# DECram for OpenVMS User's Manual

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# Appendix B
DECram I/O Functions

Table B-1 lists the I/O functions and function modifiers supported for the DECram for OpenVMS driver.

Table B-1 DECram I/O Functions
Function Code | Arguments | Type1 | Function Modifiers | Function
--- | --- | --- | --- | ---
IO$_ACCESS | P1,[P2],[P3],[P4],[P5] | V | IO$M_CREATE IO$M_ACCESS | Search a directory for a specified file and access the file if found.
IO$_ACPCONTROL | P1,[P2],[P3],[P4],[P5] | V | IO$M_DMOUNT | Perform miscellaneous control functions.
IO$_AVAILABLE |  | P |  | Clear volume valid; make DSA 2 units available.
IO$_CREATE | P1,[P2],[P3],[P4],[P5] | V | IO$M_CREATE IO$M_ACCESS IO$M_DELETE | Create a directory entry or a file.
IO$_DEACCESS | P1,[P2],[P3],[P4],[P5] | V |  | Deaccess a file and, if specified, write final attributes in the file header.
IO$_DELETE | P1,[P2],[P3],[P4],[P5] | V | IO$M_DELETE | Remove a directory entry or file header, or both.
IO$_MODIFY | P1,[P2],[P3],[P4],[P5] | V |  | Modify the file attributes or allocation, or both.
IO$_PACKACK |  | P |  | Update UCB 3 fields if RX02; initialize volume valid on other devices. Bring DSA units online.
IO$_READLBLK | P1,P2,P3 | L | IO$M_DATACHECK IO$M_INHRETRY | Read logical block.
IO$_READPBLK | P1,P2,P3 | P | IO$M_DATACHECK IO$M_INHRETRY IO$M_INHSEEK | Read physical block.
IO$_READVBLK | P1,P2,P3 | V | IO$M_DATACHECK IO$M_INHRETRY | Read virtual block.
IO$_SENSECHAR |  | P |  | Sense the device-dependent characteristics and return them in the I/O status block.
IO$_SENSEMODE |  | L |  | Sense the device-dependent characteristics and return them in the I/O status block.
IO$_UNLOAD |  | P |  | Clear volume valid; make DSA units available and spin down the volume.
IO$_WRITELBLK | P1,P2,P3 | L | IO$M_DATACHECK IO$M_ERASE IO$M_INHRETRY | Write logical block.
IO$_WRITEPBLK | P1,P2,P3 | P | IO$M_DATACHECK IO$M_ERASE IO$M_INHRETRY IO$M_INHSEEK | Write physical block.
IO$_WRITEVBLK | P1,P2,P3 | V | IO$M_DATACHECK IO$M_ERASE IO$M_INHRETRY | Write virtual block.

1V = virtual; L = logical; P = physical
2Digital Storage Architecture
3unit control block

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