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If AUTO_DLIGHT_SAV is set to 1, OpenVMS automatically makes the change to and from daylight saving time.
Some application configurations that have a large number of memory-intensive processes may benefit if the value is reduced. The value can be as low as 4.
AWSTIME expiration is checked only at quantum end. Reducing its value and not reducing QUANTUM effectively sets the value of AWSTIME equal to the value of QUANTUM.
You can monitor the active system with the DCL command SHOW MEMORY or the MONITOR PROCESSES command of the Monitor utility to determine the actual maximum number of working sets in memory. If this number is significantly lower than the value of BALSETCNT, this parameter value could be lowered. If all balance set slots are being used, raise the value of BALSETCNT.
Never set BALSETCNT to a value higher than 2 less than MAXPROCESSCNT. If physical memory is a significant system constraint, consider lowering this value even further. However, if your system runs with a number of processes nearly equal to MAXPROCESSCNT, lowering BALSETCNT forces swapping to occur, which can affect system performance.
BALSETCNT is no longer a strict setting of the number of processes that might be resident in memory. The swapper tries to reduce the number of resident processes down to BALSETCNT. However, if the total number of active processes and processes that have disabled swapping exceeds BALSETCNT, the swapper does not force processes out of memory just to meet the BALSETCNT setting.
This parameter allows a process to grow beyond the value set by the working set quota (WSQUOTA) to the working set quota extent (WSEXTENT) on a system that has a substantial memory on the free-page list. This automatic working set adjustment also depends upon the values of parameters WSINC, PFRATH, and AWSTIME.
Working set growth attempts to alleviate heavy page faulting. To make use of this growth, you must also set the user's WSEXTENT authorization quota to a larger number than the WSQUOTA value.
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
This parameter should normally be OFF (0); you should set it ON (1) only when the executive is being debugged.
Setting the SYSTEM_CHECK parameter to 1 has the effect of setting BUGCHECKFATAL to ON (1).
If the SHOW CLUSTER command displays a high number of credit waits for the VMS$VAXcluster connection, you might consider increasing the value of CLUSTER_CREDITS on the other node. However, in large cluster configurations, setting this value unnecessarily high consumes a large quantity of nonpaged pool. Each receive buffer is at least SCSMAXMSG bytes in size but might be substantially larger depending on the underlying transport.
It is not required for all nodes in the cluster to have the same value for CLUSTER_CREDITS.
The default value is currently 32. Unless a system has very constrained memory available, HP recommends that these values not be increased.
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
A value of 1 for CPU_POWER_MGMT means on (the default); a value of 0 means off. Whenever the CPU_POWER_THRSH parameter value is exceeded, the operating system places an Integrity processor in low-power mode if it is idle. OpenVMS Integrity servers does this only if CPU_POWER_MGMT is on. A CPU returns to normal power when it receives an interrupt.
For systems supporting real-time operations that require quick response time, HP recommends that this feature be turned off. Use of this feature can result in a small performance degradation.
For more information, see the Intel IA-64 Architecture Software Developer's Manual, Volume 2: IA-64 System Architecture.
See also the CPU_POWER_MGMT parameter.
CRD_CONTROL is a bit mask for corrected read data (CRD) soft error control flags. These flags control the use of CRDERROR routines.
On Alpha and Integrity servers, the following bits are defined:
Bit | Description |
---|---|
0 | Enables CRD processing for all systems. |
1 | Enables scrubbing (rewriting) of the memory location that induced the CRD. |
2 | Enables page replacement of the pages that exhibit repeated CRD errors. |
3 | Forces all memory pages to be included in the PFN database. On systems that contain more than 512 megabytes of memory, all memory is mapped by the PFN database by default. This bit allows the mapping to occur on systems with less than 512 megabytes of memory. |
4 | Enables extended CRD handling, if available. |
5 | Enables loading of driver and process for handling server management events. Platform-specific code usually sets this bit if the required hardware and firmware support are available. |
6 | Disables CRD throttling. |
7 | Disables System Event Log (SEL) polling. |
16-31 | Reserved for platform-specific error-handling control. |
On Alpha and Integrity servers, the default setting is 22, which enables scrubbing, page replacement, and extended CRD handling.
Beginning with OpenVMS Version 7.2, CRD_CONTROL can expand the function of CRDENABLE. (See CRD_CONTROL.)
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
Bits 0 and 2 control the formulation of system-generated process names for processes created using the SPAWN command or LIB$SPAWN library routine. They are provided for compatibility with behavior of prior OpenVMS versions. Note that you can eliminate the use of system-generated names by supplying your own process names.
Bit 1 controls the token size used by DCL.
Bit 3 controls the maximum number input parameters to command procedure.
Bit 4 controls the the maximum length for an user name, for which OpenVMS mail forwarding address is set.
DCL_CTLFLAGS bits are described in the following table.
Bit | Description |
---|---|
Bit 0 |
If clear (the default), the numeric portion of a system-generated
spawned process name is generated randomly. If set, the numeric portion
is generated sequentially starting with sequence number 1.
The option of sequential generation is provided for compatibility with OpenVMS versions prior to Version 7.3-1. However, this choice can be very expensive in performance terms because of the mechanism for finding the next available process name. This mechanism attempts to create all process names beginning with sequence number 1 until it finds one that is unused. Random generation is the preferred choice because it results in a very high probability of finding a unique name on the first try. |
Bit 1 |
Controls the token size used by DCL. If clear (the default), this bit
instructs DCL to use the traditional token size. A token cannot exceed
255 characters. If this bit is set, extended tokens are used. Extended
tokens are 4000 characters.
Note that if you turn on extended tokens, file specifications can exceed 255 characters, which might require larger structures for parsing file specifications. |
Bit 2 |
If clear (the default), the numeric portion of a system-generated
spawned process name has a maximum value of 65535. If set, the numeric
portion of the name has a maximum value of 255.
The option of a maximum of 255 is provided for compatibility with OpenVMS versions prior to Version 8.3, when it was the only choice. The larger maximum allows many more unique spawned process names for a given process. For this reason, it is the preferred choice. However, the larger maximum uses two additional characters from the process name, which might make it more difficult to identify users uniquely by looking at their spawned process names. If this is an issue on your system, setting bit 2 might be a better choice. |
Bit 3 | If clear (the default), command procedure supports the default eight optional parameters (that is, (P1,P2,...P8)). If set, command procedure supports up to sixteen optional parameters (that is, (P1,P2,...P16)). This is also applicable when using the CALL command to transfer control to a subroutine. |
Bit 4 |
This bit controls the the maximum length for an user name, for which
OpenVMS mail forwarding address is set. If clear (the default), user
name string length is set to a maximum length of 31 characters. If set,
user name string length is set to a maximum of 255 characters.
Note: Once this bit is set, user name length is set to maximum of 255 characters. Even if this bit is cleared, the behavior remains unchanged, that is, supports user name length of 255 characters, but there is no way to reset it to 31 characters. |
The DEADLOCK_WAIT value is expressed in seconds; therefore, the smallest value you can set is 1 second. Beginning in HP OpenVMS Version 8.3, a subsecond deadlock wait time, which is set in the system service $SET_PROCESS_PROPERTIESW item code $PPROP$C_DEADLOCK_WAIT, overrides DEADLOCK_WAIT. For more information, see the $SET_PROCESS_PROPERTIESW system service in HP OpenVMS System Services Reference Manual.
The value of DEFQUEPRI should be less than or equal to MAXQUEPRI.
DEFQUEPRI refers to relative queue scheduling priority, not the execution priority of the job. |
Option | Description |
---|---|
0 | Disable the exit handler functionality with $DELPRC. |
4 | Execute kernel mode exit handlers. |
5 (default) | Execute exec and more privileged mode exit handlers. |
6 | Execute supervisor and more privileged mode exit handlers. |
7 | Execute user and more privileged mode exit handlers. |
Following is the bit definition:
Bit | Definition |
---|---|
0 | If 1, enable new naming. |
1 | Must be 0. This bit is reserved for use by HP. |
2 | If 1, cloned device unit numbers wrap after 9999. |
For more information about port allocation classes, see HP OpenVMS Cluster Systems.
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
Increasing the value of DORMANTWAIT can increase the interval that a low priority process blocks a high priority process if that low priority process is holding a lock or resource that the higher priority process is waiting for.
DR_UNIT_BASE provides a way for unique RAID device numbers to be generated. DR devices are numbered starting with the value of DR_UNIT_BASE and then counting from there. For example, setting DR_UNIT_BASE to 10 produces device names such as $1$DRA10, $1$DRA11, and so on.
Setting DR_UNIT_BASE to appropriate, nonoverlapping values on all cluster members that share the same (nonzero) allocation class ensures that no two RAID devices are given the same name.
DUMPSTYLE is a 32-bit mask, with the following bits defined. Each bit can be set independently. The value of the system parameter is the sum of the values of the bits that have been set. Remaining or undefined values are reserved for HP use only.
Bit | Mask | Description | |
---|---|---|---|
0 | 00000001 | 0 = | Full dump (SYSGEN default). The entire contents of physical memory are written to the dump file. |
1 = | Selective dump. The contents of memory are written to the dump file selectively to maximize the usefulness of the dump file while conserving disk space. | ||
1 | 00000002 | 0 = | Minimal console output. |
1 = | Full console output (includes stack dump, register contents, and so on). | ||
2 | 00000004 | 0 = | Dump to system disk. |
1 = | Dump off system disk (DOSD) to an alternate disk. (See the HP OpenVMS System Manager's Manual for details.) | ||
3 (Alpha and Integrity servers) 1 | 00000008 | 0 = | Do not compress. |
1 = | Compress. (See note below.) | ||
4 (Alpha and Integrity servers) 2 | 00000010 | 0 = | Dump shared memory. |
1 = | Do not dump shared memory. (See note below.) | ||
5 - 14 | Reserved for HP use only. | ||
15 (VAX only) 3 | 00008000 | 0 = | Disable use of bits 16 - 27. |
1 = | Enable use of bits 16 - 27. | ||
16 - 27 (VAX only) 2 | 0FFF0000 | Range of DOSD unit numbers. | |
28 - 31 | Reserved for HP use only. |
If you plan to enable the Volume Shadowing minimerge feature on an Alpha or Integrity servers disk, be sure to specify DOSD to an alternate disk.
On Alpha and Integrity servers, you can save space on the system disk and, in the event of a crash, save time recording the system memory, by using the OpenVMS Alpha and Integrity servers dump compression feature. Unless you override the default AUTOGEN calculations (by setting DUMPSTYLE in MODPARAMS.DAT), AUTOGEN uses the following algorithm:
|
The mask of 00000006 directs the system to send a full dump, with full console output, off the system disk (to the alternate disk).
For a VAX 7000, a mask of 00098006 directs the system to send a full dump with full console output to the DOSD whose unit number is 9.
On Alpha and Integrity servers, the mask of 00000009 directs the system to compress a selective dump with minimal console output.
If you increase ERLBUFFERPAG_S2, you must either run AUTOGEN or manually increase the size of both the system dump file and the error log dump file.
If you increase ERRORLOGBUFF_S2, you must either run AUTOGEN or manually increase the size of both the system dump file and the error log dump file.
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