Technical data

Starting Up and Shutting Down the System
4.1 Understanding Booting and System Startup
7. The boot process finishes, and you can log in to the operating system.
4.1.2 Deferring Memory Testing on AlphaServer 4100 Computers
To speed up the time between system power-on and user login, you can now defer
a portion of memory testing on AlphaServer 4100 computers. When you choose
this option, the console tests a minimum amount of memory and leaves the rest
for the operating system to test.
To use this new feature, you need to specify a value for the MEMORY_TEST
environment variable at the console before booting. The values for
MEMORY_TEST are the following:
Value Description
FULL (off) The console does all the testing.
NONE 32 MB of memory are tested before booting.
PARTIAL 256 MB of memory are tested before booting.
If you set MEMORY_TEST to NONE or PARTIAL, OpenVMS tests any remaining
untested memory on an as-needed basis at either or both of the following times:
• While the operating system is booting
• In the scheduler idle loop when no processes are available to run
When you change the value of MEMORY_TEST, you must issue the INIT console
command before the new value takes effect. Therefore, you need to follow these
steps from the console before booting:
1. Change the value of MEMORY_TEST (if desired).
2. Issue the INIT command from the console.
3. Boot the operating system.
OpenVMS also gives you more control over when memory is actually tested. Bit 2
in the system parameter MMG_CTLFLAGS controls deferred memory testing:
• If the bit is clear (the default), OpenVMS tests memory in the background
and not necessarily before the bootstrap process has completed.
• If you set the bit, OpenVMS guarantees that all memory will be tested by
the end of EXEC_INIT in the system bootstrap process; that is, before IPL is
lowered from 31.
4.1.3 Types of Booting Operations
You can perform the following types of booting operations:
Type Purpose
For More
Information
Nonstop boot To boot without stopping to perform special
operations. Use this kind of boot in most cases.
Section 4.1.3.1
Conversational
boot
To perform special boot operations—for
example, to change system parameters before
booting.
Section 4.1.3.2
Starting Up and Shutting Down the System 4–3