HPlogo System Startup, Configuration, and Shutdown Reference Manual > Chapter 5 Modifying Input/Output (I/O) Configurations

I/O Paths

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An I/O path is the system address assigned to the device interface hardware and the physical path used to reach an I/O device.

I/O Paths Used to Boot a System

When a system is powered on or reset, the processor-dependent code (PDC) and I/O-dependent code (IODC) hardware routines read and initialize the I/O paths used to boot or reboot the system. The I/O paths that are used to load the system from disk or tape are referred to as boot paths. They consist of:

  • the primary boot path, for booting from disk

  • the alternate boot path, for booting from a tape

  • the console boot path, which determines whether or not the console can boot itself ("autoboot") without operator intervention

Each device configured for the boot path has been assigned a unique LDEV number which identifies a physical device associated with a system. Two of the boot paths, the primary boot path and the console boot path, require a specific LDEV. The system master volume must be mounted on LDEV 1 for the operating system to be booted from disk and LDEV 20 must be assigned to the system console.

At system installation, these devices are assigned a default boot path, which the system manager may redirect either through the system initialization prompts or the initial system load (ISL) interface. For more information on system initialization and ISL, refer to Chapter 3 System Startup Functions in this manual.

Selecting I/O Paths

An I/O path is determined by the bus converter (S) module number, the device adapter (DA) slot number, and the device address.



Chapter 5 Modifying Input/Output (I/O) Configurations

Using the SYSGEN I/O Configurator