Frequently Asked Questions

Why I don't have access to /afs/ece/usr/mems directory?

Check the following:

  1. first, make sure you are klogged. To klog, type:
    klog <username>
    then, enter your password.
  2. second make sure you are on mems:group. To check whether you are on mems:group, type:
    pts mem mems:group | grep <your ece username>
    if you are not on mems:group, contact your advisor to give you read permission.

How do I run Cadence, Coventor, Abaqus... etc?

See corresponding help file at: http://www.ece.cmu.edu/~mems/intranet/

Which machines I can use?

Most of the CAD software runs on Windows PCs, LINUX or Sun Solaris machines. There are several Linux Xeon PCs in HH1107, and some older Sun Blade 100s remotely accessible from the cluster. MEMS Lab graduate students also have access to some Sun (elvis, belushi) and Linux (boole) machines in the CSSI compute cluster or on a Linux machine (mems.ece.cmu.edu).

What is NODAS ? How to use NODAS ?

NODAS stands for Nodal Design of Actuators and Sensors, and enables simulation of MEMS in conjunction with electronic circuits. The major funcationality includes:

  • NODAS design libraries
  • veriloga models for schematic simulation
  • tools for automatic layout generation
  • tools for layout to schematic extraction
  • other tools such as slotting, MemsDRC checking ... etc

We currently support the following technologies:

  • MUMPS: to start Cadence, run mumps_cds
  • HP: to start Cadence, run hp_cds
  • AMS: to start Cadence, run ams_cds
  • TSMC: to start Cadence, run tsmc_cds
  • IBM SIGE 5, 6, 7 8: to start Cadence, run sigen_cdswhere n is 5, 6, 7 or 8
  • Jazz SiGe60:to start Cadence run jazz_cds

We also support a special version of AMS technology developed by MEMSCAP. This version contains cross section tools and 3D visualizer. To start Cadence, run xmems_cds.

Please NOTE: the technologies are NOT compatible with each other, and you can NOT run them in the same directory. For example, your should start your ams_cds cadence in a seperate directory with where you start your hp_cds cadence. Otherwise, it may screw up your directory structure.

For detailed instructions for mumps, hp and ams, please see http://www.ece.cmu.edu/~mems/cadence

Why do I get Error "..." defined differently elsewhere messages when I use NODAS ?

This started to appear when we moved to a Cadence 5.0 (as they have changed their default discipline.h). NODAS was upgraded for all the technologies in Spring '05. If you get this error it means you have your own copy of older NODAS libraries. Please verify that your library is different from the official libraries that appear when you start xxx_cds in a new directory. If they are identical, please delete your own personal copy of the NODAS libraries

When I start jazz_cds, tsmc_cds, why there are a few warnings in Cadence information window?

This is normal. We are trying to remove as many unnecessary warnings as possible to avoid confusion. But in most cases, these warnings should not give you trouble in using Cadence.

How do I see the past design archives?

We currently support several technologies (see NODAS question above)

When you run xxx_cds (where xxx is one of the supported technologies) in a newly created directory, the past design archives will be automatically included your cds.lib.

For ams_cds/xmems_cds, things are slightly different because we had submitted an entire engineering wafer run, and not single chip runs to AMS. We had 4 ams submissions. If you start Cadence in a new directory by using xmems_cds/ams_cds, the fourth submission designs will be included by default. If you want to see the previous three runs, you have to edit cds.lib.

For example, if you want to see asimps2 submission, change this line in your cds.lib:
INCLUDE /afs/ece/usr/mems/layout/cadence/ams_archive/asimps3/cds.lib
to:
INCLUDE /afs/ece/usr/mems/layout/cadence/ams_archive/asimps2/cds.lib
if you want asimps2 submission.

Similarly, for asimps1 submission, change the line to:
INCLUDE /afs/ece/usr/mems/layout/cadence/ams_archive/asimps1/cds.lib
and for sensors1 submission, change the line to:
INCLUDE /afs/ece/usr/mems/layout/cadence/ams_archive/sensors1/cds.lib

Then, quit and restart your cadence.

Note: You can only include one submission archive at a time. These submissions have library name conflicts and will not work normally if you put any two of the INCLUDE lines in one cds.lib file.

I am doing DRC/simulation on a large design, and it takes too long. How do I make it go faster?

There are two issues: storage speed and compute speed.

  • Most of us have use AFS for our Cadence design data. This works fine for storage, as it is accessible from all the machines. However, for accessing large data sets fast, it is better to use the local hard disk drive. Almost all the compute servers have a /scratch drive set up for this purpose. To use it, you can start your cadence in /scratch/user_name/xxx_cds/ directory instead of your /afs/ece/usr/user_name/xxx_cds/ directory. Since the DRC and simulation programs store temporary files in the directory where you started up Cadence, this can increase the access speed. Note that if you create new libraries in the local hard drive, you you need to copy the final result back to your afs space. The scratch directory is a temporary directory and is not backed up, and is cleaned up roughly once a month.
  • Using top command to find a machine (see which machine I can use) that is least crowded, and run on that machine.