NOTE (Note-Address) Macro

Format

Requirements for the caller

AMODE:: 24
RMODE:: 24
ASC Mode:: Primary

Parameters

filename | (1): The macro obtains identification for a physical record or logical block that was last read from or written to the file specified for filename (as a symbol or in register notation). At least one READ or WRITE operation should be successfully completed by using the CHECK macro before issuing the NOTE macro. To NOTE a wanted record successfully, the POINTR, POINTS, or POINTW macros must not be issued between CHECK and NOTE.

For magnetic tape, the last record that is read or written in the specified file is identified by the number of physical records that are read or written from the load point. The physical record number is returned in binary in the three low-order bytes of register 1. The high-order byte contains binary zero.

For CKD DASD, the binary number that is returned in register 1 is in the form cchr, where

  cc = cylinder number
   h = track number
   r = record number within the track

Register 0 contains, in the two low-order bytes, the unused space that remains on the track that follows the end of the identified record.

For FBA devices, register 1 contains an address relative to the beginning of the file in the form cccb, where ccc is the relative number of the current control interval (origin 0), and b is the relative block number within the current CI (origin 1). Register 0 contains the length of the longest logical block that could completely fit in the CI following the NOTEd logical block. A logical 3 bytes longer than the returned value fits in the CI if it is of the same length as both the NOTEd block and the block that precedes the NOTEd block. (This means that if the CI is exactly filled when the NOTE was issued, a value of -3 would be passed back in register 0.)

You must provide a 4- or 6-byte field and store in it the record identification and the remaining capacity so that it can be used later by a POINTR or POINTW macro to find the NOTEd record again. The remaining 2-byte track or CI capacity is needed only when a WRITE SQ is to follow the POINTR or POINTW.