Kernel-Managed Swap Facility (KMSF) Manual

Introduction
Kernel-Managed Swap Facility (KMSF) Manual—425824-005
1-8
Characteristics of KMS Files
•
Is an unstructured file identified by code 405 in the File Utility Program (FUP)
•
Is set to CLEARONPURGE, so the disk process overwrites the file with blank data
when the file is deleted (in NSKCOM, this process of overwriting data in a file is
referred to as “cleaning” the file)
•
Is one of two different formats: Format 1 and Format 2:
°
Format 1 files are limited in size because of the limitations of 32-bit addressing.
The maximum size of a Format 1 file is 2047 megabytes.
°
Format 2 files use 64-bit addressing and can be up to 100 gigabytes in size.
The output of the FUP INFO command indicates a Format 2 file with a plus
sign after the value for CODE (Example 1-1). The format of the file is also
displayed by the output of the NSKCOM INFO command (Example 4-12 on
page 4-20).
•
Has a set of attributes, SIZE, EXTENTS, and MAXEXTENTS, that are interrelated
and depend on the format of the file.
To understand the relationships between the various attributes of KMS swap files,
you might need this conversion reference:
1 disk page = 2048 bytes
1 memory page = 16384 bytes = 8 disk pages
1 megabyte = 512 disk pages = 64 memory pages
SIZE = EXT * MAXEXTENTS * 2048 bytes
Table 1-1 on page 1-9 shows the values of the attributes EXT, MAXEXTENTS, and
SIZE for each swap file format.
Note. This maximum size differs from that of other Format 2 files because NSKCOM
limits the extent size for KMS files.
Example 1-1. Output of FUP INFO Command for a Format 2 Swap File
-info cpu09
CODE EOF LAST MODIF OWNER RWEP TYPE REC BL
$OS1.SWAP
CPU09 O 405+ 55296000 05:51 -1 OGOG