Owner`s manual

Table 1–9: R5 Bit Functions for VMS

Bit Function

0 Conversational boot. The secondary bootstrap program, SYSBOOT, prompts you

for system parameters at the console terminal.

1 Debug. If this ﬂag bit is set, the operating system maps the code for the

XDELTA debugger into the system page tables of the running operating sys-

tem.

2 Initial breakpoint. If this ﬂag bit is set, VMS executes a breakpoint (BPT) in-

struction early in the bootstrapping process.

3 Secondary boot from boot block. The secondary boot is a single 512-

byte block whose logical block number is speciﬁed in General Purpose Regis-

ter R4.

4 Boots the VAX Diagnostic Supervisor. The secondary loader is an image called DI-

AGBOOT.EXE.

5 Boot breakpoint. This stops the primary and secondary loaders with a break-

point (BPT) instruction before testing memory.

6 Image header. The transfer address of the secondary loader im-

age comes from the image header for that ﬁle. If this ﬂag is not set, con-

trol shifts to the ﬁrst byte of the secondary loader.

8 File name. VMB prompts for the name of a secondary loader.

9 Halt before transfer. VMB executes a HALT instruction before transferring con-

trol to the secondary loader.

13 No effect, since console program tests memory.

15 Reserved for VAX Diagnostic Supervisor.

16 Do not discard CRD pages.

31:28 Speciﬁes the top-level directory number for system disks.

Table 1–10: R5 Bit Functions for ULTRIX

Bit Function

0 Forces ULTRIXBOOT to prompt the user for an image name (the default is VMU-

NIX).

1 Boots the ULTRIX kernel image in single-user mode.

3 Must be set, and R4 must be zero.

16 Must be set.

1–10 VAX 6000 Model 500 Mini-Reference