Structure of the restart file
*****************************

All data that may be retrieved from the restart file must be stored in
a specific location on the restart file. If you are simply using an
adf.rkf (TAPE21) result file or a TAPE13 checkpoint file you do not
need to bother with this: ADF has put all data in the right place; the
following discussion is primarily for those who want to manipulate the
restart file or even construct one themselves.

Since the restart file must be a KF file, the location of the data is
of the form Section%Variable, specifying the section and the variable
name. The section and variable names are case-sensitive. For more
information, see the section on KF output files.

If the specified variable is not present in the specified section on
the restart file - or if there is no such section at all - the data is
not used, usually without an error message. In some cases a few global
tests are carried out on the retrieved data; if they fail the tests
the data are not used and a warning - in some cases an error abort -
may be issued by the program.

KF files are binary files and so are the adf.rkf result file, the
TAPE13 checkpoint file, and generally any restart files. If you wish
to edit and modify the contents, or just inspect them, the standard KF
utilities can be used. Use pkf to get a survey of the sections and
variables on the file, dmpkf to get a complete ASCII version of the
file, and udmpkf to transform an ASCII version - presumably edited and
modified - back into binary format. Please consult the the section on
KF output files for further information on accessing KF files.

**AMS tasks**

Starting with ADF2020, AMS handles tasks related to exploring the PES.
For restarts related to, for example, a Geometry Optimization, a
Linear Transit, Transition State, IRC, or IR Frequencies run, you
should also look in the AMS manual.
