2 Installation 2.1 Installation and system requirements Both SCSCP client and server for GAP work in Linux, OS X and Windows. To use the SCSCP package it is necessary to install recent versions of GAP4 packages IO [Neu], GAPDoc [LN] and OpenMath [CKS]. The SCSCP package is distributed in standard formats (tar.gz, tar.bz2) and can be obtained from https://gap-packages.github.io/scscp/ or from the GAP web site (the latter also offers zoo- and win.zip-archives. To unpack the zoo-archive the program unzoo is needed, which can be obtained from the GAP homepage http://www.gap-system.org/ (see section `Distribution'). To install SCSCP package, put its zoo-archive into the pkg subdirectory of your GAP4.4 installation and enter the command unzoo -x scscp-X.X.X.zoo, then the subdirectory scscp (containing subdirectories doc, lib etc.) will be created in the pkg subdirectory. Installation using other archive formats is performed in a similar way. When there are no access rights to the root directory of the main GAP installation, it is also possible to install the package outside the GAP main directory by unpacking it inside a directory MYGAPDIR/pkg. Then to load the package GAP should be started with -l ";MYGAPDIR" option. 2.2 Configuration files There are four files in the package which may need to be modified to setup and customise the package. The first three files are related with the server's functionality:  scscp/config.g specifies:  default InfoLevel for the InfoSCSCP (9.2-1) class;  default SCSCP server name and port to be used by RunSCSCPserver (5.2-1) if GAP is started with the scscp/example/myserver.g file;  whether the server accepts calls to procedures which are standard OpenMath symbols, or only procedures installed in the transient content dictionary (see InstallSCSCPprocedure (5.1-1));  service description to be returned to the client by GetServiceDescription (5.3-1).  scscp/gapd.sh is the script to start the GAP SCSCP server as a daemon. To use it, adjust the local call of GAP and, if necessary, call options (for example, memory usage, startup from the workspace etc.) and the location of the root directory of the SCSCP package in section 1 of this script.  scscp/example/myserver.g is an example of the server configuration file which loads all necessary packages, reads all needed code, installs all procedures which will be exposed to the client and finally starts the SCSCP server (see Chapter 5). The fourth file is related with the client's functionality for parallel computations:  The file scscp/configpar.g assigns the global variable SCSCPservers which specifies a list of hosts and ports to search for SCSCP services (which may be not only represented by GAP services, but also by another SCSCP-compliant systems). It will be used to run parallel computations with the SCSCP package (see Chapter 8). See comments in these configuration files for further details and examples.