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Zenith Z-89
The Z-89 is a personal computer introduced in 1979 by Heathkit, but produced primarily by Zenith Data Systems (ZDS) in the early 1980s. It combined an updated version of the Heathkit H8 microcomputer and H19 terminal in a new case that has room for a built-in floppy disk on the right side of the display. Based on the Zilog Z80 microprocessor, it is capable of running CP/M as well as Heathkit's own HDOS. Description The Zenith Z-89 is based on the Zilog Z80 microprocessor running at 2.048 MHz, and supports the HDOS and CP/M operating systems. The US$2295 Z-89 is integrated in a terminal-like enclosure with a non-detachable keyboard, 12-inch monochrome CRT with a 80x25 character screen, 48 KB RAM, and a 5.25" floppy disk drive. The keyboard is of high build quality and has an unusual number of special purpose keys: , , , , , , , , , , , and three with white, red, and blue squares. There are five function keys and a numeric keypad. The video display has reverse video ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zenith Data Systems
Zenith Data Systems Corporation (ZDS) was an American computer systems manufacturing company active from 1979 to 1996. It was originally a division of the Zenith Radio Company (later Zenith Electronics), after they had purchased the Heath Company and, by extension, their Heathkit line of electronic kits and kit microcomputers, from Schlumberger in October 1979. ZDS originally operated from Heath's own headquarters in St. Joseph, Michigan. By the time Zenith acquired Heathkit, their H8 kit computer already had an installed fanbase of scientific engineers and computing enthusiasts. ZDS's first offerings were merely preassembled versions of existing Heathkit computers, but within a few years, the company began selling systems of their own design, including the Z-100, which was a hybrid 8085- and 8088-based computer capable of running both CP/M and MS-DOS. ZDS largely avoided the retail consumer market, instead focusing on selling directly to businesses, educational instituti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cathode Ray Tube
A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms on an oscilloscope, a Film frame, frame of video on an Analog television, analog television set (TV), Digital imaging, digital raster graphics on a computer monitor, or other phenomena like radar targets. A CRT in a TV is commonly called a picture tube. CRTs have also been Williams tube, used as memory devices, in which case the screen is not intended to be visible to an observer. The term ''cathode ray'' was used to describe electron beams when they were first discovered, before it was understood that what was emitted from the cathode was a beam of electrons. In CRT TVs and computer monitors, the entire front area of the tube is scanned repeatedly and systematically in a fixed pattern called a raster scan, raster. In color devices, an image is produced by con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zenith Z-100
The Z-100 computer is a personal computer made by Zenith Data Systems (ZDS). It was a competitor to the IBM PC. Design The Zenith Data Systems Z-100 is a pre-assembled version of the Heathkit H100 electronic kit, but unlike the Zenith Z-89 the Z-100 was designed first as a preassembled product. In the same family, the Z-120 is an all-in-one model with self-contained monitor, and the Z-110 (called the low profile model) is similar in size to the cabinet of an IBM PC. Both models have a built-in keyboard that was modeled after the IBM Selectric typewriter. * Dual processors: 8085 and 8088. * Available with CP/M and Z-DOS (non-IBM compatible MS-DOS variant). * Five S-100 expansion slots. * Two 320 KB 40-track double-sided 5.25-inch floppy disk drives. Socket enabled direct plug-in of external 8-inch floppies. * Two serial ports (2661 UART), one Centronics printer port (discrete TTL chips), light pen port. * 640×225 bitmap display, with eight colors (low-profile model), or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jerry Pournelle
Jerry Eugene Pournelle (; August 7, 1933 – September 8, 2017) was an American scientist in the area of operations research and ergonomics, human factors research, a science fiction writer, essayist, journalist, and one of the first bloggers. In the 1960s and early 1970s, he worked in the aerospace industry, but eventually focused on his writing career. In an obituary in ''Gizmodo'', he was described as "a tireless ambassador for the future." Pournelle's hard science fiction writing received multiple awards. In addition to his solo writing, he wrote several novels with collaborators including Larry Niven. Pournelle served a term as President of the Science Fiction and Fantasy Writers of America. Pournelle's journalism focused primarily on the computer industry, astronomy, and space exploration. From the 1970s until the early 1990s, he contributed to the computer magazine ''Byte (magazine), Byte'', writing from the viewpoint of an intelligent user, with the oft-cited credo, "We ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercalc
SuperCalc is a spreadsheet published by Sorcim in 1980. History VisiCalc was the first spreadsheet program, but at first was not available for the CP/M operating system. SuperCalc was created to serve that market. Alongside WordStar, it was one of the CP/M applications bundled with the Osborne 1 portable computer. It quickly became popular and was ported to MS-DOS in 1982. An improvement over VisiCalc (though using much the same command structure using the slash key), SuperCalc was one of the first spreadsheet programs capable of iteratively solving circular references (cells that depend on each other's results). It would be over 10 years after the introduction of SuperCalc before this feature was implemented in Microsoft Excel, although in Lotus 1-2-3, manual programming of iterative logic could also be used to solve this issue. According to the SuperCalc product manager, iterative calculations were added when Sorcim changed from binary-coded decimal to binary math. Si ... [...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 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 of 12, 18, 24, 30, 36, 48, or 60 bits, corresponding t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creative Computing
''Creative Computing'' was one of the earliest magazines covering the microcomputer revolution. Published from October 1974 until December 1985, the magazine covered the spectrum of hobbyist/home/personal computing in a more accessible format than the rather technically oriented ''Byte (magazine), Byte''. The magazine was created to cover educational-related topics. Early issues include articles on the use of computers in the classroom, various simple programs like madlibs and various programming challenges, mostly in BASIC. By the late 1970s, it had moved towards more general coverage as the microcomputer market emerged. Hardware coverage became more common, but type-in programs remained common into the early 1980s. The company published several books, the most successful being ''BASIC Computer Games'', the first million-selling computer book. Their ''Best of Creative Computing'' collections were also popular. ''Creative Computing'' also published software on Compact Cassette ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winchester Drive
IBM manufactured magnetic disk storage devices from 1956 to 2003, when it sold its hard disk drive business to Hitachi. Both the hard disk drive (HDD) and floppy disk drive (FDD) were invented by IBM and as such IBM's employees were responsible for many of the innovations in these products and their technologies. The basic mechanical arrangement of hard disk drives has not changed since the IBM 1301. Disk drive performance and characteristics are measured by the same standards now as they were in the 1950s. Few products in history have enjoyed such spectacular declines in cost and physical size along with equally dramatic improvements in capacity and performance. IBM manufactured 8-inch floppy disk drives from 1969 until the mid-1980s, but did not become a significant manufacturer of smaller-sized, 5.25- or 3.5-inch floppy disk drives (the dimension refers to the diameter of the floppy disk, not the size of the drive). IBM always offered its magnetic disk drives for sale but did not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double-sided Disk
In computer science, a double-sided disk is a disk of which both sides are used to store data. Early floppy disks only used one surface for recording. The term ''single-sided disk'' was not common until the introduction of the double-sided disk, which offered double the capacity in the same physical size. Initially, double-sided disks had to be removed and flipped over to access data on the other side, but eventually, devices were made that could read both sides without the need to eject the disk. Manufacturers sold both single-sided and double-sided disks with the double-sided disks being typically 50% more expensive than single-sided disks. While the magnetic-coated medium was coated on both sides, the single-sided floppies had a read-write notch on only one side, thus allowing only one side of the disk to be used. When users discovered this, they began buying the less-expensive single-sided disks and "notching" them using scissors, a hole punch, or a specially designed "notc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RS-232
In telecommunications, RS-232 or Recommended Standard 232 is a standard introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such as a computer terminal or PC, and a ''DCE'' ('' data circuit-terminating equipment'' or '' data communication equipment''), such as a modem. The standard defines the electrical characteristics and timing of signals, the meaning of signals, and the physical size and pinout of connectors. The current version of the standard is ''TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange'', issued in 1997. The RS-232 standard had been commonly used with serial ports and serial cables. It is still widely used in industrial communication devices. A serial port complying with the RS-232 standard was once a standard feature of many types of computers. Personal computers used them ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RAM Drive
A RAM drive (also called a RAM disk) is a block of random-access memory (primary storage or volatile memory) that a computer's software is treating as if the memory were a disk drive (secondary storage). RAM drives provide high-performance temporary storage for demanding tasks and protect non-volatile storage devices from wearing down, since RAM is not prone to wear from writing, unlike non-volatile flash memory. It is sometimes referred to as a virtual RAM drive or software RAM drive to distinguish it from a hardware RAM drive that uses separate hardware containing RAM, which is a type of battery-backed solid-state drive. Historically primary storage based mass storage devices were conceived to bridge the performance gap between internal memory and secondary storage devices. In the advent of solid-state devices this advantage lost most of its appeal. However, solid-state devices do suffer from wear from frequent writing. Primary memory writes do not so or in far lesser effect. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Expansion Card
In computing, an expansion card (also called an expansion board, adapter card, peripheral card or accessory card) is a printed circuit board that can be inserted into an electrical connector, or expansion slot (also referred to as a bus slot) on a computer's motherboard (see also backplane) to add functionality to a computer system. Sometimes the design of the computer's case and motherboard involves placing most (or all) of these slots onto a separate, removable card. Typically such cards are referred to as a riser card in part because they project upward from the board and allow expansion cards to be placed above and parallel to the motherboard. Expansion cards allow the capabilities and interfaces of a computer system to be extended or supplemented in a way appropriate to the tasks it will perform. For example, a high-speed multi-channel data acquisition system would be of no use in a personal computer used for bookkeeping, but might be a key part of a system used for in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
