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Table of Contents
- Terminology
- KSAM XL File Format
- Index Area
- Data Area
- Automatic Recovery
The Keyed Sequential Access Method (KSAM) is a method of organizing
data records according to the content of key fields within the record.
This method allows sequential processing of records without relying
on the physical location of the record in the file.
Every record in a KSAM file contains a primary key field.
The content of this field determines the logical sequence of each
record. Alternate keys offer different sequences for accessing the
same records.
KSAM XL and KSAM 64 are KSAM file formats that function in
the native mode (NM) environment of the MPE/iX operating system.
They comprise a single file that consists of an index area that
contains key indexes, and a data area that contains data records.
A primary key and up to fifteen alternate keys can be defined
for a KSAM XLor KSAM 64 file. Key values are arranged in ascending
order based on the data type of the field.
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NOTE: The MPE V/E KSAM file format is also available on the
MPE/iX system and is referred to as CM KSAM. It is a two-file format
consisting of a data file and a key file. Refer to the KSAM/3000
Reference Manual for a description of the format, file
building instructions, and maintenance information.
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