  The commissioning of the Swiss Light Source (SLS) started in Feb. 2000 with
the Linac, continued in May 2000 with the booster synchrotron and by Dec. 2000
first light in the storage ring were produced. The first four beam lines had to
be operational by August 2001. The thorough integration of all subsystems to
the control system and a high level of automation was prerequisite to meet the
tight time schedule. A careful balanced distribution of functionality into high
level and low level applications allowed an optimization of short development
cycles and high reliability of the applications. High level applications were
implemented as CORBA based client/server applications (tcl/tk and Java based
clients, C++ based servers), IDL applications using EZCA, medm/dm2k screens and
tcl/tk applications using CDEV. Low level applications were mainly built as
EPICS process databases, SNL state machines and customized drivers.
Functionality of the high level application was encapsulated and pushed to
lower levels whenever it has proven to be adequate. That enabled to reduce
machine setups to a handful of physical parameters and allow the usage of
standard EPICS tools for display, archiving and processing of complex physical
values. High reliability and reproducibility were achieved with that approach.
