Matt Pobursky wrote:

>>> But having a deep execution history is /really/ nice. [...] This is not
>>> something even a comfortable PC debugger can give you.
>> 
>> Quickbasic v3 (possibly v4 as well) would let you run programs
>> backwards (up to about 20 instructions IIRC) from a breakpoint. 
>> 
>> I wrote an emulator that tracked everything, and would let you jump
>> back to any point, and then restart the program.  Thankfully it was a
>> very HLL (sort of) with very few instructions per second.
> 
> Well the whole point of the hardware emulator trace buffer is being able
> to capture and analyze a large number (8K to 64K or more) of
> instructions non- intrusively in real-time so that the process you are
> observing runs as it will in the final application. There are many
> real-time applications that can only be analyzed this way. 

And it's also a very helpful tool to track down compiler/interpreter bugs
-- for which a backtracking built into the interpreter might not be /that/
useful :)

Gerhard

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