A post about GDS file format spec is posted on comp.lsi.cad

[Kuhl]

Hi, all: I have just post a question about GDS format spec on
comp.lsi.cad . But I found that there are very few people on that
group. To promote the possibility of this question getting answered, I
give a message here. Would anyone have a look? Thank you in advance.

 

[Riad KACED]

Hi Kuhl,

It would have been easier if you'd given the link to your post. This
would have saved me couple of minutes hunting your question
Anyway, here is the link in question:

http://groups.google.com/group/comp.lsi.cad/browse_thread/thread/8c061eda0fc5abd7#

I don't really know the answer to your question. I have a www link
that might help you though :
http://en.wikipedia.org/wiki/GDSII

The first 2 items in the 'See also' section are dealing with the GDS
format:

* Computer Aids for VLSI Design - Appendix C: GDS II Format by Steven
M. Rubin
* The GDSII Stream Format by Jim Buchanan
* List of various layout editors/viewers

The latter is a useful link to open-source programs related to reading/
viewing GDSII files. You might be interested comparing your script
against those already on the market. I usually go for the re-use
option myself, I don't want to reinvent the wheel

Hope this is helping you,
Regards,
Riad.

 

[Andrew Beckett]

Riad KACED wrote, on 04/13/09 14:59:

Hi Kuhl,

It would have been easier if you'd given the link to your post. This
would have saved me couple of minutes hunting your question
Anyway, here is the link in question:

http://groups.google.com/group/comp.lsi.cad/browse_thread/thread/8c061eda0fc5abd7#

I don't really know the answer to your question. I have a www link
that might help you though :
http://en.wikipedia.org/wiki/GDSII

The first 2 items in the 'See also' section are dealing with the GDS
format:

* Computer Aids for VLSI Design - Appendix C: GDS II Format by Steven
M. Rubin
* The GDSII Stream Format by Jim Buchanan
* List of various layout editors/viewers

The latter is a useful link to open-source programs related to reading/
viewing GDSII files. You might be interested comparing your script
against those already on the market. I usually go for the re-use
option myself, I don't want to reinvent the wheel

Hope this is helping you,
Regards,
Riad.

There are two optional records, ELFLAGS and PLEX which come between the element
type (e.g. BOUNDARY, PATH, TEXT etc) and LAYER record.

This is covered in <ICinstDir>/doc/transref/transref.pdf (Appendix A).

I'm not aware of any recent tools using these records - they were used by some
rather old Calma tools, if my memory is correct.

In general I've always tended to write programs that read stream file by having
a big case statement for each of the record types I'm interested in, and then
just ignoring the ones that I'm not - and then effectively use a sort of state
machine to keep track of which element type (or other) that you're currently in,
so that when you get to the ENDEL record you have collected all the info you
need. That way you don't need to build anything that assumes that one record
will immediately follow another.

Regards,

Andrew.