The printer was turn off. However, more than 10 jobs were send to the printer. Is it possible to recover and print all these files. As I understand if more than one job send to pinter, printer saves all these jobs in the system. Correct? If so where the files are saved?

Thanks

On my box it's in /var/spool/cups. The queue can be checked with the command:
lpq. If the printer is connected by parallel port, it seems that the print jobs should have started again when the printer was restarted.

I haven't tried to print anthing directly from /var/spool/cups and can't really do that right now as I don't have anything sitting there.

In theory, if you printer is off, the queued jobs should be in the spooler. We studied this in my os class. We looked at an I/O abstraction like the following:

User I/O
Device Independent I/O
Device Drivers
Interrupt Handlers
Hardware

Basically if you'd try to print something from your program. This happens in the user space. It would then propagate down to the next level and this is where it would be spooled (many other things happen here as well such as buffering, error checking etc) . If the device wasn't available (i.e. something is using it, or it isn't on) then this is where it would end up, until the device became available. I might have screwed this up a little bit, but that gives you the basic idea.

Why printer jobs are on the computer not in the printer memory?

And What happend if the computer has 10 jobs and went down? When I restart the computer will it finish all the jobs? Or the spool queue will disappear?

Thanks