MkLinux

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MkLinux - Microkernel Linux - is an open-source and free Unix-like operating system based on a Mach 3.0 microkernel on which a Linux server is based. It was jointly developed in the mid-1990s by the Research Institute of the Open Group (before 1996 Open Software Foundation , or OSF for short) in Grenoble, France, and Apple Computer . Up to 1998 three developer releases were published which already supported some Macintosh models (including PowerBooks).

The MkLinux userland comes from Red Hat Linux .

In the summer of 1998, MkLinux was abandoned by the Open Group and Apple and handed over to the newly founded developer community MkLinux Developers Association , which published two more versions, Release 1 and 2, by 2002 , with which a large number of other Macintosh models are supported.

There has been no new MkLinux version since 2002 and no updates since 2009, so the development of MkLinux must be regarded as discontinued.

history

At the OSF, plans arose in the 1990s to develop an alternative to its own OSF / 1 operating system for research and development of microkernel systems . OSF / 1 was also based on a Mach microkernel, but the personality server on top was partly under AT & T's System V license. Therefore, a free UNIX-compatible alternative was developed and Linux was chosen as the system environment. This project became the basis of MkLinux.

OSF MK, the variant of the Mach 3.0 microkernel further developed by OSF, was chosen as the basis. The porting of OSF MK to the PowerMacintosh platform began at the beginning of 1995, at the same time the revision of the monolithic Linux kernel was started in order to be able to use it as an OS server on the Mach microkernel. This was done on Intel x86 systems. Only later was the Linux server ported to PowerMacintosh. In February 1996, Apple announced the first available version of MkLinux for PowerMacintosh for summer 1996, but Developer Release 1 (DR1) was released in May 1996. This was followed by DR2 in September 1996 and DR2.1 in January 1997. This release was distributed on CD-ROM together with a reference manual by the small Californian company Prime Time Freeware in cooperation with Apple. In July 1998 the last official version on CD-ROM was Developer Release 3 (DR3).

In the following years, similar to the previous developer releases, attempts were essentially made to improve support for available hardware and to introduce new computer models such as As new PowerBooks and NewWorld - PowerMacs support. The further development was initially supervised and coordinated by a small team at Apple, but soon afterwards Apple withdrew completely from the project, so that from mid-1999 the project was continued entirely by a small group of independent developers, the MkLinux Developers Association . Since user programs under MkLinux were binary compatible with those of the LinuxPPC project (porting the Linux kernel to PowerPC systems), the MkLinux programmers now concentrated on the further development of the Mach kernel / Linux kernel server pair. Of these, various interim releases appeared in the period that followed, and finally release candidates for version 1.0 of MkLinux under the designation Pre1 and Pre2. Pre2 in the summer of 2002 was the last complete kernel / server pair.

Technical features

With MkLinux, the operating system functions are divided into two areas: The Mach microkernel provides a few basic services that are abstracted from the operating systems on top. These are: tasks (control of system resources), threads (control of CPU usage, scheduling), ports (controlled communication between tasks), messages (information exchanged via ports) and memory objects (memory management, address spaces, etc.). Mach neither provides a concept for processes nor does it offer elaborate services such as network protocols or file systems. All these things are the responsibility of the OS personality server, which, in the case of MkLinux as a Linux server, provides them in the Linux semantics (e.g. / proc file system).

Virtual memory is managed by the Mach microkernel, on whose memory objects the corresponding Linux data structures are mapped. The kernel or the Linux server does not swap and read memory pages on hard disk space, but a separate background process called default_pager.

The Linux server is implemented as a so-called single server . This means that the entire Linux server is set up as a single Mach task and thus has a single address space. This increases the performance of the system, since less inter-process communication (IPC) is required, on the other hand it makes the system more difficult to portate.

Web links

credentials

  1. ↑ David A. Gatwood: About MkLinux. In: MkLinux.org. Retrieved on June 9, 2018 (English, date unknown, but probably around 2000; linked from the MkLinux homepage with the text: A more-complete-but-still-brief history can be found on the About MkLinux page. ).
  2. ↑ Welcome to MkLinux.org. In: MkLinux.org. Retrieved on June 9, 2018 (English, section What is MkLinux? ): "MkLinux is a project begun by the OSF Research Institute (now Silicomp RI) and Apple Computer to port Linux, a freely distributed UNIX-like operating system, to a variety of Power Macintosh platforms running on top of OSF Research Institute's implementation of the Mach microkernel. Beginning in the summer of 1998, development work on MkLinux transitioned from Apple and OSF to a community-led effort. "
  3. ^ MkLinux News. In: MkLinux.org. Retrieved June 9, 2018 .
  4. ↑ M. Accetta, R. Baron, W. Bolosky, D. Golub, R. Rashid, A. Tevanian, M. Young, "Go: A New Kernel Foundation for UNIX Development," in Proceedings of the Summer 1986 USENIX Conference, Atlanta, GA.
  5. ↑ Preface from R. Morin (Editor): MkLinux - Microkernel Linux for the Power Macintosh, Reference Manual for DR2.1, Sunnyvale, CA 1997
  6. ^ F. Barbou des Places, N. Stephen, FD Reynolds: Linux on the OSF Mach3 microkernel 1995, reprinted in R. Morin (Editor): MkLinux - Microkernel Linux for the Power Macintosh, Reference Guide for DR2.1, Sunnyvale, CA 1997