Re: Persistence

[R. Koot]

William Grim wrote:
> If the OS did something similar (maybe not logs but something else... I 
> need to read the papers), then you could get something similar to 
> database recovery in the OS.  Technically, I don't think this would be 
> difficult to do.  I haven't thought about all the details, but in my 
> mind you would just have to have some way to store all the process 
> (task) contexts (servers+data/registers) as they run and keep 
> checkpointing them.  Jon Shapiro or anyone else that has read the 
> KeyKOS/EROS papers on single-level-stores can probably answer this 
> question better.

EROS makes a snapshot every 10 minutes, so if the system crashed 9 
minutes after the last snapshot you would, after a reboot, have the 
system in the state it was 9 minutes before the crash. The only way I 
can see to avoid these 'time jumps' would be making a snapshot on every 
IPC calls, but I don't think that will be feasable performance wise.


Ruud