checkpoint/restart milestone 1

[Matthew Dillon]

:
: fd = open("/foo", O_CREAT|O_RDWR, 0644);
: unlink("/foo");
: write(fd, buffer, 1024);
: CHECKPOINT
:
:-- 
:[100~Plax]sb16i0A2172656B63616820636420726568746F6E61207473754A[dZ1!=b]salax

    # restart program
    Program failed to restart, the file associated with descriptor 3
    inode 23434 was deleted.  You can still restart the program by
    specifying a file for this descriptor or you can give up.
    Have a nice day!
    # 

    In otherwords, the idea behind the checkpointing is to try to cover as
    many situations as possible, but one still needs to be running reasonably
    well behaved code for it to work.  We might, one day, provide
    persistent filesystem functionality (say, by bumping the inode's link
    count) but it would be unreasonable to try to do something that 
    sophisticated in step #1.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>