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LINC Shield
The LINC (Laboratory INstrument Computer) is a 12-bit, 2048-word transistorized computer. The LINC is considered by some the first minicomputer and a forerunner to the personal computer. Originally named the "Linc", suggesting the project's origins at MIT's Lincoln Laboratory, it was renamed LINC after the project moved from the Lincoln Laboratory. The LINC was designed by Wesley A. Clark and Charles Molnar. The LINC and other "MIT Group" machines were designed at MIT and eventually built by Digital Equipment Corporation (DEC) and Spear Inc. of Waltham, Massachusetts (later a division of Becton, Dickinson and Company). The LINC sold for more than $40,000 at the time. A typical configuration included an enclosed 6'X20" rack; four boxes holding (1) two tape drives, (2) display scope and input knobs, (3) control console and (4) data terminal interface; and a keyboard. The LINC interfaced well with laboratory experiments. Analog inputs and outputs were part of the basic design. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mary Allen Wilkes
Mary Allen Wilkes (born September 25, 1937) is a lawyer, former computer programmer and logic designer, known for her work with the LINC computer, now recognized by many as the world's first "personal computer". Career Wilkes was born in Chicago, Illinois and graduated from Wellesley College in 1959 where she majored in philosophy and theology. Wilkes planned to become a lawyer, but was discouraged by friends and mentors from pursuing law because of the challenges women faced in the field. A geography teacher in the eighth grade had told Wilkes, "Mary Allen, when you grow up, you ought to be a computer programmer." She worked in the field as one of the first programmers for a number of years before pursuing law and becoming an attorney in 1975. MIT Wilkes worked under Oliver Selfridge and Benjamin Gold on the Speech Recognition Project at MIT's Lincoln Laboratory in Lexington, Massachusetts from 1959 to 1960, programming the IBM 704 and the IBM 709. She joined the Digital Comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
19-inch Rack
A 19-inch rack is a standardized frame or enclosure for mounting multiple electronic equipment modules. Each module has a front panel that is wide. The 19 inch dimension includes the edges or "ears" that protrude from each side of the equipment, allowing the module to be fastened to the rack frame with screws or bolts. Common uses include computer servers, telecommunications equipment and networking hardware, audiovisual production gear, and scientific equipment. Overview and history Equipment designed to be placed in a rack is typically described as rack-mount, rack-mount instrument, a rack-mounted system, a rack-mount chassis, subrack, rack cabinet, rack-mountable, or occasionally simply shelf. The height of the electronic modules is also standardized as multiples of or one rack unit or U (less commonly RU). The industry-standard rack cabinet is 42U tall; however, 45U racks are also common. The term ''relay rack'' appeared first in the world of telephony. By 1911, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rollover (key)
Key rollover is the ability of a computer keyboard to correctly handle several simultaneous keystrokes. A keyboard with ''n''-key rollover (NKRO) can correctly detect input from each key on the keyboard at the same time, regardless of how many other keys are also being pressed. Keyboards that lack full rollover will register an incorrect keystroke when certain combinations of keys are pressed simultaneously. Rollover has applications for stenotype, electronic music keyboards, gaming, and touch-typing generally. Keyboard usage During normal typing on a conventional computer keyboard, only one key is usually pressed at any given time, then released before the next key is pressed. However, this is not always the case. When using modifier keys such as Shift or Control, the user intentionally holds the modifier key(s) while pressing and releasing another key. * Rapid typists may also sometimes inadvertently press a key before releasing the previous one. Certain unusual forms of keyboa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tape Transport
A tape transport is the collection of parts of a magnetic tape player or recorder that move the tape and play or record it. Transport parts include the head, capstan, pinch roller, tape pins, and tape guide. The tape transport as a whole is called the ''transport mechanism''. Tape head {{main, Tape head The tape head is the part of a tape recording or playback device which converts the magnetic fluctuations present in the tape into an electrical signal, which is then amplified and sent to speakers or headphones. The tape head is set off-center in a multitrack device in order to record or play one or more tracks running in each direction of the tape (e.g. the two different tracks present on most, if not all, compact cassettes). Capstan The capstan is a rotating spindle used to move recording tape through the mechanism of a tape recorder. The tape is threaded between the capstan and one or more rubber-covered wheels, called pinch rollers, which press against the capstan, thus prov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DECtape
DECtape, originally called Microtape, is a magnetic tape data storage medium used with many Digital Equipment Corporation computers, including the PDP-6, PDP-8, LINC-8, PDP-9, PDP-10, PDP-11, PDP-12, and the PDP-15. On DEC's 32-bit systems, VAX/VMS support for it was implemented but did not become an official part of the product lineup. DECtapes are 3/4 inch (19 mm) wide, and formatted into blocks of data that can each be read or written individually. Each tape stores 184K 12-bit PDP-8 words or 144K 18-bit words. Block size is 128 12-bit words (for the 12-bit machines), or 256 18-bit words for the other machines (16, 18, 32, or 36 bit systems). From a programming point of view, because the system is block-oriented and allows random seeking, DECtape behaves like a very slow disk drive. Origins DECtape has its origin in the LINCtape tape system, which was originally designed by Wesley Clark at the MIT Lincoln Laboratory as an integral part of the LINC computer. There a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Program Counter
The program counter (PC), commonly called the instruction pointer (IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register (IAR), the instruction counter, or just part of the instruction sequencer, is a processor register that indicates where a computer is in its program sequence. Usually, the PC is incremented after fetching an instruction, and holds the memory address of (" points to") the next instruction that would be executed. Processors usually fetch instructions sequentially from memory, but ''control transfer'' instructions change the sequence by placing a new value in the PC. These include branches (sometimes called jumps), subroutine calls, and returns. A transfer that is conditional on the truth of some assertion lets the computer follow a different sequence under different conditions. A branch provides that the next instruction is fetched from elsewhere in memory. A subroutine call not only branches but saves the preced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Debugging
In computer programming and software development, debugging is the process of finding and resolving '' bugs'' (defects or problems that prevent correct operation) within computer programs, software, or systems. Debugging tactics can involve interactive debugging, control flow analysis, unit testing, integration testing, log file analysis, monitoring at the application or system level, memory dumps, and profiling. Many programming languages and software development tools also offer programs to aid in debugging, known as ''debuggers''. Etymology The terms "bug" and "debugging" are popularly attributed to Admiral Grace Hopper in the 1940s. While she was working on a Mark II computer at Harvard University, her associates discovered a moth stuck in a relay and thereby impeding operation, whereupon she remarked that they were "debugging" the system. However, the term "bug", in the sense of "technical error", dates back at least to 1878 and Thomas Edison who describes the "litt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base Ten
The decimal numeral system (also called the base-ten positional numeral system and denary or decanary) is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers of the Hindu–Arabic numeral system. The way of denoting numbers in the decimal system is often referred to as ''decimal notation''. A ''decimal numeral'' (also often just ''decimal'' or, less correctly, ''decimal number''), refers generally to the notation of a number in the decimal numeral system. Decimals may sometimes be identified by a decimal separator (usually "." or "," as in or ). ''Decimal'' may also refer specifically to the digits after the decimal separator, such as in " is the approximation of to ''two decimals''". Zero-digits after a decimal separator serve the purpose of signifying the precision of a value. The numbers that may be represented in the decimal system are the decimal fractions. That is, fractions of the form , where is an integer, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octal
The octal numeral system, or oct for short, is the radix, base-8 number system, and uses the Numerical digit, digits 0 to 7. This is to say that 10octal represents eight and 100octal represents sixty-four. However, English, like most languages, uses a Base 10, base-10 number system, hence a true octal system might use different vocabulary. In the decimal system, each place is a power of ten. For example: : \mathbf_ = \mathbf \times 10^1 + \mathbf \times 10^0 In the octal system, each place is a power of eight. For example: : \mathbf_8 = \mathbf \times 8^2 + \mathbf \times 8^1 + \mathbf \times 8^0 By performing the calculation above in the familiar decimal system, we see why 112 in octal is equal to 64+8+2=74 in decimal. Octal numerals can be easily converted from Binary numeral system, binary representations (similar to a quaternary numeral system) by grouping consecutive binary digits into groups of three (starting from the right, for integers). For example, the binary repr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ones' Complement
The ones' complement of a binary number is the value obtained by inverting all the bits in the binary representation of the number (swapping 0s and 1s). The name "ones' complement" (''note this is possessive of the plural "ones", not of a singular "one"'') refers to the fact that such an inverted value, if added to the original, would always produce an 'all ones' number (the term "complement" refers to such pairs of mutually additive inverse numbers, here in respect to a non-0 base number). This mathematical operation is primarily of interest in computer science, where it has varying effects depending on how a specific computer represents numbers. A ones' complement system or ones' complement arithmetic is a system in which negative numbers are represented by the inverse of the binary representations of their corresponding positive numbers. In such a system, a number is negated (converted from positive to negative or vice versa) by computing its ones' complement. An N-bit ones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscilloscope
An oscilloscope (informally a scope) is a type of electronic test instrument that graphically displays varying electrical voltages as a two-dimensional plot of one or more signals as a function of time. The main purposes are to display repetitive or single waveforms on the screen that would otherwise occur too briefly to be perceived by the human eye. The displayed waveform can then be analyzed for properties such as amplitude, frequency, rise time, time interval, distortion, and others. Originally, calculation of these values required manually measuring the waveform against the scales built into the screen of the instrument. Modern digital instruments may calculate and display these properties directly. Oscilloscopes are used in the sciences, medicine, engineering, automotive and the telecommunications industry. General-purpose instruments are used for maintenance of electronic equipment and laboratory work. Special-purpose oscilloscopes may be used to analyze an automotive ign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tektronix
Tektronix, Inc., historically widely known as Tek, is an American company best known for manufacturing test and measurement devices such as oscilloscopes, logic analyzers, and video and mobile test protocol equipment. Originally an independent company, it is now a subsidiary of Fortive, a spinoff from Danaher Corporation. Several charities are, or were, associated with Tektronix, including the Tektronix Foundation and the M.J. Murdock Charitable Trust in Vancouver, Washington. History 1946–1954 The company traces its roots to the electronics revolution that immediately followed World War II. It was founded in December 1945 as Tekrad. The name was similar to that of a California company, Techrad, so in 1946, the four partners, Howard Vollum, Jack Murdock and Miles Tippery, who had both served in the Coast Guard, and accountant Glenn McDowell, formed Tektronix, Inc. Each contributed an initial $2,600 for equal shares. Howard Vollum had graduated in 1936 from Reed Coll ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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