Section 060-INDP-111 System Description 2-75
BMC II BISYNC Operation, Administration, and Maintenance Guide BMCB001 and up
command. For more information concerning the LSTDIR command, consult
the Commands and Messages Guide section.
The total number of files divides into two categories: dynamic and static.
Dynamic files are usually large, while most static files are small. Most
dynamic files are data files consisting of AMA and log (LOG) records. Each
of these files has an index file associated with it. Static files are stand-alone
files, primarily various index files that are used for the management of data,
statistics, site data, program, boot, and other files.
Due to DPR buffer limitations, a maximum of 14 files can be open (reading
from or writing to) at one time. This is further divided into seven dynamic
and seven static files. Since only seven dynamic files can be open at one time,
this the total number of data files that can be polled from or written to at one
time. The data files may have a maximum of 255 versions, after which it rolls
back to restart the count at version 1, with the previous version 1 deleted.
Note: File versions containing primary data are not deleted.
The index file is used to keep track of the data file versions. It may contain
up to 200 versions. Each version of the index file consists of 9 bytes which is
described by the following table:
The total number of bytes in an index file is 1800 (9 bytes times 200
versions). The other static files (statistics, site data, program) are
accumulated in 512 byte increments and put on disk.
Data Management
The BMC disk system supports two types of data structures: (1) files, and (2)
blocks. Files are named groups of blocks. The disk system consists of
multiple files which are named using a binary integer value range of 1-255.
Table 2-17
Byte structure of index files
Byte Description
1 Version number
2-3 Total number of blocks
4-5 Number of blocks to be polled
6, 7, 8 Starting sequence number
9 Days to delete
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