.pa 1 .he '3/15/72''BOOT PROCEDURES (VII)' .ti 0 NAME bos, maki, rom, vcboot, msys, et al .sp .ti 0 SYNOPSIS -- .sp .ti 0 DESCRIPTION On the RF disk, the highest 16K words are reserved for stand-alone programs. These 16K words are allocated as follows: .sp bos (1K) .br Warm UNIX (7K) .br Cold UNIX (8K) .sp The UNIX read only memory (ROM) is home cut with 2 programs of 16 words each. The first (address 173000) reads bos___ from the RF disk into core location 154000 and transfers to 154000. The other ROM program (address 173040) reads a DECtape sitting in the end-zone on drive 0 into core location 0 and transfers to 0. This latter operation is compatible with part of DEC's standard ROM. The disassembled code for the UNIX ROM follows: .sp .nf .in 8 173000: mov $177472,r0 12700;177472 mov $3,-(r0) 12740;3 mov $140000,-(r0) 12740;140000 mov $154000,-(r0) 12740;154000 mov $-2000,-(r0) 12740;176000 mov $5,-(r0) 12740;5 tstb (r0) 105710 bge .-2 2376 jmp *$154000 137;154000 .sp 173040: mov $177350,r0 12700;177350 clr -(r0) 5040 mov r0,-(r0) 10040 mov $3,-(r0) 12740;3 tstb (r0) 105710 bge .-2 2376 tst *$177350 5737;177350 bne . 1377 movb $5,(r0) 112710;5 tstb (r0) 105710 bge .-2 2376 clr pc 5007 .fi .in 16 .sp The program bos___ (Bootstrap Operating System) examines the console switchs and executes one of several internal programs depending on the setting. The following settings are currently recognized: .sp .in +8 .ti -8 ??? Will read Warm UNIX from the RF into core location 0 and transfer to 600. .sp .ti -8 1 Will read Cold UNIX from the RF into core location 0 and transfer to 600. .sp .ti -8 10 Will dump all of memory from core location 0 onto DECtape drive 7 and then halt. .sp .ti -8 20 Will read 256 words from RK0 into core 0 and transfer to zero. This is the procedure to boot DOS from an RK. .sp .ti -8 40 This is the same as 10 above, but instead of halting, UNIX warm is loaded. .sp .ti -8 0 Will load a standard UNIX binary paper tape into core location 0 and transfer to 0. .sp .ti -8 77500 Will load the standard DEC absolute and binary loaders and transfer to 77500. .sp .in 16 Thus we come to the UNIX warm boot procedure: put 173000 into the switches, push .ul load address and then push .ul start. The alternate switch setting of 173030 that will load warm UNIX is used as a signal to bring up a single user system for special purposes. See init(VII). For systems without a rom, UNIX (both warm and cold) have a copy of the disk boot program at location 602. This is probably a better warm boot procedure because the program at 602 also attempts to complete outstanding I/O. .sp Cold boots can be accomplished with the Cold UNIX program, but they're not. Thus the Cold UNIX slot on the RF may have any program desired. This slot is, however, used during a cold boot. Mount the UNIX INIT DECtape on drive 0 positioned in the end-zone. Put 173040 into the switches. Push .ul load address. Put 1 into the switches. Push .ul start. This reads a program called .ul vcboot from the tape into core location 0 and transfers to it. vcboot______ then reads 16K words from the DECtape (blocks 1-32) and copies the data to the highest 16K words of the RF. Thus this initializes the read-only part of the RF. vcboot______ then reads in bos___ and executes it. bos___ then reads in Cold UNIX and executes that. Cold UNIX halts for a last chance before it completely initializes the RF file system. Push .ul continue, and Cold UNIX will initialize the RF. It then sets into execution a user program that reads the DECtape for initialization files starting from block 33. .a When this is done, the program executes /etc/init which should have been on the tape. .sp The INIT tape is made by the program maki____ running under UNIX. maki____ writes vcboot______ on block 0 of .ul /dev/tap7. It then copies the RF 16K words (using .ul /dev/rf0) onto blocks 1 thru 32. It has internally a list of files to be copied from block 33 on. This list follows: .sp .nf .in +8 /etc/init /bin/chmod /bin/date /bin/login /bin/ls /bin/mkdir /etc/mount /bin/sh /bin/tap .in -8 .fi .sp Thus this is the set of programs available after a cold boot. init____ and sh__ are mandatory. For multi-user UNIX, getty_____ and login_____ are also necessary. mkdir_____ is necessary due to a bug in tap___. tap___ and mount_____ are useful to bring in new files. As soon as possible, date____ should be done. That leaves ls__ and chmod_____ as frosting. .sp The last link in this incestuous daisy chain is the program msys____. .sp msys____ char file .sp will copy the file file____ onto the RF read only slot specified by the characacter char____. Char is taken from the following set: .sp b_ bos u_ Warm UNIX 1_ Cold UNIX .sp Due to their rarity of use, maki____ and msys____ are maintained off line and must be reassembled before used. .sp .ti 0 FILES /dev/rf0, /dev/tap? .sp .ti 0 SEE ALSO init(VII), tap(I), sh(I), mkdir(I) .sp .ti 0 DIAGNOSTICS -- .sp .ti 0 BUGS This section is very configuration dependent. Thus, it does not describe the boot procedure for any one machine. .sp .ti 0 OWNER ken