Re: Feature idea: save process to disk for later manipulation

Larry 'Daffy' Daffner (vizzie@mail.airmail.net)
Sat, 14 Feb 1998 22:50:17 -0600


>>>>> "BWA" == Bradley Ward Allen <ulmo@Q.Net> writes:

BWA> On occasion, I'll want to save the state of a process for later
BWA> use. This can happen if I'm running something important and I
BWA> need to do something else with the system temporarily. Also, I
BWA> may want to move the process to a different system.

Believe it or not such a beast exists, although not for linux. It's
known as checkpoint/restart. You might want to try looking for
references to that.

The big problem is it's very difficult to implement at all, and
all but impossible to get completely correct. Even the established
implementations have their problems. (file descriptors, network ports,
generally the PID it had needs to be unused to restart it, etc.) It's
a neat idea in theory, but in practice, it only works for a small
subset of problems - generally, programs that do a lot of long term
number crunching. For this reason, it's generally only found on
operating systems that see heavy use as high performance systems.

I'm not saying that it's not going to happen - who knows what kind of
perverse streak someone will get - but simply that the expectation
will probably not meet the reality, and it probably has a much higher
cost/benefit ratio than many other worthwhile linux projects.

BWA> I do not know how easy any of this is. It is just submitted as
BWA> a thought, in case it actually is far easier than I assume.

In summary, probably not. :)

-Larry

-- 
  Larry Daffner        |  Linux: Unleash the workstation in your PC!
  vizzie@airmail.net / http://web2.airmail.net/vizzie/
"I believe every human has a finite number of heartbeats. I don't intend to
 waste any of mine running around doing exercises."  --Neil Armstrong

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