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Document revision date: 19 July 1999
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OpenVMS System Management Utilities Reference
Manual
For simple timesharing systems, the default value is adequate. If your
application uses many locks, as in the case of heavy RMS file sharing
or a database management application, you should increase this
parameter. When you change the value of LOCKIDTBL, examine the value of
RESHASHTBL and change it if necessary.
The OpenVMS Lock Management facility is described in the OpenVMS Programming Concepts Manual.
You can monitor locks with the MONITOR LOCK command of the Monitor
utility.
LOCKIDTBL_MAX
LOCKIDTBL_MAX is obsolete beginning with OpenVMS Version 7.1.
LOCKRETRY
LOCKRETRY establishes the number of attempts made to lock a
multiprocessor data structure.
This special parameter is used by Compaq and is subject to change. Do
not change this parameter unless Compaq recommends that you do so.
LONGWAIT (A on Alpha,D,G,M)
LONGWAIT defines how much real time (in seconds) must elapse before the
swapper considers a process to be temporarily idle. This parameter is
applied to local event flag (LEF) and hibernate (HIB) waits to detect
such conditions as an inactive terminal or ACP.
MAXBOBMEM (D)
(Alpha only) MAXBOBMEM defines the maximum amount of physical memory,
measured in pagelets, that can be associated with buffer objects. A
page to be associated with a buffer object is counted against this
parameter only once even if it is associated with more than 1 buffer
object at the same time.
Beginning in OpenVMS Version 7.2, memory-resident pages are not counted
against this parameter. (However, pages locked in memory through the
$LCKPAG system service are counted.)
MAXBOBS0S1 (D)
(Alpha only) MAXBOBS0S1 defines the maximum amount of 32-bit system
space, measured in pagelets, that can be used for windows to buffer
objects.
MAXBOBS2 (D)
(Alpha only) MAXBOBS2 defines the maximum amount of 64-bit system
space, measured in pagelets, that can be used for windows to buffer
objects.
MAXBUF (D)
MAXBUF sets the maximum allowable size for any single buffered I/O
packet. Buffered I/O packets are allocated from the permanently
resident nonpaged dynamic pool. The terminal, mailbox, and printer
device drivers are examples of device drivers that perform buffered I/O.
The number of bytes specified in the I/O request plus the size of a
driver-dependent and function-dependent header area determine the
required buffered I/O packet size. The size of the header area is a
minimum of 16 bytes; there is no absolute upper limit. However, this
header area is usually a few hundred bytes in size.
On OpenVMS VAX systems beginning with Version 7.1, the default value is
4112. The default value on OpenVMS Alpha systems continues to be 8192.
MAXCLASSPRI (D)
If class scheduling is enabled, MAXCLASSPRI sets the maximum range in
the priority range of class-scheduled processes.
This special parameter is used by Compaq and is subject to change. Do
not change this parameter unless Compaq recommends that you do so.
MAXPROCESSCNT (A,F,G,M)
MAXPROCESSCNT sets the number of process entry slots allocated at
bootstrap time. One slot is required for each concurrent process on the
system. Each slot requires 6 bytes of permanently resident memory.
The default value is normally configured to allow you to create the
desired number of processes. If the following message appears, you need
to increase the value of MAXPROCESSCNT:
%SYSTEM-F-NOSLOT, No PCB to create process
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MAXQUEPRI (D)
MAXQUEPRI determines the highest scheduling priority that can be
assigned to jobs entered in batch and output (printer, server, and
terminal) queues without the submitter process having OPER or ALTPRI
privilege. The value of this parameter can range from 0 to 255; the
default is 100. The value of MAXQUEPRI should be greater than or equal
to DEFQUEPRI.
Note
MAXQUEPRI refers to relative queue scheduling priority, not the
execution priority of the job.
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MAXSYSGROUP (D)
MAXSYSGROUP sets the highest value that a group number can have and
still be classified as a system UIC group number. Note that the
specification is not in octal unless preceded by the %O radix
indicator. This parameter is normally left at 8 (10 octal).
MC_SERVICES_P0 (D)
(Alpha only) MC_SERVICES_P0 controls whether other MEMORY CHANNEL nodes
in the cluster continue to run if this node bugchecks or shuts down.
A value of 1 causes other nodes in the MEMORY CHANNEL cluster to crash
with bugcheck code MC_FORCED_CRASH if this node bugchecks or shuts down.
The default value is 0. A setting of 1 is intended only for debugging
purposes; the parameter should otherwise be left at its default value.
MC_SERVICES_P1 (D)
(Alpha only) This special parameter is reserved for Compaq use. Its
value must be the same on all nodes connected by MEMORY CHANNEL.
MC_SERVICES_P2
(Alpha only) MC_SERVICES_P2 specifies whether to load the PMDRIVER
(PMA0) MEMORY CHANNEL cluster port driver.
PMDRIVER is a new driver that serves as the MEMORY CHANNEL cluster port
driver. It works together with MCDRIVER (the MEMORY CHANNEL device
driver and driver interface) to provide MEMORY CHANNEL clustering. If
PMDRIVER is not loaded, cluster connections are not made over the
MEMORY CHANNEL interconnect.
The default value is 1, which causes PMDRIVER to be loaded when you
boot the system. When you run CLUSTER_CONFIG.COM and select the MEMORY
CHANNEL option, PMDRIVER is loaded automatically when you reboot the
system.
Compaq recommends that this value not be changed. This parameter value
must be the same on all nodes connected by MEMORY CHANNEL.
MC_SERVICES_P3 (D)
(Alpha only) MC_SERVICES_P3 specifies the maximum number of tags
supported. The maximum value is 2048, and the minimum value is 100.
The default value is 800. Compaq recommends that this value not be
changed. This parameter value must be the same on all nodes connected
by MEMORY CHANNEL.
MC_SERVICES_P4
(Alpha only) MC_SERVICES_P4 specifies the maximum number of regions
supported. The maximum value is 4096, and the minimum value is 100.
The default value is 200. Compaq recommends that this value not be
changed. This parameter value must be the same on all nodes connected
by MEMORY CHANNEL.
MC_SERVICES_P5 (D)
(Alpha only) MC_SERVICES_P5 is reserved for Compaq use only and must
remain at the default value of 8000000. This value must be the same on
all nodes connected by MEMORY CHANNEL.
MC_SERVICES_P6
(Alpha only) MC_SERVICES_P6 specifies MEMORY CHANNEL message size, the
body of an entry in a free queue, or a work queue. The maximum value is
65536, and the minimum value is 544.
The default value is 992. This value is suitable in all cases except
for systems with highly constrained memory. For such systems, you can
reduce the memory consumptions of MEMORY CHANNEL by slightly reducing
the default value of 992. The value of MC_SERVICES_P6 must always be
equal to or greater than the result of the following calculations:
- Select the larger of SCS_MAXMSG and SCS_MAXDG.
- Round that value up to the next quadword.
The value of MC_SERVICES_P6 must be the same on all nodes connected by
MEMORY CHANNEL.
MC_SERVICES_P7 (D)
(Alpha only) MC_SERVICES_P7 specifies whether to suppress or display
messages about MEMORY CHANNEL activities on this node. This parameter
can be set to a value of 0, 1, or 2:
- A value of 0 indicates nonverbose mode: no informational messages
appear on the console or in the error log.
- A value of 1 indicates verbose mode: informational messages from
both MCDRIVER and PMDRIVER appear on the console and in the error log.
- A value of 2 provides the same output as a value of 1, with the
addition of PMDRIVER stalling and recovery messages.
The default value is 0. Compaq recommends that this value not be
changed except while debugging MEMORY CHANNEL problems or adjusting the
MC_SERVICES_P9 parameter.
MC_SERVICES_P8
(Alpha only) MC_SERVICES_P8 is reserved for Compaq use only and must
remain at the default value of 0. The value must be the same on all
nodes connected by MEMORY CHANNEL.
MC_SERVICES_P9
(Alpha only) MC_SERVICES_P9 specifies the number of initial entries in
a single channel's free queue. The maximum value is 2048, and the
minimum value is 10.
Note that MC_SERVICES_P9 is not a dynamic parameter; you must reboot
the system after each change for that change to take effect.
The default value is 150. Compaq recommends that this value not be
changed.
The value of MC_SERVICES_P9 must be the same on all nodes connected by
MEMORY CHANNEL.
MINCLASSPRI (D)
If class scheduling is enabled, MINCLASSPRI sets the minimum range in
the priority range of class-scheduled processes.
This special parameter is used by Compaq and is subject to change. Do
not change this parameter unless Compaq recommends that you do so.
MINPRPRI
This parameter is not used on OpenVMS VAX or Alpha systems.
MINWSCNT (A)
The value specified by MINWSCNT is added to the size of the process
header to establish the minimum working set size.
On VAX systems, MINWSCNT sets the minimum number of fluid pages (pages
not locked in the working set) required for the execution of a process.
The value of MINWSCNT must provide sufficient space to execute any VAX
instruction. Theoretically, the longest instruction requires 52 pages;
however, all code can run with 20 fluid pages. An insufficient value
may inhibit system performance or even put a process into an infinite
loop on some instructions.
On Alpha systems, MINWSCNT sets the minimum number of pages required
for the execution of a process. The default value is 20; the minimum
value is 10.
MMG_CTLFLAGS (A,D)
MMG_CTLFLAGS is a bit mask used to enable and disable proactive memory
reclamation mechanisms. Beginning with OpenVMS Version 7.2, you can
control when memory is tested. This helps reduce the time between when
you turn on the system and when you log in to an AlphaServer 4100
computer. Bit 2 in the parameter controls deferred memory testing.
The following bit mask values are defined:
| Bit |
Description |
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0
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Reclamation enabled by trimming from periodically executing, but
otherwise idle processes. This occurs when the size of the free list
drops below two times FREEGOAL.
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1
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Reclamation enabled by outswapping processes that have been idle for
longer than LONGWAIT seconds. This occurs when the size of the free
list drops below FREELIM.
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2
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Controls deferred memory testing:
- If the bit is clear (the default), OpenVMS tests memory in the
background and not necessarily before the bootstrap process has
completed.
- If the bit is set, all memory is tested by the end of EXEC_INIT in
the system bootstrap process (that is, before IPL is lowered from 31).
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3-7
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Reserved for future use.
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MPDEV_D1
(Alpha only) MPDEV_D1 is reserved for use by the operating system.
MPDEV_ENABLE
(Alpha only) MPDEV_ENABLE enables the formation of multipath sets when
set to ON (1). If set to OFF (0), the formation of additional multipath
sets is disabled. However, existing multipath sets remain in effect.
The default is ON.
MPDEV_LCRETRIES
(Alpha only) MPDEV_LCRETRIES controls the number of times the system
retries locally connected paths before moving on to local unconnected
paths or to an MSCP served path to the device. The valid range for
retries is 1 through 256. The default is 1.
MPDEV_POLLER
(Alpha only) MPDEV_POLLER enables polling of the paths to multipath set
members when set to ON (1). Polling allows early detection of errors on
inactive paths. If a path becomes unavailable or returns to service,
the system manager is notified with an OPCOM message. If set to OFF
(0), multipath polling is disabled. The default is ON.
MPDEV_REMOTE
(Alpha only) MPDEV_REMOTE enables MSCP served disks to become members
of a multipath set when set to ON (1). If set to OFF (0), only local
paths to a SCSI device will be used in the formation of additional
multipath sets. However, existing remote members of multipath sets
remain as members of them. The default is OFF.
MPW_HILIMIT (A,G)
MPW_HILIMIT sets an upper limit for the modified-page list. When the
list accumulates the number of pages specified by this limit, writing
of the list begins. The pages that are written are then transferred to
the free-page list.
If MPW_HILIMIT is too low, excessive page faulting can occur from the
page file. If it is too high, too many physical pages can be consumed
by the modified-page list.
If you increase MPW_HILIMIT, you might also need to increase
MPW_WAITLIMIT. Note that if MPW_WAITLIMIT is less than MPW_HILIMIT, a
system deadlock occurs. The values for the two parameters are usually
equal.
MPW_IOLIMIT (A on Alpha)
MPW_IOLIMIT specifies the number of outstanding I/Os to the
modified-page writer.
MPW_LOLIMIT (A,G)
MPW_LOLIMIT sets a lower limit for the modified-page list. When writing
of the list causes the number of pages on the list to drop to or below
this limit, writing stops.
MPW_LOLIMIT ensures that a certain number of pages are available on the
modified-page list for page faults. If the number is too small, the
caching effectiveness of the modified-page list is reduced. If it is
too high, less memory is available for processes, so that swap (and
page) may increase.
MPW_LOWAITLIMIT (A,D)
MPW_LOWAITLIMIT specifies the threshold at which processes in the
miscellaneous wait state MPWBUSY are allowed to resume. MPW_LOWAITLIMIT
increases system performance for fast processors with large memories by
reducing the amount of time processes spend in the MPWBUSY wait state.
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.
This special parameter is used by Compaq and is subject to change. Do
not change this parameter unless Compaq recommends that you do so.
MPW_THRESH (A on Alpha,D)
MPW_THRESH sets a lower bound of pages that must exist on the
modified-page list before the swapper writes this list to acquire free
pages. If this requirement is met, the swapper tries to write the
modified-page list rather than taking pages away from or swapping out a
process.
MPW_WAITLIMIT (A,D)
MPW_WAITLIMIT sets the number of pages on the modified-page list that
causes a process to wait until the next time the modified-page writer
writes the modified list. This parameter limits the rate at which any
single process can produce modified pages. If this value is less than
MPW_HILIMIT, a system deadlock occurs. The value for this parameter is
normally equal to MPW_HILIMIT.
MPW_WRTCLUSTER (A,G)
MPW_WRTCLUSTER sets the number of pages to be written during one I/O
operation from the modified-page list to the page file or a section
file. The actual size of the cluster may be limited by the number of
pages available for the I/O operation. This parameter can range in
value from 16 to 120, in multiples of 8. Each page in the cluster
requires 6 bytes of permanently resident memory.
If MPW_WRTCLUSTER is too small, it takes many I/O operations to empty
the modified-page list. If MPW_WRTCLUSTER is too large for the speed of
the disk that holds the page file, other I/O operations are held up for
the modified-page list write.
On VAX systems, the MPW_WRTCLUSTER default value and maximum value is
120 512-byte pages; its minimum value is 16 512-byte pages.
On Alpha systems, the MPW_WRTCLUSTER default value is 64 8192-byte
pages; its maximum value is 512 8192-byte pages; and its minimum value
is 16 8192-byte pages.
MSCP_BUFFER (A,F)
This buffer area is the space used by the server to transfer data
between client systems and local disks.
On VAX systems, MSCP_BUFFER specifies the number of pages to be
allocated to the MSCP server's local buffer area.
On Alpha systems, MSCP_BUFFER specifies the number of pagelets to be
allocated to the MSCP server's local buffer area.
MSCP_CMD_TMO (D)
MSCP_CMD_TMO is the time in seconds that the OpenVMS MSCP server uses
to detect MSCP command timeouts. The MSCP Server must complete the
command within a built-in time of approximately 40 seconds plus the
value of the MSCP_CMD_TMO parameter.
The MSCP_CMD_TMO default value of 0 is normally adequate. A value of 0
provides the same behavior as in previous releases of OpenVMS (which
did not have an MSCP_CMD_TMO system parameter). A nonzero setting
increases the amount of time before an MSCP command times out.
If command timeout errors are being logged on client nodes, setting the
parameter to a nonzero value on OpenVMS servers reduces the number of
errors logged. Increasing the value of this parameter reduces the numb
client MSCP command timeouts and increases the time it takes to detect
faulty devices.
If you need to decrease the number of command timeout errors, Compaq
recommends that you set an initial value of 60. If timeout errors
continue to be logged, you can increase this value in increments of 20
seconds.
MSCP_CREDITS
MSCP_CREDITS specifies the number of outstanding I/O requests that can
be active from one client system.
MSCP_LOAD (A)
MSCP_LOAD controls the loading of the MSCP server during a system boot.
Specify one of the following values:
| Value |
Description |
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0
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Do not load the MSCP server. This is the default value.
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1
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Load the MSCP server and serve disks as specified by the MSCP_SERVE_ALL
parameter.
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MSCP_SERVE_ALL
MSCP_SERVE_ALL is a bit mask that controls disk serving in an OpenVMS
Cluster. A disk is served regardless of its allocation class unless bit
3 has a value of 1.
Starting with OpenVMS Version 7.2, the serving types are implemented as
a bit mask. To specify the type of serving your system will perform,
locate the type you want in the following table and specify its value.
For some systems, you may want to specify two serving types, such as
serving the system disk and serving locally attached disks. To specify
such a combination, add the values of each type, and specify the sum.
In a mixed-version cluster that includes any systems running OpenVMS
Version 7.1-x or earlier, serving all available disks is
restricted to serving all disks except those whose allocation class
does not match the system's node allocation class (pre-Version 7.2). To
specify this type of serving, use the value 9 (which sets bit 0 and bit
3).
The following table describes the serving type controlled by each bit
and its decimal value.
| Bit and Value When Set |
Description |
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Bit 0 (1)
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Serve all available disks (locally attached and those connected to HS
x and DSSI controllers). Disks with allocation classes that
differ from the system's allocation class (set by the ALLOCLASS
parameter) are also served if bit 3 is not set.
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Bit 1 (2)
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Serve locally attached (non-HS
x and DSSI) disks.
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Bit 2 (4)
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Serve the system disk. This is the default setting. This setting is
important when other nodes in the cluster rely on this system being
able to serve its system disk. This setting prevents obscure contention
problems that can occur when a system attempts to complete I/O to a
remote system disk whose system has failed.
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Bit 3 (8)
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Restrict the serving specified by bit 0. All disks except those with
allocation classes that differ from the system's allocation class (set
by the ALLOCLASS parameter) are served.
This is pre-Version 7.2 behavior. If your cluster includes systems
running OpenVMS 7.1-
x or earlier, and you want to serve all available disks, you
must specify 9, the result of setting this bit and bit 0.
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Although the serving types are now implemented as a bit mask, the
values of 0, 1, and 2, specified by bit 0 and bit 1, retain their
original meanings:
- 0 --- Do not serve any disks (the default for earlier versions of
OpenVMS).
- 1 --- Serve all available disks.
- 2 --- Serve only locally attached (non-HSx and non-DSSI)
disks.
If the MSCP_LOAD system parameter is 0, MSCP_SERVE_ALL is ignored.
MULTIPROCESSING
MULTIPROCESSING controls the loading of the system synchronization
image.
Specify one of the following values:
| Value |
Description |
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0
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Load the uniprocessing synchronization image
SYSTEM_SYNCHRONIZATION_UNI.EXE.
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1
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If the CPU type is capable of SMP and two or more CPUs are present on
the system, load the full-checking multiprocessing synchronization
image SYSTEM_SYNCHRONIZATION.EXE. Otherwise, load the uniprocessing
synchronization image SYSTEM_SYNCHRONIZATION_UNI.EXE.
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2
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Always load the full-checking version SYSTEM_SYNCHRONIZATION.EXE,
regardless of system configuration or CPU availability.
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3
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If the CPU type is capable of SMP and two or more CPUs are present on
the system, load the optimized streamlined multiprocessing image:
- On VAX systems, this image is SYSTEM_SYNCHRONIZATION_SPC.EXE.
- On Alpha systems, this image is SYSTEM_SYNCHRONIZATION_MIN.EXE.
Otherwise, load the uniprocessing synchronization image
SYSTEM_SYNCHRONIZATION_UNI.EXE. The default value is 3.
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4
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Always load the streamlined multiprocessing image
SYSTEM_SYNCHRONIZATION_MIN.EXE, regardless of system configuration or
CPU availability.
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Setting the SYSTEM_CHECK parameter to 1 has the effect of setting
MULTIPROCESSING to 2.
MULTITHREAD (A)
MULTITHREAD controls the availability of kernel threads functions.
Specify one of the following values:
| Value |
Description |
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0
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Both Thread Manager upcalls and the creation of multiple kernel threads
are disabled.
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1
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Thread Manager upcalls are enabled; the creation of multiple kernel
threads is disabled.
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2-16 (Alpha only)
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Both Thread Manager upcalls and the creation of multiple kernel threads
are enabled. The number specified represents the maximum number of
kernel threads that can be created for a single process.
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The maximum value for MULTITHREAD is 256.
MVTIMEOUT (A on Alpha,D)
MVTIMEOUT is the time in seconds that a mount verification attempt
continues on a given disk volume. If the mount verification does not
recover the volume within that time, the I/O operations outstanding to
the volume terminate abnormally.
NET_CALLOUTS (D)
NET_CALLOUTS is normally set to 0. A value of 255 indicates that no
attempt is to be made to assign a new proxy connection to an active
server, but that a new process must be started to invoke the
installation security policy callout modules in LOGINOUT.EXE. Values 1
through 254 are reserved for future use.
NISCS_CONV_BOOT
NISCS_CONV_BOOT controls whether a conversational boot is permitted
during a remote system boot. The default value of 0 specifies that
conversational boots are not permitted.
NISCS_LAN_OVRHD
NISCS_LAN_OVRHD defines the number of bytes that are reserved by NISCA
for data reformatting or encapsulation in a local area network (LAN)
packet. The reserved space in the packet allows devices, such as the
DESNC, to perform their operations. Currently, this value must be
nonzero only when NISCA is run in an environment that uses the DESNC
for LAN data encryption. Refer to the description of the
NISCS_MAX_PKTSZ parameter for interactions.
Compaq recommends that NISCS_LAN_OVRVHD be set to the same value on all
nodes in the cluster.
NISCS_LOAD_PEA0
NISCS_LOAD_PEA0 controls whether the NI-SCS port driver PEDRIVER is
loaded during system boot. The default of 0 specifies that the PEDRIVER
is not loaded.
NISCS_MAX_PKTSZ (A on Alpha)
NISCS_MAX_PKTSZ defines the size in bytes of the data area in the
largest packet sent by NISCA on any local area network (LAN). PEDRIVER
uses this value, together with the NISCS_LAN_OVRHD parameter, to
compute the maximum amount of data to transmit in any LAN packet:
LAN packet size = LAN header (padded Ethernet format)
+ NISCS_MAX_PKTSZ value
- NISCS_LAN_OVRHD value
+ CRC or FCS
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For performance reasons, PEDRIVER limits the packet size so that the
packets can be allocated from a lookaside list in the nonpaged pool.
The actual allocation includes the required data structure overhead
used by PEDRIVER and the LAN drivers. However, lookaside lists are
provided for the allocation sizes required when using maximum size
packets on both Ethernet and FDDI. This allows PEDRIVER to take full
advantage of these interconnects.
NISCS_PORT_SERV (A)
NISCS_PORT_SERV provides flag bits for PEDRIVER port services. Setting
bits 0 and 1 (decimal value 3) enables data checking. The remaining
bits are reserved for future use.
NJOBLIM (D)
NJOBLIM establishes the limit for network jobs. The maximum number of
jobs is 1024. The minimum is 0, and the default is 16.
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. Set NOAUTOCONFIG to 1 (no
automatic configuration) only for debugging purposes.
This special parameter is used by Compaq and is subject to change. Do
not change this parameter unless Compaq recommends that you do so.
NOCLUSTER
NOCLUSTER controls whether page read clustering is inhibited when the
system boots. Set NOCLUSTER to 1 (inhibit page read clustering)
only for debugging purposes.