Understanding boot programs and LIF area....

[Jim Mallett]

I have a pretty good understanding of the boot process from powering on to getting to run level 3. What I'd really like to learn is the nuts and bolts of the header area of the disk. ie: what mkboot really did, what is in the LIF area and why.
I've seen a few documents that brush over it, does anybody have anything that explains it in fairly decent detail? It's been easy following the procedures, but now I want to understand the "what and why".

I've read quite a bit through the forum but this is one area where there doesn't seem to be consensus.

Thanks...

Jim

[Kent Ostby]

Jim --

Essentially, the LIF area is the part of the OS that gets us from the FW to the OS on the disk.

Found this tidbit on an internal HP site:
---- snip ----

LIF stands for "Logical Interchange Format" ... the name reveals a
curious history.

The original concept for LIF was simply to tidy up the crazy quiltwork of different disk file systems that existed back in the
1970s before the IBM PC defined a de-facto standard.

The idea behind LIF was to create, as the name implies, an interchange
format that could be used with different systems ... the systems might
still use proprietary disk formats, but they would also support LIF and
be able to transfer files over disks formatted as LIF.

To this end, the LIF spec was extremely simple, and basically emulated a
tape on a floppy disk: the disk's concentric sectors were logically
viewed as a continuous list of bytes, a directory was placed at the
head, and blocks were allocated as needed from the consecutive list.

LIFwas a "flat" file system -- that is, there was only one directory,
subdirectories were not possible. File names could be twelve characters
long and were case-sensitive.


As you noted, the LIF area is created by mkboot.

mkboot is copying, creating a set of files that the firmware will talk to at boot up.

The five files resident on 11.00 in most cases are:

HPUX -- The HP-UX Specific Secondary loader.
The HP-UX command allows you to issue boot commands and set the autofile up. (see man hpux).

ISL -- Stands for Initial Secondary Loader.
isl implements the operating system independent portion of the bootstrap process. It is loaded and executed after self-test and initialization have completed successfully. See man isl for more.


AUTO -- Contains the AUTO boot string. This has been made much easier to alter

LABEL -- Used by LVM

PAD -- Empty file to pad the alignment in the LIF

Hope that helps,

Best regards,

Kent M. Ostby

[Geoff Wild]

From the HP Certified - HP-UX System Adminstration book:

"The boot area contains a bootstrap loader and necessary information that is used at boot time. ISL is also part of the boot area. The files in this area are in logical interchange format (LIF). Important parts of the boot area are:

- a LIF volume header that identifies the LIF volume
- a file containing an HP-UX volume name
- a directory that contains a list of files contained in this area
- ISL
- secondary loader utility (hpux)
- a file with the name AUTO

After PDC has finished its job, the ISL is loaded into memory from the boot device selected by PDC. Now the ISL takes control of the boot process and accesses the AUTO file. The AUTO file contains the hpux utility name and any arguments to be passed to the hpux utility. After starting execution, the hpux utility uses these arguments to find the location and file name for the HP-UX kernel. By default, the kernel is present in the /stand directory and has the name vmunix. The hpux loads the kernel into memory and hands control over to the kernel."

Rgds...Geoff