Booting Operating Systems; Boot System Selection - HP 340 Series Service Manual

Booting Operating Systems
Boot System Selection
The Boot ROM provides two modes of operation, attended and unattended. These two modes
allow a user to either select from rnultiple operating systems on llmltiple boot devices or to
automatically boot a system with no human intervention.
Unattended Operation
In an unattended situation, the first system found will be loaded and given control. To find a
system the Boot ROM will search a boot list (operating systems listed on the right-hand side of
the power-up display) of prioritized devices. The first system found on one of these devices will
be booted. If no system is found, the boot list will be searched again until a system is found.
This allows discs not present at power-up be found after their initialization is complete.
Once a device has been successfully accessed, it will never be accessed again until re-power-up
or a reset. This minimizes wear on mass storage devices and limits the confusion of systems
disappearing and re-appearing on shared resources such as the LAN server.
To force the boot of a particular system when the machine is unattended, the user has the
following options:
• Make sure that the systelll to be booted is the first to be found according to the boot
list search. (This is quite easy to do simply by changing device addresses, select codes,
or system names, or by lllOving systems. The prioritized boot list is discussed in detail
latter in this chapter.)
• On a LAN server with multiple systems, the system adlllinistrator can determine what
operating system is booted by each workstation.
Attended Operation
To force the boot of a system not chosen by the boot list, the user must enter "attended mode."
This mode is entered by typing
I=:J
(space bar),
I
Return
I,
or any letter or number during power-
up after the input portion of the human interface (i.e., the keyboard or terminal) has been
initialized but before a default system is booted. A good way to do this is to hold down the
space bar until the system selection menu is seen. This will cause a boot selection menu to be
displayed. A user can be sure that the input human interface has been initialized when one of
the following (depending on the human interface provided) is displayed in the self-test list:
Keyboard
The boot selection menu displays all accessible systems as the Boot ROM locates them. A
system is selected by typing the two to three character string (a 1 to 2 digit number followed
by a single letter) listed in the lllenu.
Note that the character used to enter attended rnode is considered part of this string.
As the keys are pressed, they are identified the lower right hand corner of the display.
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Boot ROM Functions