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All pages are 6184 bytes.
All pages are 6184 bytes.


When a file is [[Creating a file (File management)|created]], the pages in the file are formatted into:
When a file is [[Creating a file|created]], the pages in the file are formatted into:
<ul>
<ul>
<li>6144 bytes of "usable" space (how the space is used depends on the table where the page resides)  
<li>6144 bytes of "usable" space (how the space is used depends on the table where the page resides)  

Revision as of 14:32, 10 May 2014

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 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.

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