Editing Amoeba (operating system)

{{Short description|Distributed operating system}}
{{Infobox OS
| name                   = Amoeba
| logo                   = 
| screenshot             = 
| caption                = 
| developer              = [[Andrew S. Tanenbaum]]<br />[[Frans Kaashoek]]
| source model           = 
| kernel type            = [[Microkernel]]
| supported_platforms    = [[Intel 80386|i386]]/[[Intel 80486|i486]], [[MIPS architecture|MIPS]], [[Motorola 68030]], [[NS320xx|NS 32016]], [[Sun 3]]/50 and 3/60, [[SPARC]], [[VAX]]
| ui                     = 
| family                 = [[Unix-like]]
| released               =
| latest release version = 5.3
| latest release date    = {{Start date and age|df=yes|1996|07|30}}<ref name='ftp'>{{Cite FTP |url=ftp://ftp.cs.vu.nl/pub/amoeba/amoeba5.3/ |server=cs.vu.nl |url-status=dead |title=Amoeba FTP}}</ref>
| latest test version    = 
| latest test date       = 
| marketing target       = 
| programmed in          = 
| prog language          = [[C (programming language)|C]], [[Modula 2]], [[Orca (programming language)|Orca]], [[Pascal (programming language)|Pascal]]<ref name="statusreport"/>
| language               = [[English language|English]]
| updatemodel            =
| package manager        =
| working state          = 
| license                = [[MIT License]]<ref>{{cite web|url=https://www.cs.vu.nl/pub/amoeba/amoeba5.3/LICENCE|website=cs.vu.nl|access-date=19 July 2023|title=Licence}}</ref>
| website                = {{URL|http://www.cs.vu.nl/pub/amoeba/}}
}}
'''Amoeba''' is a [[distributed operating system]] developed by [[Andrew S. Tanenbaum]] and others at the [[Vrije Universiteit Amsterdam]]. The aim of the Amoeba project was to build a [[timesharing]] system that makes an entire network of computers appear to the user as a [[Single-system image|single machine]].  Development at the Vrije Universiteit was stopped: the source code of the latest version (5.3) was last modified on 30 July 1996.<ref name='ftp' />

The [[Python (programming language)|Python programming language]] was originally developed for this platform.<ref>{{cite web|url=https://www.python.org/doc/faq/general/#why-was-python-created-in-the-first-place |title=Why was Python created in the first place? |publisher=Python FAQ |access-date=2008-02-11 |archive-url=https://web.archive.org/web/20080223222507/http://www.python.org/doc/faq/general/ |archive-date=23 February 2008 |url-status=live }}</ref>

==Overview==
The goal of the Amoeba project was to construct an operating system for networks of computers that would present the network to the user as if it were a single machine. An Amoeba network consists of a number of [[workstation]]s connected to a "pool" of processors, and executing a program from a terminal causes it to run on any of the available processors, with the operating system providing [[load balancing (computing)|load balancing]].<ref name="statusreport"/> Unlike the contemporary [[Sprite (operating system)|Sprite]], Amoeba does not support [[process migration]].<ref>Fred Douglis, [[M. Frans Kaashoek]], Andrew S. Tanenbaum and [[John K. Ousterhout|John Ousterhout]] (1991). [http://pdos.csail.mit.edu/~kaashoek/papers/amsp.ps A comparison of two distributed systems: Amoeba and Sprite]. Computing Systems '''4'''(4), pp. 353–384.</ref>
The workstations would typically function as networked [[computer terminal|terminals]] only. Aside from workstations and processors, additional machines operate as [[server (computing)|server]]s for files, directory services, [[TCP/IP]] communications etc.<ref name="statusreport">[[Andrew S. Tanenbaum]], [[M. Frans Kaashoek]], Robbert van Renesse and Henri E. Bal (1991). [http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.35.6888 The Amoeba distributed operating system — a status report]. Computer Communications '''14'''.</ref>

Amoeba is a [[microkernel]]-based operating system. It offers [[multithreading (software)|multithreaded]] programs and a [[remote procedure call]] (RPC) mechanism for communication between threads, potentially across the network; even kernel-threads use this RPC mechanism for communication. Each thread is assigned a 48-bit number called its "port", which serves as its unique, network-wide "address" for communication.<ref name="statusreport"/>

The user interface and [[Application programming interface|APIs]] of Amoeba were modeled after [[Unix]] and compliance with the [[POSIX]] standard was partially implemented; some of the Unix emulation code consists of utilities ported over from Tanenbaum's other operating system, [[MINIX]]. Early versions used a "homebrew" window system, which the Amoeba authors considered "faster ... in our view, cleaner ... smaller and much easier to understand", but version 4.0 uses the [[X Window System]] (and allows [[X terminal]]s as terminals).<ref name="statusreport"/>
The system uses [[Fast Local Internet Protocol|FLIP]] as a network protocol.

==See also==
* [[Distributed computing]]
* [[Multikernel]]
* [[Plan 9 from Bell Labs]]

==References==
{{Reflist}}

==External links==
* [http://www.cs.vu.nl/pub/amoeba/ Amoeba home page (static page, ftp links are dead)]
* [http://fsd-amoeba.sourceforge.net FSD-Amoeba page at Sourceforge (file downloads give 403 errors)]
* [https://archiveos.org/amoeba/ ArchiveOS mirror of Amoeba 5.3]

{{Distributed operating systems}}
{{Microkernel}}

[[Category:Microkernel-based operating systems]]
[[Category:Distributed computing architecture]]
[[Category:Distributed operating systems]]
[[Category:Computer science in the Netherlands]]
[[Category:Information technology in the Netherlands]]
[[Category:Microkernels]]
[[Category:X86 operating systems]]
[[Category:MIPS operating systems]]