HP 300 Service Information Manual

Booting Operating SystemsBoot System SelectionThe Boot ROM provides two modes of operation, attended and unattended. These two modesallow a user to either select from multiple operating systems on multiple boot devices or toautomatically boot an operating system with no user intervention.Unattended OperationIn an Unattended situation, the first operating system found will be loaded and given control.To find an OS, the Boot ROM will search a boot list of prioritized devices. The first OS systemfound on one of these devices will be booted. If none is found, the boot list will be searchedagain until a one is found. This allows discs not present at power-up to be found after theirinitialization is complete.Once a device has been successfully accessed, it will never be accessed again until re-power-upor a reset. This mininlizes wear on mass storage devices and limits the confusion of operatingsystems disappearing and re-appearing on shared resource management systems.To force the boot of a particular system when the machine is unattended, the user has thefollowing options:• Make sure that the OS to be booted is the first to be found according to the boot listsearch. This is quite easy to do sirnply by changing device addresses, select codes, or OSnames, or by moving OSs. The prioritized boot list is discussed in detail latter in thissection .• On an SRM with multiple OSs, make the first OS to be found one that looks at the host'sSRM node address and uses the node address to decide what secondary OS to boot. (TheBoot ROM can then be called to boot a particular OS.)Attended OperationTo force the boot of an OS not chosen by the boot list, the user must enter Attended OperationMode. This mode is entered by pressing the space bar, I RETURN I, or any letter or number duringpower-up after the input portion of the hurnan interface (i.e., the keyboard or terminal) has beeninitialized but before a default OS is booted. A good way to do this is to hold down the spacebar until the OS 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 hurnan interface provided) is displayed in the self-test list:KeyboardConsole Keyboard at XXHP 986XX at Xw here XX is the lowest select code of key board electronicsin an I/O slot.w here the Xs are the type and select code of the remotehuman interface.Boot Rom Functions 93Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com