Page (File architecture)

A page is the underlying structure applied to the data sets that comprise a Model 204 file.

All pages are 6184 bytes.

When a file is created, the pages in the file are formatted into:

• 6144 bytes of "usable" space (how the space is used depends on the table where the page resides)
• A 40 byte page trailer

The page trailer

The page trailer contains the following:

• The file name, which is the name used in the create process.
• The date/time when the individual page was last initialized.
• The date/time when the page was last written to the file.
• Data used in the checkpoint process.
• The table that this page is part of, the numeric representation for which is as follows:

  FCT = 00, Table A = 01, Table B = 02, Table C = 03, Table D = 04, Table E = 40, and Table X = 20.

• The sequential page number within the table. Three byte binary integer.

  Because of INCREASE and DECREASE commands after the initial CREATE, the pages for a table might not be contiguous.