Requesting DASD Volume Information Using LSPACE

LSPACE provides information on volume size, free space on the volume, free space on the VTOC and INDEX, volume fragmentation, and VTOC status. Also provided is information on the size of the track-managed space and its free space statistics. The LSPACE macro returns status information (such as LSPACE subfunction, return code, and reason code) in the parameter list. The LSPACE macro also returns the return code in register 15. For volumes that are configured with more than 9999 cylinders, you can use the EXPMSG option to create an expanded message return area that the LSPACE macro needs. For volumes that are configured with cylinder-managed space, you can use the XEXPMSG option to create an extended expanded message return area that the LSPACE macro needs. The use of XEXPMSG is recommended for all requests to return message data. The expanded data return area (EXPDATA) will return binary data of free space and total volume space information for volumes. For volumes with cylinder-managed space, this will be returned as free space for the entire volume and free space for the track-managed space. The two sets of free space data will be the same for a volume that does not have cylinder-managed space. The use of EXPDATA is recommended for all requests to return binary data. You can have LSPACE return additional information such as the format 4 DSCB, the total number of free extents on the volume or the fragmentation index. This information can be returned in the:

Message return area
Expanded message return area
Extended expanded message return area
Data return area
Expanded data return area
Format-4 DSCB return area

The calling program must ensure that the volume to be processed remains mounted during LSPACE processing. The volume need not be allocated.

If the device is not ready when you issue LSPACE and remains not ready, LSPACE eventually gives return code 4 with a timeout message. (See Table 1.) In the current level of the system, LSPACE defaults to waiting as long as 240 seconds. You can change this amount of time by setting the byte at offset 7 in the parameter list. (See Table 1.) You must use the list and execute forms of the macro because the macro has no parameter for this.

For more information about the LSPACE return code, subfunction code, and the subfunction return and reason codes, see Table 1 and z/OS DFSMSdfp Diagnosis.