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