[Magic-dev] Starting magic with custom tech file

[R. Timothy Edwards]

Dear Graham,

> I don't want to release a .magicrc file
> which might interfere with a user's own file in unexpected ways for him.

What you would normally expect in a user's home .magicrc file would be macro
definitions and other non-technology related commands and settings.  A
project's .magicrc file should be loading a technology file, for example, but
not mess with macros or window dimensions and such.  I think a common-sense
usage should not result in any interference.  Magic will always first source
the system default .magicrc, followed by the user's home .magicrc, followed
by the local (project) .magicrc.

I really need to have the system .magicrc file source a "site.tcl" script
that would allow people to install site-specific startup files that don't
get overwritten whenever a new version of magic is installed.  I did this
for xcircuit, but haven't ever copied that line over to the Magic distribution.

>    I have to date simply copied the same tech files into each library
> directory. But since I will also release my own versions of the style and cmap
> files, that means a lot of files to be copied. Still, if the version and
> existing layout status were checked, that would be good. If I remember right,
> there is an option to explicitly call your own startup file, so maybe then
> that's the way to go.

What you mentioned in your first email is the right way to go---set the
paths and load the techfile from the .magicrc file, which is the only file
that needs to be in each (layout) directory of your distribution.

Magic version 7.5 allows the use of "-rc <.rcfilename>" on the command line
to source a specific startup file, but magic-7.4 doesn't support that.

>    I am working with 7.4.44. Is the 7.5 release robust, or is it better to
> wait? One feature I want a *lot* is extract with 5nm layout snap grid. I
> haven't got there yet, but something I read inferred that this was a feature
> only in 7.5.

You should be able to use a 5nm snap grid with version 7.4.  The one thing
it won't do (that 7.5 does) is to limit the GDS output to a minimum grid
spacing, but that's largely a convenience and not a critical feature.
I have 7.5 in rather a state of disrepair while working on DRC issues,
and you should probably treat 7.5 as "unstable".  Once I get that and
a few other things sorted out, hopefully 7.5 can become the new stable
distribution.  But not right now. . .

					Regards,
					Tim

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| Dr. R. Timothy Edwards (Tim)   | email: tim at opencircuitdesign.com    |
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