In electronics, a chip carrier is one of several kinds of surface-mount technology packages for integrated circuits. Connections are made on all four edges of a square package. Chip carriers may have either J-shaped metal leads for connections by solder or by a socket, or may be lead-less with metal pads for connections. If the leads extend beyond the package, the preferred description is "flat pack". Chip carriers are smaller than dual in-line packages and since they use all four edges of the package it can have a larger pin count. Chip carriers may be made of plastic; some forms of chip carrier package are standardized in dimensions and registered with trade industry associations such as JEDEC. Other forms are proprietary to two manufacturers. Sometimes the term "chip carrier" is used to refer generically to any package for an integrated circuit. Types of chip-carrier package are referred to by initialisms and include: BCC: Bump Chip Carrier CLCC: Ceramic Leadless Chip Carrier Leadless chip carrier: Leadless Chip Carrier, contacts are recessed vertically.
LCC: Leaded Chip Carrier LCCC: Leaded Ceramic Chip Carrier DLCC: Dual Lead-Less Chip Carrier PLCC: Plastic Leaded Chip Carrier PoP: Package on package A plastic-leaded chip carrier has a rectangular plastic housing. It is a reduced cost evolution of the ceramic leadless chip carrier. A premolded PLCC was released in 1976, but did not see much market adoption. Texas Instruments released a postmolded variant, soon adopted by most major semiconductor companies; the JEDEC trade group started a task force in 1981 to categorize PLCCs, with the MO-047 standard released in 1984 for square packages and the MO-052 standard released in 1985 for rectangular packages. The PLCC utilizes a "J"-lead with pin spacings of 0.05". The metal strip forming the lead is wrapped around and under the edge of the package, resembling the letter J in cross-section. Lead counts range from 20 to 84. PLCC packages can be square or rectangular. Body widths range from 0.35" to 1.15". The PLCC “J” Lead configuration requires less board space versus equivalent gull leaded components, which have flat leads that extend out perpendicularly to the narrow edge of the package.
The PLCC is preferred over DIP style chip carriers when lead counts exceed 40 pins due to the PLCC's more efficient use of board surface area. The heatspreader versions are identical in form factor to the standard non-heatspreader versions. Both versions are JEDEC compliant in all respects; the heatspreader versions give the system designer greater latitude in thermally enhanced board level and / or system design. RoHS compliant, lead-free and green material sets are now qualified standards. A PLCC circuit may either surface-mounted. PLCC sockets may in turn use through-hole technology; the motivation for a surface-mount PLCC socket would be when working with devices that cannot withstand the heat involved during the reflow process, or to allow for component replacement without reworking. Using a PLCC socket may be necessary in situations where the device requires stand-alone programming, such as some flash memory devices; some through-hole sockets are designed for prototyping with wire wrapping.
A specialized tool called. This package is still used for a wide variety of device types, which would include memory, controllers, ASICs, DSPs, etc, it is common for read-only memories as it provides an swappable socketed chip. Applications range from consumer products through automotive and aerospace. A leadless chip carrier has no "leads", but instead has rounded pins through the edges of the ceramic or molded plastic package. Prototypes and devices intended for extended temperature environments are packaged in ceramic, while high-volume products for consumer and commercial markets are packaged in plastic. List of integrated circuit packaging types
X87 is a floating-point-related subset of the x86 architecture instruction set. It originated as an extension of the 8086 instruction set in the form of optional floating-point coprocessors that worked in tandem with corresponding x86 CPUs; these microchips had names ending in "87". This was known as the NPX. Like other extensions to the basic instruction set, x87 instructions are not needed to construct working programs, but provide hardware and microcode implementations of common numerical tasks, allowing these tasks to be performed much faster than corresponding machine code routines can; the x87 instruction set includes instructions for basic floating-point operations such as addition and comparison, but for more complex numerical operations, such as the computation of the tangent function and its inverse, for example. Most x86 processors since the Intel 80486 have had these x87 instructions implemented in the main CPU, but the term is sometimes still used to refer to that part of the instruction set.
Before x87 instructions were standard in PCs, compilers or programmers had to use rather slow library calls to perform floating-point operations, a method, still common in embedded systems. The x87 registers form an 8-level deep non-strict stack structure ranging from ST to ST with registers that can be directly accessed by either operand, using an offset relative to the top, as well as pushed and popped. There are instructions to push and pop values on top of this stack; the non-strict stack model allows binary operations to use ST together with a direct memory operand or with an explicitly specified stack register, ST, in a role similar to a traditional accumulator. This can be reversed on an instruction-by-instruction basis with ST as the unmodified operand and ST as the destination. Furthermore, the contents in ST can be exchanged with another stack register using an instruction called FXCH ST; these properties make the x87 stack usable as seven addressable registers plus a dedicated accumulator.
This is applicable on superscalar x86 processors, where these exchange instructions are optimized down to a zero clock penalty by using one of the integer paths for FXCH ST in parallel with the FPU instruction. Despite being natural and convenient for human assembly language programmers, some compiler writers have found it complicated to construct automatic code generators that schedule x87 code effectively; such a stack-based interface can minimize the need to save scratch variables in function calls compared with a register-based interface The x87 provides single-precision, double-precision and 80-bit double-extended precision binary floating-point arithmetic as per the IEEE 754-1985 standard. By default, the x87 processors all use 80-bit double-extended precision internally. A given sequence of arithmetic operations may thus behave differently compared to a strict single-precision or double-precision IEEE 754 FPU; as this may sometimes be problematic for some semi-numerical calculations written to assume double precision for correct operation, to avoid such problems, the x87 can be configured using a special configuration/status register to automatically round to single or double precision after each operation.
Since the introduction of SSE2, the x87 instructions are not as essential as they once were, but remain important as a high-precision scalar unit for numerical calculations sensitive to round-off error and requiring the 64-bit mantissa precision and extended range available in the 80-bit format. Clock cycle counts for examples of typical x87 FPU instructions; the A... B notation covers timing variations dependent on transient pipeline status and the arithmetic precision chosen; the L → H notation depicts values corresponding to the lowest and the highest maximal clock frequencies that were available. * An effective zero clock delay is possible, via superscalar execution. § The 5 MHz 8087 was the original x87 processor. Compared to typical software-implemented floating-point routines on an 8086, the factors would be larger by another factor of 10. Companies that have designed or manufactured floating-point units compatible with the Intel 8087 or models include AMD, Chips and Technologies, Fujitsu, Harris Semiconductor, IBM, IDT, IIT, LC Technology, National Semiconductor, NexGen, Rise Technology, ST Microelectronics, Texas Instruments, Transmeta, ULSI (the Math·Co copr
IBM PC compatible
IBM PC compatible computers are computers similar to the original IBM PC, XT, AT, able to use the same software and expansion cards. Such computers used to be referred to as PC clones, or IBM clones, they duplicate exactly all the significant features of the PC architecture, facilitated by IBM's choice of commodity hardware components and various manufacturers' ability to reverse engineer the BIOS firmware using a "clean room design" technique. Columbia Data Products built the first clone of the IBM personal computer by a clean room implementation of its BIOS. Early IBM PC compatibles used the same computer bus as AT models; the IBM AT compatible bus was named the Industry Standard Architecture bus by manufacturers of compatible computers. The term "IBM PC compatible" is now a historical description only, since IBM has ended its personal computer sales. Descendants of the IBM PC compatibles comprise the majority of personal computers on the market presently with the dominant operating system being Microsoft Windows, although interoperability with the bus structure and peripherals of the original PC architecture may be limited or non-existent.
Some computers ran MS-DOS but had enough hardware differences that IBM compatible software could not be used. Only the Macintosh kept significant market share without compatibility with the IBM PC. IBM decided in 1980 to market a low-cost single-user computer as as possible in response to Apple Computer's success in the burgeoning microcomputer market. On 12 August 1981, the first IBM PC went on sale. There were three operating systems available for it; the least expensive and most popular was PC DOS made by Microsoft. In a crucial concession, IBM's agreement allowed Microsoft to sell its own version, MS-DOS, for non-IBM computers; the only component of the original PC architecture exclusive to IBM was the BIOS. IBM at first asked developers to avoid writing software that addressed the computer's hardware directly, to instead make standard calls to BIOS functions that carried out hardware-dependent operations; this software would run on any machine using MS-DOS or PC-DOS. Software that directly addressed the hardware instead of making standard calls was however.
Software addressing IBM PC hardware in this way would not run on MS-DOS machines with different hardware. The IBM PC was sold in high enough volumes to justify writing software for it, this encouraged other manufacturers to produce machines which could use the same programs, expansion cards, peripherals as the PC; the 808x computer marketplace excluded all machines which were not hardware- and software-compatible with the PC. The 640 KB barrier on "conventional" system memory available to MS-DOS is a legacy of that period. Rumors of "lookalike", compatible computers, created without IBM's approval, began immediately after the IBM PC's release. InfoWorld wrote on the first anniversary of the IBM PC that The dark side of an open system is its imitators. If the specs are clear enough for you to design peripherals, they are clear enough for you to design imitations. Apple... has patents on two important components of its systems... IBM, which has no special patents on the PC, is more vulnerable. Numerous PC-compatible machines—the grapevine says 60 or more—have begun to appear in the marketplace.
By June 1983 PC Magazine defined "PC'clone'" as "a computer accommodate the user who takes a disk home from an IBM PC, walks across the room, plugs it into the'foreign' machine". Because of a shortage of IBM PCs that year, many customers purchased clones instead. Columbia Data Products produced the first computer more or less compatible with the IBM PC standard during June 1982, soon followed by Eagle Computer. Compaq announced its first IBM PC compatible in the Compaq Portable; the Compaq was the first sewing machine-sized portable computer, 100% PC-compatible. The company could not copy the BIOS directly as a result of the court decision in Apple v. Franklin, but it could reverse-engineer the IBM BIOS and write its own BIOS using clean room design. At the same time, many manufacturers such as Tandy/RadioShack, Hewlett-Packard, Digital Equipment Corporation, Texas Instruments, Tulip and Olivetti introduced personal computers that supported MS-DOS, but were not software- or hardware-compatible with the IBM PC.
Tandy described the Tandy 2000, for example, as having a "'next generation' true 16-bit CPU", with "More speed. More disk storage. More expansion" than the IBM PC or "other MS-DOS computers". While admitting in 1984 that many MS-DOS programs did not support the computer, the company stated that "the most popular, sophisticated software on the market" was available, either or "over the next six months". Like IBM, Microsoft's intention was that application writers would write to the application programming interfaces in MS-DOS or the firmware BIOS, that this would form what would now be termed a hardware abstraction layer; each computer would have its own Original Equipment Manufacturer version of MS-DOS, customized to its hardware. Any software written for MS-DOS would operate on any MS-DOS computer, despite variations in hardware design; this expectation seemed reasonable in the computer marketplace of the time. Until Microsoft was based on computer languages such as BASIC; the established small system operating software was CP/M from Digital Research, in use both at the hobbyist level and by the more professional of t
In computer architecture, a bus is a communication system that transfers data between components inside a computer, or between computers. This expression covers all related hardware components and software, including communication protocols. Early computer buses were parallel electrical wires with multiple hardware connections, but the term is now used for any physical arrangement that provides the same logical function as a parallel electrical bus. Modern computer buses can use both parallel and bit serial connections, can be wired in either a multidrop or daisy chain topology, or connected by switched hubs, as in the case of USB. Computer systems consist of three main parts: the central processing unit that processes data, memory that holds the programs and data to be processed, I/O devices as peripherals that communicate with the outside world. An early computer might contain a hand-wired CPU of vacuum tubes, a magnetic drum for main memory, a punch tape and printer for reading and writing data respectively.
A modern system might have a multi-core CPU, DDR4 SDRAM for memory, a solid-state drive for secondary storage, a graphics card and LCD as a display system, a mouse and keyboard for interaction, a Wi-Fi connection for networking. In both examples, computer buses of one form or another move data between all of these devices. In most traditional computer architectures, the CPU and main memory tend to be coupled. A microprocessor conventionally is a single chip which has a number of electrical connections on its pins that can be used to select an "address" in the main memory and another set of pins to read and write the data stored at that location. In most cases, the CPU and memory share signalling operate in synchrony; the bus connecting the CPU and memory is one of the defining characteristics of the system, referred to as the system bus. It is possible to allow peripherals to communicate with memory in the same fashion, attaching adaptors in the form of expansion cards directly to the system bus.
This is accomplished through some sort of standardized electrical connector, several of these forming the expansion bus or local bus. However, as the performance differences between the CPU and peripherals varies some solution is needed to ensure that peripherals do not slow overall system performance. Many CPUs feature a second set of pins similar to those for communicating with memory, but able to operate at different speeds and using different protocols. Others use smart controllers to place the data directly in memory, a concept known as direct memory access. Most modern systems combine both solutions; as the number of potential peripherals grew, using an expansion card for every peripheral became untenable. This has led to the introduction of bus systems designed to support multiple peripherals. Common examples are the SATA ports in modern computers, which allow a number of hard drives to be connected without the need for a card. However, these high-performance systems are too expensive to implement in low-end devices, like a mouse.
This has led to the parallel development of a number of low-performance bus systems for these solutions, the most common example being the standardized Universal Serial Bus. All such examples may be referred to as peripheral buses, although this terminology is not universal. In modern systems the performance difference between the CPU and main memory has grown so great that increasing amounts of high-speed memory is built directly into the CPU, known as a cache. In such systems, CPUs communicate using high-performance buses that operate at speeds much greater than memory, communicate with memory using protocols similar to those used for peripherals in the past; these system buses are used to communicate with most other peripherals, through adaptors, which in turn talk to other peripherals and controllers. Such systems are architecturally more similar to multicomputers, communicating over a bus rather than a network. In these cases, expansion buses are separate and no longer share any architecture with their host CPU.
What would have been a system bus is now known as a front-side bus. Given these changes, the classical terms "system", "expansion" and "peripheral" no longer have the same connotations. Other common categorization systems are based on the bus's primary role, connecting devices internally or externally, PCI vs. SCSI for instance. However, many common modern bus systems can be used for both. Other examples, like InfiniBand and I²C were designed from the start to be used both internally and externally; the internal bus known as internal data bus, memory bus, system bus or Front-Side-Bus, connects all the internal components of a computer, such as CPU and memory, to the motherboard. Internal data buses are referred to as a local bus, because they are intended to connect to local devices; this bus is rather quick and is independent of the rest of the computer operations. The external bus, or expansion bus, is made up of the electronic pathways that connect the different external devices, such as printer etc. to the computer.
Buses can be parallel buses, which carry data words in parallel on multiple wires, or serial buses, which carry data in bit-serial form. The addition of extra power and control connections, differential
Sweden the Kingdom of Sweden, is a Scandinavian Nordic country in Northern Europe. It borders Norway to the west and north and Finland to the east, is connected to Denmark in the southwest by a bridge-tunnel across the Öresund, a strait at the Swedish-Danish border. At 450,295 square kilometres, Sweden is the largest country in Northern Europe, the third-largest country in the European Union and the fifth largest country in Europe by area. Sweden has a total population of 10.2 million. It has a low population density of 22 inhabitants per square kilometre; the highest concentration is in the southern half of the country. Germanic peoples have inhabited Sweden since prehistoric times, emerging into history as the Geats and Swedes and constituting the sea peoples known as the Norsemen. Southern Sweden is predominantly agricultural, while the north is forested. Sweden is part of the geographical area of Fennoscandia; the climate is in general mild for its northerly latitude due to significant maritime influence, that in spite of this still retains warm continental summers.
Today, the sovereign state of Sweden is a constitutional monarchy and parliamentary democracy, with a monarch as head of state, like its neighbour Norway. The capital city is Stockholm, the most populous city in the country. Legislative power is vested in the 349-member unicameral Riksdag. Executive power is exercised by the government chaired by the prime minister. Sweden is a unitary state divided into 21 counties and 290 municipalities. An independent Swedish state emerged during the early 12th century. After the Black Death in the middle of the 14th century killed about a third of the Scandinavian population, the Hanseatic League threatened Scandinavia's culture and languages; this led to the forming of the Scandinavian Kalmar Union in 1397, which Sweden left in 1523. When Sweden became involved in the Thirty Years War on the Reformist side, an expansion of its territories began and the Swedish Empire was formed; this became one of the great powers of Europe until the early 18th century. Swedish territories outside the Scandinavian Peninsula were lost during the 18th and 19th centuries, ending with the annexation of present-day Finland by Russia in 1809.
The last war in which Sweden was directly involved was in 1814, when Norway was militarily forced into personal union. Since Sweden has been at peace, maintaining an official policy of neutrality in foreign affairs; the union with Norway was peacefully dissolved in 1905. Sweden was formally neutral through both world wars and the Cold War, albeit Sweden has since 2009 moved towards cooperation with NATO. After the end of the Cold War, Sweden joined the European Union on 1 January 1995, but declined NATO membership, as well as Eurozone membership following a referendum, it is a member of the United Nations, the Nordic Council, the Council of Europe, the World Trade Organization and the Organisation for Economic Co-operation and Development. Sweden maintains a Nordic social welfare system that provides universal health care and tertiary education for its citizens, it has the world's eleventh-highest per capita income and ranks in numerous metrics of national performance, including quality of life, education, protection of civil liberties, economic competitiveness, equality and human development.
The name Sweden was loaned from Dutch in the 17th century to refer to Sweden as an emerging great power. Before Sweden's imperial expansion, Early Modern English used Swedeland. Sweden is derived through back-formation from Old English Swēoþēod, which meant "people of the Swedes"; this word is derived from Sweon/Sweonas. The Swedish name Sverige means "realm of the Swedes", excluding the Geats in Götaland. Variations of the name Sweden are used in most languages, with the exception of Danish and Norwegian using Sverige, Faroese Svøríki, Icelandic Svíþjóð, the more notable exception of some Finnic languages where Ruotsi and Rootsi are used, names considered as referring to the people from the coastal areas of Roslagen, who were known as the Rus', through them etymologically related to the English name for Russia; the etymology of Swedes, thus Sweden, is not agreed upon but may derive from Proto-Germanic Swihoniz meaning "one's own", referring to one's own Germanic tribe. Sweden's prehistory begins in the Allerød oscillation, a warm period around 12,000 BC, with Late Palaeolithic reindeer-hunting camps of the Bromme culture at the edge of the ice in what is now the country's southernmost province, Scania.
This period was characterised by small bands of hunter-gatherer-fishers using flint technology. Sweden is first described in a written source in Germania by Tacitus in 98 AD. In Germania 44 and 45 he mentions the Swedes as a powerful tribe with ships that had a prow at each end. Which kings ruled these Suiones is unknown, but Norse mythology presents a long line of legendary and semi-legendary kings going back to the last centuries BC; as for literacy in Sweden itself, the runic script was in use among the south Scandinavian elite by at least the 2nd century AD, but all that has come down to the present from the Roman Period is curt inscriptions on artefacts of male names, demonstrating th
Die (integrated circuit)
A die, in the context of integrated circuits, is a small block of semiconducting material on which a given functional circuit is fabricated. Integrated circuits are produced in large batches on a single wafer of electronic-grade silicon or other semiconductor through processes such as photolithography; the wafer is cut into many pieces, each containing one copy of the circuit. Each of these pieces is called a die. There are three used plural forms: "dice", "dies" and "die". To simplify handling and integration onto a printed circuit board, most dice are packaged in various forms. Most dies are used for integrated circuits; the process begins with the production of monocrystalline silicon ingots. These ingots are sliced into disks with a diameter of up to 300mm; these wafers are polished to a mirror finish before going through photolithography. In many steps the transistors are connected with metal interconnect layers; these prepared wafers go through wafer testing to test their functionality. The wafers are sliced and sorted to filter out the faulty dies.
Functional dies are packaged and the completed integrated circuit is ready to be shipped. A die can host many types of circuits. One common use case of an integrated circuit die. Through advances in modern technology, the size of the transistor within the die has shrunk exponentially, following Moore's Law. Other uses for dies can range from LED lighting to power semiconductor devices. Die preparation Integrated circuit design Wire bonding and ball bonding Wedge Bonding Process on YouTube – animation Industrial Bonder on YouTube – the video shows bonding not brazing
The PC-D and PC-X were personal computers sold by Siemens between 1982 /1984 and 1986. The PC-D was the first MS-DOS-based PC sold by Siemens, though it was not compatible with the IBM PC architecture, it was succeeded by the PCD-2. The PCD-2 was IBM PC compatible. Most of the hardware was identical. While the PC-X was equipped with 1 MB of RAM, a hard disk and a MMU, the PC-D came with 128 kB of RAM and a single 5¼″ floppy disk drive in its basic configuration. More powerful configurations with 256 kB, 512 kB or 1 MB and either a second floppy disk drive or a hard disk with a capacity of 13 or 20 MB were available; the keyboard layout differed between the two models. The PC-D had a certain level of compatibility with the IBM PC architecture but differed in a number of aspects: Intel 80186 processor Double-density floppy disk drives with a proprietary 80-track format Proprietary monochrome graphics adapter with a resolution of 640×350 pixels and black-on-white text mode 12″ monochrome monitor, powered through the graphics card V.11 serial ports for keyboard and mouse Different keyboard layout: among others, the PC-D had a Help key and keys to control a connected printer but only five cursor keys Both V.11 and V.24 ports for printers A parallel port was available only as an add-on.
Optional hardware included: a two-button mouse the PT20 daisy wheel printer, the PT88 or the PT89 the UTC 101, UTC 421-1 or UTC 424-4 teletex controllers, the latter of which could be used to network up to four PC-Ds a tape drive with a capacity of 45 MB The PC-D shipped with MS-DOS 2.11, extended with a menu system through which users could launch applications without having to use the command line. Application software included: Microsoft Word Microsoft Multiplan Microsoft Chart dBase, GW-BASIC interpreter and compiler Lotus Spotlight, an application suite which consisted of a notepad, calendar, card file, phone book and file manager which could be launched on top of other running DOS applications Open Access, an office suite which included a database, a spreadsheet application, a charting tool, a calendar and a BBS terminal A 9750 terminal emulation for BS-2000 mainframe access Some simple games Microsoft Windows 1.0Hardware calls on the PC-D differed from those on IBM compatible PCs, causing most DOS applications to crash on the PC-D unless they were recompiled or patched, making them incompatible with IBM PCs.
Windows applications could be exchanged between both platforms. The PC-X shipped with SINIX