Editing Sinclair ZX81 emulators

{{Infobox console
|title = Sinclair ZX81
|logo = 1024px-Sinclair-ZX81.png
|developer = Sinclair Research
|type = [[:Category:Computers|Computers]]
|release = 1981
|discontinued = 1984
|predecessor = ZX80
|successor = [[ZX Spectrum line|ZX Spectrum]]
|emulated = {{✓}}
}}

The '''[[wikipedia:ZX81|ZX81]]''' was a Z80-based home computer produced by Sinclair Research and manufactured in Scotland by Timex Corporation released on March 5, 1981, and had a retail price of {{Inflation|USD|99.95| 1981}}. It had a Z80 at 3.25 MHz with 1KB of RAM.

It was the successor to Sinclair's ZX80 and the predecessor of the [[ZX Spectrum line|ZX Spectrum]] and was hugely successful, and more than 1.5 million units were sold before it was discontinued.
The ZX81 was designed to be small, simple, and above all cheap, using as few components as possible to keep the cost down.

Video output was to a television set rather than a dedicated monitor. Programs and data were loaded and saved onto audio tape cassettes. It had only four silicon chips on board and a mere 1 KB of memory. The machine had no power switch or any moving parts and used a pressure-sensitive membrane keyboard for manual input.

Its distinctive design brought its designer, Rick Dickinson, a Design Council award.
The ZX81 could be bought by mail order in kit form or pre-assembled. It was the first cheap mass-market home computer that could be bought from high street stores, led by W.H. Smith and soon many other retailers.

The ZX81 marked the first time that computing in Britain became an activity for the general public, rather than the preserve of businesspeople and electronics hobbyists. The ZX81's commercial success made Sinclair Research one of Britain's leading computer manufacturers and earned a fortune and an eventual knighthood for the company's founder, Sir Clive Sinclair.

==Emulators==
<div style="max-width:100%; overflow:auto;">
{| class="wikitable" style="text-align:center;"
! scope="col"|Name
! scope="col"|Platform(s)
! scope="col"|Latest Version
! scope="col"| [[libretro]]
! scope="col"|Relative Speed<ref group=N name=RelativeSpeed>As calculated by Carlo Delhez's clkfreq, originally distributed with his XTender emulator. The ZX81 has relatively complicated timing mechanics, depending on signalling of WAIT during NMI; relative speed is a measurement of how closely an emulator matches a real machine in terms of clock cycles spent processing within a frame. 100.0% denotes the same execution speed as a real machine.</ref>
! scope="col"|<abbr title="Free/Libre and Open-Source Software">FLOSS</abbr>
! scope="col"|Active
! scope="col"| [[Recommended emulators|Recommended]]
|-
! colspan="8"|PC / x86
|-
| [[Clock Signal|CLK]]
| align=left|{{Icon|Linux|macOS|FreeBSD}}
| [https://github.com/TomHarte/CLK/releases {{clkVer}}]
| {{✗}}
| 100.0%
| {{✓}}
| {{✓}}
| {{✓}}
|-
| [[ZEsarUX]]
| align=left|{{Icon|Windows|Linux|macOS|FreeBSD}}
| [https://github.com/chernandezba/zesarux/releases {{ZEsarUXVer}}]
| {{✗}}
| 110.9%
| {{✓}}
| {{✓}}
| {{✓}}
|-
|[[EightyOne]] (81)
| align=left|{{Icon|Windows}}
| [https://sourceforge.net/projects/eightyone-sinclair-emulator/files/ {{EightyOneVer}}]
| {{✓}}
| 100.0%
| {{✓}}
| {{✓}}
| {{✓}}
|-
| Spud81
| align=left|{{Icon|Windows}}
| [https://1drv.ms/u/s!Ar4VkKtk_3JzgQFkPzv4WgWTMHNc?e=trhIHh 0.221]
| {{✗}}
| 114.9%
| {{✗}}
| {{✗}}
| {{~}}
|-
| [https://sourceforge.net/projects/sz81/ SZ81] <br/><small>(xz80 & z81 based)</small>
| align=left|{{Icon|Windows|Linux|macOS|FreeBSD|AmigaOS}}
| [http://sz81.sourceforge.net/#downloads 2.1.7] <br/>[http://rullf2.xs4all.nl/sz81/ 2.3.10 (Unofficial)]
| {{✗}}
| 100.0%
| {{✓}}
| {{✗}}
| {{~}}
|-
| [[MAME]]
| align=left|{{Icon|Windows|Linux|macOS|FreeBSD}}
| [http://www.mamedev.org/release.html {{MAMEVer}}]
| {{✓}}
| Not tested
| {{✓}}
| {{✓}}
| {{✗}}
|-
| [http://zxplanet.emuunlim.com/mme-review.htm MTMW] <br/><small>(aka 'MulTiMachine')</small>
| align=left|{{Icon|Windows}}
| [https://www.zophar.net/sinclair/multi-machine.html 1.30b]
| {{✗}}
| Not tested
| {{✗}}
| {{✗}}
| {{✗}}
|-
| [[No$|No$ZX]]
| align=left|{{Icon|Windows|DOS}}
| [http://problemkaputt.de/zx.htm 2.0]
| {{✗}}
| 100.1% <br/><ref group=N name=NoCashSpeed>After turning off the simulated hardware improvements that were not standard in the original computer.</ref>
| {{✗}}
| {{✗}}
| {{✗}}
|-
| [http://zx81.vb81.free.fr VB81 XuR]
| align=left|{{Icon|Windows}}
| [http://zx81.vb81.free.fr/download/VB81_XuR_EXE.zip 13/08/2022]
| {{✗}}
| 100.5%
| {{✓}}
| {{✓}}
| {{✗}}
|-
| [http://freestuff.grok.co.uk/vb81/ VB81]
| align=left|{{Icon|Windows}}
| [http://zx81.vb81.free.fr/vb81/download/vb81-full.exe 1.30]
| {{✗}}
| Not tested
| {{✓}}
| {{✗}}
| {{✗}}
|-
| [http://zxplanet.emuunlim.com/xtender-review.htm XTender2]
| align=left|{{Icon|DOS}}
| [http://www.zx81.nl/ beta 13]
| {{✗}}
| Not tested
| {{✗}}
| {{✗}}
| {{✗}}
|-
| [http://www.retroisle.com/sinclair/zx81/emulators.php ZX81 Emulator] <br/><small>(Paul Robson)</small>
| align=left|{{Icon|DOS}}
| [http://www.zx81.nl/ 4.00]
| {{✗}}
| 101.5%
| {{✗}}
| {{✗}}
| {{✗}}
|-
! colspan="8"|Mobile / ARM
|-
| [https://sourceforge.net/projects/sz81/ SZ81] <br/><small>(xz80 & z81 based)</small>
| align=left|{{Icon|Zaurus|Dingoo|Wiz}}
| [http://sz81.sourceforge.net/#downloads 2.1.7]
| {{✗}}
| 100.0%
| {{✓}}
| {{✗}}
| {{✗}}
|-
| [https://zx81-ios.weebly.com ZX81 iOS]
| align=left|{{Icon|iOS}}
| [https://itunes.apple.com/us/app/zx81/id1180117434?mt=8 1.12.0]
| {{✗}}
| 100.0% <br/><ref group=N name=ZX81iOSSpeed>Provided by Kevin Palser the developer (and author of this note) because the app cannot load external programs, such as Carlo Delhez's clkfreq, due to Apple developer restrictions for iOS. Permission to include clkfreq in the app cannot be granted because Dr Delhez sadly passed away in 2015.</ref>
| ?
| {{✓}}
| {{~}} <br/><ref group=N name=ZX81iOSNeutered>This app is neutered as loading of external programs into emulator apps from the App Store is prohibited by Apple. However, it does have a growing selection of programs included with permission granted by their authors.</ref>
|-
! colspan="8"|Consoles
|-
| DS81
| align=left|{{icon|NDS}}
| [https://www.gamebrew.org/wiki/DS81 1.3]
| {{✗}}
| Not tested
| {{✓}}
| {{✗}}
| {{✓}}
|}
</div>

<references group=N />

==Notes==
* [http://www.retroisle.com/sinclair/zx81/emulators.php www.retroisle.com] (Page showing five old emulators for ZX81, and sometimes the Spectrum and other machines)
* [https://www.worldofspectrum.org/faq/emulators/other.htm www.worldofspectrum.org's list] (Short list of old Science of Cambridge MK-14, ZX80, ZX81 / TS1000, Sinclair QL and Jupiter ACE emulators)
* [http://zx81.eu5.org/emulators.htm zx81.eu5.org] (Brazilian ZX81 fan-site - emulators list page is in English. Shows list of old ZX81 emulators & links to other resources.)
* [http://floppydays.libsyn.com/floppy-days-86-the-sinclair-zx80-part-ii-with-earl-evans floppydays.libsyn.com] (Podcast episode describing the emulators available for the ZX80 / ZX81 which also uses the Carlo Delhez's clkfreq rating. Also has huge lists of resources for all things ZX80/81 related.)

[[Category:Computers]]
[[Category:ZX81 emulators|*]]
[[Category:Z80-based]]