Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

#### HYPMAP

Prolog

Control Block Contents
HYPMAP DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### HYPMAP Prolog

     Name       : HYPMAP
     Description: Hyperblock Mapping Table
     DSECT      : HYPMAP
     Function   : HYPMAP is the hyperblock mapping table for
                  read-only disks. It contains a header plus an
                  entry for each 4K page of hyperblocks (or FSTs
                  for a STAT) associated with the accessed disk.
                  HYPMAP is used mainly by file management to
                  reduce the paging overhead when searching for a
                  file on a read-only disk. HYPMAP is called by
                  the HYPMAP macro.

#### HYPMAP Control Block Content

#### HYPMAP DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      HYPMAP         Hyperblock Mapping Table
                 H E A D E R
    0000    0 Signed       4 HYPMSIZE       Size of table (DWORDS)
    0004    4 Signed       4 HYPMENTS       Number of entries in table
              00000001       HYPMHSIZ       (*-HYPMAP+7)/8 Size of header
                                            (DWORDS)
                 T A B L E   E N T R I E S
    0008    8 Signed       4 HYPTAB (0)     Start of table
    0008    8 Signed       2 HYPMBLKC       Number of hyperblocks/FST's on
                                            the page mapped by this table
                                            entry
    000A   10 Signed       2 *              ** Unused **
    000C   12 Address      4 HYPMAHYP       Pointer to hyperblock
    0010   16 Character   16 HYPMFID (0)    ID of last file in this block
    0010   16 Character    8 HYPMFN (0)     Filename
    0010   16 Character    4 HYPMFN1        First half of filename
    0014   20 Character    4 HYPMFN2        Second half of filename
    0018   24 Character    8 HYPMFT (0)     Filetype
    0018   24 Character    4 HYPMFT1        First half of filetype
    001C   28 Character    4 HYPMFT2        Second half of filetype
    0020   32 Character    1 HYPMNEXT (0)   Start of next entry
              00000018       HYPMLEN        *-HYPTAB Length of table entry

#### HYPMAP Storage Layout

    *** HYPMAP - Hyperblock Mapping Table
    *
    *     +---------------------------+---------------------------+
    *   0 |         HYPMSIZE          |         HYPMENTS          |
    *     +-------------+-------------+---------------------------+
    *   8 |  HYPMBLKC   |/////////////|         HYPMAHYP          |
    *     +-------------+-------------+---------------------------+
    *  10 |         HYPMFN1           |         HYPMFN2           |
    *     +---------------------------+---------------------------+
    *  18 |         HYPMFT1           |         HYPMFT2           |
    *     +---------------------------+---------------------------+
    *
    *** HYPMAP - Hyperblock Mapping Table

#### HYPMAP Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    HYPMAHYP       000C
    HYPMBLKC       0008
    HYPMENTS       0004
    HYPMFID        0010
    HYPMFN         0010
    HYPMFN1        0010
    HYPMFN2        0014
    HYPMFT         0018
    HYPMFT1        0018
    HYPMFT2        001C
    HYPMHSIZ       0004 00000001
    HYPMLEN        0020 00000018
    HYPMNEXT       0020
    HYPMSIZE       0000
    HYPTAB         0008

This information is based on z/VM V5R2.0.
Last updated on 6 Dec 2005 at 15:39:54 EDT.
Copyright IBM Corporation, 1990, 2005