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From an installation standpoint, you install the basic FOCUS system as one set of libraries. The basic configuration consists of the libraries described in The FOCUS Libraries. The basic system contains everything except the graphics support for IBM 3270 type terminals, interfaces to complex data sources from other database vendors, and the optional Simultaneous Usage (SU) facility that enables concurrent users to update FOCUS data sources simultaneously. The basic system contains FOCUS data-management functions, the FOCUS full-screen data entry facility (FIDEL) and the FOCUS query language and report writer. The report writer works with FOCUS data sources and with sequential, ISAM, and VSAM data sources. The basic system includes high-resolution graphics for a limited set of ASCII graphics terminals, but does not support IBM 3270 type terminals.

The basic system is required to use all other optional FOCUS features. FOCUS is sensitive to its operating environment and the basic system runs under TSO, or as a z/OS batch job. It also runs under CICS or MSO with the appropriate front-end interfaces installed.

To install the basic system, simply unload the FOCUS distribution tape and create a TSO logon procedure or batch JCL. You can then test almost every FOCUS feature that you will use.

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FOCUS high-resolution graphics on IBM 3278, 3279, and compatible terminals require IBM's GDDM graphics support program. From the standpoint of GDDM, FOCUS is just another application-level program, so your success with 3270-type graphics will depend largely on the state of GDDM support at your site. GDDM hardware and software requirements are fairly complex, so those planning to use it extensively with FOCUS should make sure that it is properly installed. You can test it by writing a COBOL program that creates 3270-type graphics. Consult appropriate IBM manuals for the required hardware and software configurations.

To add GDDM support to FOCUS, link-edit a GDDM stub from the GDDM library into the basic FOCUS system. You can do this at any time after installing the basic system.

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FOCUS can also be used to generate graphs in conjunction with the IBM Interactive Chart Utility (ICU). Standard FOCUS GRAPH syntax is used, and all graphing capabilities are available. The ICU Interface can either place users directly in the ICU environment or can save their graph formats and data for subsequent ICU processing. To use the ICU Interface, FOCUS must first be installed with the High Resolution Graphics for 3270 Type Terminals option described in High-Resolution Graphics on IBM 3270 Type Terminals.

For more information, see Interface Installation.

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The following user exits can be link-edited to FOCUS:

• The Usage Accounting Exit (UACCT).

  The Usage Accounting Exit can be used to capture FOCUS usage statistics, such as number of records retrieved and lines printed, aggregated at the FOCUS command level rather than at the job step or TSO session levels. The Usage Accounting Exit is alerted to log attempted violations of FOCUS security, and can also be used to limit access to FOCUS procedures and files.

• An External Password Security System (FOCUSID).

  The user exit FOCUSID enables an external security system to set passwords automatically. This removes the need for users to know passwords for applications.

• The Data Set Naming Enforcement Exit (DSNCHK).

  DSNCHK can be used to enforce strict data set naming conventions for FOCUS Master Files, FOCEXEC files, ERROR files, and FOCUS data sources.

The distributed version of FOCUS contains dummy routines for resolving these exit calls, so uninterested parties need do nothing. The exits are independent and can be added later, through a simple link-edit.

Detailed information on user exits is provided in User Exits.

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Installation options enable you to change the default allocation table and default naming conventions. FOCUS defaults must be changed at installation time. For instructions, see Customizing FOCUS.

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Simultaneous Usage allows concurrent TSO users or batch jobs to update the same FOCUS data source simultaneously. Database I/O for all users is performed by the FOCUS Database Server (sink machine), which has exclusive control of the data source. It serializes I/O at the logical record level, rather than the database level. With this feature, users can update FOCUS data sources at any time, without concern about whether other users are also updating it. Without this feature, users would all have to allocate FOCUS data sources in their own address spaces, and the updates would be serialized by means of enqueues on the entire database. If several users attempted an update, one might have to wait or might have to try the update later.

Keep in mind that even without this feature it is safe to allocate all FOCUS data sources in SHR mode because FOCUS serialization prevents destructive updates by concurrent online users. However, DISP=SHR does not protect against destructive updates by concurrent Host Language Interface (HLI) programs, so if concurrent HLI programs might make simultaneous updates, or if a single HLI program could update a data source concurrently with online TSO users, you must use the FOCUS Database Server.

The FOCUS Database Server can service all users on the same CPU. Simultaneous Usage requires use of the IBI Subsystem.

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If your site has licensed the zIIP enablement feature, you can offload processing to a zIIP engine by issuing the command SET ZIIP=ON. To enable this feature for all users, you can issue this command in a global profile such as FOCPARM.

In order to offload FOCUS processing to a zIIP engine, you must install a FOCUS licensing file that gives your site access to this feature. For information about obtaining and installing the appropriate FLICENSE file, see Installing the FOCUS Licensing File.

Note: All load libraries invoked on the zIIP processor must be APF authorized. If any load module in your STEPLIB allocation is not authorized, FOCUS will set ZIIP=OFF and start in an unauthorized state. The job will then run on the Central Processor.

If FOCUS has already started running in an authorized state and encounters a load library that is not authorized, it abends.

The FOCUS module is shipped as authorized (the AC flag is set to 1). Note that user function libraries as well as the FOCUS function libraries must be authorized.

For more information about offloading FOCUS processing to a zIIP engine, see the z/OS Guide to Operations chapter in the Overview and Operating Environments manual.