Editing Hobbyist operating system

{{short description|Operating system made by computer hobbyists}}
The development of a '''hobbyist operating system''' is one of the more involved and technical options for a computer hobbyist. The definition of a hobby [[operating system]] can sometimes be vague. It can be from the developer's view, where the developers do it just for fun or learning; it can also be seen from the user's view, where the users are only using it as a novelty; or it can be defined as an operating system which doesn't have a very big user base.<ref>
{{cite web
|url=https://www.osnews.com/story/22638/my-os-is-less-hobby-than-yours/
|work=OSnews
|title=Discussion of "My OS is less hobby than yours"
|date=December 5, 2012
|access-date=June 4, 2024}}
</ref><ref>{{cite web
|url=https://wiki.osdev.org/Introduction#Why_develop_an_OS.3F
|work=OSDev Wiki
|title=Why develop an OS?
}}</ref>

[[software developer|Development]] can begin from existing resources like a [[Kernel (operating system)|kernel]], an [[operating system]], or a [[bootloader]], or it can also be made completely from scratch. The development platform could be a [[Bare machine|bare hardware machine]], which is the nature of an operating system, but it could also be developed and tested on a virtual machine. Since the hobbyist must claim more ownership for adapting a complex system to the ever-changing needs of the technical terrain, much enthusiasm is common amongst the  different groups attracted to operating system development.

==Development==
Elements of operating system development include:

* [[Kernel (operating system)|Kernel]]:
** [[Bootstrapping (computing)|Bootstrapping]]
** [[Memory management]]
** [[Process management (computing)|Process management]] and [[Scheduling (computing)|scheduling]]
** [[Device driver]] management
** [[Application programming interface|Program API]]
* [[Computer program|External programs]]
* [[User interface]]

The [[C (programming language)|C programming language]] is frequently used for hobby operating system programming, as well as [[assembly language]], though other languages, such as [[C++]] can be used as well. For instance, [[SerenityOS]] is a notable hobby operating system written primarily in C++.

The use of assembly language is common with small systems, especially those based on eight bit microprocessors such as the [[MOS Technology 65xx|MOS Technology 6502 family]] or the [[Zilog Z80]], or in systems with a lack of available resources because of its small output size and low-level efficiency.<ref>[http://mathscitech.org/articles/assembly-value Uses of assembly language]</ref>

==User interface==
Most hobby operating systems use a [[command-line interface]] or a simple [[text user interface]] due to ease of development. More advanced hobby operating systems may have a [[graphical user interface]]. For example, [[AtheOS]] was a hobby operating system with a graphical interface written entirely by one programmer.

===Examples===
<gallery>
File:Icaros131.jpg|[[AROS Research Operating System|AROS]]
File:DexOS GUI.PNG|DexOS
File:EmuTOS 1.0.png|[[EmuTOS]]
File:GeckOS 20.png|[[GeckOS]]
File:Ghost screenshot 0.12.0.png|Ghost
File:Helenos-0.11.1-gui.png|[[HelenOS]]
File:KolibriOS nightly build desktop.png|[[KolibriOS]]
File:LUnix.png|LUnix
File:Menuet.png|[[MenuetOS]]
File:Phantom screen 17.10.2019.png|[[Phantom OS]]
File:Redox running Orbital.png|[[Redox (operating system)|Redox]]
File:SerenityOS 2023-07-14.png|[[SerenityOS]]
File:Syllable-0.6.5-pl.png|[[Syllable Desktop]]
File:Symbos-cpc.png|[[SymbOS]]
File:VirtualBox TempleOS x64 27 02 2021 20 43 48.png|[[TempleOS]]
File:SkyOS.jpg|[[SkyOS]]
</gallery>

==Use of BIOS==
{{Main article|BIOS interrupt call}}

This section is predominantly [[x86]] oriented.

The term [[BIOS]] (Basic Input/Output System) refers to [[firmware]] that initialises computer hardware and has provisions to load an [[operating system]].<ref>{{Cite web |url=http://www.bioscentral.com/misc/biosbasics.htm |title=About BIOS |access-date=2012-11-28 |archive-date=2023-03-04 |archive-url=https://web.archive.org/web/20230304180601/http://www.bioscentral.com/misc/biosbasics.htm |url-status=dead }}</ref> The BIOS also sets up a standard interface for several low-level device drivers at boot time. BIOS resources are often used by hobbyist operating systems, especially those written on 16-bit x86 machines, as many hobby operating systems developers lack the time to write complex low level drivers themselves or they simply want to get into writing software for the system as soon as possible.

The most commonly used BIOS functions are [[INT 10h|VideoBIOS]] and [[INT 13h|Disk services]]. These are used because video cards and disk drives vary significantly on different machines and specialised drivers are often difficult to write.

The use of the BIOS is uncommon in operating systems that operate in [[Protected mode]] or [[Long mode]], because the system must switch back to [[real mode]] which BIOS drivers run in.<ref>[http://wiki.osdev.org/BIOS#BIOS_in_Protected_Mode OSDev - Use of BIOS in protected or long mode]</ref>

==See also==
* [[List of hobbyist operating systems]]
* [[Computer architecture]]

==References==
{{Reflist}}

==External links==
* [http://www.osdev.org OSDev.org] - A hobby OSDev community
* [https://osdev.wiki osdev.wiki] - New operating system wiki and community
* [http://www.independent-software.com/writing-your-own-toy-operating-system Independent Software] - Set of tutorials on boot loader development and entering protected mode
* [https://littleosbook.github.io/ The little book about OS development] - This book is a practical guide to writing your own x86 operating system
* [http://arjunsreedharan.org/post/82710718100/kernel-101-lets-write-a-kernel Kernel 101 – Let’s write a Kernel]
* [http://aodfaq.wikidot.com aodfaq] - OS development FAQ
* [http://www.osdever.net/tutorials/ Bona Fide OS Development] - OS development tutorials and other documents
* [http://www.brokenthorn.com/Resources/OSDevIndex.html A step by step tutorial]
* [https://web.archive.org/web/20010505042451/http://www.nondot.org/sabre/os/articles Operating System Resource Center] - Information and resources on various OSDev topics (both software and hardware)

{{Hobbyist operating systems}}
{{Operating systems}}

[[Category:Hobbyist operating systems| ]]
[[Category:Operating system technology]]