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Macintosh IIfx
The Macintosh IIfx is a personal computer designed, manufactured and sold by Apple Computer from March 1990 to April 1992. At introduction it cost from to , depending on configuration, and it was the fastest Macintosh available at the time. The IIfx is the most powerful of the 68030-based Macintosh II family and was replaced at the top of Apple's lineup by the Macintosh Quadra in 1991. It is the last Apple computer released that was designed using the Snow White design language. Overview Dubbed "Wicked Fast" by its Product Manager, Frank Casanova – who came to Apple from Apollo Computer in Boston, Massachusetts, where the Boston term "wicked" is commonly used to denote anything extreme – the IIfx runs at a clock rate of 40 megahertz, has 32 KB of Level 2 cache, six NuBus slots, and includes a number of proprietary ASICs and coprocessors. Designed to speed up the machine even further, these chips require system-specific drivers. The 40 MHz speed refers to the main l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macintosh II Family
The Macintosh II is a family of personal computers that was designed, manufactured and sold by Apple Computer, Inc. from 1987 to 1993. The Macintosh II was the initial model, representing the high-end of the Macintosh line for the time. Over the course of the next six years, seven more models were produced, culminating with the short-lived Macintosh IIvi and Macintosh IIvx models. Apple retired the Macintosh II name when it moved to Motorola 68040 processors; the Centris and Quadra names were used instead. Features Unlike prior Macintosh models, which are "all-in-one" designs, the Macintosh II models are "modular" systems which do not include built-in monitors and are expandable. Beginning with the Macintosh II and culminating in the Macintosh IIfx, the Macintosh II family was Apple's high-end line from 1987 until the introduction of the Motorola 68040-based Macintosh Quadra computers in 1991. Expansion was provided by way of NuBus, which become the standard expansion bus for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boston Accent
A Boston accent is a local accent of Eastern New England English, native specifically to the city of Boston and its suburbs. Northeastern New England English is classified as traditionally including New Hampshire, Maine, and all of eastern Massachusetts, though some uniquely local vocabulary appears only around Boston. A 2006 study co-authored by William Labov claims that the accent remains relatively stable,Labov, William (2010). The Politics of Language Change: Dialect Divergence in America'. The University of Virginia Press. Pre-publication draft. p. 53. though a 2018 study suggests the accent's traditional features may be retreating, particularly among the city's younger residents, and becoming increasingly confined to the historically Irish-American neighborhood of South Boston. Phonological characteristics Boston accents typically have the cot-caught merger but not the father-bother merger. This means that instead of merging the historical "short ''o''" sound (as in ) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macintosh IIci
The Macintosh IIci is a personal computer designed, manufactured, and sold by Apple Computer, Inc. from September 1989 to February 1993. It is a more powerful version of the Macintosh IIcx, released earlier that year, and shares the same compact case design. With three NuBus expansion slots and a Processor Direct Slot, the IIci also improved upon the IIcx's 16 MHz Motorola 68030 CPU and 68882 FPU, replacing them with 25 MHz versions of these chips. The Macintosh Quadra 700 was introduced at the end of 1991 as Apple's mainstream workstation product to replace the IIci, albeit at a significantly higher price point: by this time, Apple authorized resellers were offering entry-level IIci systems for US$4,000 or less, whereas the Quadra 700 entered the market above US$6,000. Because of this, Apple continued to sell the IIci until early 1993 when the less expensive Quadra 650 and comparably-priced Quadra 800 were introduced. Hardware The IIci introduced several techn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SIMM
A SIMM (single in-line memory module) is a type of memory module containing random-access memory used in computers from the early 1980s to the early 2000s. It differs from a dual in-line memory module (DIMM), the most predominant form of memory module since the late 1990s, in that the contacts on a SIMM are redundant on both sides of the module. SIMMs were standardised under the JEDEC JESD-21C standard. Most early PC motherboards (8088-based PCs, XTs, and early ATs) used socketed DIP chips for DRAM. As computer memory capacities grew, memory modules were used to save motherboard space and ease memory expansion. Instead of plugging in eight or nine single DIP chips, only one additional memory module was needed to increase the memory of the computer. History SIMMs were invented in 1982 by James J. Parker at Zenith Microcircuits and the first Zenith Microcircuits customer was Wang Laboratories. Wang Laboratories tried to patent it and were granted a patent in April 1987. Th ... [...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] |
Nanosecond
A nanosecond (ns) is a unit of time in the International System of Units (SI) equal to one billionth of a second, that is, of a second, or 10 seconds. The term combines the SI prefix ''nano-'' indicating a 1 billionth submultiple of an SI unit (e.g. nanogram, nanometre, etc.) and ''second'', the primary unit of time in the SI. A nanosecond is equal to 1000 picoseconds or microsecond. Time units ranging between 10 and 10 seconds are typically expressed as tens or hundreds of nanoseconds. Time units of this granularity are commonly found in telecommunications, pulsed lasers, and related aspects of electronics. Common measurements * 0.001 nanoseconds – one picosecond * 0.5 nanoseconds – the half-life of beryllium-13. * 0.96 nanoseconds – 100 Gigabit Ethernet Interpacket gap * 1.0 nanosecond – cycle time of an electromagnetic wave with a frequency of 1 GHz (1 hertz). * 1.0 nanosecond – electromagnetic wavelength of 1 light-nanosecond. Equiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floating Point Unit
Floating may refer to: * a type of dental work performed on horse teeth * use of an isolation tank * the guitar-playing technique where chords are sustained rather than scratched * ''Floating'' (play), by Hugh Hughes * Floating (psychological phenomenon), slipping into altered states * Floating exchange rate, a market-valued currency * Floating voltage, and floating ground, a voltage or ground in an electric circuit that is not connected to the Earth or another reference voltage * Floating point, a representation in computing of rational numbers most commonly associated with the IEEE 754 standard * ''Floating'' (film), a 1997 American drama film Albums and songs * ''Floating'' (Eloy album) (1974) * ''Floating'' (Ketil Bjørnstad album) (2005) * ''Floating'' (EP), a 1991 EP by Bill Callahan * "Floating" (The Moody Blues song) (1969) * "Floating" (Megan Rochell song) (2006) * "Floating" (Jape song) (2004) * "Floating", a song by Jolin Tsai from the 2000 album '' Don't Stop' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorola 68882
The Motorola 68881 and Motorola 68882 are floating-point units (FPUs) used in some computer systems in conjunction with Motorola's 32-bit 68020 or 68030 microprocessors. These coprocessors are external chips, designed before floating point math became standard on CPUs. The Motorola 68881 was introduced in 1984. The 68882 is a higher performance version produced later. Overview The 68020 and 68030 CPUs were designed with the separate 68881 chip in mind. Their instruction sets reserved the "F-line" instructions – that is, all opcodes beginning with the hexadecimal digit "F" could either be forwarded to an external coprocessor or be used as "traps" which would throw an exception, handing control to the computer's operating system. If an FPU is not present in the system, the OS would then either call an FPU emulator to execute the instruction's equivalent using 68020 integer-based software code, return an error to the program, terminate the program, or crash and require a reboot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Processing Unit
A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions in the program. This contrasts with external components such as main memory and I/O circuitry, and specialized processors such as graphics processing units (GPUs). The form, design, and implementation of CPUs have changed over time, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic–logic unit (ALU) that performs arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that orchestrates the fetching (from memory), decoding and execution (of instructions) by directing the coordinated operations of the ALU, registers and other co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NuBus
NuBus (pron. 'New Bus') is a 32-bit parallel computer bus, originally developed at MIT and standardized in 1987 as a part of the NuMachine workstation project. The first complete implementation of the NuBus was done by Western Digital for their NuMachine, and for the Lisp Machines Inc. LMI Lambda. The NuBus was later incorporated in Lisp products by Texas Instruments (Explorer), and used as the main expansion bus by Apple Computer and a variant called NeXTBus was developed by NeXT. It is no longer widely used outside the embedded market. Architecture Early microcomputer buses like S-100 were often just connections to the pins of the microprocessor and to the power rails. This meant that a change in the computer's architecture generally led to a new bus as well. Looking to avoid such problems in the future, NuBus was designed to be independent of the processor, its general architecture and any details of its I/O handling. Among its many advanced features for the era, NuBu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CPU Cache
A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, located closer to a processor core, which stores copies of the data from frequently used main memory locations. Most CPUs have a hierarchy of multiple cache levels (L1, L2, often L3, and rarely even L4), with different instruction-specific and data-specific caches at level 1. The cache memory is typically implemented with static random-access memory (SRAM), in modern CPUs by far the largest part of them by chip area, but SRAM is not always used for all levels (of I- or D-cache), or even any level, sometimes some latter or all levels are implemented with eDRAM. Other types of caches exist (that are not counted towards the "cache size" of the most important caches mentioned above), such as the translation lookaside buffer (TLB) which is part of the memory management unit (MMU) w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
