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## tech

Query properties of the current technology, or change the current technology.

### Usage:

> tech option

> > where option may be one of the following:
> > load filename [-noprompt][-nooverride]
> >   Load a new technology from the file filename[`.tech`].
> > help
> >   Display help information
> > name
> >   Show current technology name
> > filename
> >   Show current technology filename
> > version
> >   Show current technology version and description strings
> > lambda
> >   Show internal units per lambda
> > planes
> >   Show defined planes
> > layers [layer]
> >   Show defined layers
> > drc option
> >   Query the DRC ruleset, where option is one of the following:
> >   width layer
> >     Return the minimum allowed width for the indicated layer type.
> >   spacing layer1 [layer2]
> >     Return the minimum allowed spacing between layer1 and layer2, if layer2 is specified, or between layer1 and itself, if not.

### Summary:

> The tech command queries aspects of the current technology, and can also be used to change the current technology. The tech load command completely replaces the technology. Normally a call to tech load generates a dialog window asking the user for confirmation, since the tech load command is potentially destructive and can cause loss of an existing layout. The -noprompt option forces a technology load without presenting a dialog. This is particularly useful to put a "tech load name -noprompt" command in a `.magic` startup file in the directory of a project, so that it is not necessary to specify the technology on the command line when invoking magic. However, occasionally one may want to run magic from the same project directory with a different technology. The -nooverride option prevents the tech load command from overriding a technology name entered on the UNIX command line when starting magic.

> Technology file reloading is especially useful when developing a technology file, to immediately see the results of a change made to the file. The current technology can be reloaded with the simple Tcl command "tech load [tech filename]".

> Note that there is a slightly different meaning between the command "tech layers" and "tech layers "*"". The former prints a formatted list of layers, including all aliases for each layer, to the console. The second returns a Tcl list of all layers, with only the primary name for each layer.

> A few aspects of the technology must be queried from other commands. The CIF/GDS input and output styles are given by the cif istyle and cif ostyle commands, while the extraction style is given by the extract style command.

> The drc option is intended for use by Tcl scripted procedures that wish to place layout while satisfying the DRC rules. The two accepted rule options are spacing and width.

### Implementation Notes:

> tech is implemented as a built-in command in magic. The command replaces the original techinfo command, which no longer exists.

### Bugs:

> tech drc may not return the correct value in all cases.

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Last updated: October 16, 2004 at 1:59pm