Minix
Encyclopedia
MINIX is a Unix-like
computer operating system
based on a microkernel
architecture
created by Andrew S. Tanenbaum
for educational purposes; MINIX also inspired the creation of the Linux kernel
.
MINIX (from "mini-Unix") was first released in 1987, with its complete source code made available to universities for study in courses and research. It has been free and open source software
since it was re-licensed under the BSD license in April 2000.
created MINIX at Vrije Universiteit
in Amsterdam
to exemplify the principles conveyed in his textbook
, Operating Systems: Design and Implementation
(1987).
An abridged 12,000 lines of the C
source code
of the kernel
, memory manager
, and file system
of MINIX 1.0 are printed in the book. Prentice-Hall also released MINIX source code and binaries on floppy disk
with a reference manual. MINIX 1 was system-call compatible with Seventh Edition Unix.
Tanenbaum originally developed MINIX for compatibility with the IBM PC
and IBM PC/AT microcomputer
s available at the time.
IBM PS/2 systems and was also ported
to the Motorola 68000
and SPARC
architectures, supporting the Atari ST
, Commodore Amiga, Apple Macintosh and Sun
SPARCstation
computer platforms
. There were also unofficial ports to Intel 386 PC compatibles (in 32-bit
protected mode
), National Semiconductor
NS32532
, ARM and INMOS
transputer processors. Meiko Scientific
used an early version of MINIX as the basis for the MeikOS operating system for its transputer-based Computing Surface parallel computers. A version of MINIX running as a user process under SunOS
and Solaris was also available, a simulator called SMX.
included with the book. MINIX 2.0 added POSIX
.1 compliance, support for 386 and later processors in 32-bit mode and replaced the Amoeba
network protocols included in MINIX 1.5 with a TCP/IP stack. Unofficial ports of MINIX 2.0.2 to the 68020-based ISICAD Prisma 700 workstation and the Hitachi SH3
-based HP Jornada 680/690 PDA
were also developed.
is a variant of MINIX 2 for Intel IA-32
-compatible processors, created by two Vrije Universiteit researchers, which adds virtual memory
and support for the X Window System
.
Symposium Operating Systems Principles conference. Although it still serves as an example for the new edition of Tanenbaum and Woodhull's textbook, it is comprehensively redesigned to be "usable as a serious system on resource-limited and embedded computers and for applications requiring high reliability."
MINIX 3 currently supports only IA-32
architecture PC compatible systems. It is available in a Live CD
format that allows it to be used on a computer without installing it on the hard drive, and in versions compatible with hardware emulation/virtualization systems, including Bochs
, Qemu
, VMware Workstation
/Fusion
, VirtualBox
and Microsoft Virtual PC
.
Version 3.1.5 was released 5 November 2009. It contains X11, emacs
, vi
, cc, gcc
, perl
, python
, ash, bash, zsh, ftp, ssh
, telnet
, pine
, and over 400 other common Unix
utility programs. With the addition of X11, this version marks the transition away from a text-only system. It can also withstand driver crashes. In many cases it can automatically replace drivers without affecting running processes. This feature will be improved in future releases. In this way, MINIX is self-healing and can be used in applications demanding high reliability. MINIX 3 also has support for virtual memory
management, making it suitable for desktop OS use. Desktop applications such as Firefox and OpenOffice.org
are not yet available for MINIX 3 however.
With the creation of MINIX 3, and its transition to a graphical interface, some commercial software and hardware developers have started to implement some systems with MINIX in the late 2000s.
applied in the creation of the Linux kernel
. Torvalds used and appreciated MINIX, however, his design deviated from the MINIX architecture in significant ways, most notably by employing a monolithic kernel
instead of a microkernel
. This was famously disapproved of by Tanenbaum in the Tanenbaum–Torvalds debate. Tanenbaum explained again his rationale for using a microkernel in May 2006.
Early Linux kernel development was done on a MINIX host system, which led to Linux inheriting various features from MINIX, such as the MINIX file system
.
In May 2004, Kenneth Brown
of the Alexis de Tocqueville Institution
made the accusation that major parts of the Linux kernel had been copied from the MINIX codebase, in a book called Samizdat
. These accusations were rebutted universally—most prominently by Andrew Tanenbaum himself, who strongly criticised Kenneth Brown and published a long rebuttal on his own personal website.
s, his publisher was not prepared to offer material (such as the source code) that could be copied freely, so a restrictive license requiring a nominal fee (included in the price of Tanenbaum's book) was applied as a compromise. This prevented the use of MINIX as the basis for a freely distributed software system.
When free and open source
Unix-like operating systems such as Linux
and 386BSD
became available in the early 1990s many volunteer software developer
s abandoned MINIX in favor of these. In April 2000, MINIX became free/open source software under a permissive free software license, but by this time other operating systems had surpassed its capabilities, and it remained primarily an operating system for students and hobbyists.
Unix-like
A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....
computer operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
based on a microkernel
Microkernel
In computer science, a microkernel is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system . These mechanisms include low-level address space management, thread management, and inter-process communication...
architecture
Software architecture
The software architecture of a system is the set of structures needed to reason about the system, which comprise software elements, relations among them, and properties of both...
created by Andrew S. Tanenbaum
Andrew S. Tanenbaum
Andrew Stuart "Andy" Tanenbaum is a professor of computer science at the Vrije Universiteit, Amsterdam in the Netherlands. He is best known as the author of MINIX, a free Unix-like operating system for teaching purposes, and for his computer science textbooks, regarded as standard texts in the...
for educational purposes; MINIX also inspired the creation of the Linux kernel
Linux kernel
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....
.
MINIX (from "mini-Unix") was first released in 1987, with its complete source code made available to universities for study in courses and research. It has been free and open source software
Free and open source software
Free and open-source software or free/libre/open-source software is software that is liberally licensed to grant users the right to use, study, change, and improve its design through the availability of its source code...
since it was re-licensed under the BSD license in April 2000.
MINIX 1.0
Andrew S. TanenbaumAndrew S. Tanenbaum
Andrew Stuart "Andy" Tanenbaum is a professor of computer science at the Vrije Universiteit, Amsterdam in the Netherlands. He is best known as the author of MINIX, a free Unix-like operating system for teaching purposes, and for his computer science textbooks, regarded as standard texts in the...
created MINIX at Vrije Universiteit
Vrije Universiteit
The Vrije Universiteit is a university in Amsterdam, Netherlands. The Dutch name is often abbreviated as VU and in English the university uses the name "VU University". The university is located on a compact urban campus in the southern part of Amsterdam in the Buitenveldert district...
in Amsterdam
Amsterdam
Amsterdam is the largest city and the capital of the Netherlands. The current position of Amsterdam as capital city of the Kingdom of the Netherlands is governed by the constitution of August 24, 1815 and its successors. Amsterdam has a population of 783,364 within city limits, an urban population...
to exemplify the principles conveyed in his textbook
Textbook
A textbook or coursebook is a manual of instruction in any branch of study. Textbooks are produced according to the demands of educational institutions...
, Operating Systems: Design and Implementation
Operating Systems: Design and Implementation
Operating Systems: Design and Implementation ISBN 0-13-142938-8 ISBN 978-0136373315 is a Computer Science textbook written by Andrew S. Tanenbaum, with help from Albert S. Woodhull. It includes Tanenbaum's MINIX, a free Unix-like operating system designed for teaching purposes. Publisher is...
(1987).
An abridged 12,000 lines of the C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
source code
Source code
In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...
of the kernel
Kernel (computing)
In computing, the kernel is the main component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level. The kernel's responsibilities include managing the system's resources...
, memory manager
Memory manager
In IBM PC compatible computing, DOS memory management refers to software and techniques employed to give applications access to more than 640K of "conventional memory". The 640kB limit was specific to the IBM PC and close compatibles; other machines running MS-DOS had different limits, for example...
, and file system
File system
A file system is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device which contain it. A file system organizes data in an efficient manner and is tuned to the...
of MINIX 1.0 are printed in the book. Prentice-Hall also released MINIX source code and binaries on floppy disk
Floppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
with a reference manual. MINIX 1 was system-call compatible with Seventh Edition Unix.
Tanenbaum originally developed MINIX for compatibility with the IBM PC
IBM PC
The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...
and IBM PC/AT microcomputer
Microcomputer
A microcomputer is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers...
s available at the time.
MINIX 1.5
MINIX 1.5, released in 1991, included support for MicroChannelMicrochannel
Microchannel can refer to* Basic structure used in microtechnology, see Microchannel .* Micro Channel architecture in computing...
IBM PS/2 systems and was also ported
Porting
In computer science, porting is the process of adapting software so that an executable program can be created for a computing environment that is different from the one for which it was originally designed...
to the Motorola 68000
Motorola 68000
The Motorola 68000 is a 16/32-bit CISC microprocessor core designed and marketed by Freescale Semiconductor...
and SPARC
SPARC
SPARC is a RISC instruction set architecture developed by Sun Microsystems and introduced in mid-1987....
architectures, supporting the Atari ST
Atari ST
The Atari ST is a home/personal computer that was released by Atari Corporation in 1985 and commercially available from that summer into the early 1990s. The "ST" officially stands for "Sixteen/Thirty-two", which referred to the Motorola 68000's 16-bit external bus and 32-bit internals...
, Commodore Amiga, Apple Macintosh and Sun
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
SPARCstation
SPARCstation
The SPARCstation, SPARCserver and SPARCcenter product lines were a series of SPARC-based computer workstations and servers in desktop, deskside and rack-based form factor developed and sold by Sun Microsystems...
computer platforms
Platform (computing)
A computing platform includes some sort of hardware architecture and a software framework , where the combination allows software, particularly application software, to run...
. There were also unofficial ports to Intel 386 PC compatibles (in 32-bit
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....
protected mode
Protected mode
In computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units...
), National Semiconductor
National Semiconductor
National Semiconductor was an American semiconductor manufacturer, that specialized in analog devices and subsystems,formerly headquartered in Santa Clara, California, USA. The products of National Semiconductor included power management circuits, display drivers, audio and operational amplifiers,...
NS32532
NS320xx
The 320xx or NS32000 was a series of microprocessors from National Semiconductor . They were likely the first 32-bit general-purpose microprocessors on the market, but due to a number of factors never managed to become a major player...
, ARM and INMOS
INMOS
Inmos Limited was a British semiconductor company, founded by Iann Barron, with both the head office and the design office at Aztec West in Bristol, it was incorporated in November 1978.- Products :...
transputer processors. Meiko Scientific
Meiko Scientific
Meiko Scientific Ltd. was a British supercomputer company based in Bristol, founded by members of the design team working on the INMOS transputer microprocessor.-History:...
used an early version of MINIX as the basis for the MeikOS operating system for its transputer-based Computing Surface parallel computers. A version of MINIX running as a user process under SunOS
SunOS
SunOS is a version of the Unix operating system developed by Sun Microsystems for their workstation and server computer systems. The SunOS name is usually only used to refer to versions 1.0 to 4.1.4 of SunOS...
and Solaris was also available, a simulator called SMX.
MINIX 2.0
Demand for the 68k-based architectures waned, however, and MINIX 2.0, released in 1997, was only available for the x86 and Solaris-hosted SPARC architectures. It was the subject of the second edition of Tanenbaum's textbook, co-written with Albert Woodhull and was distributed on a CD-ROMCD-ROM
A CD-ROM is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer for data storage and music playback. The 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data....
included with the book. MINIX 2.0 added POSIX
POSIX
POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...
.1 compliance, support for 386 and later processors in 32-bit mode and replaced the Amoeba
Amoeba distributed operating system
Amoeba is an open source microkernel-based distributed operating system developed by Andrew S. Tanenbaum and others at the Vrije Universiteit. The aim of the Amoeba project is to build a timesharing system that makes an entire network of computers appear to the user as a single machine...
network protocols included in MINIX 1.5 with a TCP/IP stack. Unofficial ports of MINIX 2.0.2 to the 68020-based ISICAD Prisma 700 workstation and the Hitachi SH3
SuperH
SuperH is a 32-bit reduced instruction set computer instruction set architecture developed by Hitachi. It is implemented by microcontrollers and microprocessors for embedded systems....
-based HP Jornada 680/690 PDA
Personal digital assistant
A personal digital assistant , also known as a palmtop computer, or personal data assistant, is a mobile device that functions as a personal information manager. Current PDAs often have the ability to connect to the Internet...
were also developed.
Minix-vmd
Minix-vmdMinix-vmd
Minix-vmd is a free software operating system which was created from Minix, and added some additional features such as virtual memory and X Window System support.Minix-vmd = Minix + virtual memory + X11...
is a variant of MINIX 2 for Intel IA-32
IA-32
IA-32 , also known as x86-32, i386 or x86, is the CISC instruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture...
-compatible processors, created by two Vrije Universiteit researchers, which adds virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
and support for the X Window System
X Window System
The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...
.
MINIX 3
MINIX 3 was publicly announced on 24 October 2005 by Andrew Tanenbaum during his keynote speech on top of the ACMAssociation for Computing Machinery
The Association for Computing Machinery is a learned society for computing. It was founded in 1947 as the world's first scientific and educational computing society. Its membership is more than 92,000 as of 2009...
Symposium Operating Systems Principles conference. Although it still serves as an example for the new edition of Tanenbaum and Woodhull's textbook, it is comprehensively redesigned to be "usable as a serious system on resource-limited and embedded computers and for applications requiring high reliability."
MINIX 3 currently supports only IA-32
IA-32
IA-32 , also known as x86-32, i386 or x86, is the CISC instruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture...
architecture PC compatible systems. It is available in a Live CD
Live CD
A live CD, live DVD, or live disc is a CD or DVD containing a bootable computer operating system. Live CDs are unique in that they have the ability to run a complete, modern operating system on a computer lacking mutable secondary storage, such as a hard disk drive...
format that allows it to be used on a computer without installing it on the hard drive, and in versions compatible with hardware emulation/virtualization systems, including Bochs
Bochs
Bochs is a portable x86 and x86-64 IBM PC compatible emulator and debugger mostly written in C++ and distributed as free software under GNU Lesser General Public License...
, Qemu
QEMU
QEMU is a processor emulator that relies on dynamic binary translation to achieve a reasonable speed while being easy to port on new host CPU architectures....
, VMware Workstation
VMware Workstation
VMware Workstation is a virtual machine software suite for x86 and x86-64 computers from VMware, a division of EMC Corporation, which allows users to set up multiple x86 and x86-64 virtual machines and use one or more of these virtual machines simultaneously with the hosting operating system...
/Fusion
VMware Fusion
VMware Fusion is a virtual machine software product developed by VMware for Macintosh computers with Intel processors. Fusion allows Intel-based Macs to run x86 and x86-64 "guest" operating systems, such as Microsoft Windows, Linux, NetWare and Solaris as virtual machines simultaneously with Mac OS...
, VirtualBox
VirtualBox
Oracle VM VirtualBox is an x86 virtualization software package, originally created by software company Innotek GmbH, purchased by Sun Microsystems, and now developed by Oracle Corporation as part of its family of virtualization products...
and Microsoft Virtual PC
Microsoft Virtual PC
Windows Virtual PC is a virtualization program for Microsoft Windows. In July 2006 Microsoft released the Windows-hosted version as a free product...
.
Version 3.1.5 was released 5 November 2009. It contains X11, emacs
Emacs
Emacs is a class of text editors, usually characterized by their extensibility. GNU Emacs has over 1,000 commands. It also allows the user to combine these commands into macros to automate work.Development began in the mid-1970s and continues actively...
, vi
Vi
vi is a screen-oriented text editor originally created for the Unix operating system. The portable subset of the behavior of vi and programs based on it, and the ex editor language supported within these programs, is described by the Single Unix Specification and POSIX.The original code for vi...
, cc, gcc
GNU Compiler Collection
The GNU Compiler Collection is a compiler system produced by the GNU Project supporting various programming languages. GCC is a key component of the GNU toolchain...
, perl
Perl
Perl is a high-level, general-purpose, interpreted, dynamic programming language. Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions and become widely popular...
, python
Python (programming language)
Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...
, ash, bash, zsh, ftp, ssh
Secure Shell
Secure Shell is a network protocol for secure data communication, remote shell services or command execution and other secure network services between two networked computers that it connects via a secure channel over an insecure network: a server and a client...
, telnet
TELNET
Telnet is a network protocol used on the Internet or local area networks to provide a bidirectional interactive text-oriented communications facility using a virtual terminal connection...
, pine
Pine (e-mail client)
Pine is a freeware, text-based email client developed at the University of Washington. The first version of this client was written in 1989. Source code was available for only the Unix version under a license written by the University of Washington...
, and over 400 other common Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
utility programs. With the addition of X11, this version marks the transition away from a text-only system. It can also withstand driver crashes. In many cases it can automatically replace drivers without affecting running processes. This feature will be improved in future releases. In this way, MINIX is self-healing and can be used in applications demanding high reliability. MINIX 3 also has support for virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
management, making it suitable for desktop OS use. Desktop applications such as Firefox and OpenOffice.org
OpenOffice.org
OpenOffice.org, commonly known as OOo or OpenOffice, is an open-source application suite whose main components are for word processing, spreadsheets, presentations, graphics, and databases. OpenOffice is available for a number of different computer operating systems, is distributed as free software...
are not yet available for MINIX 3 however.
With the creation of MINIX 3, and its transition to a graphical interface, some commercial software and hardware developers have started to implement some systems with MINIX in the late 2000s.
MINIX and Linux
The design principles Tanenbaum applied to MINIX greatly influenced the design decisions Linus TorvaldsLinus Torvalds
Linus Benedict Torvalds is a Finnish software engineer and hacker, best known for having initiated the development of the open source Linux kernel. He later became the chief architect of the Linux kernel, and now acts as the project's coordinator...
applied in the creation of the Linux kernel
Linux kernel
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....
. Torvalds used and appreciated MINIX, however, his design deviated from the MINIX architecture in significant ways, most notably by employing a monolithic kernel
Monolithic kernel
A monolithic kernel is an operating system architecture where the entire operating system is working in the kernel space and alone as supervisor mode...
instead of a microkernel
Microkernel
In computer science, a microkernel is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system . These mechanisms include low-level address space management, thread management, and inter-process communication...
. This was famously disapproved of by Tanenbaum in the Tanenbaum–Torvalds debate. Tanenbaum explained again his rationale for using a microkernel in May 2006.
Early Linux kernel development was done on a MINIX host system, which led to Linux inheriting various features from MINIX, such as the MINIX file system
MINIX file system
-History:MINIX was written from scratch by Andrew S. Tanenbaum in the 1980s, as a Unix-like operating system whose source code could be used freely in education...
.
In May 2004, Kenneth Brown
Kenneth Brown (author)
Kenneth P. Brown, Jr. is an American lobbyist and author, and the former president of the Alexis de Tocqueville Institution , a think tank based in Arlington, Virginia....
of the Alexis de Tocqueville Institution
Alexis de Tocqueville Institution
The Alexis de Tocqueville Institution is a Washington, D.C.–based conservative think tank that produced reports and policy research....
made the accusation that major parts of the Linux kernel had been copied from the MINIX codebase, in a book called Samizdat
Samizdat (book)
Samizdat: And Other Issues Regarding the 'Source' of Open Source Code is a book by Kenneth Brown, which was prereleased in May 2004 and was to be published later that year by the Alexis de Tocqueville Institution...
. These accusations were rebutted universally—most prominently by Andrew Tanenbaum himself, who strongly criticised Kenneth Brown and published a long rebuttal on his own personal website.
Licensing
At the time of its original development, the license for MINIX was considered to be rather liberal. Its licensing fee was very small ($69) compared to those of other operating systems. Although Tanenbaum wished for MINIX to be as accessible as possible to studentStudent
A student is a learner, or someone who attends an educational institution. In some nations, the English term is reserved for those who attend university, while a schoolchild under the age of eighteen is called a pupil in English...
s, his publisher was not prepared to offer material (such as the source code) that could be copied freely, so a restrictive license requiring a nominal fee (included in the price of Tanenbaum's book) was applied as a compromise. This prevented the use of MINIX as the basis for a freely distributed software system.
When free and open source
Free and open source software
Free and open-source software or free/libre/open-source software is software that is liberally licensed to grant users the right to use, study, change, and improve its design through the availability of its source code...
Unix-like operating systems such as Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
and 386BSD
386BSD
386BSD, sometimes called "Jolix", was a free Unix-like operating system based on BSD, first released in 1992. It ran on PC compatible computer systems based on the Intel 80386 microprocessor...
became available in the early 1990s many volunteer software developer
Software developer
A software developer is a person concerned with facets of the software development process. Their work includes researching, designing, developing, and testing software. A software developer may take part in design, computer programming, or software project management...
s abandoned MINIX in favor of these. In April 2000, MINIX became free/open source software under a permissive free software license, but by this time other operating systems had surpassed its capabilities, and it remained primarily an operating system for students and hobbyists.