Predication (computer architecture)In computer architecture, predication is a feature that provides an alternative to conditional transfer of control, as implemented by conditional branch machine instructions. Predication works by having conditional (predicated) non-branch instructions associated with a predicate, a Boolean value used by the instruction to control whether the instruction is allowed to modify the architectural state or not. If the predicate specified in the instruction is true, the instruction modifies the architectural state; otherwise, the architectural state is unchanged.
ULTRIXULTRIX (également écrit Ultrix, sans les majuscules) était un système d'exploitation de type Unix possédé par Digital Equipment Corporation (DEC). Il est basé sur BSD4.2 avec des apports provenant de System V. Le développement initial d'Unix se fit sur des ordinateurs produits par DEC, notamment le PDP-7 et le PDP-11. Leurs successeurs, les VAX, furent également populaires par la suite : le premier portage d'Unix pour cette architecture fut terminé en 1978, soit un an seulement après sa commercialisation, en .
Alpha 21364The Alpha 21364, code-named "Marvel", also known as EV7 is a microprocessor developed by Digital Equipment Corporation (DEC), later Compaq Computer Corporation, that implemented the Alpha instruction set architecture (ISA). The Alpha 21364 was revealed in October 1998 by Compaq at the 11th Annual Microprocessor Forum, where it was described as an Alpha 21264 with a 1.5 MB 6-way set-associative on-die secondary cache, an integrated Direct Rambus DRAM memory controller and an integrated network controller for connecting to other microprocessors.
Sun-3Sun-3 is a series of UNIX computer workstations and servers produced by Sun Microsystems, launched on September 9, 1985. The Sun-3 series are VMEbus-based systems similar to some of the earlier Sun-2 series, but using the Motorola 68020 microprocessor, in combination with the Motorola 68881 floating-point co-processor (optional on the Sun 3/50) and a proprietary Sun MMU. Sun-3 systems were supported in SunOS versions 3.0 to 4.1.1_U1 and also have current support in NetBSD and Linux.
AlphaServerAlphaServer is a series of server computers, produced from 1994 onwards by Digital Equipment Corporation, and later by Compaq and HP. AlphaServers were based on the DEC Alpha 64-bit microprocessor. Supported operating systems for AlphaServers are Tru64 UNIX (formerly Digital UNIX), OpenVMS, MEDITECH MAGIC and Windows NT (on earlier systems, with AlphaBIOS ARC firmware), while enthusiasts have provided alternative operating systems such as Linux, NetBSD, OpenBSD and FreeBSD.
Classic RISC pipelineIn the history of computer hardware, some early reduced instruction set computer central processing units (RISC CPUs) used a very similar architectural solution, now called a classic RISC pipeline. Those CPUs were: MIPS, SPARC, Motorola 88000, and later the notional CPU DLX invented for education. Each of these classic scalar RISC designs fetches and tries to execute one instruction per cycle. The main common concept of each design is a five-stage execution instruction pipeline.
R2000 microprocessorThe R2000 is a 32-bit microprocessor chip set developed by MIPS Computer Systems that implemented the MIPS I instruction set architecture (ISA). Introduced in January 1986, it was the first commercial implementation of the MIPS architecture and the first commercial RISC processor available to all companies. The R2000 competed with Digital Equipment Corporation (DEC) VAX minicomputers and with Motorola 68000 and Intel Corporation 80386 microprocessors. R2000 users included Ardent Computer, DEC, Silicon Graphics, Northern Telecom and MIPS's own Unix workstations.
Alpha 21464The Alpha 21464 is an unfinished microprocessor that implements the Alpha instruction set architecture (ISA) developed by Digital Equipment Corporation and later by Compaq after it acquired Digital. The microprocessor was also known as EV8 (codenamed Araña). Slated for a 2004 release, it was canceled on 25 June 2001 when Compaq announced that Alpha would be phased out in favor of Itanium by 2004. When it was canceled, the Alpha 21464 was at a late stage of development but had not been taped out.
Delay slotIn computer architecture, a delay slot is an instruction slot being executed without the effects of a preceding instruction. The most common form is a single arbitrary instruction located immediately after a branch instruction on a RISC or DSP architecture; this instruction will execute even if the preceding branch is taken. Thus, by design, the instructions appear to execute in an illogical or incorrect order. It is typical for assemblers to automatically reorder instructions by default, hiding the awkwardness from assembly developers and compilers.
Sun-4Sun-4 is a series of Unix workstations and servers produced by Sun Microsystems, launched in 1987. The original Sun-4 series were VMEbus-based systems similar to the earlier Sun-3 series, but employing microprocessors based on Sun's own SPARC V7 RISC architecture in place of the 68k family processors of previous Sun models. Sun 4/280 was known as base system that was used for building of first RAID prototype. Models are listed in approximately chronological order. {| class="wikitable sortable" |- !Model !Codename !CPU board !CPU !CPU MHz !Max.
