MPE/iX System Utilities Reference Manual (32650-90882)

Chapter 25 219
STANDARDS
The initial system loader
Each directory is organized as follows:
The file type is a 16-bit signed integer. The defined file types that are recognized by
systems are
• 0 -- Purged file
• 30001 -- Bootable, executable file
• 30002 -- Boot data file
• 30003 -- Autoexecutable file list
• 30004 -- Data protect file
• 30010 -- HPE system file
A file is deleted from the directory by changing its file type to -2, to represent a purged file.
The data itself need not be removed from the media.
Bootable utility format
All of the bootable utilities accessible through the LIF directory must have enough of a
common format for IPL to load and launch the utilities through a standard method. IPL
may need to know the intended physical memory destination address for which the module
was linked, as well as the length of the image and the entry point. For those utilities that
are position independent, the destination address can be set to -1 and IPL will load it at
the first available memory after IPL.
All software implementation intends to support the system object module (SOM) format,
using the linker; therefore, an auxilary SOM header for IPL, as described below, would
meet IPL's needs for loading and launching bootable utilities. For further description of the
linker and the SOM format, refer to the System Linker External Specifications and the
System Object File Format Architectural Control Document.
Table 25-7. LIF addressing
BYTE CONTENTS
0-9 File name (1-10 ASCII characters, trailing blanks)
10-11 File type
12-15 Starting address (in blocks)
16-19 Length of file (in blocks)
20-25 Time of creation
26-27 1 /volume number
28-31 Set to 0 (implementation)