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Updated: 11 December 1998

OpenVMS System Management Utilities Reference Manual


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While a high value takes space away from user working sets, a low value can seriously impair system performance. Appropriate values vary, depending on the level of system use. When the system is running at full load, check the rate of system faults with the MONITOR PAGE command of the Monitor utility. An average system page fault rate of between 0 and 3 page faults per second is desirable. If the system page fault rate is high, and especially if the system seems to be slow, you should increase the value of SYSMWCNT. However, do not set this parameter so high that system page faulting never occurs.

SYSPFC

SYSPFC sets the number of pages to be read from disk on each system paging operation.

This special parameter is used by Compaq and is subject to change. Do not change this parameter unless Compaq recommends that you do so.

SYSTEM_CHECK

SYSTEM_CHECK investigates intermittent system failures by enabling a number of run-time consistency checks on system operation and recording some trace information.

Enabling SYSTEM_CHECK causes the system to behave as if the following system parameter values are set (although the values of the following parameters are not actually changed):
Parameter Value Description
BUGCHECKFATAL 1 Crash the system on nonfatal bugchecks
POOLCHECK %X616400FF Enable all poolchecking, with an allocated pool pattern of %x61616161 ('aaaa') and deallocated pool pattern of x64646464 ('dddd')
MULTIPROCESSING 2 Enable full synchronization checking

While SYSTEM_CHECK is enabled, the previous settings of the BUGCHECKFATAL and MULTIPROCESSING parameters are ignored. However, setting the parameter POOLCHECK to a nonzero value overrides the setting imposed by SYSTEM_CHECK.

Setting SYSTEM_CHECK creates certain image files that are capable of the additional system monitoring. These image files are located in SYS$LOADABLE_IMAGES and can be identified by the suffix _MON.

For information about the type of data checking performed by SYSTEM_CHECK, see the description of the ACP_DATACHECK parameter. For information about the performance implications of enabling SYSTEM_CHECK, see OpenVMS Performance Management.

On VAX systems, SYSTEM_CHECK is a special parameter, which is subject to change at any time and should be modified only if recommended by Compaq.

TAILORED

TAILORED specifies whether or not the system is tailored during installation. Compaq recommends that you use the default value.

TAPE_ALLOCLASS

TAPE_ALLOCLASS determines the tape allocation class for the system. The tape allocation class creates a unique clusterwide device name for multiple access paths to the same tape.

The TAPE_ALLOCLASS parameter can also be used to generate a unique clusterwide name for tape devices with identical unit numbers.

TAPE_MVTIMEOUT (D)

TAPE_MVTIMEOUT is the time in seconds that a mount verification attempt continues on a given magnetic tape volume. If the mount verification does not recover the volume within that time, the I/O operations outstanding to the volume terminate abnormally.

TBSKIPWSL

TBSKIPWSL specifies the maximum number of working set list entries that may be skipped while scanning for a "good" entry to discard. Setting this parameter to 0 disables skipping.

This special parameter is used by Compaq and is subject to change. Do not change this parameter unless Compaq recommends that you do so.

TIME_CONTROL (D)

This special parameter is used by Compaq and is subject to change. Do not change this parameter unless Compaq recommends that you do so.

TIME_CONTROL is an SMP bit mask 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.

TIMEPROMPTWAIT

TIMEPROMPTWAIT defines the number of seconds that you want a processor to wait for the time and date to be entered when a system boot occurs, if the processor's time-of-year clock does not contain a valid time. (The time unit of micro-fortnights is approximated as seconds in the implementation.) If the time specified by TIMEPROMPTWAIT elapses, the system continues the boot operation, and the date and time are set to the last recorded time that the system booted.

Note

Compaq recommends that you set the correct system time before allowing the system to run, so that all functions using time-stamping (such as the operator log, the error log, accounting records, file creation dates, and file expiration dates) contain correct time values.

Depending on the value specified for the TIMEPROMPTWAIT parameter, the system acts in one of the following ways:

TIMVCFAIL (D)

TIMVCFAIL specifies the time required for an adapter or virtual circuit failure to be detected. Compaq recommends that the default value be used. Compaq also recommends that this value be lowered only in OpenVMS Cluster of three CPUs or less, that the same value be used on each computer in the cluster, and that dedicated LAN segments be used for cluster I/O.

TMSCP_LOAD (A)

TMSCP_LOAD allows the loading of the tape mass storage control protocol server software. The TMSCP_LOAD parameter also sets locally connected tapes served. Refer to OpenVMS Cluster Systems for information about setting the TMSCP_LOAD parameter.

Setting TMSCP_LOAD to 0 inhibits the loading of the tape server and the serving of local tapes. Setting TMSCP to 1 loads the tape server into memory at the time the system is booted and makes all directly connected tape drives available clusterwide. The following table describes the two states of the TMSCP_LOAD parameter:
State Function
0 Do not load the TMSCP tape server. Do not serve any local tape devices clusterwide. This is the default value.
1 Load the TMSCP tape server. Serve all local TMSCP tape devices clusterwide.

TMSCP_SERVE_ALL

TMSCP_SERVE_ALL is a bit mask that controls the serving of tapes. The settings take effect when the system boots. You cannot change the settings when the system is running.

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 all tapes except those whose allocation class does not match. 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 tapes is restricted to serving all tapes except those whose allocation class does not match the system's allocation class (pre-Version 7.2 meaning). 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 Value When Set Description
Bit 0 1 Serve all available tapes (locally attached and those connected to HS x and DSSI controllers). Tapes 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.
Bit 1 2 Serve locally attached (non-HS x and non-DSSI) tapes.
Bit 2 N/A Reserved.
Bit 3 8 Restrict the serving specified by bit 0. All tapes 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 Version 7.1- x or earlier, and you want to serve all available tapes, you must specify 9, the result of setting this bit and bit 0.

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:

If the TMSCP_LOAD system parameter is 0, TMSCP_SERVE_ALL is ignored.

TTY_ALTALARM

TTY_ALTALARM sets the size of the alternate type-ahead buffer alarm. This value indicates at what point an XOFF should be sent to terminals that use the alternate type-ahead buffers with the size specified by the TTY_ALTYPAHD parameter.

TTY_ALTYPAHD

TTY_ALTYPAHD sets the size of the alternate type-ahead buffer. Use this parameter to allow the block mode terminals and communications lines to operate more efficiently.

The default value is usually adequate. Do not exceed the maximum value of 32767 when setting this parameter.

TTY_AUTOCHAR (D)

TTY_AUTOCHAR sets the character the terminal driver echoes when the job controller has been notified.

TTY_BUF

TTY_BUF sets the default line width for terminals.

TTY_CLASSNAME

TTY_CLASSNAME provides the 2-character prefix for the terminal class driver name that is required when booting. Changing the prefix can be useful when debugging a new terminal driver.

TTY_DEFCHAR

TTY_DEFCHAR sets the default characteristics for terminals, using a code derived by summing the following hexadecimal values:
Characteristic Value (Hex) Function
PASSALL 1 Passall.
NOECHO 2 Noecho mode.
NOTYPEAHEAD 1 4 No type-ahead buffer.
ESCAPE 8 Escape sequence processing.
HOSTSYNC 10 Host can send XON and XOFF.
TTSYNC 20 Terminal can send XON and XOFF.
SCRIPT 40 Internal use only.
LOWER 80 Lowercase.
MECHTAB 100 Mechanical tabs.
WRAP 200 Wraparound at end of line.
CRFILL 1 400 Perform carriage return fill.
LFFILL 1 800 Perform line feed fill.
SCOPE 1000 Terminal is a scope.
REMOTE 2000 Internal use only.
EIGHTBIT 8000 Eight-bit terminal.
MBXDSABL 10000 Disable mailbox.
NOBRDCST 20000 Prohibit broadcast.
READSYNC 40000 XON and XOFF on reads.
MECHFORM 80000 Mechanical form feeds.
HALFDUP 100000 Set for half-duplex operation.
MODEM 200000 Set for modem signals.
PAGE FF000000 Page size. Default is 24.

1Do not set this characteristic as the default in TTY_DEFCHAR.

Where a condition is false, the value is 0.

The upper byte is the page length. The default characteristics are 24 lines per page, terminal synchronization, wraparound, lowercase, scope, and full-duplex.

TTY_DEFCHAR2

TTY_DEFCHAR2 sets a second longword of default terminal characteristics. The default characteristics are represented as a code that is derived by summing the following hexadecimal values:
Characteristic Value (Hex) Function
LOCALECHO 1 Enable local echo terminal logic; use with the TTY_DEFCHAR NOECHO characteristic.
AUTOBAUD 2 Enable autobaud detection.
HANGUP 4 Hang up on logout.
MODHANGUP 8 Allow modification of HANGUP without privileges.
BRDCSTMBX 10 Allow sending of broadcasts to mailboxes.
XON 20 (No effect in this parameter.)
DMA 40 (No effect in this parameter.)
ALTYPEAHD 80 Use the alternate type-ahead parameters.
SETSPEED 100 Clear to allow setting of speed without privileges.
DCL_MAILBX 200 Function reserved for Compaq use only.
DECCRT4 400 Terminal is DIGITAL CRT Level 4.
COMMSYNC 800 Enable flow control using modem signals.
EDITING 1000 Line editing allowed.
INSERT 2000 Sets default mode for insert.
FALLBACK 4000 Do not set this bit with SYSGEN. Refer to the OpenVMS Terminal Fallback Utility Manual 1 for information about setting the FALLBACK terminal characteristic using the Terminal Fallback utility.
DIALUP 8000 Terminal is a dialup line.
SECURE 10000 Guarantees that no process is connected to terminal after Break key is pressed.
DISCONNECT 20000 Allows terminal disconnect when a hangup occurs.
PASTHRU 40000 Terminal is in PASTHRU mode.
SYSPWD 80000 Log in with system password only.
SIXEL 100000 Sixel graphics.
DRCS 200000 Terminal supports loadable character fonts.
PRINTER 400000 Terminal has printer port.
APP_KEYPAD 800000 Notifies application programs of state to set keypad on exit.
ANSICRT 1000000 Terminal conforms to ANSI CRT programming standards.
REGIS 2000000 Terminal has REGIS CRT capabilities.
BLOCK 4000000 Block mode terminal.
AVO 8000000 Terminal has advanced video.
EDIT 10000000 Terminal has local edit capabilities.
DECCRT 20000000 Terminal is a DIGITAL CRT.
DECCRT2 40000000 Terminal is a DIGITAL CRT Level 2.
DECCRT3 80000000 Terminal is a DIGITAL CRT Level 3.

1This manual has been archived but is available in PostScript and DECW$BOOK (Bookreader) formats on the OpenVMS Documentation CD-ROM. A printed book can be ordered through DECdirect (800-354-4825).

The defaults are AUTOBAUD and EDITING.

TTY_DEFPORT

TTY_DEFPORT provides flag bits for port drivers. Bit 0 set to 1 indicates that the terminal controller does not provide automatic XON/XOFF flow control. This bit should not be set for Compaq controllers, but it is needed for some foreign controllers. Currently only the YCDRIVER (DMF32, DMZ32) uses this bit. The remaining bits are reserved for future use. This special parameter should be modified only if recommended by Compaq.

TTY_DIALTYPE

TTY_DIALTYPE provides flag bits for dialups. Bit 0 is 1 for United Kingdom dialups and 0 for all others. Bit 1 controls the modem protocol used. Bit 2 controls whether a modem line hangs up 30 seconds after seeing CARRIER if a channel is not assigned to the device. The remaining bits are reserved for future use. See the OpenVMS I/O User's Reference Manual for more information about flag bits.

TTY_DMASIZE (D)

TTY_DMASIZE specifies a number of characters in the output buffer. Below this number, character transfers are performed; above this number, DMA transfers occur if the controller is capable of DMA I/O.

TTY_PARITY

TTY_PARITY sets terminal default parity.

TTY_RSPEED

TTY_RSPEED defines the receive speed for terminals. If TTY_RSPEED is 0, TTY_SPEED controls both the transmit and the receive speed. Maximum value is 17. This parameter is only applicable for controllers that support split-speed operations, such as the DZ32 and the DMF32.

TTY_SCANDELTA

TTY_SCANDELTA sets the interval for polling terminals for dialup and hangup events. Shorter intervals use more processor time; longer intervals may result in missing a hangup event.

TTY_SILOTIME

TTY_SILOTIME defines the interval at which the DMF32 hardware polls the input silo for received characters. The DMF32 asynchronous terminal controller can delay the generation of a single input interrupt until multiple characters have accumulated in the input silo. TTY_SILOTIME specifies the number of milliseconds that the characters are allowed to accumulate prior to the generation of an input interrupt by the hardware.

TTY_SPEED

TTY_SPEED sets the systemwide default speed for terminals. Low byte is transmit speed, and high byte is receive speed. If high byte is set to 0, receive speed is identical to transmit speed. Maximum value is 17. Baud rates are defined by the $TTDEF macro.

TTY_TIMEOUT (D)

TTY_TIMEOUT sets the number of seconds before a process associated with a disconnected terminal is deleted. The default value (900 seconds) is usually adequate. Note that using values for TTY_TIMEOUT greater than one year (value %X01E13380) can cause overflow errors and result in a disconnected device timing out immediately.

TTY_TYPAHDSZ

TTY_TYPAHDSZ sets the size of the terminal type-ahead buffer. The default value is usually adequate. Do not exceed the maximum value of 32767 when setting this parameter.

UAFALTERNATE (G,M)

UAFALTERNATE enables or disables the assignment of SYSUAF as the logical name for SYSUAFALT, causing all references to the user authorization file (SYSUAF) to be translated to SYS$SYSTEM:SYSUAFALT. Use of the normal user authorization file (SYS$SYSTEM:SYSUAF) can be restored by deassigning the system logical name SYSUAF. This parameter should be set on (1) only when the system is being used by a restricted set of users. You must create a user authorization file named SYSUAFALT prior to setting UAFALTERNATE to 1.

UDABURSTRATE (G)

UDABURSTRATE is reserved for Compaq use only.

USERD1 (D)

USERD1 is reserved for definition at the user's site. The reserved longword is referenced by the symbol SGN$GL_USERD1.

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.

USERD2 (D)

USERD2 is reserved for definition at the user's site. The reserved longword is referenced by the symbol SGN$GL_USERD2.

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.

USER3

USER3 is a parameter that is reserved for definition at the user's site. The reserved longword is referenced by the symbol SGN$GL_USER3.

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.

USER4

USER4 is a parameter that is reserved for definition at the user's site. The reserved longword is referenced by the symbol SGN$GL_USER4.

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.

VAXCLUSTER (A)

VAXCLUSTER controls loading of the cluster code. Specify one of the following:
Value Description
0 Never form or join a cluster.
1 Base decision of whether to form (or join) a cluster or to operate standalone on the presence of cluster hardware.
2 Always form or join a cluster.

The default value is 1.

VBN_CACHE_S

(VAX only) This special parameter is used by Compaq and is subject to change. Do not change this parameter unless Compaq recommends that you do so.

The static system parameter VBN_CACHE_S enables or disables file system data caching. By default its value is 1, which means that caching is enabled and the Virtual I/O Cache is loaded during system startup.

Setting the value to 0 disables file system data caching on the local node and throughout the OpenVMS Cluster. In an OpenVMS Cluster, none of the other nodes in the cluster can cache any file data until this node either leaves the cluster or reboots with VBN_CACHE_S set to 1.

VBSS_ENABLE (A)

(VAX only) This special parameter is used by Compaq and is subject to change. Do not change this parameter unless Compaq recommends that you do so.

This parameter 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.


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