Tarantella Administration Guide > Before you begin > What operating system changes do I need to make?

What operating system changes do I need to make?

This page lists the recommended changes to operating systems for running Tarantella:

• Linux kernel 2.4+ (all distributions)
• SPARC Solaris™ 2.8+

If you are using the Tarantella Mainframe Connectivity Pack, there is also some additional kernel tuning.

Linux kernel 2.4+ (all distributions)

The 2.4+ kernel is much more demanding of swap than earlier versions.

We recommend you allocate a swap file twice the size of physical memory. So if you have 1Gb RAM, increase your swap to 2Gb.

For more information, see Linux swapfile notes and LWN.net Kernel development.

SPARC Solaris 2.8+

Patches

You should install the appropriate patches for your Solaris version. These are available from the SunSolve Online Patches page.

Note: The patches recommended by Sun for Solaris may not apply to Siemens Solaris-based systems. For information about which patches to install on these systems, refer to your Siemens contact or the Siemens web site.

Using Solaris as an application server

Each emulator session requires one pseudo-tty. For example, 50 users running 10 applications each on one application server requires 500 pseudo-ttys.

To set the number of pseudo-ttys, first back up your /etc/system file. Then edit the file and add the following line:
set pt_cnt=limit
where limit is the number of pseudo-ttys you require.

To create the new devices, reboot with the -r option.

See the SunSolve site for advice on increasing pseudo-ttys.

Additional kernel tuning for the Tarantella Mainframe Connectivity Pack

The Mainframe Connectivity Pack uses the third-party TN3270E product, which may require additional kernel tuning on your system.

The information provided lists the resources that TN3270E requires. To determine the actual values required for your system, you need to know the resource requirements of other applications running on the system.

Kernel parameters required for supported operating systems

Some operating systems only require some of the parameters to be tuned:

Definitions

TN3270E invocations is the maximum number of TN3270E programs which will be running concurrently on the system.

HLLAPI sessions is the total number of TN3270E sessions, for all of the TN3270E programs running with an HLLAPI session ID assigned. HLLAPI session IDs are assigned through the style file or with the -h option.

Command line options

-h allows a hexadecimal HLLAPI session ID to be specified for a TN3270E session.

-b starts the TN3270E program as a background process.

-e disables the menu interface.

Formulas for TN3270E with neither the -b or -e command line options:

• SHMMNI = 1 + (TN3270E invocations) + (HLLAPI sessions)
• SEMMNI = (2 x TN3270E invocations) + (HLLAPI sessions)
• SEMMNS = (2 x TN3270E invocations) + (2 x HLLAPI sessions)
• SEMMAP = half the value of SEMMNS
• SEMMNU = (2 x TN3270E invocations) + (HLLAPI sessions)

Formulas for TN3270E with the -b or -e command line option specified:

• SHMMNI = same as above
• SEMMNI = HLLAPI sessions
• SEMMNS = 2 x HLLAPI sessions
• SEMMAP = half the value of SEMMNS
• SEMMNU = HLLAPI sessions

Additional kernel tuning for HLLAPI applications

• SHMSEG must be set on all operating systems when a single HLLAPI application must access multiple TN3270E sessions.
• SHMSEG = 1 + the maximum number of HLLAPI sessions to be accessed by a single HLLAPI application process.

Shared memory sizes

In most cases the shared memory sizes configured by default will be sufficient. For the few cases where this is not true, formulas are provided to calculate the approximate shared memory size required by TN3270E:

• Without the -b option = (90K x TN3270E invocations) + (14K x HLLAPI sessions)
• With the -b option = (19K x TN3270E invocations) + (14K x HLLAPI sessions)

Process and socket requirements

• TN3270E uses two processes per invocation when run without either the -b or the -e options. Only one process is used with either the -b or -e option specified. This is true for both the Motif and character TN3270E versions.
• TN3270E uses one TCP socket per host session.