Configuration Settings

Configuration settings consist of a number of persistent global options as well as the locations for installed model libraries.

When the simulator is run in GUI mode, its configuration settings are controlled by the front end and stored wherever the front end's settings are stored. See the User's Manual for more details.

The settings when run in non-GUI mode are stored in a configuration file which in fact defaults to the same location as the default location for the front end's settings. You can change this location using the /config switch detailed in Running in non-GUI Mode.

The format of the configuration file is: 

[Options]
option_settings

[Models]
model_libraries

Where:

option_settings These are of the form name=value and specify a number of global settings. Boolean values are of the form name= without a value. If the entry is present it is TRUE if absent it is FALSE. Available global settings are detailed below.
model_libraries A list of entries specifying search locations for model libraries. These are of the form name=value where name is a string and value is a search location. The string used for name is arbitrary but must be unique. Entries are sorted alphabetically according to the name and used to determine the search order. value is a path name and may contain wildcards (i.e. '*' and '?').

In this topic:

Global Settings

Name Type Default Description
NoStopOnUnknownParam String WARN Specifies action to be taken in the event of an unknown parameter being encountered in a .MODEL statement. Choices are:

TRUE: No action taken, simulation continues normally FALSE: An error will be raised and the simulation will abort WARN: A warning will be displayed but the simulation will continue

This will be overridden by a .OPTIONS setting of the same name. See the List of Simulator Options.
MaxVectorBufferSize Numeric 32760 See Data Buffering.
TotalVectorBufferSize Numeric Available RAM/10 See Data Buffering.
TempDataDir String %STARTDIR% Location of temporary binary data file if data_file is not specified on command line
LibraryDiagnostics String Full Controls output of messages relating to model library search. Specify None to disable

Data Buffering

The simulator buffers data before writing it to disk. By doing so the binary data file can be organised more efficiently allowing data to be recovered from it quickly.

By default, the simulator won't allocate more than 10% of your system RAM to vector buffers. Clearly if you are running a large circuit and saving many vectors, the buffer sizes could reduce to levels that would make data retrieval very slow. In this case you may wish to consider increasing the memory that is allowed for these buffers. Two configuration settings control the vector buffering. These are:

  • MaxVectorBufferSize. This sets the maximum size that will be used for any individual vector. The default is 32768 bytes. If you have a high performance SCSI disk system, you may benefit from increasing this value
  • TotalVectorBufferSize. This sets the maximum amount of memory in bytes used for all buffers. It defaults to a value equal to 10% of your system RAM. This is usually sufficient for most applications but if you are simulating a very large circuit and have sufficient RAM you may like to increase this value
The disk will not be written to until the buffers are full. With an all analog circuit all the buffers reach their full state at the same time so they all get written to disk at the same time. If you have 2G of RAM and are simulating a large circuit, approximately 200M of data will be written to the disk at regular intervals. This will result in a pause in the simulation coupled with a great deal of disk activity.

Note that both MaxVectorBufferSize and TotalVectorBufferSize may be set from the front end using the Set command. See User's Manual/Sundry Topics/Using the Set and Unset Commands for details.

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