The access-method-support vector list

The access-method-support vector list is pointed to by the ACB's ACBAMSVL field in the ACB DSECT. This list describes the global variables for the VTAM® program that processed the OPEN macroinstruction.

For the complete layout of the ISTAMSVL DSECT, see Access-method-support vector list (ISTAMSVL).

The access-method-support vector list consists of the following vectors:

Release-level vector

This vector contains the access method version and release number. The vector ID is X'01'.

Component-identification vector

This vector contains product identification information about a major component or feature of the VTAM licensed program. This information is used by IBM® for VTAM program maintenance. When a vector list contains multiple component-identification vectors, the first vector designates the base VTAM product; subsequent vectors designate features or other major components of VTAM. The vector ID is X'04'.

Function-list vector

This vector contains a variable-length bit string in which each bit corresponds to a particular VTAM function. If a bit is on, the corresponding function is present in the particular release of VTAM. If a bit is off, the function is not available. If the vector is not present, or if it is shorter than expected, you can assume the missing bits to be 0. The vector ID is X'05'.

The information contained in the function-list vector is also available at assembly time in global variables created with the ISTGLBAL macroinstruction. ISTGLBAL macroinstruction describes the use of global variables.

LU 6.2-support-function-list vector

This vector is provided to indicate which LU 6.2 options are supported by this release of VTAM. This vector is not present for application's that do not use VTAM's APPC API. The vector ID is X'06'.

Each subvector in this vector list can have one of the following values that correspond one-to-one with LU 6.2 global variables:

X'00': Option is not supported
X'01': Option is supported
X'02': Pass-through (VTAM offers support for the function, but the application program must implement the function.)

The vector list information is not available until execution time. Refer to the z/OS Communications Server: SNA Resource Definition Reference.