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Tube (BBC Micro)
In computing, the Tube is the expansion interface and architecture of the BBC Microcomputer System which allows the BBC Micro to communicate with a second processor, or ''coprocessor''. Under the Tube architecture, the coprocessor runs the application software for the user, whilst the Micro (acting as a ''host'') provides all I/O functions, such as screen display, keyboard and storage devices management. A coprocessor unit can be coldplugged into any BBC Micro with a disk interface (whose ROM contained the necessary host software) and used immediately. Implementation The 40-pin IDC "Tube" connector is a simple slave connection to the host processor's main bus, with 8 data lines, 7 address lines, and an interrupt input. The Tube protocols are implemented by hardware in the attached device. Inside the coprocessor unit a proprietary chip (the ''Tube ULA'', manufactured initially by Ferranti) interfaces and logically isolates the host and coprocessor buses. This allows the T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BBC Micro
The British Broadcasting Corporation Microcomputer System, or BBC Micro, is a series of microcomputers and associated peripherals designed and built by Acorn Computers in the 1980s for the BBC Computer Literacy Project. Designed with an emphasis on education, it was notable for its ruggedness, expandability, and the quality of its operating system. An accompanying 1982 television series, ''The Computer Programme'', featuring Chris Serle learning to use the machine, was broadcast on BBC2. After the Literacy Project's call for bids for a computer to accompany the TV programmes and literature, Acorn won the contract with the ''Proton'', a successor of its Atom computer prototyped at short notice. Renamed the BBC Micro, the system was adopted by most schools in the United Kingdom, changing Acorn's fortunes. It was also successful as a home computer in the UK, despite its high cost. Acorn later employed the machine to simulate and develop the ARM architecture. While nine models ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Call
In computing, a system call (commonly abbreviated to syscall) is the programmatic way in which a computer program requests a service from the operating system on which it is executed. This may include hardware-related services (for example, accessing a hard disk drive or accessing the device's camera), creation and execution of new processes, and communication with integral kernel services such as process scheduling. System calls provide an essential interface between a process and the operating system. In most systems, system calls can only be made from userspace processes, while in some systems, OS/360 and successors for example, privileged system code also issues system calls. Privileges The architecture of most modern processors, with the exception of some embedded systems, involves a security model. For example, the ''rings'' model specifies multiple privilege levels under which software may be executed: a program is usually limited to its own address space so that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ARM Architecture
ARM (stylised in lowercase as arm, formerly an acronym for Advanced RISC Machines and originally Acorn RISC Machine) is a family of reduced instruction set computer (RISC) instruction set architectures for computer processors, configured for various environments. Arm Ltd. develops the architectures and licenses them to other companies, who design their own products that implement one or more of those architectures, including system on a chip (SoC) and system on module (SOM) designs, that incorporate different components such as memory, interfaces, and radios. It also designs cores that implement these instruction set architectures and licenses these designs to many companies that incorporate those core designs into their own products. There have been several generations of the ARM design. The original ARM1 used a 32-bit internal structure but had a 26-bit address space that limited it to 64 MB of main memory. This limitation was removed in the ARMv3 series, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel 80186
The Intel 80186, also known as the iAPX 186, or just 186, is a microprocessor and microcontroller introduced in 1982. It was based on the Intel 8086 and, like it, had a 16-bit external data bus multiplexed with a 20-bit address bus. The 80188 variant, with an 8-bit external data bus was also available. Description The 80186 series was generally intended for embedded systems, as microcontrollers with external memory. Therefore, to reduce the number of integrated circuits required, it included features such as clock generator, interrupt controller, timers, wait state generator, DMA channels, and external chip select lines. The initial clock rate of the 80186 was 6 MHz, but due to more hardware available for the microcode to use, especially for address calculation, many individual instructions completed in fewer clock cycles than on an 8086 at the same clock frequency. For instance, the common ''register+immediate'' addressing mode was significantly faster than on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acorn Business Computer
The Acorn Business Computer (ABC) was a series of microcomputers announced at the end of 1983 by the British company Acorn Computers. The series of eight computers was aimed at the business, research and further education markets. Demonstrated at the Personal Computer World Show in September 1984, having been under development for "about a year" and having been undergoing field trials from May 1984, the range "understandably attracted a great deal of attention" and was favourably received by some commentators. The official launch of the range was scheduled for January 1985. Acorn had stated in a February 1985 press release that the ABC machines would soon be available in 50 stores, but having been rescued by Olivetti, no dealers were stocking the range and only the Personal Assistant and 300 series models were expected to be on display by the end of March. However, the ABC range was cancelled before any of the models were shipped to customers. The ABC 210 was subsequently relaunched ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panos (operating System)
PANOS is a discontinued computer operating system developed by Acorn Computers in the 1980s and released in 1985, which ran on the 32016 Second Processor for the BBC Micro and the Acorn Cambridge Workstation. These systems had essentially the same architecture, based on a 32-bit NS32016 CPU; the ACW having a BBC Micro-based " I/O processor". Access to the I/O processor was through a NS32016 firmware kernel called ''Pandora''. Panos ran on the NS32016 and was a rudimentary single-user operating system, written in Modula-2. It provided a simple command line interpreter, a text editor and access to DFS, ADFS or NFS file systems via the I/O processor. Targeted at the academic and scientific user community, it came bundled with compilers for the FORTRAN 77, C, Pascal and LISP programming languages. Commands The following list of commands is supported by the Panos command line interpreter. * .''space'' * .Delete * .Help * .key * .NewCommand * .Obey * .pwd * .Quit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NS320xx
The NS32000, sometimes known as the 32k, is a series of microprocessors produced by National Semiconductor. The first member of the family came to market in 1982, briefly known as the 16032 before becoming the 32016. It was the first 32-bit general-purpose microprocessor on the market: the Motorola 68000 could process 32-bit data and stored addresses in 32 bits but could only address 16MiB of RAM and had a 16-bit ALU, whereas the 32000 series was described in 1983 as the only microprocessor available at that time with 32-bit internal data paths and ALU. However, the 32016 contained a large number of bugs and often could not be run at its rated speed. These problems, and the presence of the similar Motorola 68000 which had been available since 1980, led to little use in the market. Several improved versions followed, including 1985's 32032 which was essentially a bug-fixed 32016 with an external 32-bit data bus. While it offered about 50% better speed than the 32016, it was outperfo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CP/M
CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/ 85-based microcomputers by Gary Kildall of Digital Research, Inc. Initially confined to single-tasking on 8-bit processors and no more than 64 kilobytes of memory, later versions of CP/M added multi-user variations and were migrated to 16-bit processors. The combination of CP/M and S-100 bus computers became an early standard in the microcomputer industry. This computer platform was widely used in business through the late 1970s and into the mid-1980s. CP/M increased the market size for both hardware and software by greatly reducing the amount of programming required to install an application on a new manufacturer's computer. An important driver of software innovation was the advent of (comparatively) low-cost microcomputers running CP/M, as independent programmers and hackers bought them and shared their crea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zilog Z80
The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples were delivered in March 1976, and it was officially introduced on the market in July 1976. With the revenue from the Z80, the company built its own chip factories and grew to over a thousand employees over the following two years. The Zilog Z80 is a software-compatible extension and enhancement of the Intel 8080 and, like it, was mainly aimed at embedded systems. Although used in that role, the Z80 also became one of the most widely used CPUs in desktop computers and home computers from the 1970s to the mid-1980s. It was also common in military applications, musical equipment such as synthesizers (like the Roland Jupiter-8), and coin-operated arcade games of the late 1970s and early 1980s, including '' Pac-Man''. Zilog licensed the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MOS Technology 6502
The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit microprocessor that was designed by a small team led by Chuck Peddle for MOS Technology. The design team had formerly worked at Motorola on the Motorola 6800 project; the 6502 is essentially a simplified, less expensive and faster version of that design. When it was introduced in 1975, the 6502 was the least expensive microprocessor on the market by a considerable margin. It initially sold for less than one-sixth the cost of competing designs from larger companies, such as the 6800 or Intel 8080. Its introduction caused rapid decreases in pricing across the entire processor market. Along with the Zilog Z80, it sparked a series of projects that resulted in the home computer revolution of the early 1980s. Popular video game consoles and home computers of the 1980s and early 1990s, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asynchronous Systems
The primary focus of this article is asynchronous control in digital electronic systems. In a synchronous system, operations (instructions, calculations, logic, etc.) are coordinated by one, or more, centralized clock signals. An asynchronous system, in contrast, has no global clock. Asynchronous systems do not depend on strict arrival times of signals or messages for reliable operation. Coordination is achieved using event-driven architecture triggered by network packet arrival, changes (transitions) of signals, handshake protocols, and other methods. Modularity Asynchronous systems – much like object-oriented software – are typically constructed out of modular 'hardware objects', each with well-defined communication interfaces. These modules may operate at variable speeds, whether due to data-dependent processing, dynamic voltage scaling, or process variation. The modules can then be combined to form a correct working system, without reference to a global clock si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Message Passing
In computer science, message passing is a technique for invoking behavior (i.e., running a program) on a computer. The invoking program sends a message to a process (which may be an actor or object) and relies on that process and its supporting infrastructure to then select and run some appropriate code. Message passing differs from conventional programming where a process, subroutine, or function is directly invoked by name. Message passing is key to some models of concurrency and object-oriented programming. Message passing is ubiquitous in modern computer software. It is used as a way for the objects that make up a program to work with each other and as a means for objects and systems running on different computers (e.g., the Internet) to interact. Message passing may be implemented by various mechanisms, including channels. Overview Message passing is a technique for invoking behavior (i.e., running a program) on a computer. In contrast to the traditional technique of callin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
