Owner`s manual

Table 4–1: Boot Procedure

Step Procedure

1 You enter BOOT command from the console terminal in console mode.

The BOOT command speciﬁes the boot device and the path needed to reach it.

2 System reinitializes and performs self-test.

3 Boot primitive is invoked from console ROM on the boot processor.

Boot primitive reads the bootblock from the speciﬁed boot device and

transfers control to the bootblock.

4 The bootblock contains code and a pointer to VMB.

The bootblock loads VMB into the ﬁrst 256-Kbyte block of

available memory.

5 Once VMB is loaded into memory, the bootblock transfers control to VMB,

which in turn starts the operating system.

Boot primitive

Each boot device has a small program called a boot primitive that is

stored in ROM on each processor with the console program. The boot

primitive reads the bootblock from its boot device. How to load boot

primitives is explained in Appendix E.

Boot device

The boot device contains the bootblock and typically also contains VMB.

The system can be booted from one of four boot devices: the system

console load device, a local system disk connected through a KDM70 or a

KFMSA, a disk connected to the system through a CI adapter (CIXCD),

or a disk connected to the system through an Ethernet adapter. See

Appendix D for a list of boot devices connected to the system by VAXBI

adapters.

Bootblock

The bootblock is logical block zero on the system disk; it contains the

block number where the virtual memory boot (VMB) program is located

on the system disk and contains a program that, with the boot primitive,

reads VMB from the system load device into memory.

VMB

The virtual memory boot program (VMB.EXE) boots the operating

system. VMB is the primary bootstrap program and is stored on the

boot device. The goal of booting is to read VMB from the boot device

and load the operating system.

Booting 4–3