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REBOOT(8) System Manager's Manual REBOOT(8) NAME reboot - bootstrapping procedures DESCRIPTION Here are some recipes for booting and crashing the operating system on VAXes. Rebooting a running system The preferred way to reboot is to log in on the console as super-user, invoke kill 1 to take the system to single user, unmount file systems with /etc/umount -a and halt and restart the system as described below under `Console boots.' Power fail and crash recovery The system will reboot itself at power-up or after crashes if auto-boot is enabled on the machine front panel or in the console software. If auto-restart is enabled, the system will first attempt to save a copy of physical memory on a reserved piece of disk. An automatic consis- tency check of the file systems is performed. Unless this fails the system will resume multi-user operations. Console boots Sync the disks if necessary and possible. To recover hardware control of the console, type a control-P. This will yield a prompt from the VAX console subsystem (sic). The command >>> H will halt the CPU (except on the 11/750, where control-P halts the CPU right away). On MicroVAXes, control-P doesn't work; hit the BREAK key instead. To boot multi-user with an automatic file system check, give the con- sole command >>> B Commands to boot single-user vary. On the VAX-11/750 and on Mi- croVAXes, use >>> B/3 On the VAX-11/780 and VAX 8550 and 8700, use >>> B MAN This will prompt with for the name of the file to boot. The filename should be an executable image in the root directory of the filesystem at the beginning of the disk. System core images If the system crashes and auto-restart is enabled, a copy of physical memory is written to a reserved piece of disk. To save a core image of a hung system, type on the console (after control-P if necessary): >>> S 80000010 The system will write the core image, then reboot automatically. If the core image was written on the following incantation will print a stack traceback from the time of the crash: adb /unix /dev/ra11 $<crash $c To save disk space, the core image is sometimes overlaid on part of the swap area, where normal system operation will soon overwrite it. Savecore(8) will copy the core image to an ordinary disk file. FILES default system binary SEE ALSO fsck(8), init(8), rc(8), savecore(8) BUGS Older boot programs with different syntax are still around in a few places, especially on machines with Emulex UNIBUS disk controllers, for which silly boot ROMs are common. There are commands /etc/reboot and /etc/halt which attempt to reboot and halt the system; their function is indeterminate and likely to change. REBOOT(8)