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| Prolog Control Block Contents SNTBK DSECT Storage Layout Cross Reference (Contains links to field and bit definitions) |
Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

SNTBK Prolog | Top of page

     NAME       : HCPSNTBK
     DESCRIPTION: System Name Table Block
     DSECT      : SNTBK
     FUNCTION   : This block is used to keep track of a system data
                  file that is brought into the system.
     LOCATED BY : The pointer to this chain of blocks is located in
                  HCPNSU, using NSUNSYAN for NSSs, NSUNSGAN for
                  DCSSs, NSUIMGAN for images, and NSUNLSAN for
                  NLS files.
                  - In HCPSHRBK, pointer SHRSNTPT will point to the
                  associated HCPSNTBK.
                  Pointer SHRLSSA will point to the segment space
                  through which the shared segment was loaded.
                  - In HCPPGMBK, using the PGMVM pointer will point to the
                  associated HCPSNTBK.
                  - SNTFWDPT will point to the next HCPSNTBK in the chain.
                  - The end of chain is located when the SNTFWDPT equals
                  the address of NSUNSYAN, NSUNSGAN OR NSUIMGAN.
                  - In HCPIMGBK, IMGSNTBK will point to the
                  associated HCPSNTBK.
     CREATED BY : HCPNSL when loading the NSS or DCSS for the first
                  time.
                  - HCPNSD will build this block for the duration of the
                  processing of the DEFSEG and DEFSYS commands.
                  - HCPNSS will build this block for the duration of the
                  processing of the SAVESEG and SAVESYS commands.
                  - HCPNSI will build this block for the duration
                  of processing of the diagnose X'74' instruction
                  to save or load an image, and the diagnose
                  X'CC' instruction to create an NLS message
                  repository.
                  - HCPNSR will build this block when opening an
                  image library or NLS message repository file.
     DELETED BY : HCPNSP will delete this block when the count fields
                  of an NSS or DCSS go to zero. The fields are
                  SNTUSRSH and SNTUSREX.
                  - HCPNSD will delete this block after processing
                  the DEFSEG or DEFSYS command.
                  - HCPNSS will delete this block after processing the
                  SAVESEG or SAVESYS command.
                  - HCPNSI will delete this block after processing
                  diagnose X'74' to save or load an image, or
                  diagnose X'CC' to create an NLS message
                  repository.
                  - HCPNSR will delete this block when closing the
                  image library or NLS message repository.
     RELOCATION CONSIDERATIONS : None
     COMMENTS   :
                  - The size of this block is 4K, a page of storage.
                  - *****NOTE***** This control block maps the
                  descriptor page for certain system data files.
                  Extreme care must be exercised when updating this
                  block, to avoid causing files created prior to
                  the update to break. Changes must be made in an
                  upward-compatible way
                  - Two formats (31-bit and 64-bit) of the SNTBK are
                  defined here.  The 31-bit format is an old format
                  that exists only on spool for a below-2G NSS,
                  DCSS, NLS, or IMG. When a 31-bit format SNTBK is
                  read-in it is converted to 64-bit format by
                  HCPNSBTG. Similarly, when a below-2G file is
                  written out, HCPNSBGT converts it from 64-bit
                  format to 31-bit format before the write is done.
                  All in-storage accesses of the SNTBK block by CP
                  are done using the 64-bit format. When converting
                  between the 31-bit and 64-bit formats, HCPNSB
                  uses only a subset of the original 31-bit field
                  names (specifically those defined at the
                  higher-level encapsulating several smaller
                  fields). As a result, some of the 31-bit field
                  names are no longer referenced by CP and have
                  been "removed" or "reserved" as indicated in the
                  list below.  See PITS 2U00987 for more details.
                  Reserved --> points to labels that have been
                  removed, but their corresponding DS statements
                  are still used as "Reserved" declarations to
                  preserve SNTBK offsets.
                  Removed --> points to labels and EQUates that
                  have been completely removed, for doing so
                  does not disrupt SNTBK offsets.
                  31-bit format      64-bit format
                  SNTMEMSR(3-word)   SNTMSRG(5-word)
                  SNTSTPAG(32-bit)   SNTSTPGG(64-bit)_
                  SNTENPAG(32-bit)   SNTENPGG(64-bit)
      eserved --> SNTLODCT(32-bit)   SNTLODCG(32-bit)
                  SNTCPNTL(32-bit)   SNTCPNTG(32-bit)
                  SNTNOTAM(32-bit)   SNTNOTAG(32-bit)
                  SNTMENVF(1-byte)   SNTMENVG(1-byte)
                  SNTRANGE(2-word)   SNTRANGG(4-word)
                  SNTPRMAX(=128)     SNTPRMXG(=64)
                  SNTRANS (32-bit)   SNTRANSG(64-bit)
                  Removed --> SNTRSNOF(3-byte)   SNTRSNOG(7-byte)
                  Removed --> SNTRNGFG(1-byte)   SNTRGFGG(1-byte)
                  SNTRANE (32-bit)   SNTRANEG(64-bit)
                  SNTMEMDA(4-word)   SNTMEMDG(6-word)
                  SNTMSSNM(2-word)   SNTMSSNG(2-word)
                  SNTMEMST(32-bit)   SNTMEMSG(64-bit)
                  Removed --> SNTMEMSP(3-byte)   SNTMSPG (7-byte)
                  Removed --> SNTMSTAT(1-byte)   SNTMSTAG(1-byte)
                  SNTMSSA (32-bit)   SNTMSSAG(32-bit)

SNTBK Control Block Content | Top of page

     SNTBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SNTBK          System Name Table Block
    0000    0 Dbl-Word     8 SNTASM0 (128)  General Information SNTBK/SHRBK
                                            queue lock (SNTSHRLK)
    0400 1024 Dbl-Word     8 SNTASM1 (128)  Reserved
    0800 2048 Dbl-Word     8 SNTASM2 (128)  Page Range Information Segment
                                            Space Member List
    0C00 3072 Dbl-Word     8 SNTASM3 (128)  Member's Segment Space List
                                            Variable list of ASAs for Image
                                            Files
         |                                                          |
         |        SNTASM0 - General Information                     |
         |                - SNTBK/SHRBK queue lock (SNTSHRLK)       |
         |                                                          |
    0000    0 Address      4 SNTFWDPT       Forward pointer to the next
                                            SNTBK.
    0004    4 Address      4 SNTBCKPT       Backward pointer to the next
                                            SNTBK.
    0008    8 Character   12 SNTNAMFL (0)   This field used to move the
                                            following two fields in HCPNSBWD.
    0008    8 Character    8 SNTNAME        Name of the NSS, DCSS, image, or
                                            NLS.
    0010   16 Signed       4 SNTFLAGS (0)   Flags for the SNTBK.
    0010   16 Bitstring    1 SNTTYPFG       Type information flag.
              1... ....      SNTRSTD        X'80' SNTRSTD Indicates that this
                                            NSS or DCSS has restricted use
                                            and must have a NAMESAVE entry in
                                            the user's directory.
              .1.. ....      SNTCPUSE       X'40' SNTCPUSE Indicates that
                                            this is a CP NSS/DCSS - meaning
                                            CP will write to the parts of
                                            this NSS/DCSS with ranges defined
                                            as 'SC'.
              ..1. ....      SNTLSS         X'20' SNTLSS This bit indicates
                                            that this is a segment space
                                            definition that contains member
                                            saved segments.
              ...1 ....      SNTMSS         X'10' SNTMSS This bit indicates
                                            that this is a member saved
                                            segment definition. NOTES : If
                                            both SNTLSS and SNTMSS are off
                                            then this is a named saved
                                            segment.
              .... 1...      SNTNLS         X'08' SNTNLS This is an NLS.
              .... .1..      SNTIMG         X'04' SNTIMG This is an Image.
              .... ..1.      SNTSYS         X'02' SNTSYS This is an NSS.
              .... ...1      SNTSEG         X'01' SNTSEG This is a DCSS.
              1... ....      SNTRSTD        X'80' SNTRSTD Indicates that this
                                            NSS or DCSS has restricted use
                                            and must have a NAMESAVE entry in
                                            the user's directory.
              .1.. ....      SNTCPUSE       X'40' SNTCPUSE Indicates that
                                            this is a CP NSS/DCSS - meaning
                                            CP will write to the parts of
                                            this NSS/DCSS with ranges defined
                                            as 'SC'.
              ..1. ....      SNTLSS         X'20' SNTLSS This bit indicates
                                            that this is a segment space
                                            definition that contains member
                                            saved segments.
              ...1 ....      SNTMSS         X'10' SNTMSS This bit indicates
                                            that this is a member saved
                                            segment definition. NOTES : If
                                            both SNTLSS and SNTMSS are off
                                            then this is a named saved
                                            segment.
              .... 1...      SNTNLS         X'08' SNTNLS This is an NLS.
              .... .1..      SNTIMG         X'04' SNTIMG This is an Image.
              .... ..1.      SNTSYS         X'02' SNTSYS This is an NSS.
              .... ...1      SNTSEG         X'01' SNTSEG This is a DCSS.
    0011   17 Bitstring    1 SNTSTAFG       Status information flag.
              .... .1..      SNTABEND       X'04' SNTABEND This bit indicates
                                            that an abend should be issued
                                            when the Auxiliary Storage
                                            Manager or Real Storage Manager
                                            in use counts are not the same.
              .... ...1      SNTPENDP       X'01' SNTPENDP This bit indicates
                                            that the NSS, DCSS, image, or NLS
                                            file should be purged when the
                                            total user count goes to zero.
              The following are the flags that indicate status.
           The field below, SNTENVFG, is kept in this block for
           compatibility only. It has been superceded by SNTMENVG.
           The values in this field should not be used in code other
           than the compatibility code currently referencing it.
           This field is defined to contain the virtual machine mode
           in which the NSS was saved. It therefore can have only
           one value.
           The field that supercedes this one, SNTMENVF/SNTMENVG,
           was defined as indicating which virtual machine modes
           were specified on the DEFSYS command. It now is defined
           as indicating in which mode(s) the NSS can be IPLed.
    0012   18 Bitstring    1 SNTENVFG       Flag information byte
              00000001       SNT370MD       X'01' SNT370MD Indicates a 370
                                            mode machine
              00000002       SNTESAMD       X'02' SNTESAMD Indicates an
                                            ESA-370 mode machine
              00000004       SNTXCMD        X'04' SNTXCMD Indicates an ESA/XC
                                            mode machine
    0013   19 Bitstring    1 SNTTYPF2       Type information byte 2.
              1... ....      SNTSHWRT       X'80' SNTSHWRT Indicates that
                                            there at least one shared
                                            writeable page range (SW or SN).
              .1.. ....      SNTVMGRP       X'40' SNTVMGRP Indicates that a
                                            VMGROUP attribute is assigned to
                                            this NSS.
              ..1. ....      SNTLNSHR       X'20' SNTLNSHR Indicates that any
                                            user is allowed to load an
                                            exclusive version of this saved
                                            segment. Note that this bit is
                                            only valid for DCSS and segment
                                            space SNTBKs.
            To update the SNTUSRSH or SNTUSREX count for NSSs or
            saved segments the SNTBK-SHRBK Queue lock (SNTSHRLK)
            must be held exclusively.
    0014   20 Signed       4 SNTUSRSH       Count of NSS or DCSS users in
                                            shared mode or count of all users
                                            of an image library.
    0018   24 Signed       4 SNTUSREX       Count of NSS or DCSS users in
                                            exclusive mode. NOTES : SNTUSRSH
                                            + SNTUSREX = The number of loads
                                            of this name. This is the number
                                            of SHRBKs on this SNTBK's SHRBK
                                            chain.
    001C   28 Address      4 SNTSTLPT       Pointer to the STLBK. It contains
                                            PGMBK info
    0020   32 Address      4 SNTSDFBK       Pointer to the SDFBK. Used to
                                            communicate with the SDF system.
                 The following field SNTCOUNT is used to allow a move
          of the following fields in HCPNSBWD:
           SNTMINSZ, SNTRNGCT, SNTDESCT, SNTENVCT, SNTKEYCT, SNTSTRCT,
           SNTNDTCT, SNTPRFLG, Reserved byte, SNTPREGS
    0024   36 Character   32 SNTCOUNT (0)
    0024   36 Signed       4 SNTMINSZ       Indicates the minimum size in
                                            which the NSS can be IPLed.
    0028   40 Signed       4 SNTRNGCT       Count of valid page range entries
                                            for an NSS or DCSS.
    002C   44 Signed       4 SNTDESCT       Count of descriptor pages defined
                                            for an NSS, DCSS, image, or NLS
                                            file.
    0030   48 Signed       4 SNTENVCT       Count of environment pages for an
                                            NSS.
    0034   52 Signed       4 SNTKEYCT       Count of key pages for an NSS or
                                            DCSS.
    0038   56 Signed       4 SNTSTRCT       Count of storage pages saved for
                                            an NSS, DCSS, image, or NLS file.
    003C   60 Signed       4 SNTNDTCT       Count of storage pages defined
                                            with the no-data-saved attribute.
                                            This count is not calculated
                                            until the NSS or DCSS is saved.
                                            The total number of pages defined
                                            is SNTSTRCT+SNTNDTCT
    0040   64 Bitstring    1 SNTPRFLG       PARMREGS flags
              1... ....      SNTPRDEF       X'80' SNTPRDEF PARMREGS OPTION
                                            SPECIFIED ON DEFSYS
              .1.. ....      SNTPRNO        X'40' SNTPRNO PARMREGS=NONE
                                            SPECIFIED ON DEFSYS
              1... ....      SNTPRDEF       X'80' SNTPRDEF PARMREGS OPTION
                                            SPECIFIED ON DEFSYS
              .1.. ....      SNTPRNO        X'40' SNTPRNO PARMREGS=NONE
                                            SPECIFIED ON DEFSYS
    0041   65 Bitstring    1 *              Reserved for IBM use
    0042   66 Bitstring    2 SNTPREGS (0)   PARMREGS registers
    0042   66 Signed       1 SNTPRBEG       PARMREGS beginning register
    0043   67 Signed       1 SNTPREND       PARMREGS ending register
    0044   68 Address      4 SNTSHRPT       Forward anchor for SHRBK chain.
    0048   72 Address      4 SNTCPNTE       CP Notification Address - this
                                            address will be called each time
                                            a virtual machine releases the
                                            system data file.
              The following definition of SNTMEMSR is for the
                              31-bit format
    004C   76 Character   12 SNTMEMSR (0)
    004C   76 Signed       2 SNTMEMCT       Count of member saved segments
                                            within this segment space. This
                                            field is only valid if SNTLSS is
                                            on. This field indicates the
                                            number of member saved segment
                                            directory entries located in the
                                            directory area (SNTASM2 &
                                            SNTASM3). It may not be larger
                                            than SNTMAXCT.
    004E   78 Signed       2 *              Reserved for IBM use
    0050   80 Signed       4 SNTSTPAG       The lowest page defined for this
                                            segment. This page number has not
                                            been rounded down to the nearest
                                            megabyte boundary for segment
                                            spaces.
    0054   84 Signed       4 SNTENPAG       The highest page defined for this
                                            segment. This page number has not
                                            been rounded up to the nearest
                                            megabyte boundary for segment
                                            spaces.
    0058   88 Signed       4 *              Reserved for IBM use
    005C   92 Address      4 SNTCPNTL       CP Notification Address - this
                                            address will be called when the
                                            last virtual machine releases the
                                            system data file.
    0060   96 Address      4 SNTNOTAM       CP Notification Address - this
                                            address will be called when a
                                            saved segment is purged.
    0064  100 Signed       4 *              Reserved for IBM use.
    0068  104 Bitstring    1 SNTMENVF       Flag used to indicate the virtual
                                            machine environments in which the
                                            NSS can be IPLed.
    0069  105 Bitstring    1 * (7)          Reserved for IBM use.
              Redefinition of SNTMEMSR for 64-bit format SNTBK
          SNTMSRG is used to move the following fields in HCPNSBWD:
                 SNTMEMCT, Reserved field, SNTSTPGG, SNTENPGG
    004C   76 Character   20 SNTMSRG (0)
    004C   76 Signed       2 *              SNTMEMCT
    004E   78 Signed       2 *              Reserved for IBM use
    0050   80 Dbl-Word     8 SNTSTPGG       Lowest page for this segment
    0058   88 Dbl-Word     8 SNTENPGG       Highest page for this segment
            To update the SNTLODCG count for NSSs or saved segments
            the SNTBK-SHRBK Queue lock (SNTSHRLK) must be held
            exclusively.
    0060   96 Signed       4 SNTLODCG       The number of loads via this
                                            segment space. This is the number
                                            of SHRBKs that point to this
                                            segment space. This count is only
                                            valid if SNTLSS is on.
    0064  100 Address      4 SNTCPNTG       CP Notification Address - this
                                            address will be called when the
                                            last virtual machine releases the
                                            system data file
    0068  104 Address      4 SNTNOTAG       CP Notification Address - this
                                            address will be called when a
                                            saved segment is purged
    006C  108 Bitstring    1 SNTMENVG       Flag used to indicate the virtual
                                            machine environments in which the
                                            NSS can be IPLed
              1... ....      SNTMULT        X'80' SNTMULT This NSS can be
                                            IPLed in more than one virtual
                                            machine mode.
              .... 1...      SNTZMM         X'08' SNTZMM This bit indicates
                                            the z-arch virtual machine can
                                            IPL this NSS.
              .... .1..      SNTXCMM        X'04' SNTXCMM This bit indicates
                                            the ESA/XC virtual machine can
                                            IPL this NSS.
              .... ..1.      SNTESAMM       X'02' SNTESAMM This bit indicates
                                            the ESA-370 virtual machine can
                                            IPL this NSS.
              .... ...1      SNT370MM       X'01' SNT370MM This bit indicates
                                            the System/370 virtual machine
                                            can IPL this NSS.
    006D  109 Bitstring    1 * (3)          Reserved for IBM use
                End of redefinitions for 64-bit format SNTBK
                        SNTBK/SHRBK queue lock (SNTSHRLK)
                        ******************************---
             Lock type: This is a formal shared or exclusive lock
             Resource serialized: This lock manages the SHRBK queue
             chained from the SNTBK. The lock will be obtained
             shared when scanning the queue and exclusive when
             adding to, or deleting from, the queue. This lock is
             also used to serialize the following SNTBK
             'use-counts': SNTUSRSH, SNTUSREX, SNTLODCG. The lock
             must be obtained exclusive when updating these counts.
             Notes      : If the Saved Segment SNTBK queue or Named Saved
             System SNTBK queue lock is held exclusively then the
             SNTBK/SHRBK lock does not need to be obtained to add/
             remove a SHRBK or increment/decrement the
             'use-counts'.
             See the general comments in HCPNSUBK COPY file for
             detailed Saved Segment or NSS locking information.
    0070  112 Dbl-Word     8 SNTSHRLK (3)   SNTBK/SHRBK queue defer lock
    0088  136 Dbl-Word     8 SNTPURID       User id who issued PURGE command
                                            while SAVESEG/SAVESYS command is
                                            processing.
    0090  144 Address      4 *              Reserved for IBM use
    0094  148 Address      4 SNTXBLBK       Address of XBLBK for NSSs
    0098  152 Address      4 SNTENVPG       Address of environment page. This
                                            is a System Virtual address.
    009C  156 Address      4 SNTASCBK       Address of ASCBK for this space
    00A0  160 Bitstring    4 SNTTODLD       TOD(0-31) when image was loaded
    00A4  164 Bitstring    4 *              Reserved for IBM use
    00A8  168 Character    8 SNTMARKR       Eye-catcher
                                            C'>>SNT<<<'
    004C   76 Signed       2 SNTLOGCT       Count of segment spaces
                                            containing this member save
                                            segment. This field is only valid
                                            if SNTMSS is on. This field
                                            indicates the number of segment
                                            space directory entries located
                                            in the directory area (SNTASM3).
                                            It may not be larger than
                                            SNTMAXCT.
                              End of SNTASM0
         |                                                          |
         | SNTASM2 - Page Range Information                         |
         |                    OR                                    |
         |           Segment Space Member List                      |
         |                                                          |
              Redefinition of SNTRANGE for 31-bit Page Range
              The page range will be in the form SSSPP0FF
                    where  SSS  = segment number
                            PP  = page number
                            0   = always 0
                            FF  = flag byte
    0800 2048 Dbl-Word     8 SNTRANGE       A pair of start/end page ranges.
    0800 2048 Signed       4 SNTRANS        First page of range. This field
                                            for NSSs and DCSSs will contain a
                                            flag in the rightmost byte.
    0804 2052 Signed       4 SNTRANE        Last page of range.
                   Redefinitions for 64-bit Page Range
              The page range will be in the form RRRRRRRRSSSPP0FF
                    where  RRRRRRRR  = region number
                                SSS  = segment number
                                 0   = always 0
                                 FF  = flag byte
    0800 2048 Bitstring   16 SNTRANGG       A pair of start/end page ranges.
              .1.. ....      SNTPRMXG       64 SNTPRMXG The maximum number of
                                            page range entries plus one entry
                                            for the fence for NSSs and DCSSs.
                                            Images have only one page range.
    0800 2048 Dbl-Word     8 SNTRANSG       First page of range. This field
                                            for NSSs and DCSSs will contain a
                                            flag in the rightmost byte.
    0808 2056 Dbl-Word     8 SNTRANEG       Last page of range.
    0800 2048 Bitstring    7 SNTRSNOG       The start page range minus the
                                            flag byte. The page range will be
                                            in the form RRRRRRRRSSSPP0FF:
                                            where RRRRRRRR = region number
                                            SSS = segment number 0 = always 0
                                            FF = flag byte
    0807 2055 Bitstring    1 SNTRGFGG       Page range storage type flag for
                                            NSSs and DCSSs.
              .... ...1      SNTEXCL        X'01' SNTEXCL This bit indicates
                                            segments that may not be shared
                                            among several users. Each user
                                            gets a separate copy of this
                                            segment.
              .... ..1.      SNTPROT        X'02' SNTPROT This bit indicates
                                            page ranges that are page
                                            protected. Users may access these
                                            pages only in read-only mode.
              .... .1..      SNTNDAT        X'04' SNTNDAT This bit indicates
                                            page ranges whose data is not
                                            saved into the SDF (no data).
             The following describes how page descriptor codes
                  correspond to settings of SNTRGFGG.
     CODE SNTRGFGG SNTNDAT  SNTPROT                    SNTEXCL
     ---- -------- -------  -------                    -------
     SW   000     0=data   0=unprotected (read/write) 0=shared
     EW   001     0=data   0=unprotected (read/write) 1=exclusive
     SR   010     0=data   1=protected   (read-only)  0=shared
     ER   011     0=data   1=protected   (read-only)  1=exclusive
     SN   100     1=nodata 0=unprotected (read/write) 0=shared
     EN   101     1=nodata 0=unprotected (read/write) 1=exclusive
     SC   110     1=nodata 1=protected   (read-only)  0-shared
          111     (reserved)
              00000000       SNTRNGSW       0 Range flag value for 'SW'
              00000001       SNTRNGEW       SNTEXCL Range flag value for 'EW'
              00000002       SNTRNGSR       SNTPROT Range flag value for 'SR'
              00000003       SNTRNGER       SNTPROT+SNTEXCL Range flag value
                                            for 'ER'
              00000004       SNTRNGSN       SNTNDAT Range flag value for 'SN'
              00000005       SNTRNGEN       SNTNDAT+SNTEXCL Range flag value
                                            for 'EN'
              00000006       SNTRNGSC       SNTNDAT+SNTPROT Range flag value
                                            for 'SC'
              00000007       SNTRNGR2       SNTNDAT+SNTPROT+SNTEXCL Reserved
                End of redefinitions for 64-bit Page Range
         |                                                          |
         |              Segment Space Member List                   |
         |                                                          |
                          Individual Member Entry
          Notes      : This is a list of entries that can overlay both
                            SNTASM2 and SNTASM3.
    0800 2048 Character   32 SNTMEMBR       Member entry
                  Redefinition of Member Entry (SNTMEMBR)
                           for 31-bit format
    0800 2048 Character   16 SNTMEMDA (0)   Used to move the next three
                                            fields
    0800 2048 Character    8 SNTMSSNM       Name of the member saved segment
    0808 2056 Signed       4 SNTMEMST       First page of range. This field
                                            will contain status information
                                            in the rightmost byte. The page
                                            number will be in form:
                        SSSPP0FF, where SSS = segment number
                                        PP  = page number
                                        0   = always 0
                                        FF  = status byte
    080C 2060 Signed       4 SNTMEMEN       Last page of range
    0810 2064 Address      4 SNTMSSA        Address of the SNTBK defining the
                                            member saved segment.
    0814 2068 Signed       4 *              Reserved for IBM use
    0818 2072 Dbl-Word     8 *              Reserved for IBM use
              00000020       SNTNTSZM       *-SNTMSSNM Length of a member
                                            saved seg entry
                   Redefinition of Member Entry (SNTMEMBR)
                            for 64-bit format
    0800 2048 Character   24 SNTMEMDG (0)   Used to move the next 3 fields in
                                            HCPNSBWD
    0800 2048 Character    8 SNTMSSNG       Name of the member saved segment
    0808 2056 Dbl-Word     8 SNTMEMSG       First page of range. This field
                                            will contain status information
                                            in the rightmost byte. The page
                                            number will be in form:
                        RRRRRRRRSSSPP0FF:
                            where RRRRRRRR  = region number
                                       SSS  = segment number
                                        PP  = page number
                                        0   = always 0
                                        FF  = status byte
    0810 2064 Dbl-Word     8 SNTMEMEG       Last page of range
    0818 2072 Address      4 SNTMSSAG       Address of the SNTBK defining the
                                            member saved segment.
    081C 2076 Signed       4 *              Reserved for IBM use
    0808 2056 Bitstring    7 SNTMSPG        Starting page number for the
                                            member
    080F 2063 Bitstring    1 SNTMSTAG       Member saved segment status byte.
              .... .1..      SNTMQNTF       X'04' SNTMQNTF Flag to indicate
                                            this entry not found during QUERY
                                            NAMES command processing
              .... ..1.      SNTMSAVD       X'02' SNTMSAVD This member saved
                                            segment has been saved
              .... ...1      SNTMPENP       X'01' SNTMPENP This member saved
                                            segment is in pending
                               End of SNTASM2
         |                                                          |
         | SNTASM3 - Member's Segment Space List                    |
         |         - Variable list of ASAs for Image Files          |
         |                                                          |
    0C00 3072 Character   16 SNTLGSEG       Segment Space Entry
                       Individual Segment Space Entry
    0C00 3072 Character    8 SNTLSSNM       Name of the segment space
    0C08 3080 Address      4 SNTLSSA        Address of the segment space's
                                            SNTBK. This field is zero if the
                                            segment space is not being used.
                                            WARNING - this field may be
                                            inaccurate under certain
                                            circumstances (like SNTBKs of
                                            members that were defined using
                                            the 'SAME' option). It is
                                            recommended that the segment
                                            space be located through SHRLSSA
                                            and compared be done on the SNTBK
                                            names, not with this address.
    0C0C 3084 Bitstring    1 SNTLSTAT       Segment space status byte
              .... .1..      SNTLQNTF       X'04' SNTLQNTF Flag to indicate
                                            this entry not found during QUERY
                                            NAMES command processing.
              .... ..1.      SNTLOPEN       X'02' SNTLOPEN Segment space
                                            found open don't compress.
              .... ...1      SNTLPENP       X'01' SNTLPENP This segment space
                                            is in pending purge status.
    0C0D 3085 Bitstring    3 SNTLSSCT       Number of segment space SNTBKs by
                                            this name pointing to this member
                                            SNTBK. Note 3 bytes are enough as
                                            each SNTBK occupies a full page
                                            and we can never have X'FFFFFF'
                                            SNTBKs.
              00000010       SNTNTSZL       *-SNTLSSNM The size of a segment
                                            space directory entry.
                      End of Member's Segment Space List
                     Variable list of ASAs for Image Files
              0000000A       SNTAPMAX       10 The maximum number of address
                                            entries in this ASA/virtual
                                            address table for an image or NLS
                                            file.
    0C00 3072 Address      4 SNTASALT       Address of the next page in the
                                            ASA/virtual address table. This
                                            field applies only to image and
                                            NLS files.
              00000C04       SNTNASA        * Next ASA in the table for image
                                            files.
                 End of Variable List of ASAs for Image Files
                               End of SNTASM3

SNTBK Storage Layout | Top of page

    *** SNTBK - System Name Table Block
    *
    *     +-------------------------------------------------------+
    *   0 |                                                       |
    *     =                       SNTASM0                         =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 400 |                                                       |
    *     =                       SNTASM1                         =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 800 |                                                       |
    *     =                       SNTASM2                         =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * C00 |                                                       |
    *     =                       SNTASM3                         =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *1000
    *
    *** SNTBK - System Name Table Block

    *** Overlay for SNTASM0 in SNTBK
    *
    *     +---------------------------+---------------------------+
    *   0 |         SNTFWDPT          |         SNTBCKPT          |
    *     +---------------------------+---------------------------+
    *   8 |                       SNTNAME                         |
    *     +------+------+------+------+---------------------------+
    *  10 |:TYPFG|:STAFG|:ENVFG|:TYPF2|         SNTUSRSH          |
    *     +------+------+------+------+---------------------------+
    *  18 |         SNTUSREX          |         SNTSTLPT          |
    *     +---------------------------+---------------------------+
    *  20 |         SNTSDFBK          |         SNTMINSZ          |
    *     +---------------------------+---------------------------+
    *  28 |         SNTRNGCT          |         SNTDESCT          |
    *     +---------------------------+---------------------------+
    *  30 |         SNTENVCT          |         SNTKEYCT          |
    *     +---------------------------+---------------------------+
    *  38 |         SNTSTRCT          |         SNTNDTCT          |
    *     +------+------+------+------+---------------------------+
    *  40 |:PRFLG|//////|:PRBEG|:PREND|         SNTSHRPT          |
    *     +------+------+------+------+-------------+-------------+
    *  48 |         SNTCPNTE          |  SNTMEMCT   |/////////////|
    *     +---------------------------+-------------+-------------+
    *  50 |         SNTSTPAG          |         SNTENPAG          |
    *     +---------------------------+---------------------------+
    *  58 |///////////////////////////|         SNTCPNTL          |
    *     +---------------------------+---------------------------+
    *  60 |         SNTNOTAM          |///////////////////////////|
    *     +------+--------------------+---------------------------+
    *  68 |:MENVF|////////////////////////////////////////////////|
    *     +------+------------------------------------------------+
    *  70
    *
    *** Overlay for SNTASM0 in SNTBK

    *** Overlay for SNTMEMSR in SNTBK
    *
    *                                 +-------------+-------------+
    *  48 ...                      4C |/////////////|/////////////|
    *                                 +-------------+-------------+
    *  50
    *
    *** Overlay for SNTMEMSR in SNTBK

    *** Overlay for SNTSTPAG in SNTBK
    *
    *     +-------------------------------------------------------+
    *  50 |                       SNTSTPGG                        |
    *     +-------------------------------------------------------+
    *  58 |                       SNTENPGG                        |
    *     +---------------------------+---------------------------+
    *  60 |         SNTLODCG          |         SNTCPNTG          |
    *     +---------------------------+------+--------------------+
    *  68 |         SNTNOTAG          |:MENVG|////////////////////|
    *     +---------------------------+------+--------------------+
    *  70 |                                                       |
    *     =                       SNTSHRLK                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  88 |                       SNTPURID                        |
    *     +---------------------------+---------------------------+
    *  90 |///////////////////////////|         SNTXBLBK          |
    *     +---------------------------+---------------------------+
    *  98 |         SNTENVPG          |         SNTASCBK          |
    *     +---------------------------+---------------------------+
    *  A0 |         SNTTODLD          |///////////////////////////|
    *     +---------------------------+---------------------------+
    *  A8 |                       SNTMARKR                        |
    *     +-------------------------------------------------------+
    *  B0
    *
    *** Overlay for SNTSTPAG in SNTBK

    *** Overlay for SNTMEMCT in SNTBK
    *
    *                                 +-------------+
    *  48 ...                      4C |  SNTLOGCT   | 4E
    *                                 +-------------+
    *
    *** Overlay for SNTMEMCT in SNTBK

    *** Overlay for SNTASM2 in SNTBK
    *
    *     +-------------------------------------------------------+
    * 800 |                       SNTRANGE                        |
    *     +-------------------------------------------------------+
    * 808
    *
    *** Overlay for SNTASM2 in SNTBK

    *** Overlay for SNTRANGE in SNTBK
    *
    *     +---------------------------+---------------------------+
    * 800 |         SNTRANS           |         SNTRANE           |
    *     +---------------------------+---------------------------+
    * 808
    *
    *** Overlay for SNTRANGE in SNTBK

    *** Overlay for SNTASM2 in SNTBK
    *
    *     +-------------------------------------------------------+
    * 800 |                       SNTRANGG                        |
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 810
    *
    *** Overlay for SNTASM2 in SNTBK

    *** Overlay for SNTRANGG in SNTBK
    *
    *     +-------------------------------------------------------+
    * 800 |                       SNTRANSG                        |
    *     +-------------------------------------------------------+
    * 808 |                       SNTRANEG                        |
    *     +-------------------------------------------------------+
    * 810
    *
    *** Overlay for SNTRANGG in SNTBK

    *** Overlay for SNTRANSG in SNTBK
    *
    *     +------------------------------------------------+------+
    * 800 |                   SNTRSNOG                     |:RGFGG|
    *     +------------------------------------------------+------+
    * 808
    *
    *** Overlay for SNTRANSG in SNTBK

    *** Overlay for SNTASM2 in SNTBK
    *
    *     +-------------------------------------------------------+
    * 800 |                                                       |
    *     =                       SNTMEMBR                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 820
    *
    *** Overlay for SNTASM2 in SNTBK

    *** Overlay for SNTMEMBR in SNTBK
    *
    *     +-------------------------------------------------------+
    * 800 |                       SNTMSSNM                        |
    *     +---------------------------+---------------------------+
    * 808 |         SNTMEMST          |         SNTMEMEN          |
    *     +---------------------------+---------------------------+
    * 810 |         SNTMSSA           |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 818 |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 820
    *
    *** Overlay for SNTMEMBR in SNTBK

    *** Overlay for SNTMEMBR in SNTBK
    *
    *     +-------------------------------------------------------+
    * 800 |                       SNTMSSNG                        |
    *     +-------------------------------------------------------+
    * 808 |                       SNTMEMSG                        |
    *     +-------------------------------------------------------+
    * 810 |                       SNTMEMEG                        |
    *     +---------------------------+---------------------------+
    * 818 |         SNTMSSAG          |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 820
    *
    *** Overlay for SNTMEMBR in SNTBK

    *** Overlay for SNTMEMSG in SNTBK
    *
    *     +------------------------------------------------+------+
    * 808 |                    SNTMSPG                     |:MSTAG|
    *     +------------------------------------------------+------+
    * 810
    *
    *** Overlay for SNTMEMSG in SNTBK

    *** Overlay for SNTASM3 in SNTBK
    *
    *     +-------------------------------------------------------+
    * C00 |                       SNTLGSEG                        |
    *     |                                                       |
    *     +-------------------------------------------------------+
    * C10
    *
    *** Overlay for SNTASM3 in SNTBK

    *** Overlay for SNTLGSEG in SNTBK
    *
    *     +-------------------------------------------------------+
    * C00 |                       SNTLSSNM                        |
    *     +---------------------------+------+--------------------+
    * C08 |         SNTLSSA           |:LSTAT|     SNTLSSCT       |
    *     +---------------------------+------+--------------------+
    * C10
    *
    *** Overlay for SNTLGSEG in SNTBK

    *** Overlay for SNTASM3 in SNTBK
    *
    *     +---------------------------+
    * C00 |         SNTASALT          | C04
    *     +---------------------------+
    *
    *** Overlay for SNTASM3 in SNTBK

SNTBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    SNTABEND       0011 04
    SNTAPMAX       0C0D 0000000A
    SNTASALT       0C00
    SNTASCBK       009C
    SNTASM0        0000
    SNTASM1        0400
    SNTASM2        0800
    SNTASM3        0C00
    SNTBCKPT       0004
    SNTCOUNT       0024
    SNTCPNTE       0048
    SNTCPNTG       0064
    SNTCPNTL       005C
    SNTCPUSE       0010 40
    SNTCPUSE       0010 40
    SNTDESCT       002C
    SNTENPAG       0054
    SNTENPGG       0058
    SNTENVCT       0030
    SNTENVFG       0012
    SNTENVPG       0098
    SNTESAMD       0012 00000002
    SNTESAMM       006C 02
    SNTEXCL        0807 01
    SNTFLAGS       0010
    SNTFWDPT       0000
    SNTIMG         0010 04
    SNTIMG         0010 04
    SNTKEYCT       0034
    SNTLGSEG       0C00
    SNTLNSHR       0013 20
    SNTLODCG       0060
    SNTLOGCT       004C
    SNTLOPEN       0C0C 02
    SNTLPENP       0C0C 01
    SNTLQNTF       0C0C 04
    SNTLSS         0010 20
    SNTLSS         0010 20
    SNTLSSA        0C08
    SNTLSSCT       0C0D
    SNTLSSNM       0C00
    SNTLSTAT       0C0C
    SNTMARKR       00A8
    SNTMEMBR       0800
    SNTMEMCT       004C
    SNTMEMDA       0800
    SNTMEMDG       0800
    SNTMEMEG       0810
    SNTMEMEN       080C
    SNTMEMSG       0808
    SNTMEMSR       004C
    SNTMEMST       0808
    SNTMENVF       0068
    SNTMENVG       006C
    SNTMINSZ       0024
    SNTMPENP       080F 01
    SNTMQNTF       080F 04
    SNTMSAVD       080F 02
    SNTMSPG        0808
    SNTMSRG        004C
    SNTMSS         0010 10
    SNTMSS         0010 10
    SNTMSSA        0810
    SNTMSSAG       0818
    SNTMSSNG       0800
    SNTMSSNM       0800
    SNTMSTAG       080F
    SNTMULT        006C 80
    SNTNAME        0008
    SNTNAMFL       0008
    SNTNASA        0C00 00000C04
    SNTNDAT        0807 04
    SNTNDTCT       003C
    SNTNLS         0010 08
    SNTNLS         0010 08
    SNTNOTAG       0068
    SNTNOTAM       0060
    SNTNTSZL       0C0D 00000010
    SNTNTSZM       0818 00000020
    SNTPENDP       0011 01
    SNTPRBEG       0042
    SNTPRDEF       0040 80
    SNTPRDEF       0040 80
    SNTPREGS       0042
    SNTPREND       0043
    SNTPRFLG       0040
    SNTPRMXG       0800 40
    SNTPRNO        0040 40
    SNTPRNO        0040 40
    SNTPROT        0807 02
    SNTPURID       0088
    SNTRANE        0804
    SNTRANEG       0808
    SNTRANGE       0800
    SNTRANGG       0800
    SNTRANS        0800
    SNTRANSG       0800
    SNTRGFGG       0807
    SNTRNGCT       0028
    SNTRNGEN       0807 00000005
    SNTRNGER       0807 00000003
    SNTRNGEW       0807 00000001
    SNTRNGR2       0807 00000007
    SNTRNGSC       0807 00000006
    SNTRNGSN       0807 00000004
    SNTRNGSR       0807 00000002
    SNTRNGSW       0807 00000000
    SNTRSNOG       0800
    SNTRSTD        0010 80
    SNTRSTD        0010 80
    SNTSDFBK       0020
    SNTSEG         0010 01
    SNTSEG         0010 01
    SNTSHRLK       0070
    SNTSHRPT       0044
    SNTSHWRT       0013 80
    SNTSTAFG       0011
    SNTSTLPT       001C
    SNTSTPAG       0050
    SNTSTPGG       0050
    SNTSTRCT       0038
    SNTSYS         0010 02
    SNTSYS         0010 02
    SNTTODLD       00A0
    SNTTYPFG       0010
    SNTTYPF2       0013
    SNTUSREX       0018
    SNTUSRSH       0014
    SNTVMGRP       0013 40
    SNTXBLBK       0094
    SNTXCMD        0012 00000004
    SNTXCMM        006C 04
    SNTZMM         006C 08
    SNT370MD       0012 00000001
    SNT370MM       006C 01

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:30:41 EDT.
Copyright IBM Corporation, 1990, 2020