# What is the cost to use the RCE?

The RCE is free to use for qualified individuals in the pursuit of social science research, within certain limits.

If your needs exceed the capacities of the shared RCE environment, we can work with you to establish dedicated RCE resources for your exclusive use. If you are planning a large project, please contact us prior to your grant application so that we can assist in budgetary estimation.

# How do I get an account, or get help?

For fastest service, please email directly support@help.hmdc.harvard.edu. Or, you may also call 617-495-4734 (x54734) from 9AM-5PM weekdays.

# Will MPlus be available on the RCE?

Unfortunately, licensing for MPlus is complex, and places an undue financial burden on HMDC. From the MPlus developers:

Mplus was not developed for more than one analysis to be run on the same computer at the same time.

This is the exact opposite behavior of what the RCE is designed for, so at this time we cannot offer MPlus on our research cluster.

# Is there temp or scratch storage available?

Yes, the top-level /scratch directory on our batch nodes is the same as using /tmp. On our interactive nodes, /scratch is a separate 1TB shared storage space.

Top level scratch space is world-writeable and -readable (Unix 1777 permissions). User created directories are only owner writeable/readable (1700) or owner/group (2770) if you are a member of a research group.

In either case, if you need several gigabytes of storage, please request a project directory.

# How do I use compressed data with R?

R supports two primary ways of accessing compressed data. This allows you to keep your data files on disk compressed saving space, and often time (since the file I/O saved by compression is often more expensive than the cpu cycles it uses).

If you are storing your data in native format, simply use the compress option of save:

tst.df=as.data.frame(cbind(1:10,2:11)) # just some testing data save(tst.df,file="test.Rbin", compress=T) # save a compressed R file

# My Stata batch job keeps running even after a fatal error!

When running a Stata .do file on the batch cluster via condor_submit_util, you have to add some additional arguments in order to get your job to stop when Stata encounters an unrecoverable error (which is probably the behavior you want).

The command line below runs Stata with the example file my_dofile.do:

@condor_submit_util --executable /usr/local/bin/stata-se --arguments '-b /my_dofile.do' --noinput

# How do I automate actions when connecting to the RCE?

To configure your user account such that every time you connect to the RCE, some action is performed:

1. Write a script that performs the desired action. The scripting languages available in the RCE include BASH, (/bin/bash), multiple versions of Python (/usr/bin/python) and Perl (/usr/bin/perl).

# Firefox or Thunderbird won't start!

The error Firefox is already running usually indicates that you must remove lock files before you can launch Firefox. To resolve this problem:

• If you are working inside the HMDC RCE navigate to ApplicationsRCE UtilitiesClear Firefox Locks or Clear Thunderbird Locks. Then, try launching Firefox or Thunderbird again.