REBOOT(8) REBOOT(8) NAME reboot - UNIX bootstrapping procedures SYNOPSIS /etc/reboot [ -n ] [ -q ] DESCRIPTION UNIX is started by placing it in memory at location zero and transfer‐ ring to the entry point. Since the system is not reenterable, it is necessary to read it in from disk or tape each time it is to be boot‐ strapped. Rebooting a running system. When a UNIX is running and a reboot is desired, _s_h_u_t_d_o_w_n(8) is normally used. If there are no users then /etc/reboot can be used. Reboot causes the disks to be synced and allows the system to perform other shutdown activities such as resyn‐ chronizing hardware time-of-day clocks. A multi-user reboot (as described below) is then initiated. This causes a system to be booted and an automatic disk check to be performed. If all this succeeds without incident, the system is then brought up for many users. Options to reboot are: -n option avoids the sync. It can be used if a disk or the proces‐ sor is on fire. -q reboots quickly and ungracefully, without shutting down running processes first. _R_e_b_o_o_t normally logs the reboot using _s_y_s_l_o_g(8) and places a shutdown record in the login accounting file /usr/adm/wtmp. These actions are inhibited if the -n or -q options are present. Power fail and crash recovery. Normally, the system will reboot itself at power-up or after crashes. Provided the auto-restart is enabled on the machine front panel, an automatic consistency check of the file systems will be performed, and unless this fails, the system will resume multi-user operations. Cold starts. These are processor type dependent. On an 11/780, there are two floppy files for each disk controller, both of which cause boots from unit 0 of the root file system of a controller located on mba0 or uba0. One gives a single user shell, while the other invokes the multi-user automatic reboot. Thus these files are HPS and HPM for the single and multi-user boot from MASSBUS RP06/RM03/RM05 disks, UPS and UPM for UNIBUS storage module controller and disks such as the EMULEX SC-21 and AMPEX 9300 pair, or HKS and HKM for RK07 disks. There is also a script for booting from the default device, which is normally a copy of one of the standard multi-user boot scripts, but which may be modified to perform other actions or to boot from a different unit. The situation on the 8600 is similar, with scripts loaded from the con‐ sole RL02. Giving the command >>>BOOT HPM Would boot the system from (e.g.) an RP06 and run the automatic consis‐ tency check as described in _f_s_c_k(8). (Note that it may be necessary to type control-P and halt the processor to gain the attention of the LSI-11 before getting the >>> prompt.) The command >>>BOOT ANY invokes a version of the boot program in a way which allows you to specify any system as the system to be booted. It reads from the con‐ sole a device specification (see below) followed immediately by a path‐ name. The scripts may be modified for local configuration if necessary. The boot device type is set in register 10 as the device major number. The flags and minor device are placed in register 11. The register is used in four one-byte fields; from least to most significant, they are boot flags (as defined in _<_s_y_s_/_r_e_b_o_o_t_._h_>), disk partition, drive unit, and adaptor number (UNIBUS or MASSBUS as appropriate). On an 11/750, the reset button will boot from the device selected by the front panel boot device switch. In systems with RK07’s, position B normally selects the RK07 for boot. This will boot multi-user. To boot from RK07 with boot flags you may specify >>>B/_n DMA0 where, giving a _n of 1 causes the boot program to ask for the name of the system to be bootstrapped, giving a _n of 2 causes the boot program to come up single user, and a _n of 3 causes both of these actions to occur. The ‘‘DM’’ specifies RK07, the ‘‘A’’ represents the adaptor number (UNIBUS or MASSBUS), and the ‘‘0’’ is the drive unit number. Other disk types which may be used are DB (MASSBUS), DD (TU58), and DU (UDA-50/RA disk). A non-zero disk partition can be used by adding (partition times 1000 hex) to _n. The 11/750 boot procedure uses the boot roms to load block 0 off of the specified device. The /usr/mdec directory contains a number of boot‐ strap programs for the various disks which should be placed in a new pack automatically by _n_e_w_f_s(8) when the ‘‘a’’ partition file system on the pack is created. On any processor, the _b_o_o_t program finds the corresponding file on the given device (_v_m_u_n_i_x by default), loads that file into memory location zero, and starts the program at the entry address specified in the pro‐ gram header (after clearing off the high bit of the specified entry address). The file specifications used with “BOOT ANY” or “B/3” are of the form: device(unit,minor) where _d_e_v_i_c_e is the type of the device to be searched, _u_n_i_t is 8 * the mba or uba number plus the unit number of the disk or tape, and _m_i_n_o_r is the disk partition or tape file number. Normal line editing charac‐ ters can be used when typing the file specification. The following list of supported devices may vary from installation to installation: hp MASSBUS disk drive up UNIBUS storage module drive ht TE16,TU45,TU77 on MASSBUS mt TU78 on MASSBUS hk RK07 on UNIBUS ra storage module on a UDA50 rb storage module on a 730 IDC rl RL02 on UNIBUS tm TM11 emulation tape drives on UNIBUS ts TS11 on UNIBUS ut UNIBUS TU45 emulator For example, to boot from a file system which starts at cylinder 0 of unit 0 of a MASSBUS disk, type “hp(0,0)vmunix” to the boot prompt; “up(0,0)vmunix” would specify a UNIBUS drive, “hk(0,0)vmunix” would specify an RK07 disk drive, “ra(0,0)vmunix” would specify a UDA50 disk drive, and “rb(0,0)vmunix” would specify a disk on a 730 IDC. For tapes, the minor device number gives a file offset. On an 11/750 with patchable control store, microcode patches will be installed by _b_o_o_t if the file _p_s_c_7_5_0_._b_i_n exists in the root of the filesystem from which the system is booted. In an emergency, the bootstrap methods described in the paper ‘‘Installing and Operating 4.3bsd’’ can be used to boot from a distri‐ bution tape. FILES /vmunix system code /boot system bootstrap /usr/mdec/xxboot sector-0 boot block for 750, xx is disk type /usr/mdec/bootxx second-stage boot for 750, xx is disk type /usr/mdec/installboot program to install boot blocks on 750 /pcs750.bin microcode patch file on 750 SEE ALSO arff(8V), crash(8V), fsck(8), halt(8), init(8), newfs(8), rc(8), shut‐ down(8), syslogd(8) 4th Berkeley Distribution May 28, 1986 REBOOT(8)