Gasboy CFN III Manager Manual V3.6 - Manual (Page 227)

MDE-4871 CFN III Manager’s Manual for Windows® XP Embedded - Version 3.6 · August 2010 Page 21-1
What Conditions can be Specified for Cron Automatic Cron Commands
21 – Automatic Cron Commands
The CFN3 application’s cron (chronological) function allows you to have commands executed
automatically at specified times or when certain events occur.
Like EXECUTE commands, cron commands run in background and do not delay normal sales
operations.
Each cron entry loaded by LOAD CRON is numbered and has two parts:
• a string of characters representing the conditions for execution
• a command that will be executed every time the conditions become true. The Site
Controller tests the conditions of each entry at least once per minute as part of its normal
housekeeping activities.
An entry remains in effect until it is overwritten with LOAD CRON or erased with REMOVE
CRON or LOAD CRON;I.
Commands executed by cron can be regular Site Controller system commands, disk-based
commands (.BIN commands), or command files (.CMD commands). Most of the time, cron is
used to execute user command files.
Almost any sequence of commands that can be executed interactively by a human user can be
put into a command file to be executed automatically by cron. Commands that require data
must have data supplied, either by including the data in the command file or by redirecting it
from a separate file. Cron will search the normal command search path for command files.
The commands that can be executed by a cron entry follow the permission level of the user
that loads the cron.
Note: If a cron or command file attempts to run a disk-based program and finds that the
program space is busy, it will wait until the space is free. This is the opposite of the case
where if you invoke a disk-based command directly at the prompt and the program
space is busy, the command will be terminated with an error.
What Conditions can be Specified for Cron
The first character of a cron entry determines what condition will cause that entry to be
executed. The four types of cron entries are:
• timed entry
• restart entry
• boot entry
• transaction memory full
The most common type of cron entry is a timed entry. A timed entry begins with an at sign
(@). Timed entries will be executed whenever the system date and time matches the date and
time specified in the entry.