NAME

savecore − save a memory dump of the operating system

SYNOPSIS

/etc/savecore dirname

DESCRIPTION

Savecore is meant to be called when the operating system starts up.  Savecore’s function is to save the memory dump of the system (assuming one was made) and to write a reboot message in the shutdown log. Often when the system crashes, it saves a copy of of the contents of memory in the swap area on disk.  Savecore reads the swap area to determine if a dump was actually taken, and if so, performs the procedure described below.  Otherwise, savecore simply exits with no action taken. 

Savecore checks the memory dump to be certain it corresponds with the current running UNIX.  If so, savecore saves the memory image in the file dirname/vmcore.n and it’s brother, the namelist, dirname/vmunix.n. The trailing .n in the pathnames is replaced by a number which grows every time savecore is run in that directory.  The number is obtained from the file dirname/bounds.

Savecore reads a number from the file dirname/minfree before attempting to write out a memory image. This number is the amount of free space in Kilobytes (K is 1024 bytes) which must exist on the filesystem which contains dirname, after the dump is taken.  If the filesystem would not have that much free space, the memory dump is not done.  If the minfree file does not exist, a value of 0 is used.  Savecore never writes a memory file or partial file when this would fill the file system. 

Savecore also writes a reboot message in the shut down log.  If the system crashed as a result of a panic, savecore records the panic string in the shut down log too. 

FILES

/etc/rcsystem startup script
/usr/adm/shutdownlogshut down log
/vmunixCurrent UNIX
dirname/vmcore.nMemory image
dirname/vmunix.nCurrent UNIX
dirname/minfreeMinimum free space specification
dirname/boundsNumber of next dump

Sun System Release 0.3  —  31 March 1983