Computer Dictionary Online

Intel 4004 definition

<processor> The world's first microprocessor, released in 1971. The 4004 contained 2300 transistors (compared with 5.5 million in the 1996 Pentium Pro) and was intended for use in a calculator. It processed data in 4 bits, but its instructions were 8 bits long. Program and Data memory were separate, it had 1 kilobyte of data memory and a 12-bit PC for 4K of program memory (in the form of a 4 level stack, used for CALL and RET instructions). There were also sixteen 4-bit (or eight 8-bit) general purpose registers. The 4004 had 46 instructions.

(1997-03-30)

Intel 4040 definition

<processor> An enhanced version of the Intel 4004, adding 14 instructions, larger (8 level) stack, 8 kbyte program memory and interrupt abilities (including shadows of the first 8 registers). The 4040 was similar to the Intel 8008.

(1994-10-31)

Intel 486 definition

<processor> (Or "i486", "iAPX 80486", and "Intel DX4" but usually just "486"). A range of Intel CISC microprocessors which is part of the Intel 80x86 family of processors.

The 486s are very similar to their immediate predecessor, the Intel 80386DX. The main differences are that the 486 has an optimised instruction set, has an on-chip unified instruction and data cache, an optional on-chip floating-point unit (FPU), and an enhanced bus interface unit. These improvements yield a rough doubling in performance over an Intel 80386 at the same clock rate.

There are several suffixes and variants including:

Intel 486SX - a 486DX with its FPU disabled (see crippleware).

Intel 486DX - 486SX with a working FPU.

486DX-2 - runs at twice the external clock rate.

486SX-2 - runs at twice the external clock rate.

486SL - 486DX with power conservation circuitry.

486SL-NM - 486SX with power conservation circuitry; SL enhanced suffix, denotes a 486 with special power conservation circuitry similar to that in the 486SL processors.

487 - 486DX with a slightly different pinout for use in 486SX systems.

OverDrive - 486DX-2 with a slightly different pinout for use in 486SX systems.

RapidCAD - 486DX in a special package with a companion FPU dummy package for use in Intel 80386 systems.

Intel DX4, Cyrix Cy486SLC.

External clock rates include 16MHz, 20MHz, 25MHz, 33MHz, 40MHz, although 16Mhz is rare now, and the 20MHz processors are often clock doubled.

The 486 processor has been licensed or reverse engineered by other companies such as IBM, AMD, Cyrix, and Chips & Technologies. Some are almost exact duplicates in specications and performance, some aren't.

The successor to the 486 is the Pentium.

(1995-02-21)

Intel 486DX definition

<processor> One of Intel's Intel 486 family of microprocessors (one of the last before the Pentium). The 486DX has a working built-in floating point unit (FPU). The Intel 486SX is effectively a DX with the FPU disabled. The DX has a pin to select the external data bus width (16 or 32).

The Intel 487SX is a 486DX with a 486SX pinout.

(1995-05-09)

Intel 486SX definition

<processor> An Intel 486DX microprocessor with its floating-point unit disconnected. All 486SX chips were fabricated with FPUs. If testing showed that the CPU was OK but the FPU was defective, the FPU's power and bus connections were destroyed with a laser and the chip was sold cheaper as an SX, if the FPU worked it was sold as a DX.

[Was this true of all 486SX chips?]

Some systems, e.g. Aopen 486SX, allowed a DX to be plugged into an expansion socket. A board jumper would disable the SX which was hard to remove because it was surface mounted.

Some SX chips only had a 16-bit wide external data bus. The DX has a pin to select the data bus width (16 or 32). On the smaller SX, that line is hard-wired to 16 inside the package. This is similar to the 286 SX, which was a 16-bit processor with an 8-bit external data bus.

The Jargon File claimed that the SX was deliberately disabled crippleware. The German computer magazine, "c't", made this same theory the basis of an April Fools Joke. They claimed that if one drilled a hole of a specified diameter through the right point on a SX chip, this would brake the circuit that disables the FPU. Some people actually tried (and then bought themselves new processors).

(1997-02-14)

Intel 487SX definition

<processor> A version of the Intel 486DX microprocessor with an extra pin, for use in the coprocessor socket of an Intel 486SX system. The 487SX provides the FPU which is missing in the 486SX.

Although the 486SX is completely disabled when you install a 487SX, the 487SX design requires that you leave the 486SX in your PC [why?], rather than use it elsewhere. Intel admits that in some systems you can unplug the 486SX and fit a 487SX in its place but they don't guarantee that it will always work.

See Intel 486.

(1995-05-10)

Intel 8008 definition

<processor> A microprocessor intended for use as a terminal controller, and similar to the Intel 4040. The 8008 had a 14-bit PC and addressing and an eight level internal stack. It was followed by the Intel 8080.

[Date?]

(1994-10-31)

Intel 80186 definition

<processor> A microprocessor developed by Intel circa 1982. The 80186 was an improvement on the Intel 8086 and Intel 8088. As with the 8086, it had a 16-bit external bus and was also available as the Intel 80188, with an 8-bit external data bus. The initial clock rate of the 80186 and 80188 was 6 MHz. They were not used in many computers, but one notable exception was the Mindset, a very advanced computer for the time. They were used as embedded processors.

One major function of the 80186/80188 series was to reduce the number of chips required.

"To satisfy this market, we defined a processor with a significant performance increase over the 8086 that also included such common peripheral functions as software-controlled wait state and chip select logic, three timers, priority interrupt controller, and two channels of DMA (direct memory access). This processor, the 80186, could replace up to 22 separate VLSI (very large scale integration) and TTL (transistor-transistor logic) packages and sell for less than the cost of the parts it replaced."

-- Paul Wells of Intel Corporation writing in Byte (reference below)

New instructions were also introduced as follows:

 ENTER	Make stcak frame for procedure parameters
 LEAVE	High-level procedure exit
 PUSHA	Push all general registers
 POPA	Pop all general registers
 BOUND	Check array index against bounds
 IMUL	Signed (integer) multiply
 INS	Input from port to string
 OUTS	Output string to port

["The 80286 Microprocessor", Paul Wells, Intel Corporation, Byte, November 1984, p. 231].

(1999-05-10)

Intel 80188 definition

<processor> A version of the Intel 80186 with an 8 bit external data bus (instead of 16 bit). This makes it cheaper to connect to peripherals.

(1995-01-13)

Intel 80286 definition

<processor> (Or "286", "i286") A microprocessor developed by Intel. THe 80286 processor has a 16-bit data bus and incorporates a memory management unit that allowed a limited amount of multitasking. The 80286 only has a segmented MMU while the later processors add a paged MMU "behind" the segmented one.

The 80286 was the processor in the IBM PC AT personal computer.

(1995-02-21)

Intel 80386 definition

<processor> (Commonly abbreviated to "386", trademark "Intel386") The successor to the Intel 80286 microprocessor. It was the first Intel processor with 32-bit data and address busses. It can address four gigabytes (2^32 bytes) of memory; however, 16 megabytes is a typical maximum in IBM PCs. The 386 allows multiple application programs to run at the same time (when running under 386-specific operating systems) using "protected mode".

The first IBM compatible to use the 386 was the Compaq 386, before IBM used it in high-end models of their PS/2 series. It is also used in HP's RS series and many others.

It does not require special EMS memory boards to expand MS-DOS memory limits. With the 386, the EMS standard can be simulated in normal extended memory, and many DOS add-ons provide this "Expanded Memory Manager" feature.

See also Intel 80386SX, BSD386.

(1995-02-21)

Intel 80386DX definition

<processor> A version of the Intel 80386 with a 32-bit data bus and 32-bit address bus, a BGA. The 386DX was clocked at 16 to 33 MHz by Intel and up to 40 MHz by AMD. It comes in a BGA package.

(2003-07-05)

Intel 80386SX definition

<processor> A lower-speed version of the Intel 80386. It uses a 16-bit data bus instead of a 32-bit data bus. It has a 24-bit address bus. It is faster than the 286, and more importantly, like the full-size 386, provides more flexibility in running existing DOS applications. Intel's version runs at 16 MHz, while AMD's can run at up to 33 MHz. It comes in a PFP package.

(2003-07-05)

Intel 8048 definition

<processor> The microcontroller used in IBM PC keyboards. The 8048 was inspired by, and similar to, the Fairchild F8 microprocessor but, being a microcontroller, was designed for low cost and small size. The 8048 has a modified Harvard architecture, with program ROM on chip and 64 to 256 bytes of RAM also on chip. I/O is mapped in its own address space.

Though the 8048 was eventually replaced by the very popular but bizarre Intel 8051 and Intel 8052, even in 2000 it is still very popular due to its low cost, wide availability, and development tools.

[Was it really _the_first_ microcontroller? Are the ROM and RAM both on-chip?]

(2000-06-01)

Intel 80486 definition

Intel 486

Intel 8051 definition

<processor> A microcontroller developed by Intel in 1980 for use in embedded products and still (1999) one of the most popular microcontrollers.

The 8051/8031 cores are used in over 100 devices from 10 independent manufacturers such as Dallas and Philips.

[What is the difference between the 8031/8051/8052?]

See also CAS 8051 Assembler, as31 assembler, 51forth.

8051 FAQ.

The 8031/51 series microcontroller.

Intel MCS51 series microcontrollers.

(1999-11-21)

Intel 8080 definition

<processor> The successor to the Intel 8008. The 8080 had a 16-bit address bus and an 8-bit data bus. It had seven 8-bit registers (six which could also be combined as three 16-bit registers), a 16-bit stack pointer to memory which replaced the 8008's internal stack and a 16-bit program counter. It also had 256 I/O ports (so I/O devices could be connected without needing to allocate any addressing space as is required for memory mapped devices) and a signal pin that allowed the stack to occupy a separate bank of memory.

Shortly after the 8080, the Motorola 6800 was introduced.

[Date?]

(1994-10-31)

Intel 8085 definition

<processor> A microprocessor intended to be an improved Intel 8080, as was the Zilog Z80.

(1994-10-31)

Intel 8086 definition

<processor> A sixteen bit microprocessor chip used in early IBM PCs. The Intel 8088 was a version with an eight-bit external data bus.

The Intel 8086 was based on the design of the Intel 8080 and Intel 8085 (it was source compatible with the 8080) with a similar register set, but was expanded to 16 bits. The Bus Interface Unit fed the instruction stream to the Execution Unit through a 6 byte prefetch queue, so fetch and execution were concurrent - a primitive form of pipelining (8086 instructions varied from 1 to 4 bytes).

It featured four 16-bit general registers, which could also be accessed as eight 8-bit registers, and four 16-bit index registers (including the stack pointer). The data registers were often used implicitly by instructions, complicating register allocation for temporary values. It featured 64K 8-bit I/O (or 32K 16 bit) ports and fixed vectored interrupts. There were also four segment registers that could be set from index registers.

The segment registers allowed the CPU to access 1 meg of memory in an odd way. Rather than just supplying missing bytes, as most segmented processors, the 8086 actually shifted the segment registers left 4 bits and added it to the address. As a result, segments overlapped, and it was possible to have two pointers with the same value point to two different memory locations, or two pointers with different values pointing to the same location. Most people consider this a brain damaged design.

Although this was largely acceptable for assembly language, where control of the segments was complete (it could even be useful then), in higher level languages it caused constant confusion (e.g. near/far pointers). Even worse, this made expanding the address space to more than 1 meg difficult. A later version, the Intel 80386, expanded the design to 32 bits, and "fixed" the segmentation, but required extra modes (suppressing the new features) for compatibility, and retains the awkward architecture. In fact, with the right assembler, code written for the 8008 can still be run on the most recent Intel 486.

The Intel 80386 added new op codes in a kludgy fashion similar to the Zilog Z80 and Zilog Z280. The Intel 486 added full pipelines, and clock doubling (like the Zilog Z280).

So why did IBM chose the 8086 series when most of the alternatives were so much better? Apparently IBM's own engineers wanted to use the Motorola 68000, and it was used later in the forgotten IBM Instruments 9000 Laboratory Computer, but IBM already had rights to manufacture the 8086, in exchange for giving Intel the rights to its bubble memory designs. Apparently IBM was using 8086s in the IBM Displaywriter word processor.

Other factors were the 8-bit Intel 8088 version, which could use existing Intel 8085-type components, and allowed the computer to be based on a modified 8085 design. 68000 components were not widely available, though it could use Motorola 6800 components to an extent.

Intel bubble memory was on the market for a while, but faded away as better and cheaper memory technologies arrived.

(1994-12-23)

Intel 8088 definition

<processor> An Intel 8086 with 16-bit registers and an 8-bit data bus.

The 8088 was the processor used in the original IBM PC.

(1995-02-21)

Intel 80x86 definition

<processor> (x86) One of the family of Intel microprocessors including the Intel 80186, Intel 80286, Intel 80386, Intel 486, in a more general sense also Intel 8086, Pentium, Pentium Pro, and Pentium II.

The abbreviation "x86" also includes compatible processors, e.g. from Cyrix or AMD.

(2004-02-27)

Intel 8751 definition

<processor> A microcontroller from Intel including a CPU, two timers. 128 bytes of RAM, 4 kBytes of EEPROM, four eight-bit biderectional I/O ports and an EIA-232 port.

The 8751 belongs to the Intel i51 Microcontroller family. It was designed by Intel but is now manufactured by Intel, Philips, Siemens, AMD and others. Motorola's microcontroller families (68HC05, 68HC08 and 68HC11) are meant to compete with the i51 family.

(1995-04-22)

Intel Comparative Microprocessor Performance index definition

<benchmark, unit> (iCOMP) A unit used by Intel to indicate the relative performance of their 80x86 microprocessors.

http://134.134.214.1/procs/perf/icomp/.

(1997-06-07)

Intel Corporation definition

<company> A US microelectronics manufacturer. They produced the Intel 4004, Intel 8080, Intel 8086, Intel 80186, Intel 80286, Intel 80386, Intel 486 and Pentium microprocessor families as well as many other integrated circuits and personal computer networking and communications products.

Gordon Moore and Robert Noyce founded Intel in 1968 to design, manufacture, and market semiconductor computer memory to replace magnetic core memory, the dominant computer memory at that time. Dr. Andrew S. Grove joined Intel soon after its incorporation. Three years later, in 1971, Intel introduced the world's first microprocessor, the Intel 4004.

Intel has design, development, production, and administration facilities throughout the western US, Europe and Asia. In 1995 nearly 75% of the world's personal computers use Intel architecture. Annual revenues are rapidly approaching $10 billion. In March, 1994, "Business Week" named Intel one of the top ten American companies in terms of profit, one of the top 15 market value winners, and 16th out of the magazine's top 1,000 companies overall.

Intel invested a record $2.9 billion in capital and R&D in 1993, and expects to increase combined spending on these activities to $3.5 billion in 1994. Quarterly sales were $2770M and profits, $640M in Aug 1994.

http://www.intel.com/.

Address: Santa Clara, CA, USA.

(1995-03-01)

IntelDX4 definition

<processor> Essentially an Intel 486DX microprocessor with a 16 kilobyte on-chip cache.

The DX4 is the fastest member of the Intel 486 family. 75 and 100MHz versions are available. At an iCOMP index rating of 435, the 100 MHz DX4 performs up to 50% faster than the 66 MHz Intel DX2. The DX4's clock multiplier allows the processor to run three times faster than the system clock. This performance is achieved in part by a 16K on-chip cache (double that of the other 486s). The DX4 has an integrated floating point unit.

Like the other 486s, the DX4 achieves performance through a RISC integer core that executes frequently used instructions in a single clock cycle (the Pentium's can execute multiple instructions in a single clock cycle).

Low power consumption has been achieved with SL Technology and a 0.6 micron manufacturing process, giving 1.6 million transistors on a single chip operating at only 3.3 Volts.

"IntelDX4" is the entire name, the "486" has been dropped and I am assured that there is no space in the same.

(1995-04-28)

Intel i960 definition

<processor> A superscalar 32-bit RISC microprocessor from Intel intended for embedded applications.

The i960 CA variant can reach 66 native MIPS peak performance with a sustained execution of two instructions per clock cycle. The i960 CF has an on-chip, four kilobyte two-way set-associative instruction cache and a one kilobyte data cache. Both the CA and CF processors have on-chip RAM; a four-channel DMA unit; and integrated peripherals.

(1996-05-23)

INTELLECT definition

<language> A query language written by Larry Harris in 1977, close to natural English.

(1995-04-14)

intellectual property definition

<legal> (IP) The ownership of ideas and control over the tangible or virtual representation of those ideas. Use of another person's intellectual property may or may not involve royalty payments or permission, but should always include proper credit to the source.

(1997-03-27)

intelligent backtracking definition

<algorithm> An improved backtracking algorithm for Prolog interpreters, which records the point at which each logic variable becomes bound and, when a given set of bindings leads to failure, ignores any choice point which does not bind any of those variables. No choice from such a choice point can succeed since it does not change the bindings which caused the failure.

(1996-04-06)

intelligent database definition

<database> A database management system which performs data validation and processing traditionally done by application programs. Most DBMSs provide some data validation, e.g. rejecting invalid dates or alphabetic data entered into money fields, but often most processing is done by application programs. There is however no limit to the amount of processing that can be done by an intelligent database as long as the process is a standard function for that data.

Examples of techniques used to implement intelligent databases are constraints, triggers and stored procedures.

Moving processing to the database aids data integrity because it is guaranteed to be consistent across all uses of the data. Mainframe databases have increasingly become more intelligent and personal computer database systems are rapidly following.

(1998-10-07)

Intelligent Input/Output definition

<architecture> /i:-too-oh/ (I2O) A specification which aims to provide an I/O device driver architecture that is independent of both the specific device being controlled and the host operating system. The Hardware Device Module (HDM) manages the device and the OS Services Module (OSM) interfaces to the host operating system. The HDM is portable across multiple operating systems, processors and busses. The HDM and OSM communicate via a two layer message passing protocol. A Message Layer sets up a communications session and runs on top of a Transport Layer which defines how the two parties share information.

I2O is also designed to facilitate intelligent I/O subsystems, with support for message passing between multiple independent processors. By relieving the host of interrupt intensive I/O tasks required by the various layers of a driver architecture, the I2O intelligent I/O architecture greatly improves I/O performance. I2O systems will be able to more efficiently deliver the I/O throughput required by a wide range of high bandwidth applications, such as networked video, groupware and client-server processing. I2O does not restrict where the layered modules execute, providing support for single processor, multiprocessor, and clustered systems.

I2O is not intended to replace the driver architectures currently in existence. Rather, the objective is to provide an open, standards-based approach, which is complementary to existing drivers, and provides a framework for the rapid development of a new generation of portable, intelligent I/O.

Home.

(1997-11-04)

Intelligent I/O definition

Intelligent Input/Output

intelligent key definition

<database> A relational database key which depends wholly on one or more other columns in the same table. An intelligent key might be identified for implementation convenience, where there is no good candidate key.

For example, if the three-letter initials of a group of people are known to be unique but only their full names are recorded, a three letter acronym for their names (e.g. John Doe Smith -> JDS) would be an intelligent key.

Intelligent keys are a Bad Thing because it is hard to guarantee uniqueness, and if the value on which an intelligent key depends changes then the key must either stay the same, creating an inconsistency within the containing table, or change, requiring changes to all other tables in which it appears as a foreign key. The correct solution is to use a surrogate key.

(1999-12-07)

intelligent terminal definition

<hardware> (or "smart terminal", "programmable terminal") A terminal that often contains not only a keyboard and screen, but also comes with a disk drive and printer, so it can perform limited processing tasks when not communicating directly with the central computer. Some can be programmed by the user to perform many basic tasks, including both arithmetic and logic operations. In some cases, when the user enters data, the data will be checked for errors and some type of report will be produced. In addition, the valid data that is entered may be stored on the disk, it will be transmitted over communication lines to the central computer.

An intelligent terminal may have enough computing capability to draw graphics or to offload some kind of front-end processing from the computer it talks to.

The development of workstations and personal computers has made this term and the product it describes semi-obsolescent, but one may still hear variants of the phrase "act like a smart terminal" used to describe the behaviour of workstations or PCs with respect to programs that execute almost entirely out of a remote server's storage, using said devices as displays.

The term once meant any terminal with an addressable cursor; the opposite of a glass tty. Today, a terminal with merely an addressable cursor, but with none of the more-powerful features mentioned above, is called a dumb terminal.

There is a classic quote from Rob Pike (inventor of the blit terminal): "A smart terminal is not a smart*ass* terminal, but rather a terminal you can educate". This illustrates a common design problem: The attempt to make peripherals (or anything else) intelligent sometimes results in finicky, rigid "special features" that become just so much dead weight if you try to use the device in any way the designer didn't anticipate. Flexibility and programmability, on the other hand, are *really* smart.

Compare hook.

(1995-04-14)

IntelliMouse definition

Microsoft IntelliMouse Explorer

Intel Literature Sales definition

Address: PO Box 58130, Santa Clara, CA 95052, USA.

Telephone: +1 800 548 4725.

(1995-01-12)

Intelsat definition

<company, communications> A private satellite communications company that provides telephony, corporate network, video and Internet solutions around the globe via capacity on 25 geosynchronous satellites.

(2003-05-13)

Intel x86 definition

Intel 80x86