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On Alpha systems, this symbol is in the SYS$LOADABLE_IMAGES:SYS$BASE_IMAGE module.
On VAX systems, the symbol is in the SYS$SYSTEM:SYS.STB module.
On Alpha systems, this symbol is in the SYS$LOADABLE_IMAGES:SYS$BASE_IMAGE module.
On VAX systems, the symbol is in the SYS$SYSTEM:SYS.STB module.
On Alpha systems, this symbol is in the SYS$LOADABLE_IMAGES:SYS$BASE_IMAGE module.
On VAX systems, the symbol is in the SYS$SYSTEM:SYS.STB module.
On Alpha systems, this symbol is in the SYS$LOADABLE_IMAGES:SYS$BASE_IMAGE module.
On VAX systems, the symbol is in the SYS$SYSTEM:SYS.STB module.
| Value | Description |
|---|---|
| 0 | Never load. |
| 1 | Load if SCSLOA is being loaded. |
| 2 | Always load (and also load SCSLOA). |
The default value is 1.
The default value of the VECTOR_MARGIN parameter is 20010.
| Value | Result |
|---|---|
| 0 | Do not load the vector processing support code, regardless of the system configuration. |
| 1 | Load the vector processing support code if at least one vector-present processor exists. This is the default value. |
| 2 | Load the vector processing support code if the system is vector-capable. This setting is most useful for a system in which processors have separate power supplies. With this setting, you can reconfigure a vector processor into the system without rebooting the operating system. |
| 3 | Always load the vector processing support code. |
If you use SYS$UPDATE:LIBDECOMP.COM to decompress libraries and the VIRTUALPAGECNT setting is low, make sure you set the PGFLQUOTA field in the user authorization file to at least twice the size of the library.
At installation time, AUTOGEN automatically sets an appropriate value for VIRTUALPAGECNT. The value depends on the particular configuration---the type and number of graphics adapters on the system, if any exist. You will not be able to set VIRTUALPAGECNT value below the minimum value required for your graphics configuration.
Because the VIRTUALPAGECNT setting supports hardware address space rather than system memory, do not use the value of VIRTUALPAGECNT that AUTOGEN sets to gauge the size of your page file.
On Alpha systems, starting with OpenVMS Alpha V7.0, VIRTUALPAGECNT ceases to be a tunable parameter and is no longer used to specify the virtual size of a process. The process page tables have migrated from system space to a dedicated page table space that is guaranteed to be large enough to accommodate the virtual address space provided by the system. This migration has rendered the parameter obsolete, and OpenVMS ignores its contents entirely.
Note, however, that on Alpha systems the parameter remains in existence for compatibility purposes and now has a default and maximum value of %X7FFFFFFF. SYSBOOT and AUTOGEN enforce this default value.
| Value | Description |
|---|---|
| 1 | Load the DECwindows Motif for OpenVMS workstation environment. |
| 2 | Load the UIS workstation environment. |
On VAX systems, WSDEC specifies the number of pages by which the limit of a working set is automatically decreased at each adjustment interval (which is quantum end). At a setting of 35, for example, the system will decrease the limit of a working set by 35 pages each time a decrease is required.
On Alpha systems, WSDEC specifies the number of pagelets by which the limit of a working set is automatically decreased at each adjustment interval (which is quantum end). At a setting of 35, for example, the system will decrease the limit of a working set by 35 pagelets each time a decrease is required.
On VAX systems, WSINC specifies the number of pages by which the limit of a working set is automatically increased at each adjustment interval (which is quantum end). At a setting of 150, for example, the system will increase the limit of a working set by 150 pages each time an increase is required. On VAX systems, the default value is 150 512-byte pages.
On Alpha systems, WSINC specifies the number of pagelets by which the limit of a working set is automatically increased at each adjustment interval (which is quantum end). At a setting of 150, for example, the system will increase the limit of a working set by 150 pagelets each time an increase is required. On Alpha systems, the default value is 2400 512-byte pagelets (150 8192-byte Alpha pages).
A value of 0 for WSINC disables the automatic adjustment of working set limits for all processes. Limits stay at their base values. You can disable the automatic adjustment of working set limits on a per-process basis by using the DCL command SET WORKING_SET.
These parameters are subject to change at any time and should be modified only if recommended by Digital.
AFFINITY_SKIP
AFFINITY_SKIP controls the breaking of implicit affinity. The value indicates the number of times a process is skipped before being moved.AFFINITY_TIME
AFFINITY_TIME controls the breaking of implicit affinity. The value indicates how long a process remains on the compute queue.BREAKPOINTS
If XDELTA is loaded, BREAKPOINTS enables additional built-in calls for XDELTA during the boot sequence. The breakpoints that are enabled may change from release to release of OpenVMS.CHANNELCNT
CHANNELCNT specifies the number of permanent I/O channels available to the system.CLOCK_INTERVAL
On VAX systems, CLOCK_INTERVAL sets the number of microseconds between the hardware interval timer clock interrupts. It has no effect on processors that have implemented only the subset interval clock registers.CONCEAL_DEVICES
CONCEAL_DEVICES enables or disables the use of concealed devices. By default, this parameter is set to enable concealed devices (1).CRD_CONTROL
On VAX systems, CRD_CONTROL is a bit mask for corrected read data (CRD) soft error control flags. These flags control the use of CRDERROR routines. 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. The default is 7, which enables CRD processing, scrubbing, and page replacement.
CRD_CONTROL replaces the memory CRD control parameter CRDENABL.
CTLIMGLIM
CTLIMGLIM specifies the size of the default image I/O segment; that is channel table and initial buffer pool for image-related file and RMS I/O.CTLPAGES (A)
CTLPAGES specifies the size of P1 pool. CTLPAGES is changed only when the process logical name table, DCL symbols, or some layered products require an increase in the size of the P1 pool area.DISABLE_UPCALLS (D)
DISABLE_UPCALLS is primarily a debugging aid. It allows the system manager to disable threads upcalls of specific types for the entire system. The value is a bit mask, with the bits corresponding to the upcall types. The upcall types are defined in the definition macro $TMCDEF.DLCKEXTRASTK
On VAX systems, DLCKEXTRASTK specifies the amount of extra interrupt stack (in bytes) to leave when doing a deadlock search.DNVOSI1
DNVOSI1 is reserved to DECnet-Plus for OpenVMS.EXUSRSTK
EXUSRSTK specifies the amount of space provided by the image activator to recover from a stack overflow error.FAST_PATH
On Alpha systems, FAST_PATH enables (1) or disables (0) Fast Path I/O on a system. See the IO_PREFER_CPUS system parameter.IMGIOCNT
IMGIOCNT specifies the default number of pages of image I/O address space to be allocated for the image activator if not specified at program link time.IOTA
IOTA specifies the amount of time (in 10-millisecond units) to charge to the current residence quantum for each voluntary wait. The correct value approximates the cost of a disk I/O neglecting wait time.JOBCTLD
JOBCTLD is not normally altered by system managers; this word of debug flags is used in rolling upgrades of OpenVMS. If bit 0 is set, the queue manager will not start. The default is 0.LOAD_SYS_IMAGES (A on Alpha)
LOAD_SYS_IMAGES controls the loading of system images described in the system image data file, VMS$SYSTEM_IMAGES. This parameter is a bitmask.On VAX systems, the following bit is defined:
Bit Description 0 (SGN$V_LOAD_SYS_IMAGES) Enables loading alternate execlets specified in VMS$SYSTEM_IMAGES.DATA. On Alpha systems, the following bits are defined:
Bit Description 0 (SGN$V_LOAD_SYS_IMAGES) Enables loading alternate execlets specified in VMS$SYSTEM_IMAGES.DATA. 1 (SGN$V_EXEC_SLICING) Enables executive slicing. 2 (SGN$V_RELEASE_PFNS) Enables releasing unused portions of the Alpha huge pages. These bits are on by default. Using conversational bootstrap exec slicing can be disabled.
LOCKRETRY
LOCKRETRY establishes the number of attempts made to lock a multiprocessor data structure.MAXCLASSPRI (D)
If class scheduling is enabled, MAXCLASSPRI sets the maximum range in the priority range of class-scheduled processes.MC_SERVICES_P[0-9]
MC_SERVICES_P[0-9] parameters are reserved for OpenVMS.MINCLASSPRI (D)
If class scheduling is enabled, MINCLASSPRI sets the minimum range in the priority range of class-scheduled processes.MPW_PRIO
MPW_PRIO sets the priority of I/O transfers initiated by the modified page writer. The maximum value is 31, the minimum is 0, and the default is 4.NOAUTOCONFIG (D)
NOAUTOCONFIG controls whether all devices are automatically configured when the system boots. The default value of 0 sets the system to automatically configure all devices. NOAUTOCONFIG should only be set to 1 (no automatic configuration) for debugging purposes.NOCLUSTER
On VAX systems, NOCLUSTER controls whether page read clustering is inhibited when the system boots. NOCLUSTER should be set to 1 (inhibit page read clustering) only for debugging purposes.NOPGFLSWP
If enabled, NOPGFLSWP disables swapping into page files.PAGTBLPFC
PAGTBLPFC specifies (in pages) the maximum number of page tables to read to satisfy a fault for a nonresident page table.PE
PE1, PE2, PE3, PE4, PE5, PE6 are reserved to Digital. These parameters are for cluster algorithms and their usages can change from release to release. Digital recommends using the default values.
PFN_COLOR_COUNT
On Alpha systems, PFN_COLOR_COUNT specifies the number of buckets (colors) into which all members of the zeroed page list and all unencumbered members of the free page list are sorted. OpenVMS Alpha systems may derive a preferred page color from a request to map a given virtual page and attempt to map that virtual page to a PFN of matching "color". This results in less variance in which cache blocks may be used when accessing that page. This may or may not improve performance, depending upon the application. Note that when you increase this parameter, you should also increase the ZERO_LIST_HI parameter.
PHYSICAL_MEMORY (A)
On Alpha systems, PHYSICAL_MEMORY specifies the amount of physical memory available for use. The default setting is --1, which equates to all memory in the system. Decreasing this parameter allows you to test smaller configurations of memory without having to remove memory boards.PHYSICALPAGES (A)
On VAX systems, PHYSICALPAGES sets the maximum number of physical pages of memory to be used on the system. Decreasing this parameter allows you to test smaller configurations of memory without the need to remove memory boards.PIOPAGES (A,D)
PIOPAGES specifies the size of the process I/O segment, which holds data structures and buffer pool space for RMS to use when handling I/O involving process-permanent files. Once PIOPAGES has been reset in SYSGEN, any new process will receive the changed value.
PIXSCAN (A,D)
PIXSCAN specifies the number of process index slots scanned each second for computable or computable-outswapped processes. These processes receive an automatic priority boost for 1 quantum, unless the priority of the currently executing process is greater than 15. The priority boost is done to avoid potential deadlocks on the system.POOLCHECK (D)
POOLCHECK is used to investigate frequent and inexplicable failures in a system. When POOLCHECK is enabled, pool-checking routines execute whenever pool is deallocated or allocated.Two loadable forms of SYSTEM_PRIMITIVES.EXE are available at boot time. The default image, which contains no pool-checking code and no statistics maintenance, is loaded when POOLCHECK is set to zero. When POOLCHECK is set to a nonzero value, the monitoring version of SYSTEM_PRIMITIVES.EXE, which contains both pool-checking code and statistics maintenance, will be loaded.
For further information on pool checking, refer to the OpenVMS VAX Device Support Manual or the Writing OpenVMS Alpha Device Drivers in C. (These manuals have been archived but are available in PostScript and DECW$BOOK (Bookreader) formats on the OpenVMS Documentation CD-ROM. Printed books can be ordered through DECdirect (800-354-4825).)
POOLPAGING
POOLPAGING enables (1) paging of pageable dynamic pool.PRIORITY_OFFSET
PRIORITY_OFFSET specifies the difference in priority required by the scheduler for one process to preempt the current process. A value of 2, for example, would mean that if the current process was executing at priority 1, a computable process at priority 2 or 3 would not be allowed to preempt the current process. However, a priority 4 or higher process could preempt the current process. This mechanism affects only normal priority (0-15) processes. The default value is 0.PSEUDOLOA
On VAX systems, PSEUDOLOA specifies (in pages) the size of the PDA0 system image. PSEUDOLOA is used to boot standalone BACKUP from magnetic tape.PU_OPTIONS
PU_OPTIONS is reserved to Digital.QBUS_MULT_INTR
On VAX systems, QBUS_MULT_INTR enables (1) multilevel interrupt dispatching on systems that use the Q22-bus adapter. Refer to the OpenVMS VAX Device Support Manual for more information about the QBUS_MULT_INTR system parameter. (This manual has been archived but is available in PostScript and DECW$BOOK (Bookreader) formats on the OpenVMS Documentation CD-ROM. Printed books can be ordered through DECdirect (800-354-4825).)RESALLOC
RESALLOC controls whether resource allocation checking is performed. The default value of 0 disables resource allocation checking.RSRVPAGCNT
RSRVPAGCNT sets the number of pages that are reserved and escrowed for the current process page file.
S0_PAGING
S0_PAGING controls paging of system code:
- Setting bit 0 disables paging of all Exec code and data.
- Setting bit 1 disables paging of all RMS code and data.
SA_APP
SA_APP is reserved to Digital.SBIERRENABLE
On VAX systems, this parameter enables (1) SBI error detection and logging.SCH_CTLFLAGS (D)
On VAX systems, the vector scheduling subsystem presently provides an enlarged quantum to processes requiring vector capability. Customer sites can disable vector quantum adjustment by setting bit NO_VEC_QUANTADJ (bit 9) in the system parameter SCH_CTLFLAGS. Setting this bit causes the scheduler to treat the vector processes and scalar processes uniformly. However, doing so will result in more frequent vector context switches when the number of vector processes exceeds the number of vector processors in the system.SCSI_NOAUTO (D)
On VAX systems, SCSI_NOAUTO prevents the loading of a disk or tape SCSI class driver for any given device ID in a configuration that includes an SCSI third-party device. The SCSI_NOAUTO system parameter stores a bit mask of 32 bits, where the low-order byte corresponds to the first SCSI bus (PKA0), the second byte corresponds to the second SCSI bus (PKB0), and so on, as follows:#31 24 23 16 15 8 7 0 +-------+-------+-------+-------+ | D | C | B | A | +-------+-------+-------+-------+For each SCSI bus, setting the low-order bit inhibits automatic configuration of the device with SCSI device ID 0; setting the second low-order bit inhibits automatic configuration of the device with SCSI device ID 1, and so forth. For instance, the value 00002000_16 would prevent the device with SCSI ID 5 on the bus identified by SCSI port ID B from being configured. By default, all of the bits in the mask are cleared, allowing all devices to be configured.
SCSICLUSTER_P[1-4]
On Alpha systems, SCSICLUSTER_P[1-4] parameters allow non-Digital peripherals (CPU-lookalikes) in SCSI clusters.SMP_CPUSH
SMP_CPUSH is reserved to Digital. Digital recommends that you use the default value.SMP_TICK_CNT
SMP_TICK_CNT sets the frequency of sanity timer checks by each CPU in a multiprocessing system.SSINHIBIT
SSINHIBIT controls whether system services are inhibited (1) (on a per-process basis). By default, system services are not inhibited (0).SWPALLOCINC
SWPALLOCINC sets the size (in blocks) to use to back up swap file space allocation in the swap or page file. Space in the file will be allocated in multiples of this unit (up to WSQUOTA) to guarantee swap space.SWPFAIL
SWPFAIL sets the number of consecutive swap failures allowed before the swap schedule algorithm is changed to ignore the swap quantum protection.SWPRATE
SWPRATE sets the swapping rate (in 10-millisecond units). This parameter limits the amount of disk bandwidth consumed by swapping.SWP_PRIO
SWP_PRIO sets the priority of I/O transfers initiated by the swapper.SYSPFC
SYSPFC sets the number of pages to be read from disk on each system paging operation.TBSKIPWSL
TBSKIPWSL specifies the maximum number of working set list entries that may be skipped while scanning for a "good" entry to discard. Set this parameter to 0 to disable skipping.TIME_CONTROL (D)
TIME_CONTROL is an SMP bitmask parameter that controls debugging functions. The following bits are defined:
Bit Description 0 Obsolete. 1 (EXE$V_SANITY) Disables the SMP sanity timer support. 2 (EXE$V_NOSPINWAIT) Disables the functional behavior of the SMP spinwait support. VBN_CACHE_S
On VAX systems, VBN_CACHE_S enables or disables virtual I/O caching. By default, virtual I/O caching is disabled. Change the value of the VBN_CACHE_S parameter in MODPARAMS.DAT as follows:
- VBN_CACHE_S = 1 to enable caching
- VBN_CACHE_S = 0 to disable caching
The virtual I/O cache is a clusterwide, file-oriented, disk cache that reduces I/O bottlenecks. The virtual I/O cache is transparent to system management and application software. This new feature maintains system reliability while it significantly improves virtual read performance.
The virtual I/O cache works on all supported configurations from single-node systems to large mixed-interconnect VAXcluster systems. Any OpenVMS system can support virtual I/O caching; a VAXcluster license is not required to use the caching functionality.
Note
If any member of a cluster does not have caching enabled, then no caching can occur on any node in the cluster (including the nodes that have caching enabled). This condition will remain until the node or nodes that have caching disabled either enable caching, or leave the cluster.
VBSS_ENABLE (A)
On VAX systems, enables virtual balance slots (VBS) to be created. A virtual balance slot holds the mapping for a memory-resident process that does not currently own a real balance slot (RBS). The set of real balance slots is timeshared among all memory-resident processes. With VBS enabled, the quantity of memory resident processes is limited by the system parameter MAXPROCESSCNT. With VBS disabled, the quantity of memory-resident processes is limited by the system parameter BALSETCNT.When creating a new process, if the set of real balance slots is allocated, then a virtual balance slot is created and the owner of a real balance slot is selected and transitioned to the virtual balance slot. The new process is created in the real balance slot. Processes are transitioned (faulted) back to a real balance slot as they are scheduled to execute on a CPU.
Bit Result 0 Enables VBS. All other VBS enables are subordinate to this enable. The default is disabled. 1 Enables the creation of a map for process-based direct I/O, allowing the process with direct I/O (DIO) outstanding to be transitioned to a virtual balance slot. Without DIO maps, a process with DIO outstanding retains its real balance slot for the duration of the DIO. This reduces the pool of available real balance slots for timesharing, which may result in a higher rate of faulting into the limited set of real balance slots. The default is enabled. 2-7 Reserved to Digital for future use. VBSS_ENABLE2
On VAX systems, this cell is used for enabling and disabling VBS dynamic capabilities that are valid only when VBS is enabled. The following table indicates the result for each value:
Bit Result 0 Enables VBS to perform first-level data reduction when switching processes. The default is enabled. 1 Enables VBS to perform second-level data reduction when switching processes. The default is enabled. 2 Requests VBS to perform an optimization that will detect empty private page table pages on the modified list and free them directly to the free list versus writing them to the page file. The default setting is enabled. 3-7 Reserved to Digital for future use. VCC_FLAGS (A)
On Alpha systems, VCC_FLAGS enables or disables virtual I/O caching. The virtual I/O cache is a file-oriented disk cache that reduces I/O bottlenecks and improves performance. Cache operation is transparent to application software and requires very little system management. This new functionality provides a write-through cache that maintains the integrity of disk writes while significantly improving read performance. The virtual I/O cache works on standalone systems and in an OpenVMS Cluster environment provided that all nodes in the cluster support virtual I/O caching.By default, virtual I/O caching is enabled. Change the value of the VCC_FLAGS parameter as follows:
- VCC_FLAGS = 1 to enable caching
- VCC_FLAGS = 0 to disable caching
By default, memory is allocated for caching 6400 disk blocks. This requires 3.2 MB of memory. Use the system parameter VCC_MAXSIZE to control memory allocation in units of disk blocks.
VCC_MAXSIZE (A)
On Alpha systems, VCC_MAXSIZE controls memory allocation virtual I/O cache in units of disk blocks.VCC_PTES
On VAX systems, VCC_PTES specifies the MAXIMUM size that the virtual I/O cache is permited to dynamically expand. VCC_PTES is a static parameter and requires that the system reboot after being changed by the AUTOGEN mechanism.VMS (D)
VMSD1, VMSD2, VMSD3, VMSD4, VMS5, VMS6, VMS7, and VMS8 are reserved for Digital use. VMSD1 through VMSD4 are dynamic.WPRE_SIZE (D)
WPRE_SIZE represents the number of pages to be allocated to accommodate WatchPoint Recovery Entries (WPRE) on the Watchpoint Driver.WPTTE_SIZE (D)
WPTTE_SIZE is the number of entries that the WPDRIVER creates in the WatchPoint Trace Table.WRITABLESYS
WRITABLESYS controls whether system code is writable. This parameter is set (value of 1) for debugging purposes only.WRITESYSPARAMS (D)
On VAX systems, WRITESYSPARAMS indicates that parameters are modified during SYSBOOT and are written out to VAXVMSSYS.PAR by STARTUP.COM.
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6048P069.HTM OSSG Documentation 26-NOV-1996 12:44:08.60Copyright © Digital Equipment Corporation 1996. All Rights Reserved.