LAM Installation Guide

The LAM source directory is packaged as a compressed tape archive.

lam.tar.Z

The release number will also be present in the filename. Uncompress the archive and extract the LAM sources.

% uncompress lam.tar.Z
% tar xvf lam.tar

Another distribution file with the same release number is a tape archive containing patches for serious bugs. Extract the patches from the archive as shown above. Read the preamble to each patch. Apply the relevant patches to the the specified files using your favourite editor. Or, apply all the patches with the UNIX patch(1) utility, run from the source directory.

% tar xvf lam61-patch.tar
% cat lam61-patch[0-9][0-9] | patch -p0

Machine-Dependent Configuration

The machines and UNIX flavours listed below are supported by the current version of LAM. Other variations may require source code changes.

Sun, SunOS 5.4
SGI, IRIX 6.2
IBM, AIX version 3, release 2
DEC, DEC UNIX V4.0
HP, HP-UX 10.01
Intel X86, LINUX v2.0.24

In the source directory, create the symbolic link Config/config pointing at one of the machine-dependent configuration files under Config/.

% ln -s config.sun4_sol config

Customizing LAM

The configuration file contains information for building and installing the libraries and executables on a particular architecture. Many variables are rarely changed or not intended to be changed by you. Only one of these variables must be set.

HOME = installation directory

Libraries and executables are built in the source directory (actually in object subdirectories of the source directory) and installed in the installation directory. The installation directory, which can be located anywhere, is configured by the HOME variable.

Other variables which can be set are described below. However, they should be modified from the default values only if you thoroughly understand their usage.

Timers

TO_BOOT: LAM considers a new daemon started on a remote node to be dead because it has not received initial contact.
TO_DLO_ACK: A previously transmitted network packet is re-transmitted because an acknowledgement has not been received.
TO_DLO_IDLE: A heartbeat message is sent to quiet nodes to verify that they are still alive. This feature is enabled with the -x option to lamboot(1).

Counters

TO_DLO_ESTIMATE: After so many requests to the LAM daemon, a pending timeout period is declared to have expired. This compensates for deficiencies in select(2).
DOMAXRESEND: After so many network packet retransmissions, the destination node is considered dead. This feature is enabled with the -x option to lamboot(1).
MPI_GER: A minimum number of message envelopes is protected for each process pair in an MPI application.

Building LAM

The build procedure is a two step process. First the Makefiles establish dependencies on header and source files. In the second step, the executables and libraries are compiled, linked and archived as necessary. Both of these steps are performed by locating to the top of the source directory and running the make(1) utility with the default target. We suggest that you capture standard output and error in case you need to diagnose problems with the build.

% make >& LOG &

You can monitor progress with the tail(1) utility.

% tail -f LOG

A convenient feature of LAM is the ability to support multiple installations for experimentation. To build another installation directory, simply repeat the building steps with a different value of the HOME variable. (A command line setting of this variable is not sufficient - you must edit the configuration file.) Users choose among different installations by setting their shell's search path accordingly.

Boot Schema

A boot schema is a description of a multicomputer on which LAM will be run. You can create boot schema files (see bhost(5) for syntax) for typical configurations of the local multicomputer(s). Place these files under boot/ in the installation directory. They will be found by LAM tools such as lamboot(1), recon(1) and wipe(1).

Using LAM

If the LAM installation directory is moved after it is built, users must set the LAMHOME environment variable to the new location. On each UNIX machine, users must add the LAM executable directory to their shell's search path. LAM executables are found under bin/ in the installation directory. These steps must be taken on each and every machine that might be part of a multicomputer running LAM. Set the variables in the shell's start-up file, not the .login file.

The recon(1) tool checks if LAM can be started on the given boot schema. There are several prerequisites that enable LAM to be started on a remote machine.

The machine must be reachable and operational.
The user must have an account on the machine.
The user must be able to rsh(1) to the machine (permissions must be set in either the /etc/hosts.equiv file or the user's .rhosts file on the machine).
The LAM executables must be locatable on that machine, using the shell's search path and possibly the LAMHOME environment variable, as described above.
The shell's start-up script must not print anything on standard error. The user can take advantage of the fact that rsh(1) will start the shell non-interactively. The start-up script can exit early in this case, before executing many commands relevant only to interactive sessions and likely to generate output.

Refer users to the lam(7) manual page to get started using LAM tools and libraries.

Clearing Space

After LAM has been built, all of the objects can be removed by running the make(1) utility with the "clean" target in the source directory.

% make clean

If further space is required, the source directory can be taken off-line. Only the installation directory need be maintained on-line.

Ohio Supercomputer Center, lam@tbag.osc.edu, http://www.osc.edu/lam.html