3BSD/usr/man/man8/bproc.8

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.TH BPROC 8 VAX-11
.UC
.tr |
.SH NAME
boot procedures \- UNIX startup
.SH DESCRIPTION
.I "How to start UNIX.||"
UNIX is started by placing it in memory
at location zero and transferring to zero.
Since the system is not reenterable,
it is necessary to read it in from disk or tape.
.PP
To boot from disk: type the console command ``BOOT''
(which may be abbreviated ``B'')
when the console is in LSI-11 mode.
It may be necessary to type control-P
to gain the attention of the LSI-11.
This loads and executes a standalone boot program
.I boot
off the floppy.
The boot program relocates itself into high memory, and types a `:'
as a prompt on the console.
It then reads from the console a device specification (see below) followed
immediately by a pathname.
.I Boot
finds the corresponding file on the given device, loads that file
into memory location zero, and starts the program at the entry address
specified in the program header (after clearing off the high bit
of the specified entry address.)
Normal line editing character can be used in specifying the pathname.
.PP
If you have an rp06 or rm03 disk and wish to boot off of a file
system which starts at cylinder 0 of unit 0, you can type ``hp(0,0)vmunix''
to the boot prompt.  On Ernie Co-vax, ``up(0,0)vmunix'' would specify
a UNIBUS ampex 9300 drive.
.PP
.B "Device specifications."
A device specificaion has the following form:
.IP
device(unit, minor)
.PP
where
.I device
is the type of the device to be searched,
.I unit
is the unit number of the device,
and
.I minor
is the minor device index.
The following list of supported devices may vary from installation to
installation:
.ta 5 10
.nf
	rp	RP06 or RM03 on MASSBUS
	up	AMPEX 9300 on UNIBUS
	ht	TE16
.fi
.PP
For tapes, the minor device number gives a file offset.
.PP
.B "Emergency bootstraps."
If the console BOOT command does not work, here is a position-independent
program which will read the boot block (block 0) from a RP06 or RM03 disk,
on the MASSBUSS; the boot block will then boot in the file
.B /boot
off the file system at cylinder 0 of the RP, in the same way that the
console floppy would bring the program in.
.PP
.nf
.if n .ta 3 14 21 41 49
.if t .ta .3i 1i 1.6i 3.5i
RP06 disk (MBA 0, drive 0)
	00009fde	moval	*$0x20010000,r1	# MBA 0
	\0\0512001
	d0      	movl	$1,4(r1)	# initialize MBA
	\0\004a101
	d0      	movl	$0x13,0x400(r1)	# volume valid
	0400c113
	10008f32	cvtwl	$0x1000,0x424(r1)	# 16-bit format
	\0\00424c1
	d4      	clrl	12(r1)	# map reg. 0, offset 0
	\0\0\0\00ca1
	8fd0    	movl	$0x80000000,0x800(r1)	# valid, page 0/0
	80000000
	\0\00800c1
	32      	cvtwl	$-512,16(r1)	# byte count
	a1fe008f
	\0\0\0\0\0\010
	28c1d4  	clrl	0x428(r1)	# cylinder
	\0\0\0\0\0\004
	14c1d4  	clrl	0x414(r1)	# sector, track
	\0\0\0\0\0\004
	c139d0  	movl	$0x39,0x400(r1)	# read 1 block
	\0\0\0\00400
	\0\000    	halt
.fi
.PP
To boot from magnetic tape:  The
.IR tp (1)
command places the bootstrap program
.I mboot
on block 0 of the tape.  When read into memory at location 0 and executed,
.I mboot
prompts with an equal sign `=', reads a file name from the console,
then loads and executes that file from the
.I tp
tape.  Unfortunately DEC does not provide a console command to read
a block from tape to memory.  Here is a position-independent program
which does:
.PP
.nf
TM03 magtape (MBA 1, drive 0) from load point:
.if n .ta 3 14 21 41 49
.if t .ta .3i 1i 1.6i 3.5i
	20009fde	moval	*$0x20012000,r1	# MBA 1
	\0\0512001
	d0      	movl	$1,4(r1)	# initialize
	\0\004a101
	32      	cvtwl	$0x14c0,0x424(r1)	# drive characteristics
	c114c08f
	\0\0\0\00424
	a1d4    	clrl	12(r1)	# map reg. 0, offset 0
	\0\0\0\0\0\00c
	008fd0  	movl	$0x80000000,0x800(r1)	# valid, page 0/0
	c1800000
	\0\0\0\00800
	8f32    	cvtwl	$-512,16(r1)	# byte count
	10a1fe00
	00c139d0	movl	$0x39,0x400(r1)	# read 1 block
	\0\0\0\0\0\004
	\0\0\0\000  	halt
Then give the console command ``START 0\er''.
.fi
.PP
.I mboot
does not perform character erase and line kill editing.  Instead,
it starts over with the prompt for file name whenever the requested
file cannot be found.
.PP
Be sure that
.I mboot
exists whenever a
.I tp
tape is made.  Remember to put an appropriate block 0 boot and a
.IR /boot
in file systems when running
.IR mkfs .
.SH FILES
.ta \w'/usr/mdec/mboot   'u
/vmunix	UNIX code
.br
/usr/mdec/uboot	rp disk bootstrap
.br
/boot	backup system bootstrap
.br
/usr/mdec/mboot	
.IR tp ""
magtape bootstrap
.SH "SEE ALSO"
tp(1), init.vm(8)