VSAM Demystified

Accessing the VSAM Shared Information (VSI)

You can code the following instructions to get the length and address of VSI the data to be sent to anotherOS/390 image:

• Load ACB address into register RY.

• To locate the VSI for a data component:

  L RX,04(,RY)	Put AMBL address into register RX
  L 1,52(,RX)	Get data AMB address
  L 1,68(,1)	Get VSI address
  LH 0,62(,1)	Load data length
  LA 1,62(,1)	Point to data to be communicated

• To locate the VSI information for an index component of a key-sequenced data set:

  L RX,04(,RY)	Put AMBL address into register RX
  L 1,56(,RX)	Get index AMB address
  L 1,68(,1)	Get VSI address
  LH 0,62(,1)	Load data length
  LA 1,62(,1)	Point to data to be communicated

Similarly, the location of the VSI on the receiving processor can be located. The VSI level ...