Document revision date: 30 March 2001

## OpenVMS System Management Utilities Reference Manual

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## Appendix J
System Parameters

This appendix describes OpenVMS system parameters.

Note Compaq recommends that you use AUTOGEN to modify system parameters. In special cases, however, you can use a conversational boot to modify a parameter value temporarily. To change a parameter value permanently, you must edit MODPARAMS.DAT and run AUTOGEN. For instructions, see the OpenVMS System Manager's Manual.

## J.1 How the Parameters Are Described

System parameters can be grouped into categories, as shown in Section J.1.1. Also, each parameter can have one or more attributes, listed in Section J.1.1. Each parameter also has a value.

The parameters in this appendix are listed alphabetically along with their attributes.

### J.1.1 Parameter Categories and Attributes

The system parameters can be divided into the following categories (see also Table J-1):

Category | Description
--- | ---
ACP | Parameters associated with file system caches and Files-11 ancillary control processes (ACPs)
CLUSTER | Parameters that affect OpenVMS Cluster operation
JOB | Job control parameters
LGI | Login security parameters
PQL | Parameters associated with process creation limits and quotas
RMS | Parameters associated with OpenVMS Record Management Services (RMS)
SCS | Parameters that control System Communications Services (SCS) and port driver operation. The parameters that affect SCS operation have the prefix SCS. The parameters that affect the CI780/CI750 port driver have the prefix PA.
SPECIAL | Special parameters used by Compaq. These parameters should only be changed if recommended by Compaq personnel, or if they are clearly stated to change in the installation guide or release notes of a Compaq-supplied layered product.
SYS | Parameters that affect overall system operation
TTY | Parameters associated with terminal behavior

The user can also define four parameters: USERD1, USERD2, USER3, and USER4. USERD1 and USERD2 are dynamic.

Attributes for Parameters

Parameters can have one or more of the following attributes:

Attribute | Description
--- | ---
AUTOGEN | AUTOGEN calculates and modifies values
DYNAMIC | Active values can be modified
FEEDBACK | FEEDBACK information available for AUTOGEN calculations
GEN | Affects the creation and initialization of data structures at bootstrap time
MAJOR | Most likely to require modification

These attributes are noted in the detailed parameter descriptions in Section J.2.

Table J-1 lists system parameters according to category. Footnotes indicate dynamic and system-specific parameters.

Table J-1 System Parameters
ACP Parameters |  |
--- | --- | ---
ACP_BASEPRIO 1 | ACP_DATACHECK 1 | ACP_DINDXCACHE 1
ACP_DIRCACHE 1 | ACP_EXTCACHE 1 | ACP_EXTLIMIT 1
ACP_FIDCACHE 1 | ACP_HDRCACHE 1 | ACP_MAPCACHE 1
ACP_MAXREAD 1 | ACP_MULTIPLE 1 | ACP_QUOCACHE 1
ACP_REBLDSYSD | ACP_SHARE 1 | ACP_SWAPFLGS 1
ACP_SYSACC 1 | ACP_WINDOW 1 | ACP_WORKSET 1
ACP_WRITEBACK 1 | ACP_XQP_RES 1 |
CLUSTER Parameters |  |
ALLOCLASS | +CHECK_CLUSTER | CLUSTER_CREDITS
CWCREPRC_ENABLE | DISK_QUORUM 1 | ++DR_UNIT_BASE
EXPECTED_VOTES | LOCKDIRWT | MPW_WRTCLUSTER
MSCP_BUFFER | MSCP_CMD_TMO | MSCP_CREDITS
MSCP_LOAD | MSCP_SERVE_ALL | NISCS_CONV_BOOT
NISCS_LOAD_PEA0 | NISCS_MAX_PKTSZ | NISCS_PORT_SERV
QDSKINTERVAL | QDSKSVOTES | RECNXINTERVAL 1
TAPE_ALLOCLASS | TMSCP_LOAD | TMSCP_SERVE_ALL
VAXCLUSTER | VOTES |
JOB Parameters |  |
DEFPRI 1 | DEFQUEPRI 1 | IJOBLIM 1
MAXQUEPRI 1 | NJOBLIM 1 | RJOBLIM 1
LGI Parameters |  |
LGI_BRK_DISUSER 1 | LGI_BRK_LIM 1 | LGI_BRK_TERM 1
LGI_BRK_TMO 1 | LGI_CALLOUTS 1 | LGI_HID_TIM 1
LGI_PWD_TMO 1 | LGI_RETRY_LIM 1 | LGI_RETRY_TMO 1
MULTIPROCESSING Parameters |
++IO_PREFER_CPUS | MULTIPROCESSING | SMP_CPUS
SMP_LNGSPINWAIT | SMP_SANITY_CNT | SMP_SPINWAIT
PQL Parameters |  |
PQL_DASTLM 1 | PQL_DBIOLM 1 | PQL_DBYTLM 1
PQL_DCPULM 1 | PQL_DDIOLM 1 | PQL_DENQLM 1
PQL_DFILLM 1 | PQL_DJTQUOTA | PQL_DPGFLQUOTA 1
PQL_DPRCLM 1 | PQL_DTQELM 1 | PQL_DWSDEFAULT
PQL_DWSEXTENT 1 | PQL_DWSQUOTA 1 | PQL_MASTLM 1
PQL_MBIOLM 1 | PQL_MBYTLM 1 | PQL_MCPULM 1
PQL_MDIOLM 1 | PQL_MENQLM 1 | PQL_MFILLM 1
PQL_MJTQUOTA 1 | PQL_MPGFLQUOTA 1 | PQL_MPRCLM 1
PQL_MTQELM 1 | PQL_MWSDEFAULT | PQL_MWSEXTENT 1
PQL_MWSQUOTA 1 |  |
RMS Parameters |  |
RMS_DFMBC 1 | RMS_DFMBFIDX 1 | RMS_DFMBFREL 1
RMS_DFMBFSDK 1 | RMS_DFMBFSMT 1 | RMS_DFMBFSUR 1
RMS_DFNBC 1 | RMS_EXTEND_SIZE 1 | RMS_FILEPROT
RMS_PROLOGUE 1 |  |
SCS Parameters |  |
PAMAXPORT 1 | PANOPOLL 1 | PANUMPOLL 1
PAPOLLINTERVAL 1 | PAPOOLINTERVAL 1 | PASANITY 1
PASTDGBUF | PASTIMOUT 1 | PRCPOLINTERVAL 1
SCSBUFFCNT | SCSCONNCNT | SCSFLOWCUSH 1
SCSMAXDG | SCSMAXMSG | SCSNODE
SCSRESPCNT | SCSSYSTEMID | SCSSYSTEMIDH
++SMCI_FLAGS 1 | ++SMCI_PORTS | TIMVCFAIL 1
UDABURSTRATE |  |
Special Parameters |  |
AFFINITY_SKIP | AFFINITY_TIME | BREAKPOINTS
CHANNELCNT | +CLOCK_INTERVAL | CONCEAL_DEVICES
CRD_CONTROL | CTLIMGLIM | CTLPAGES
DISABLE_UPCALLS 1 | +DLCKEXTRASTK | DNVOSI1
EXUSRSTK | ++FAST_PATH | ++FAST_PATH_PORTS
IMGIOCNT | IOTA | JOBCTLD
LOAD_SYS_IMAGES | LOCKRETRY | MAXCLASSPRI 1
++MC_SERVICES_P0-9 | MINCLASSPRI 1 | MPW_PRIO
NOAUTOCONFIG 1 | NOCLUSTER | NOPGFLSWP
PAGTBLPFC | PE* | ++PFN_COLOR_COUNT
++PHYSICAL_MEMORY | +PHYSICALPAGES | PIOPAGES 1
PIXSCAN 1 | POOLCHECK 1 | POOLPAGING
PRIORITY_OFFSET | +PSEUDOLOA | PU_OPTIONS
+QBUS_MULT_INTR | RESALLOC | RSRVPAGCNT
S0_PAGING | SA_APP | +SBIERRENABLE
+SCH_CTLFLAGS 1 | +SCSI_NOAUTO 1 | ++SCSICLUSTER_P[1-4]
SMP_CPUSH | SMP_TICK_CNT | SSINHIBIT
+SWPALLOCINC | SWPFAIL | SWPRATE
SWP_PRIO | SYSPFC | TBSKIPWSL
TIME_CONTROL 1 | TTY_DEFPORT | +VBN_CACHE_S
+VBSS_ENABLE | +VBSS_ENABLE2 | ++VCC_FLAGS
++VCC_MAXSIZE | +VCC_MINSIZE | +VCC_PTES
VMS | WPRE_SIZE 1 | WPTTE_SIZE 1
WRITABLESYS | WRITESYSPARAMS 1 | XQPCTL2
XQPCTLD1 |  |
SYS Parameters |  |
++ARB_SUPPORT 1 | AUTO_DLIGHT_SAV | AWSMIN 1
AWSTIME 1 | BALSETCNT | BORROWLIM 1
BUGCHECKFATAL 1 | BUGREBOOT 1 | CLASS_PROT 1
CLISYMTBL 1 | ++CRDENABLE | ++DBGTK_SCRATCH
DEADLOCK_WAIT 1 | DEFMBXBUFQUO 1 | DEFMBXMXMSG 1
++DEVICE_NAMING | DORMANTWAIT 1 | DUMPBUG
DUMPSTYLE 1 | ERLBUFFERPAGES | ERRORLOGBUFFERS
EXTRACPU 1 | FREEGOAL 1 | FREELIM
++GALAXY | GBLPAGES 1 | GBLPAGFIL 1
GBLSECTIONS | ++GH_EXEC_CODE | ++GH_EXEC_DATA
++GH_RES_CODE | ++GH_RES_DATA | GH_RSRVPGCNT
++GLX_INST_TMO | GLX_SHM_REG | GROWLIM 1
++IMGREG_PAGES | +INTSTKPAGES 1 | ++KSTACKPAGES
+LAMAPREGS | ++LAN_FLAGS 1 | LCKMGR_MODE 1
LNMPHASHTBL | LNMSHASHTBL | LOAD_PWD_POLICY
LOCKIDTBL | LONGWAIT 1 | ++MAXBOBMEM 1
MAXBUF 1 | MAXPROCESSCNT | MAXSYSGROUP 1
MINWSCNT | MMG_CTLFLAGS 1 | ++MPDEV_ENABLE
++MPDEV_LCRETRIES | ++MPDEV_POLLER | ++MPDEV_REMOTE
MPW_HILIMIT | MPW_IOLIMIT | MPW_LOLIMIT
MPW_LOWAITLIMIT 1 | MPW_THRESH 1 | MPW_WAITLIMIT 1
MULTITHREAD | MVTIMEOUT 1 | NET_CALLOUTS 1
NPAGEDYN | ++NPAGERAD | NPAGEVIR
++NPAG_AGGRESSIVE 1 | ++NPAG_BAP_MAX | ++NPAG_BAP_MAX_PA
++NPAG_BAP_MIN | ++NPAG_BAP_MIN_PA | ++NPAG_GENTLE 1
++NPAG_INTERVAL 1 | ++NPAG_RING_SIZE | PAGEDYN
+PAGFILCNT | PFCDEFAULT 1 | PFRATH 1
PFRATL 1 | POWEROFF 1 | PROCSECTCNT
QUANTUM 1 | ++RAD_SUPPORT | +REALTIME_SPTS 1
RESHASHTBL | ++S2_SIZE | SAVEDUMP
SECURITY_POLICY | SETTIME | SHADOWING
SHADOW_MAX_COPY 1 | SHADOW_MAX_UNIT | SHADOW_MBR_TMO 1
SHADOW_SYS_DISK | SHADOW_SYS_TMO | SHADOW_SYS_UNIT
SHADOW_SYS_WAIT | +SPTREQ | STARTUP_P1-8
+SWPFILCNT | SWPOUTPGCNT 1 | SYSMWCNT
SYSTEM_CHECK | TAILORED | TAPE_MVTIMEOUT 1
TIMEPROMPTWAIT | UAFALTERNATE | USERD1 1
USERD2 1 | USER3 | USER4
++VCC_MAX_CACHE 1 | ++VCC_MAX_IO_SIZE 1 | ++VCC_MAX_LOCKS
++VCC_READAHEAD 1 | ++VCC_WRITEBEHIND | +VECTOR_MARGIN 1
+VECTOR_PROC | VIRTUALPAGECNT | WBM_MSG_INT 1
WBM_MSG_LOWER 1 | WBM_MSG_UPPER 1 | WBM_OPCOM_LVL 1
WINDOW_SYSTEM 1 | ++WLKSYSDSK | WSDEC 1
WSINC 1 | WSMAX | +WS_OPA0
XFMAXRATE 1 | ++ZERO_LIST_HI 1 |
TTY Parameters |  |
TTY_ALTALARM | TTY_ALTYPAHD | TTY_AUTOCHAR 1
TTY_BUF | TTY_CLASSNAME | TTY_DEFCHAR
TTY_DEFCHAR2 | TTY_DIALTYPE | TTY_DMASIZE 1
TTY_PARITY | TTY_RSPEED | TTY_SCANDELTA
TTY_SILOTIME | TTY_SPEED | TTY_TIMEOUT 1
TTY_TYPAHDSZ |  |

1Dynamic parameter
++Alpha specific
+VAX specific

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