| OSF/1 | |
|---|---|
| Developer | Open Software Foundation |
| OS family | Unix |
| Working state | Discontinued |
| Initial release | January 1992; 34 years ago (1992-01) |
| Available in | English |
| Supported platforms | MIPS,DEC Alpha,PA-RISC |
| Kernel type | Hybrid,[1]Microkernel[2] |
OSF/1 is a variant of theUnixoperating system developed by theOpen Software Foundation during the late 1980s and early 1990s. OSF/1 is one of the first operating systems to have used theMach kernel developed atCarnegie Mellon University, and is probably best known as the native Unix operating system forDEC Alpha architecture systems.
In 1994, after AT&T had soldUNIX System V toNovell and the rivalUnix International consortium had disbanded, the Open Software Foundation ceased funding of research and development of OSF/1. TheTru64 UNIX variant of OSF/1 was supported byHP until 2012.
In 1988, during the so-called "Unix wars",Digital Equipment Corporation (DEC) joined withIBM,Hewlett-Packard, and others to form theOpen Software Foundation (OSF) to develop a version of Unix named OSF/1. The aim was to compete withSystem V Release 4 fromAT&T Corporation andSun Microsystems, and it has been argued that a primary goal was for the operating system to be free of AT&Tintellectual property.[3] The fact that OSF/1 is one of the first operating systems to have used the Mach kernel is cited as support of this assertion.[citation needed] Digital also strongly promoted OSF/1 forreal-time applications, and with traditional UNIX implementations at the time providing poor real-time support at best, the real-time andmulti-threading support can be interpreted as having been heavily dependent on the Mach kernel. At the time of its introduction, OSF/1 became the third major flavor of UNIX together withSystem V and BSD.
OSF/1 at its inception combined Mach 2.5 with a large part of theBSD kernel (based on the 4.3-Reno release) to implement the UNIXAPI,[4]: 451 with this monolithic kernel arrangement continuing through the OSF/1 1.2 release, although the adoption of a microkernel had already been foreseen.[5] OSF/1 1.3 introduced such a microkernel in the form of Mach 3.0, hosting Unix system services separately in user space to provide the existing OSF/1 functionality.[2]
DEC's first release of OSF/1 (OSF/1 Release 1.0) in January 1992 was for its line ofMIPS-basedDECstation workstations,[6] however this was never a fully supported product. DEC ported OSF/1 to their newAlpha AXP platform as DEC OSF/1 AXP Release 1.2, released in March 1993. OSF/1 AXP is a full64-bit operating system, preserving the kernel architecture based on Mach 2.5 and 4.3BSD components.[1] From OSF/1 AXP 2.0 onwards,UNIX System V compatibility was also integrated into the system, but the architecture remained centred on the Mach 2.5 modular kernel, unlike later OSF versions of the system.[7] Although OSF/1 2.0 was also developed for DECStation MIPS systems, it was "never officially released or sold".[8] Subsequent releases are named Digital UNIX, and later,Tru64 UNIX.
Upon its acquisition ofApollo Computer in 1989,HP announced plans to introduce OSF/1 on both companies' products by late 1990.[9] HP released a port of OSF/1 to the earlyHP 9000/700 workstations based on thePA-RISC 1.1 architecture. This was withdrawn soon afterwards due to lack of software and hardware support compared to competing operating systems, specificallyHP-UX.[10]
As part of theAIM alliance and the resultingPowerOpen specification,Apple Computer intended to baseA/UX 4.0 for itsPowerPC-basedMacintoshes upon OSF/1,[11] but the project was cancelled and PowerOpen deprecated.
IBM used OSF/1 as the basis of theAIX/ESA operating system forSystem/370 andSystem/390 mainframes.[12]
Intel Paragon supercomputers used a version of OSF/1 featuring the Mach 3.0 kernel.[13]
OSF/1 was also ported byKendall Square Research to its proprietarymicroarchitecture used in the KSR1supercomputer.
The Open Software Foundation created OSF MK, an evolution of OSF/1, incorporating the OSF Mach kernel (or OSF Microkernel[14]) based on Mach 3.0 along with a variety of other functionality including the OSF/1 Single Server providing the Unix system personality. The complete system in the form of MK 5.0 was made available under commercial terms to OSF/1 licensees in April 1993.[15] In contrast to the OSF/1 server, which was encumbered by proprietary Unix licensing, the microkernel itself remained freely available for adoption by other projects.[16] In OSF MK, it contains applicable code from theUniversity of Utah Mach 4 kernel (such as the "Shuttles" modification used to speed up message passing) and applicable code from the many Mach 3.0 variants that sprouted off from the originalCarnegie Mellon University Mach 3.0 kernel.[17][18] It also consists of improvements made by the OSF such as built-in collocation capability, realtime improvements, and rewriting of theIPCRPC component for better performance.[15]
OSF/1 AD (Advanced Development) was adistributed version of OSF/1 developed formassively parallel supercomputers byLocus Computing Corporation.[19] Variants of OSF/1 AD are on several such systems, including theIntel Paragon XP/S andASCI Red,Convex Exemplar SPP-1200 (asSPP-UX) and theHitachi SR2201 (asHI-UX MPP).
OSF/2, a successor to OSF/1, was described as being based on the TMach system developed byTrusted Information Systems.[20] TMach, or Trusted Mach, was an operating system architecture incorporating the OSF Mach MK++ kernel, introducing a trusted computing base layer consisting of trusted server components, hosting an application layer in which untrusted programs would run.[21] In 1989, HP announced plans to merge the software platforms of its own products and those of newly acquired Apollo Computer to form a single OSF/2-compliant platform to be delivered by 1992.[9]
Other interpretations of the OSF/2 name were associated with various plans to remove AT&T-licensed code from early forms of OSF/1 and the Mach kernel in particular,[22] leading to speculation that a system based on theChorus microkernel might supplant Mach entirely and become OSF/2 itself.[23] With such a Chorus-based architecture having been rejected in favour of the Mach 3.0 microkernel, the OSF/2 designation persisted in reporting of this particular form of OSF/1.[24]
DEC OSF/1 operating system version 1.2 for Alpha AXP systems is an implementation of the Open Software Foundation (OSF) OSF/1 version 1.0 and version 1.1 technology. The operating system is a 64-bit kernel architecture based on Carnegie-Mellon University's Mach version 2.5 kernel. Components from 4.3 BSD are included, in addition to UNIX System Laboratories System V interface compatibility.
Currently, OSF/1 integrates the core kernel services with the system services into one monolithic kernel. In future versions, the kernel will contain only the primitive objects and operations provided by a microkernel; most of what is now contained in the system services will be moved into its own, separate address space.
