The IECTRKAD callable service or the TRKADDR macro can be used
to perform the following operations on both 16-bit and 28-bit cylinder
addresses:
- Calculate the relative track number on the volume
- Compare two track addresses
- Extract the 28-bit cylinder number
- Extract the 4-bit track number
- Increment the track address by one track and increment the cylinder
number if necessary.
- Normalize cylinder number to permit comparing one cchh against
another
- Convert a relative track number to a 28-bit cylinder address
- Set the cylinder number in a 28-bit track address
- Convert a normalized track address into an absolute 28-bit track
address.
See
Call for converting and comparing 28-bit cylinder addresses (IECTRKAD) and
Perform calculations and conversions with 28-bit cylinder addresses (TRKADDR macro) for more
information.