boot \- startup procedures
A PDP11/45 and PDP11/70 UNIX system is started by
The first is a primary bootstrap
which is able to read in relatively small stand-alone programs;
is used to read in the system itself.
The primary bootstrap must reside
in the otherwise unused block zero of the boot device.
It can be read in and started by the standard ROM
or if necessary by keying in a small startup routine.
This program is capable of loading type 407 executable
files (not shared, not separate I&D).
The user types on the system console
the name of the program wished, in this case
followed by a carriage return;
the named program is retrieved from the file system
that starts at block 0 of drive 0 of the boot device.
no diagnostic results if the file cannot be found, and no
provision is made for correcting typographical errors.
actually brings in the system.
When read into location 0 and executed,
sets up memory management, relocates itself into
high memory, and types a `:' on the console.
a device specification (see below) followed immediately by
finds the corresponding file on the given device,
loads that file into memory location zero,
sets up memory management as required,
and calls the program by executing a `trap' instruction.
line editing characters can be used.
Conventionally, the name of the secondary boot program
is `/boot' and the name of the current version of the system
Load block 0 of the boot device by fiddling with the
console keys as appropriate for your hardware.
If you have no appropriate ROM, some programs suitable
for manual use are given below.
When the prompt is given, type
depending on whether you are loading from an RP04/5/6 or an RP03
The first 0 indicates the physical unit number;
the block number of the beginning of the logical file
When the system is running, it types a `#' prompt.
After doing any file system checks and setting the date
a multi-user system is brought up by typing an EOT
in response to the `#' prompt.
.B Device specifications.
A device specification has the following form:
is the type of the device to be searched,
is the unit number of the device,
is the block offset of the file system on the device.
For example, the specification
indicates an RP03 disk, unit 1, and the file system found
starting at block 7000 (cylinder 35).
The following programs to call the primary bootstrap
may be installed in read-only memories
or manually keyed into main
Each program is position-independent
but should be placed well above location 0
so it will not be overwritten.
Each reads a block from the
beginning of a device into core location
The octal words constituting the program are
.if t .ta .3i 1i 1.4i 2i 3.5i
005040 clr \-(r0) / rkda cleared by start
/usr/mdec/rpuboot, /usr/mdec/hpuboot \- copies of primary bootstrap
/boot \- second stage bootstrap