Editing Guru Meditation

{{Short description|Error notice displayed by the Amiga computer}}
{{for|the practice|meditation}}
{{more citations needed|date=January 2020}}
'''Guru Meditation''' is an error notice originally displayed by the [[Amiga]] computer when it [[crash (computing)|crashes]]. It is now also used by [[Varnish (software)|Varnish]],<ref name="varnish">{{cite web|url=https://varnish-cache.org/docs/trunk/users-guide/troubleshooting.html#varnish-gives-me-guru-meditation|title=Varnish Troubleshooting: Varnish gives me Guru meditation|access-date=2011-12-18}}</ref> a software component used by many content-heavy websites. This has led to many internet users seeing a "Guru Meditation" message (or the variant "Guru Mediation")<ref>{{cite web |title=Glossary of Terms: Guru mediation |url=https://developer.fastly.com/reference/glossary/#term-guru-mediation |website=Fastly Developer Hub |access-date=6 January 2023}}</ref> when these websites suffer crashes or other issues. It is analogous to the "[[Blue Screen of Death]]" in [[Microsoft Windows]] [[operating system]]s, or a [[kernel panic]] in [[Unix-like|Unix]].  

It has also been used as a message for unrecoverable errors in software packages such as [[VirtualBox]]<ref name="VirtualBox">{{cite web|url=https://forums.virtualbox.org/viewtopic.php?f=6&t=9373|title=What is guru meditation? (VirtualBox forum)|access-date=2012-11-11}}</ref> and other operating systems (see Legacy section below).

==Origins==
The term "Guru Meditation Error" originated as an in-house joke in Amiga's early days. The company had a product called the ''[[Joyboard]]'' for the [[Atari 2600]] [[home video game console]], a game controller much like a [[joystick]] but operated by the feet, similar to the [[Wii Balance Board]]. Early in the development of the Amiga computer operating system, the company's developers became so frustrated with the system's frequent [[crash (computing)|crashes]] that, as a relaxation technique, a game was developed where a person would sit cross-legged on the Joyboard, resembling an Indian [[guru]].<ref>{{Cite magazine |last=Mical |first=Robert J. |date=January 1987 |title=How We Created the AMIGA Computer |url=https://archive.org/details/info-magazine-13 |archive-url= |archive-date= |magazine=[[Info Magazine]] |pages=45–46 |issue=13}}</ref> The player tried to remain extremely still; the winner was the player who stayed still the longest. If the player moved too much, a "guru meditation" error occurred.<ref name="meditation">
{{cite web|url=http://www.bogost.com/games/guru_meditation.shtml|title=Guru Meditation|first=Ian|last=Bogost|author-link=Ian Bogost|access-date=2007-07-21}}
</ref>

==Description of "Guru Meditation" errors on the Amiga==

The alert occurred when there was a fatal problem with the system. If the system had no means of recovery, it could display the alert, even in systems with numerous critical flaws. In extreme cases, the alert could even be displayed if the system's memory was completely exhausted.

The text of the alert messages was completely baffling to most users. Only highly technically adept Amiga users would know, for example, that exception 3 was an address error, and meant the program was accessing a word on an unaligned boundary. Users without this specialized knowledge would have no recourse but to look for a "Guru" or to simply reboot the machine and hope for the best.

==Technical description (Amiga)== 

When a Guru Meditation is displayed, the options are to [[booting|reboot]] by pressing the left mouse button, or to invoke ROMWack by pressing the right mouse button or to manually reboot. ROMWack is a minimalist [[debugger]] built into the [[operating system]] which is accessible by connecting a 9600 [[bit]]/s terminal to the [[serial port]].

{{multiple image
 | align = right
 | direction = vertical
 | width = 400
 | image1 = Amiga Guru Meditation.gif
 | alt1 = Simulation of the Guru Meditation error message
 | caption1 = Simulation of the Guru Meditation error message
 | image2 = Amiga Recoverable Alert.gif
 | alt2 = Simulation of the Recoverable Alert message
 | caption2 = Simulation of the Recoverable Alert message
}}

The alert itself appears as a black rectangular box located in the upper portion of the screen. Its border and text are red for a normal Guru Meditation, or green/yellow for a Recoverable Alert, another kind of Guru Meditation. The screen may go black, but the power [[LED]]s always alternates between full and half-brightness for a few seconds before the alert appears. In [[AmigaOS]] 1.x, programmed in [[Read-only memory|ROMs]] known as [[Kickstart (Amiga)|Kickstart]] 1.1, 1.2 and 1.3, the errors are always red. In AmigaOS 2.x and 3.x, recoverable alerts are yellow, except for some very early versions of 2.x where they were green.

Dead-end alerts are always red and terminal in all OS versions except in a rare series of events, as in when a deprecated Kickstart (example: 1.1) program conditionally boots from disk on a more advanced Kickstart 3.x ROM Amiga running in compatibility mode (therefore eschewing the on-disk OS) and crashes with a red Guru Meditation but subsequently restores itself by pressing the left mouse button, the newer Kickstart recognizing an inadvised low level chipset call for the older ROM directly poking the hardware, and addressing it.

The error is displayed as two [[field (computer science)|fields]], separated by a period. The format is <code>#0000000x.yyyyyyyy</code> in case of a CPU error, or <code>#aabbcccc.dddddddd</code> in case of a system software error. The first field is either the [[Motorola 68000#Interrupts|Motorola 68000 exception]] number that occurred (if a CPU error occurs) or an internal error identifier (such as an "Out of Memory" code), in case of a system software error. The second can be the address of a ''Task'' structure, or the address of a memory block whose allocation or deallocation failed. It is never the address of the code that caused the error. If the cause of the crash is uncertain, this number is rendered as <code>48454C50</code>, which stands for "HELP" in hexadecimal [[ASCII]] characters (48=H, 45=E, 4C=L, 50=P).

===Guru Meditation handler===
There was a commercially available error handler for AmigaOS, before version 2.04, called GOMF (Get Outta My Face) made by Hypertek/Silicon Springs Development corp. It was able to deal with many kinds of errors and gave the user a choice to either remove the offending process and associated screen, or allow the machine to show the Guru Meditation. In many cases, removal of the offending process gave one the choice to save one's data and exit running programs before rebooting the system. When the damage was not extensive, one was able to continue using the machine. However, it did not save the user from all errors, as one may have still seen this error occasionally.

===Recoverable Alerts===
Recoverable Alerts are non-critical crashes in the computer system. In most cases, it is possible to resume work and save files after a Recoverable Alert, while a normal, red Guru Meditation always results in an immediate reboot.

It is, however, still recommended to reboot as soon as possible after encountering a Recoverable Alert, because the system may be in an unpredictable state that can cause data corruption.{{citation needed|date=November 2011}}

===System software error codes===
The first byte specifies the area of the system affected. The top bit will be set if the error is a dead end alert.{{citation needed|date=October 2011}}

{| class="wikitable"
|-
! Area of system !! Value !! Specific part of system
|-
! rowspan="9" | [[Library (computing)|Libraries]]
| 01 || Exec library
|-
| 02 || Graphics library
|-
| 03 || Layers library
|-
| 04 || [[Intuition (Amiga)|Intuition]] library
|-
| 05 || Math library
|-
| 06 || CList library
|-
| 07 || [[AmigaDOS]] library
|-
| 08 || RAM Handler library
|-
| 09 || [[Icon (computing)|Icons]] library
|-
! rowspan="6" | [[Device driver|Devices]]
| 10 || Audio device
|-
| 11 || Console device
|-
| 12 || Gameport device
|-
| 13 || Keyboard device
|-
| 14 || Trackdisk device
|-
| 15 || Timer device
|-
! rowspan="3" | [[Resource (computer science)|Resources]]
| 20 || [[Complex Interface Adaptor|CIA]] resource
|-
| 21 || Disk resource
|-
| 22 || Misc resource
|-
! rowspan="3" | Other areas
| 30 || [[Booting|Bootstrap]]
|-
| 31 || [[Workbench (AmigaOS)|Workbench]]
|-
| 32 || Diskcopy
|}

==Legacy==
[[File:DS Guru Meditation Error.jpg|thumb|Guru Meditation on a 3DS playing a Homebrew DS game.]]
* [[AmigaOS]] versions 4.0 and onwards replaced "Guru Meditation" with "Grim Reaper", but briefly mentions the Guru Meditation number in the prompt box.
* [[MorphOS]] displays an "Application Is ''Meditating''" error message. Attempting to close the application may revive the operating system, but restarting is still recommended.
* [[Varnish (software)|Varnish]] references Guru Meditation for severe errors.<ref name="varnish" />
* The [[ESP8266]] and [[ESP32]] microcontrollers will display "Guru Meditation Error: Core X panic'ed" (where X is 0 or 1 depending on which core crashed) along with a [[core dump]] and [[stack trace]].<ref>{{cite web
 | url = https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/fatal-errors.html?highlight=reboot#guru-meditation-errors
 | title = Fatal Errors — ESP-IDF Programming Guide v4.1-dev-279-g96b96ae24 documentation
 | access-date = 2019-09-24
 | quote = This section explains the meaning of different error causes, printed in parens after ''Guru Meditation Error: Core panic'ed''  message.
}}</ref>
* [[VirtualBox]] uses the term "Guru Meditation" for severe errors in the virtual machine monitor, for example caused by a [[triple fault]] in the virtual machine.
* [[Enlightenment (software)|E23]] displays a "Guru Meditation" and restarts when severe errors occur.<ref>{{Cite web|title=Guru Meditation|url=https://forum.elivelinux.org/t/guru-meditation/2116/4|date=2020-04-21|website=Elive Forums|language=en-US|access-date=2020-05-04}}{{Dead link|date=June 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
* Some [[Nintendo DS]] homebrew titles display a "Guru Meditation" error when an issue occurs, likely when the title crashes.
* [https://openmediavault.org/ OpenMediaVault] has Guru Meditation like errors (such as with session timeouts) as well as emulating the Amiga's pointer and wait pointer (when executing a task) in the web interface.

==See also==
*[[Screen of death]]
==References==
{{reflist}}

{{error messages}}
{{AmigaOS}}
{{AmigaOS 4}}

[[Category:AmigaOS]]
[[Category:Amiga]]
[[Category:Screens of death]]
[[Category:Computer errors]]