Operating Facilities
This section provides an overview of the facilities for operating system resources from the Reality environment.
Note
For detailed information on the facilities outlined below, refer to User's Reference: Operation.
Spooler
The Spooler handles multiple print reports generated by Reality processors, including DataBasic, TCL, Proc and the Editors and writes them to disk where they are temporarily stored in a queuing system before being despooled to a printer, tape or terminal device. This enables multiple users to share devices.
The queuing system comprises multiple "formqueues", each comprising an item in the FORM.QUEUES file which groups together and schedules print jobs waiting to be despooled. Any number of formqueues can be created. TCL commands are provided to manage formqueues.
Spooler Output Devices
The Spooler provides the facility to despool any formqueue to a number of different output devices. These include printers that are shared with the host system and printers and other devices that are dedicated to the Reality environment.
Despooler Monitor
Reality provides the facility to restrict the number of active Despooler processes being used, at any one time, to a specified number, while allowing any number of output devices to be serviced. The Despooler Monitor process (DSPMON) carries out this function. The DSPMON command is invoked at TCL to configure and manage the Despooler Monitor.
Types of Output Devices
Types of output device supported by Reality include:
- System printers. These are printers which are shared by both the host system and Reality users.
- Private printers (UNIX only). These are UNIX system printers which are dedicated to Reality. Print jobs are despooled directly to them, giving maximum control from the Reality environment. A private printer is dedicated to one database and is disconnected from the UNIX Spooler sub-system.
- Network printers. These are printers which are connected to across a network and are shared with other network users. On UNIX, this requires the special network utility (npu) to drive the device. On Windows, it only requires a configuration value. See Overview of Spooler Operation for more details.
- Reality ports (UNIX only). These are connections to a Reality database with a number allocated by Reality. It can connect to a printer or terminal with or without a slave printer.
- Tape devices. Spooler data can be despooled to tape for transport to specialised output devices.
- Files. Data can be despooled to an ordinary Reality file.
Save and Restore Utilities
A number of TCL commands are available to save selected Reality files, one or more accounts or an entire database to tape. A utility is also provided to verify the integrity of the data written to tape and it is strongly recommended that this is used on every save tape. Restore commands are provided to restore selected items, files, accounts or an entire database back to disk.
Magnetic Tape Unit Operation Utilities
A set of TCL commands are available to operate tape units from the Reality environment. Before a tape unit can be operated from a terminal the tape unit must be attached to that terminal's port. Two commands are provided to do this, T-ATT and ASSIGN. However, the main save commands, such as FILE-SAVE, ACCOUNT-SAVE, etc. and some restore commands, such as M-A-R are Procs which perform the assignment, after prompting you for the necessary parameters. Other commands are provided to move the tape backwards and forwards, unload the tape, execute read and write operations, check for parity errors and data mismatches, perform tape-to-tape copies and report the status of tape units.
Terminal Independent Process Handler
PH-START provides the capability to run a process in the background without a terminal. Hence, processes which do not require user involvement, "batch processes", can be run as TIPH processes, leaving terminals free to run interactive processes.
File Triggers
A file trigger is a cataloged DataBasic subroutine that is called automatically whenever an item is written to or deleted from a particular file. A trigger can be set to run before or after an item is written and before or after an item is deleted.
Triggers that run before file operations are mainly used to validate the attempted change to the database against user-defined constraints, or 'business rules', and allow the change only if the constraint is satisfied.
Triggers that run after file operations are normally used to create audit trails and other transaction logs.
All types of trigger can be used to create relationships between files, to ensure that whenever one file is updated, other related files are also updated.