1 Bomb (Bus Error)
Atari Atari ST
Severity: CriticalWhat Does This Error Mean?
One bomb on an Atari ST means a Bus Error — the 68000 CPU tried to access a memory address that does not exist or is not accessible. This is a fatal crash. Press the reset button on the side of the machine to restart.
Affected Models
- Atari ST
- Atari STF
- Atari STE
- Atari Mega ST
- Atari TT
- Steem emulator
- Hatari emulator
Common Causes
- Software bug — program jumped to or read from a non-existent memory address
- Incompatible software — game or app written for a different TOS version
- RAM fault — bad memory chip returning garbage addresses
- Cartridge or hardware expansion with faulty addressing
- Program running out of stack space, causing the stack pointer to go wild
How to Fix It
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Press the reset button on the right side of the Atari ST case.
The bomb screen is a fatal crash — there is no way to recover the current session. The reset button performs a warm restart of TOS without fully cutting power.
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If the bomb recurs every time you run the same software, the software is incompatible.
Early ST software was written for TOS 1.0. Running it on TOS 1.4, 2.06, or later can cause bus errors due to changes in the OS memory map. Check whether the software specifies a TOS version requirement.
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Remove any cartridges or hardware expansions and retry.
Poorly designed cartridges can respond to bus cycles they should ignore, causing conflicts. Removing all peripherals helps isolate whether the crash is hardware or software.
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On Hatari or Steem emulator: check TOS version and RAM size settings.
Match the emulated TOS version to what the software requires. Some programs need TOS 1.02 or 1.04 and crash on TOS 2.06 with bus errors.
Frequently Asked Questions
Why does the Atari ST use bomb icons to show errors?
The bomb icons were designed by Atari's software team as a dark-humour way to indicate a fatal crash. The number of bombs indicates the type of 68000 CPU exception — 1 bomb = Bus Error (exception type 2), and so on.
Is a bus error the same as the Amiga Guru Meditation?
They are equivalent crashes. Both the Atari ST and Amiga use the Motorola 68000 CPU. A bus error on the 68000 causes a bomb screen on the ST and a Guru Meditation on the Amiga — same underlying exception, different visual presentations.