|This article needs additional citations for verification. (October 2011)|
Guru Meditation is an error notice displayed by early versions of the Commodore Amiga computer when they crashed. It is analogous to the "Blue Screen of Death" in Microsoft Windows operating systems, or a kernel panic in Unix. It has later been used as a message for unrecoverable errors elsewhere, such as Varnish, a reverse proxy, and HTTP accelerator, and VirtualBox, a Hypervisor environment.
When a Guru Meditation is displayed, the options are to reboot by pressing the left mouse button, or to invoke ROMWack by pressing the right mouse button. (ROMWack is a minimalist debugger built into the operating system which is accessible by connecting a 9600 bit/s terminal to the serial port.)
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 goes black, and the power and disk-activity LEDs may blink immediately before the alert appears. In AmigaOS 1.x, programmed in ROMs known as 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 red in all OS versions.
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 error is displayed as two fields, separated by a period. The format is #0000000x.yyyyyyyy in case of a CPU error, or #aabbcccc.dddddddd in case of a system software error. The first field is either the 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 48454C50, which stands for "HELP" in hexadecimal ASCII characters (48=H, 45=E, 4C=L, 50=P).
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.
Guru Meditation handler
There was a commercially available error handler for AmigaOS, before version 2.04, called GOMF (Get Outa 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 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.
Many experts[who?] nevertheless recommend 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 .
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.
|Area of system||Value||Specific part of system|
|08||RAM Handler library|
The term "Guru Meditation Error" originated as an in-house joke in Amiga's early days. The company had a product called the Joyboard, a game controller much like a joystick but operated by one's feet, similar to the modern-day 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 crashes that, as a relaxation technique, a game developed where a person would sit cross-legged on the joyboard, resembling an Indian guru. The player tried to remain extremely still; the winner of the game stayed still the longest. If the player moved too much, a "guru meditation" error occurred. The final unlockable balance activity in Wii Fit represents a similar game. The same game is unlocked from the start in Wii Fit Plus.
- "Varnish Troubleshooting: Varnish gives me Guru meditation". Retrieved 2011-12-18.
- "What is guru meditation? (VirtualBox forum)". Retrieved 2012-11-11.
- "How We Created the Amiga Computer by RJ Mical, Info Magazine issue 13".
- Bogost, Ian. "Guru Meditation". Retrieved 2007-07-21.