettes (via HP-IL). Other features included a text editor as well as an appointment reminder with alarms, similar to functions of modern PDAs. The HP-75D (1984–1986) added a port for a bar code wand, often used for inventory control tasks. The HP-75 was comparatively expensive with an MSRP of $995 ($2,014 in 2005) for the 75C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Personal Digital Assistant
A personal digital assistant (PDA), also known as a handheld PC, is a variety mobile device which functions as a personal information manager. PDAs have been mostly displaced by the widespread adoption of highly capable smartphones, in particular those based on iOS and Android. A PDA has an electronic visual display. Most models also have audio capabilities, allowing usage as a portable media player, and also enabling many of them to be used as telephones. Nearly all modern PDAs can access the Internet, intranets or extranets via Wi-Fi or Wireless WANs, letting them include a web browser. Sometimes, instead of buttons, PDAs employ touchscreen technology. The first PDA, the Organiser, was released in 1984 by Psion, followed by Psion's Series 3, in 1991. The latter began to resemble the more familiar PDA style, including a full keyboard. The term ''PDA'' was first used on January 7, 1992 by Apple Inc. CEO John Sculley at the Consumer Electronics Show in Las Vegas, Nevad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hewlett-Packard Products
The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company headquartered in Palo Alto, California. HP developed and provided a wide variety of hardware components, as well as software and related services to consumers, small and medium-sized businesses ( SMBs), and large enterprises, including customers in the government, health, and education sectors. The company was founded in a one-car garage in Palo Alto by Bill Hewlett and David Packard in 1939, and initially produced a line of electronic test and measurement equipment. The HP Garage at 367 Addison Avenue is now designated an official California Historical Landmark, and is marked with a plaque calling it the "Birthplace of 'Silicon Valley'". The company won its first big contract in 1938 to provide test and measurement instruments for Walt Disney's production of the animated film ''Fantasia'', which allowed Hewlett and Packard to formally esta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BYTE
The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit of memory in many computer architectures. To disambiguate arbitrarily sized bytes from the common 8-bit definition, network protocol documents such as The Internet Protocol () refer to an 8-bit byte as an octet. Those bits in an octet are usually counted with numbering from 0 to 7 or 7 to 0 depending on the bit endianness. The first bit is number 0, making the eighth bit number 7. The size of the byte has historically been hardware-dependent and no definitive standards existed that mandated the size. Sizes from 1 to 48 bits have been used. The six-bit character code was an often-used implementation in early encoding systems, and computers using six-bit and nine-bit bytes were common in the 1960s. These systems often had memory words ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Codename
A code name, call sign or cryptonym is a Code word (figure of speech), code word or name used, sometimes clandestinely, to refer to another name, word, project, or person. Code names are often used for military purposes, or in espionage. They may also be used in industrial espionage, industrial counter-espionage to protect secret projects and the like from business rivals, or to give names to projects whose marketing name has not yet been determined. Another reason for the use of names and phrases in the military is that they transmit with a lower level of cumulative errors over a walkie-talkie or radio link than actual names. Military origins During First World War, World War I, names common to the Allies of World War I, Allies referring to nations, cities, geographical features, military units, military operations, diplomatic meetings, places, and individual persons were agreed upon, adapting pre-war naming procedures in use by the governments concerned. In the British case n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printed Circuit Board
A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in Electrical engineering, electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a Lamination, laminated sandwich structure of conductive and insulating layers: each of the conductive layers is designed with an artwork pattern of traces, planes and other features (similar to wires on a flat surface) Chemical milling, etched from one or more sheet layers of copper Lamination, laminated onto and/or between sheet layers of a Insulator (electricity), non-conductive substrate. Electrical components may be fixed to conductive pads on the outer layers in the shape designed to accept the component's terminals, generally by means of soldering, to both electrically connect and mechanically fasten them to it. Another manufacturing process adds Via (electronics), vias: plated-through holes that allow interconnections between layers. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HP-71B
The HP-71B was a hand-held computer or calculator programmable in BASIC, made by Hewlett-Packard from 1984 to 1989. Description Smaller and less expensive (US$595 $525 in 1984 ≈ $990 in 2005 (seInflation Conversion Factors for Dollars) MSRP) than the preceding model HP-75, the 71B had a single-line 22-character liquid crystal display, 64K system ROM and 17.5K user memory. It operated on four AAA batteries. Four plug-in ports permitted ROM-based programs or additional user memory to be added. Separate compartments could accommodate an optional magnetic card reader and an optional HP-IL interface (HP 82401A) that could be used to connect printers, storage and electronic test equipment. The 71B was the first handheld to implement the IEEE 854-1987 radix-independent floating-point standard. Programming features included a real-time clock, programmable timers and subroutine calls with parameter passing and recursion. It was also HP's first calculator based on the ''Saturn'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MSRP
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] |
Random-access Memory
Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A Random access, random-access memory device allows data items to be read (computer), 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, CD-RWs, DVD-RWs and the older Magnetic tape data storage, magnetic tapes and drum memory), where 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. RAM contains multiplexer, multiplexing and demultiplexing circuitry, to connect the data lines to the addressed storage for reading or writing the entry. Usually more than one bit of storage is accessed by the same address, and RAM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Personal Computer
A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or technician. Unlike large, costly minicomputers and mainframes, time-sharing by many people at the same time is not used with personal computers. Primarily in the late 1970s and 1980s, the term home computer was also used. Institutional or corporate computer owners in the 1960s had to write their own programs to do any useful work with the machines. While personal computer users may develop their own applications, usually these systems run commercial software, free-of-charge software ("freeware"), which is most often proprietary, or free and open-source software, which is provided in "ready-to-run", or binary, form. Software for personal computers is typically developed and distributed independently from the hardware or operating system ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HP-IL
The HP-IL (''Hewlett-Packard Interface Loop''), was a short-range interconnection bus or network introduced by Hewlett-Packard in the early 1980s. It enabled many devices such as printers, plotters, displays, storage devices (floppy disk drives and tape drives), test equipment, etc. to be connected to programmable calculators such as the HP-41C, HP-71B and HP-75C/D, the 80-series and HP-110 computers, as well as generic ISA bus based PCs. Principles As its name implies, an HP-IL network formed a loop (i.e. it was a Ring network): each device in the loop had a pair of two-wire connections, one designated ''in'', which received messages from the previous device in the loop; and one designated ''out'', which delivered messages to the next device in the loop. One device on the loop is designated the ''controller'', and manages all other devices on the loop. HP-IL cables utilize a unique two-pin connector design with polarizing "D"-shaped shells, and can be connected together ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Read-only Memory
Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing software that is rarely changed during the life of the system, also known as firmware. Software applications (like video games) for programmable devices can be distributed as plug-in cartridges containing ROM. Strictly speaking, ''read-only memory'' refers to memory that is hard-wired, such as diode matrix or a mask ROM integrated circuit (IC), which cannot be electronically changed after manufacture. Although discrete circuits can be altered in principle, through the addition of bodge wires and/or the removal or replacement of components, ICs cannot. Correction of errors, or updates to the software, require new devices to be manufactured and to replace the installed device. Floating-gate ROM semiconductor memory in the form of erasab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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