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nclist(5) [hpux man page]

nclist(5)							File Formats Manual							 nclist(5)

NAME

       nclist - number of cblocks for pty and tty data transfers

VALUES

   Default
   Allowed Values
       Minimum Maximum limited by available memory.

DESCRIPTION

       specifies how many are allocated in the system.	Data traffic is stored in as it passes through tty and pty devices.

       The  default value for is based on a formula of 100 for system use in handling traffic to the console, etc., plus an average of 16 per user
       session, assuming 512 user sessions.  are also used for serial connections other than login sessions, such as  as  SLIP	connections,  UUCP
       transfers, terminal emulators, and such.  If your system is using these other kinds of connections, should be increased accordingly.

       If  the	pool is exhausted, data being passed through a tty or pty device might be lost because a was not available when it was needed.	If
       this occurs, the warning message "cblock exhaustion has occurred n times (see termio(7)) is placed in the system message buffer.

   Who Is Expected to Change This Tunable?
       Users with the privilege.  See privileges(5) for more information about privileged access on systems that support fine-grained privileges.

   Restrictions on Changing
       Changes to this tunable take effect at the next reboot.

   When Should the Value of This Tunable Be Raised?
       The tunable value can be increased in the following instances:

	      o  When the kernel sends the error message the system is running out of This indicates that needs to be increased.

	      o  The system may run slow for terminal I/O resulting in some data loss, without displaying a warning message.  Increasing the value
		 may solve this problem.

       The minimum value for is There is no maximum, but each consumes 32 bytes of resident (non-swappable) machine memory, so the value should be
       selected with this in mind.

   What Are the Side Effects of Raising the Value of This Tunable?
       More resident (non-swappable) machine memory is used.

   When Should the Value of This Tunable Be Lowered?
       This value should be lowered when a minimal system is being created.

   What Are the Side Effects of Lowering the Value of This Tunable?
       The system may run out of

   What Other Tunables Should Be Changed at the Same Time?
       None.

WARNINGS

       All HP-UX kernel tunable parameters are release specific.  This parameter may be removed or have its meaning changed in future releases	of
       HP-UX.

       Installation  of  optional  kernel  software, from HP or other vendors, may cause changes to tunable parameter values.  After installation,
       some tunable parameters may no longer be at the default or recommended values.  For information about the effects of installation  on  tun-
       able  values,  consult  the documentation for the kernel software being installed.  For information about optional kernel software that was
       factory installed on your system, see at

AUTHOR

       was developed by HP.

SEE ALSO

       kctune(1M), privileges(5), termio(7).

							     Tunable Kernel Parameters							 nclist(5)

Check Out this Related Man Page

nstrpty(5)							File Formats Manual							nstrpty(5)

NAME

       nstrpty - maximum number of STREAMS-based pseudo terminals (pts)

VALUES

   Default
   Allowed Values
DESCRIPTION

       is  the number of STREAMS-based pseudo terminal (pts) drivers that a system can support.  The pty driver provides support for a device-pair
       called a pseudo terminal.  A pseudo terminal is a pair of character devices, a master device, and a slave device.  These  allow	communica-
       tion between an application process and a server process.  When sending data to pty devices (such as  windows), a pty device must exist for
       every window that is open at any given time.

       should  be set to a value that is equal to, or greater than, the number of pty devices on the system that will be using	STREAMS-based  I/O
       pipes.	Using a parameter value significantly larger than the number of ptys is not recommended.  is used when creating data structures in
       the kernel to support STREAMS-based ptys, and an excessively large value wastes kernel memory space.

   Who Is Expected to Change This Tunable?
       Users with the privilege.  See privileges(5) for more information about privileged access on systems that support fine-grained privileges.

   Restrictions on Changing
       Changes to this tunable take effect at the next reboot.

   When Should the Value of This Tunable Be Raised?
       This tunable value needs to be raised when the system runs out of ptys.

   What Are the Side Effects of Raising the Value?
       More system memory is used.

   When Should the Value of This Tunable Be Lowered?
       This value should be lowered when a minimal system is being created.

   What Are the Side Effects of Lowering the Value?
       The system may run out of ptys.

WARNINGS

       All HP-UX kernel tunable parameters are release specific.  This parameter may be removed or have its meaning changed in future releases	of
       HP-UX.

       Installation  of  optional  kernel  software, from HP or other vendors, may cause changes to tunable parameter values.  After installation,
       some tunable parameters may no longer be at the default or recommended values.  For information about the effects of installation  on  tun-
       able  values,  consult  the documentation for the kernel software being installed.  For information about optional kernel software that was
       factory installed on your system, see at

AUTHOR

       was developed by HP.

SEE ALSO

       kctune(1M), privileges(5), pts(7).

							     Tunable Kernel Parameters							nstrpty(5)
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