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VAXft
The VAXft was a family of fault-tolerant minicomputers developed and manufactured by Digital Equipment Corporation (DEC) using processors implementing the VAX instruction set architecture (ISA). "VAXft" stood for "Virtual Address Extension, fault tolerant". These systems ran the OpenVMS operating system, and were first supported by VMS 5.4. Two layered software products, VAXft System Services and VMS Volume Shadowing, were required to support the fault-tolerant features of the VAXft and for the redundancy of data stored on hard disk drives. Architecture All VAXft systems shared the same basic system architecture. A VAXft system consisted of two "zones" that operated in lock-step: "Zone A" and "Zone B". Each zone was a fully functional computer, capable of running an operating system, and was identical to the other in hardware configuration. Lock-step was achieved by hardware on the CPU module. The CPU module of each zone was connected to the other with a crosslink cable. The cros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenVMS
OpenVMS, often referred to as just VMS, is a multi-user, multiprocessing and virtual memory-based operating system. It is designed to support time-sharing, batch processing, transaction processing and workstation applications. Customers using OpenVMS include banks and financial services, hospitals and healthcare, telecommunications operators, network information services, and industrial manufacturers. During the 1990s and 2000s, there were approximately half a million VMS systems in operation worldwide. It was first announced by Digital Equipment Corporation (DEC) as VAX/VMS (''Virtual Address eXtension/Virtual Memory System'') alongside the VAX-11/780 minicomputer in 1977. OpenVMS has subsequently been ported to run on DEC Alpha systems, the Itanium-based HPE Integrity Servers, and select x86-64 hardware and hypervisors. Since 2014, OpenVMS is developed and supported by VMS Software Inc. (VSI). OpenVMS offers high availability through clustering — the ability to distribute the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VAX Unit Of Performance
The VAX Unit of Performance, or VUP for short, is an obsolete measurement of computer performance used by Digital Equipment Corporation (DEC). 1 VUP was equivalent to the performance of a VAX 11/780 completing a given task. Other VAX machines and later workstation designs were compared in performance terms by defining system speed in VUPs, for instance, the VAXft Model 310 ran at 3.8 VUPs, meaning it ran roughly 3.8 times as fast as the 11/780. The term was used largely within the DEC and its community, and fell from use as more standard ratings like SPEC became more widely used. This was especially true with the introduction of DEC workstations running Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ..., in which case the VUP was of little use comparing the platforms to comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lockstep (computing)
Lockstep systems are fault-tolerant computer systems that run the same set of operations at the same time in parallel. The redundancy (duplication) allows error detection and error correction: the output from lockstep operations can be compared to determine if there has been a fault if there are at least two systems (dual modular redundancy), and the error can be automatically corrected if there are at least three systems (triple modular redundancy), via majority vote. The term "lockstep" originates from army usage, where it refers to synchronized walking, in which marchers walk as closely together as physically practical. To run in lockstep, each system is set up to progress from one well-defined state to the next well-defined state. When a new set of inputs reaches the system, it processes them, generates new outputs and updates its state. This set of changes (new inputs, new outputs, new state) is considered to define that step, and must be treated as an atomic transaction; in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NVAX
The NVAX is a CMOS microprocessor developed and produced by Digital Equipment Corporation (DEC) that implemented the VAX instruction set architecture (ISA). A variant of the NVAX, the NVAX+, differed in the bus interface and external cache supported, but was otherwise identical in regards to microarchitecture. The NVAX+ was designed to have the same bus as the DECchip 21064, allowing drop-in replacement. The NVAX and NVAX+ was used in late-model VAX systems released in 1991 such as the MicroVAX 3100, VAXstation 4000, VAX 4000, VAX 6000, VAX 7000/10000 and VAXft. Although Digital updated the design throughout the early 1990s, the processors, and the VAX platform itself, were ultimately superseded by the introduction of the DECchip 21064, an implementation of the Alpha (then Alpha AXP) architecture, and the resulting systems in November 1992. The NVAX was offered at a variety of clock speeds, 83.3 MHz (12 ns), 71 MHz (14 ns) and 62.5 MHz (16 ns), while the NVAX+ is clocked at a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault-tolerant System
Fault tolerance is the property that enables a system to continue operating properly in the event of the failure of one or more faults within some of its components. If its operating quality decreases at all, the decrease is proportional to the severity of the failure, as compared to a naively designed system, in which even a small failure can cause total breakdown. Fault tolerance is particularly sought after in high-availability, mission-critical, or even life-critical systems. The ability of maintaining functionality when portions of a system break down is referred to as graceful degradation. A fault-tolerant design enables a system to continue its intended operation, possibly at a reduced level, rather than failing completely, when some part of the system fails. The term is most commonly used to describe computer systems designed to continue more or less fully operational with, perhaps, a reduction in throughput or an increase in response time in the event of some partial f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VAXcluster
A VMScluster, originally known as a VAXcluster, is a computer cluster involving a group of computers running the OpenVMS operating system. Whereas tightly coupled multiprocessor systems run a single copy of the operating system, a VMScluster is loosely coupled: each machine runs its own copy of OpenVMS, but the disk storage, lock manager, and security domain are all cluster-wide, providing a single system image abstraction. Machines can join or leave a VMScluster without affecting the rest of the cluster. For enhanced availability, VMSclusters support the use of dual-ported disks connected to two machines or storage controllers simultaneously. Initial release Digital Equipment Corporation (DEC) first announced VAXclusters in May 1983. At this stage, clustering required specialised communications hardware, as well as some major changes to low-level subsystems in VMS. The software and hardware were designed jointly. VAXcluster support was first added in VAX/VMS V4.0, which was rele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computerworld
''Computerworld'' (abbreviated as CW) is an ongoing decades old professional publication which in 2014 "went digital." Its audience is information technology (IT) and business technology professionals, and is available via a publication website and as a digital magazine. As a printed weekly during the 1970s and into the 1980s, ''Computerworld'' was the leading trade publication in the data processing industry. Indeed, based on circulation and revenue it was one of the most successful trade publications in any industry. Later in the 1980s it began to lose its dominant position. It is published in many countries around the world under the same or similar names. Each country's version of ''Computerworld'' includes original content and is managed independently. The parent company of Computerworld US is IDG Communications. History The first issue was published in 1967. Going international The company IDG offers the brand "Computerworld" in 47 countries worldwide, the name and fre ... [...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] |
Electronic News
''Electronic News'' was a publication that covered the electronics industry, from semiconductor equipment and materials to military/aerospace electronics to supercomputers. It was originally a weekly trade newspaper, which covered all aspects of the electronics industry, including semiconductors, computers, software, communications, space and even television electronics. History and profile Fairchild Publications started the newspaper in 1957, as a complement to its other trade newspapers, including Women's Wear Daily, Home Furnishing Daily, Supermarket News, among others. At its peak in 1984, ''Electronic News'' took in $25 million in revenue with margins above 50%. The following year, the newspaper began losing advertising and influence to rival ''Electronic Engineering Times'', beginning a decline that eventually led to the newspaper's demise. In 1971, journalist Don Hoefler published a series of articles entitled "Silicon Valley, USA" in ''Electronic News''. This is thought t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CVAX+
The CVAX is a microprocessor chipset developed and fabricated by Digital Equipment Corporation (DEC) that implemented the VAX instruction set architecture (ISA). The chipset consisted of the CVAX 78034 CPU, CFPA floating-point accelerator, CVAX clock chip, and the associated support chips, the CVAX System Support Chip (CSSC), CVAX Memory Controller (CMCTL), and CVAX Q-Bus Interface Chip (CQBIC). CVAX 78034 The CVAX 78034, also known as the MicroVAX 78034, is a second-generation single-chip VAX microprocessor. Systems featuring the CVAX chip set became available in late 1987. It is clocked at frequencies of 12.5 MHz (80 ns) in higher-end systems such as the VAX 6000 Model 200 and at 11.11 MHz (90 ns) in lower-end systems such as the MicroVAX 3500 and 3600. The 78034 was the first VAX microprocessor to have internal caches, a 1 KB combined instruction and data stream cache. The cache is quite unusual as it is implemented with one-transistor DRAM, whereas the majority o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CVAX
The CVAX is a microprocessor chipset developed and fabricated by Digital Equipment Corporation (DEC) that implemented the VAX instruction set architecture (ISA). The chipset consisted of the CVAX 78034 CPU, CFPA floating-point accelerator, CVAX clock chip, and the associated support chips, the CVAX System Support Chip (CSSC), CVAX Memory Controller (CMCTL), and CVAX Q-Bus Interface Chip (CQBIC). CVAX 78034 The CVAX 78034, also known as the MicroVAX 78034, is a second-generation single-chip VAX microprocessor. Systems featuring the CVAX chip set became available in late 1987. It is clocked at frequencies of 12.5 MHz (80 ns) in higher-end systems such as the VAX 6000 Model 200 and at 11.11 MHz (90 ns) in lower-end systems such as the MicroVAX 3500 and 3600. The 78034 was the first VAX microprocessor to have internal caches, a 1 KB combined instruction and data stream cache. The cache is quite unusual as it is implemented with one-transistor DRAM, whereas the majority o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
