NAME
npty — maximum number of BSD pseudo terminals (ptys)
VALUES
Allowed Values
Minimum : 1
Maximum : System memory size
DESCRIPTION
npty
is the number of pseudo terminal (pty) 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 communication 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.
Using a parameter value significantly larger than the number of
ptys is not recommended.
An excessively large value wastes kernel memory space.
Who Is Expected to Change This Tunable?
Users with the
SYSATTR
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 tunable values, consult the documentation
for the kernel software being installed.
For information about optional kernel software that was
factory installed on your system, see
HP-UX Release Notes
at
http://docs.hp.com.
AUTHOR
npty
was developed by HP.
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