After shutting down your system, you will eventually need to boot it back up again. the goal of the system boot process is to load the kernel executable from the boot disk into memory and start all the daemons and services necessary to bring the system back up to a fully functional state. There are several players involved in this process:
BootROM:every HP9000 SPU has a BootROM chip containing the "Processor Dependent Code/Boot Console Handler"(PDC/BCH) firmware executable. The PDC/BCH executes in memory in the early stages of the boot process to do a hardware self-test,and identify the system boot disk
Stable Storage:The PDC/BCH consults "Stable Storage" to determine which disk to boot from. Stable Storage is a non-volatile area of memory that contains the hardware paths of the primary boot disk,an alternate boot source, and the system console.The contents of stable storage may be modified by the administrator
Boot Area:every system requires at least one boot disk. Each boot disk has a 2MB "Boot Area" containing the utilities needed to find and load the kernel. Files in the boot area are stored in a special "Logical interchange format"(LIF) that is not directly viewable with ls,cat or other regular UNIX commands. The primary files of interest in the LIF area are the intial system/program loader(ISL/IPL),the AUTO file, and the HPUX utility. these will be discussed in more detail on the next slide.
/stand:The boot disk must also have a file system containing a kernel to boot. The kernel is typically stored in the /stand file system, with filename /stand/vmunix, currently, the utilities used to load the kernel in memory are unable to read JFS file systems; thus the file system containing the kernel must be HFS
/:the boot disk also typically contains the "/"(root) file system.the "/" file system contains the /etc, /sbin,and /dev directories which are required in the early stages of the system startup process. the "/" file system may be aither HFS or JFS.
primary swap:finally, the boot disk contains a primary swap area that is enabled and used early in the boot process
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