Job File Table: Difference between revisions

Revision as of 17:20, 28 March 2005

Revision as of 19:39, 17 August 2005

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The '''Job File Table''' (JFT) is a [[DOS]] data structure in the [[Program Segment Prefix]] (PSP). It starts at PSP offset 0x18 and is 20 bytes long. For each open file handle, [[DOS]] stores the index into the [[System File Table]] (SFT). A file handle that is returned by open, _open and other similar functions is simply an index into the JFT where [[DOS]] stored the SFT entry index for the file or device that the program opened.

When a program starts, the first 5 entries in the JFT are preconnected to the standard devices. All other handelshandles are marked as closed by setting the value of the entry to 0xFF.

The standard devices are initialised as follows

Handle Description