Physical files are created in offline mode. Allocate a physical file to the OpenTP1 file system by using the function dc_dam_create() [CBLDCDMB('CRAT')]. Set the following information upon the allocation:

• Name of the physical file to be allocated
• Length of a block, and the number of blocks
• Number of blocks to be processed collectively, which is used as an input/output unit
• File owner, the owner group, and access right from another UAP

When a physical file is allocated, the file descriptor is returned.

The file descriptor is used for processing after the file is opened. The file descriptor returned by the function dc_dam_create() is available with the following functions:

• dc_dam_put() (Output a block)
• dc_dam_iclose() (Close a file)

The file descriptor returned by the function dc_dam_create() is unavailable with the following functions and an error is returned if used:

• dc_dam_get() (Input a block)
• dc_dam_dget(), dc_dam_dput() (Input/Output directly a block)
• dc_dam_bseek() (Seek a block)

The figure below shows the procedure for creating a DAM file as the first physical file in the OpenTP1 file system.

Figure 4-4 Procedure for creating DAM file