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TI-990
{{Short description, Series of 16-bit computers by Texas Instruments. The TI-990 was a series of 16-bit minicomputers sold by Texas Instruments (TI) in the 1970s and 1980s. The TI-990 was a replacement for TI's earlier minicomputer systems, the TI-960 and the TI-980. It had several unique features, and was easier to program than its predecessors. Among its core concepts was the ability to easily support multiprogramming using a software-switchable set of processor registers that allowed it to perform rapid context switches between programs. This was enabled through the use of register values stored in main memory that could be swapped by changing a single pointer. TI later implemented the TI-990 in a single-chip implementation, the TMS9900, among the first 16-bit microprocessors. Intended for use in low-end models of the TI-990, it retained the 990's memory model and main memory register system. This design was ultimately much more widely used in the TI-99/4A, where details of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Texas Instruments TMS9900
Introduced in June 1976, the TMS9900 was one of the first commercially available, single-chip 16-bit microprocessors. It implemented Texas Instruments' TI-990 minicomputer architecture in a single-chip format, and was initially used for low-end models of that lineup. Its 64-pin DIP format made it more expensive to implement in smaller machines than the more common 40-pin format, and it saw relatively few design wins outside TI's own use. Among those uses was their TI-99/4 and TI-99/4A home computers, which ultimately sold about 2.8 million units. Microcomputer-on-chip implementations of the 9900 in 40-pin packages included the TMS9940, TMS9980/81, TMS9995. The TMS99105/10 was the last iteration of the 9900 in 1981 and incorporated features of TI's 990/10 minicomputer. By the mid-1980s the microcomputer field was moving to 16-bit systems like the Intel 8088 and newer 16/32-bit designs like the Motorola 68000. With no obvious future for the chip, TI turned its attention to sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Texas Instruments TMS9900
Introduced in June 1976, the TMS9900 was one of the first commercially available, single-chip 16-bit microprocessors. It implemented Texas Instruments' TI-990 minicomputer architecture in a single-chip format, and was initially used for low-end models of that lineup. Its 64-pin DIP format made it more expensive to implement in smaller machines than the more common 40-pin format, and it saw relatively few design wins outside TI's own use. Among those uses was their TI-99/4 and TI-99/4A home computers, which ultimately sold about 2.8 million units. Microcomputer-on-chip implementations of the 9900 in 40-pin packages included the TMS9940, TMS9980/81, TMS9995. The TMS99105/10 was the last iteration of the 9900 in 1981 and incorporated features of TI's 990/10 minicomputer. By the mid-1980s the microcomputer field was moving to 16-bit systems like the Intel 8088 and newer 16/32-bit designs like the Motorola 68000. With no obvious future for the chip, TI turned its attention to sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minicomputers
A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ''The New York Times'' suggested a consensus definition of a minicomputer as a machine costing less than (), with an input-output device such as a teleprinter and at least four thousand words of memory, that is capable of running programs in a higher level language, such as Fortran or BASIC. The class formed a distinct group with its own software architectures and operating systems. Minis were designed for control, instrumentation, human interaction, and communication switching as distinct from calculation and record keeping. Many were sold indirectly to original equipment manufacturers (OEMs) for final end use application. During the two decade lifetime of the minicomputer class (1965–1985), almost 100 companies formed and only a half ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minicomputer
A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ''The New York Times'' suggested a consensus definition of a minicomputer as a machine costing less than (), with an input-output device such as a teleprinter and at least four thousand words of memory, that is capable of running programs in a higher level language, such as Fortran or BASIC. The class formed a distinct group with its own software architectures and operating systems. Minis were designed for control, instrumentation, human interaction, and communication switching as distinct from calculation and record keeping. Many were sold indirectly to original equipment manufacturers (OEMs) for final end use application. During the two decade lifetime of the minicomputer class (1965–1985), almost 100 companies formed and only a half ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TI-DNOS
Distributed Network Operating System (DNOS) The Distributed Network Operating System (DNOS) is a general purpose, multitasking operating system designed to operate with the Texas Instruments 990/10, 990/10A and 990/12 minicomputers. DNOS includes a sophisticated file management package which provides support for key indexed files, sequential files, and relative record files. DNOS is a multiterminal system that is capable of making each of several users appear to have exclusive control of the system. DNOS supports output spooling and program accessible accounting data. Job level and task level operations enable more efficient use of system resources. In addition to multiterminal applications, DNOS provides support for advanced program development. Users communicate with DNOS by entering commands at a terminal or by providing a file of commands. The System Command Interpreter (SCI) processes those commands and directs the operating system to initiate the action specified by a comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DX10 Operating System
DX10 was a general purpose international, multitasking operating system designed to operate with the Texas Instruments 990/10, 990/10A and 990/12 minicomputers using the memory mapping feature. The Disk Executive Operating System (DX10) DX10 was a versatile disk-based operating system capable of supporting a wide range of commercial and industrial applications. DX10 was also a multiterminal system capable of making each of several users appear to have exclusive control of the system. DX10 was an international operating system designed to meet the commercial requirements of the United States, most European countries, and Japan. DX10 supported several models of video display terminals (VDTs), most of which permit users to enter, view, and process data in their own language. DX10 Capabilities DX10 required a basic hardware configuration, but allows additional members of an extensive group of peripherals to be included in the configuration. During system generation, the user coul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TI-99/4A
The TI-99/4 and TI-99/4A are home computers released by Texas Instruments in 1979 and 1981, respectively. Based on the Texas Instruments TMS9900 microprocessor originally used in minicomputers, the TI-99/4 was the first 16-bit home computer. The associated video display controller provides color graphics and sprite support which were only comparable with those of the Atari 400 and 800 released a month after the TI-99/4. The calculator-style keyboard of the TI-99/4 was cited as a weak point, and TI's reliance on ROM cartridges and their practice of limiting developer information to select third parties resulted in a lack of software for the system. The TI-99/4A was released in June 1981 to address some of these issues with a simplified internal design, full-travel keyboard, improved graphics, and a unique expansion system. At half the price of the original model, sales picked up significantly and TI supported the 4A with peripherals, including a speech synthesizer and a "Per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Execute Instruction
In a computer instruction set architecture (ISA), an execute instruction is a machine language instruction which treats data as a machine instruction and executes it. It can be considered a fourth mode of instruction sequencing after ordinary sequential execution, branching, and interrupting. Since it is an instruction that operates on other instructions like the repeat instruction, it has also been classified as a meta-instruction. Computer models Many computer families introduced in the 1950s and 1960s include ''execute'' instructions: the IBM 709 and IBM 7090 ( op code mnemonic: ), the IBM 7030 Stretch (, ), the PDP-1/ -4/ -9/ -15 (), the UNIVAC 1100/2200 (), the CDC 924 (), the PDP-6/ -10 (), the IBM System/360 (), the GE-600/ Honeywell 6000 (, ), the SDS-9xx (). Fewer 1970s designs include ''execute'' instructions. An ''execute'' instruction was proposed for the PDP-11 in 1970, but never implemented for it or its successor, the VAX. Architectures with an ''execute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microprocessor
A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circuitry required to perform the functions of a computer's central processing unit. The integrated circuit is capable of interpreting and executing program instructions and performing arithmetic operations. The microprocessor is a multipurpose, clock-driven, register-based, digital integrated circuit that accepts binary data as input, processes it according to instructions stored in its memory, and provides results (also in binary form) as output. Microprocessors contain both combinational logic and sequential digital logic, and operate on numbers and symbols represented in the binary number system. The integration of a whole CPU onto a single or a few integrated circuits using Very-Large-Scale Integration (VLSI) greatly reduced the cost of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Context Switch
In computing, a context switch is the process of storing the state of a process or thread, so that it can be restored and resume execution at a later point, and then restoring a different, previously saved, state. This allows multiple processes to share a single central processing unit (CPU), and is an essential feature of a multitasking operating system. The precise meaning of the phrase "context switch" varies. In a multitasking context, it refers to the process of storing the system state for one task, so that task can be paused and another task resumed. A context switch can also occur as the result of an interrupt, such as when a task needs to access disk storage, freeing up CPU time for other tasks. Some operating systems also require a context switch to move between user mode and kernel mode tasks. The process of context switching can have a negative impact on system performance. Cost Context switches are usually computationally intensive, and much of the design of opera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthogonal Instruction Set
In computer engineering, an orthogonal instruction set is an instruction set architecture where all instruction types can use all addressing modes. It is "orthogonal" in the sense that the instruction type and the addressing mode vary independently. An orthogonal instruction set does not impose a limitation that requires a certain instruction to use a specific register so there is little overlapping of instruction functionality. Orthogonality was considered a major goal for processor designers in the 1970s, and the VAX-11 is often used as the benchmark for this concept. However, the introduction of RISC design philosophies in the 1980s significantly reversed the trend against more orthogonality. Modern CPUs often simulate orthogonality in a preprocessing step before performing the actual tasks in a RISC-like core. This "simulated orthogonality" in general is a broader concept, encompassing the notions of decoupling and completeness in function libraries, like in the mathematic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Addressing Mode
Addressing modes are an aspect of the instruction set architecture in most central processing unit (CPU) designs. The various addressing modes that are defined in a given instruction set architecture define how the machine language instructions in that architecture identify the operand(s) of each instruction. An addressing mode specifies how to calculate the effective memory address of an operand by using information held in registers and/or constants contained within a machine instruction or elsewhere. In computer programming, addressing modes are primarily of interest to those who write in assembly languages and to compiler writers. For a related concept see orthogonal instruction set which deals with the ability of any instruction to use any addressing mode. Caveats Note that there is no generally accepted way of naming the various addressing modes. In particular, different authors and computer manufacturers may give different names to the same addressing mode, or the same na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
