Guru Meditation

Guru Meditation is the name of the error that occurred on early versions of the Commodore Amiga computer when they crashed. It is analogous to the "Blue Screen Of Death" in Microsoft Windows operating systems. Guru Meditation errors also occur on Nintendo DS Homebrew applications, and the Varnish http accelerator.

Description

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.)

A simulation of the Guru Meditation error 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 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.

This error is sometimes referred to colloquially as a "trip to India," or the "Unwelcome Visitor from the East", or just "alert".

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.

A Guru Meditation error is also known to occur in Winamp. The freeform skinning engine will generate a Guru meditation error when there is a problem with a MAKI script, which shows the same error box as the Commodore Amiga Guru meditation error, except the Winamp guru meditation error does not have a flashing red border, but a solid red border.

A Guru Meditation error also existed in DSOrganize, a homebrew application for Nintendo DS for organizer purposes. The Guru Meditation shown on the bottom touch screen, whereas the top LCD is left blank. Usually the error happens when playing an MP3 file on a disk which has file system errors. The file system errors can be removed by using chkdsk in Windows or fsck in Linux.

System software error codes

The first byte specifies the particular 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
Libraries	01	Exec library
	02	Graphics library
	03	Layers library
	04	Intuition library
	05	Math library
	06	CList library
	07	AmigaDOS library
	08	RAM Handler library
	09	Icons library
Devices	10	Audio device
	11	Console device
	12	Gameport device
	13	Keyboard device
	14	Trackdisk device
	15	Timer device
Resources	20	CIA resource
	21	Disk resource
	22	Misc resource
Other areas	30	Bootstrap
	31	Workbench
	32	Diskcopy

Origins

The term "Guru Meditation Error" was an in-house joke from Amiga's early days. One of the company's products was 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 was developed where a person would sit cross-legged on the joyboard, resembling an Indian guru. The player was supposed to remain perfectly still with the goal of the game being to stay still the longest. If the player moved, a "guru meditation error" resulted. A similar game is the final unlockable balance activity in Wii Fit.

The error was removed from subsequent versions of the Amiga ROM (Kickstart), but some users chose to patch it back in.

Trivia

File:503errorgurumeditation.PNG

A 503 error from the Varnish cache HTTP accelerator that includes the text "Guru Meditation".

• The blinking border of the original guru meditation number was created by writing the border in black 6,809 times and then writing it in red 6,809 times. This was in honor of the Motorola 6809, a popular arcade CPU that was the favourite of one of the AmigaOS designers (R J Mical) when he worked at Williams arcade games back an early eighties.
• VirtualBox uses a "Guru Meditation" VM state. [1].
• Deliplayer (for Windows) also display a guru meditation if somethings goes wrong.
• The Varnish HTTP accelerator also adopted Guru Meditation errors, for example:

  "Error 503 Service Unavailable Backend did not respond. Guru Meditation: XID: 456452130"

• TechCrunch sometimes displays a text guru meditation error when its website is having technical issues.
• Prevue Channel ran on AmigaOS from 1985 to December 1999. In its early days, errors could be prevalent – Guru Meditation errors among them. Once the channel went to a blue grid in 1993, errors decreased, but still could occur. After TV Guide bought the channel in 1999, a new guide was brought in that ran on Windows NT-based equipment.
• The game Captive displays a fake "Guru Meditation" error from time to time.

Later versions of AmigaOS

A visit from the Grim Reaper

Since version 4.0 of the OS, many alerts are replaced by an error handler known as "The Grim Reaper". The Grim Reaper displays the task which caused an error and the nature of the error (illegal memory access etc.), whereupon it presents the user with several options such as suspending/killing the task, displaying more information such as a register dump or attaching a debugger (gdb).

File:Amiga-grim2.png

After selecting "More..."

Although the Grim Reaper replaces many of the alerts, the error is still called a "Guru Meditation" as seen in the first screenshot.

The program which caused the particular error used as an example here was the following:

 int main(void)
 {
   int *bad=0;
   *bad=0;
   return(0);
 }

External links

• Guru Meditation code explained
• Joyboard Controller
• Guru Meditation (the introduction page contains an image of the effect)
• CGI::GuruMeditation Perl die handler to catch abnormal CGI termination and visually mimicking Amiga behavior
• Guru Meditation (a simulation of the effect when a corrupted disk is inserted – there are minor changes to the images)