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

#### FSCBK

Prolog

Control Block Contents
FSCBK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### FSCBK Prolog

     NAME       : HCPFSCBK
     DESCRIPTION: Free Storage Counter Block
     DSECT      : FSCBK
     FUNCTION   : Storage accounting for control blocks used in
                  the free storage limit detection function.
     LOCATED BY : VMDFSCBK field of HCPVMDBK
     CREATED BY : HCPBVM for an origin VMDBK. Non-origin VMDBKs
                  are assigned the address of the origin FSCBK.
     DELETED BY : HCPUSP deletes the FSCBK when the origin VMDBK
                  logs off if FSCCOUNT is zero, Otherwise it will
                  be released when HCPFRGDC decrements FSCCOUNT
                  to zero.
     SERIALIZED : Informal spin lock FSCLOCK will be used to
                  serialize the FSCCOUNT, FSCGRACE and FSCFLAG
                  fields.

#### FSCBK Control Block Content

#### FSCBK DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      FSCBK          Free Storage Counter Block
    0000    0 Dbl-Word     8 FSCUSER (0)    Userid if user has logged off.
    0000    0 Signed       4 FSCVMDBK       Origin VMDBK address if user is
                                            logged on.
    0004    4 Signed       4 *              Reserved for IBM use.
    0008    8 Dbl-Word     8 FSCGRACE       Timestamp for grace period.
                                            FSCLOCK must be held to update
                                            this field.
    0010   16 Signed       4 FSCCOUNT       Number of doublewords of free
                                            storage currently held by user
                                            for monitored control blocks.
                                            FSCLOCK must be held to update
                                            this field.
    0014   20 Signed       4 FSCSTATS (0)   Limit detection status
    0014   20 Bitstring    1 * (3)          Reserved for IBM use.
    0017   23 Bitstring    1 FSCFLAG        Flags. Serialized with FSCLOCK.
              .1.. ....      FSCWRNG        X'40' FSCWRNG Warning message was
                                            issued.
              ..1. ....      FSCSTOP        X'20' FSCSTOP Virtual machine is
                                            placed in a stopped sta 2nd
                                            message was issued.
              ...1 ....      FSCFORCE       X'10' FSCFORCE Logoff message was
                                            issued.
              .... 1...      FSCEXMPT       X'08' FSCEXMPT User is exempt
                                            from the stop and force ac of the
                                            free storage limit detection
                                            function.
              .... .1..      FSCGRCON       X'04' FSCGRCON A 1 minute grace
                                            period is allowed
    0018   24 Signed       4 FSCLOCK        This is an informal spin lock.
                                            The lock must be held to update
                                            COUNT, GRACE and FLAGS. Use test
                                            and set to update.
              00000004       FSCSIZE        ((*-FSCBK)+7)/8 FSCBK size in
                                            double-words

#### FSCBK Storage Layout

    *** FSCBK - Free Storage Counter Block
    *
    *     +---------------------------+---------------------------+
    *   0 |         FSCVMDBK          |///////////////////////////|
    *     +---------------------------+---------------------------+
    *   8 |                       FSCGRACE                        |
    *     +---------------------------+--------------------+------+
    *  10 |         FSCCOUNT          |////////////////////|:FLAG |
    *     +---------------------------+--------------------+------+
    *  18 |         FSCLOCK           | 1C
    *     +---------------------------+
    *
    *** FSCBK - Free Storage Counter Block

#### FSCBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    FSCCOUNT       0010
    FSCEXMPT       0017 08
    FSCFLAG        0017
    FSCFORCE       0017 10
    FSCGRACE       0008
    FSCGRCON       0017 04
    FSCLOCK        0018
    FSCSIZE        0018 00000004
    FSCSTATS       0014
    FSCSTOP        0017 20
    FSCUSER        0000
    FSCVMDBK       0000
    FSCWRNG        0017 40

This information is based on z/VM V6R1.0. Last updated on 18 Feb 2010 at 08:42:00 EDT.
Copyright IBM Corporation, 1990, 2008