Research Computing >> Hardware >> skew >> Accounts & usage policies


Kellogg's Research Computing Unix systems are intended to facilitate scholarly research by current Kellogg faculty and doctoral students. In selected cases, individuals who do not fall into either of these categories may have access to certain systems on a more restricted basis.


General Policies

  • Skew accounts are available for all current Kellogg faculty and PhD students upon request.  Others may be eligible for an account as explained below.

  • The Skew Account Application Form is accessible online at The turnaround time for account creation is up to five business days, but typically much less.  After a new account is created, the user will be notified. The passwords are synchronized with the central Northwestern authentication system, and are the same as for other University services (such as email). You have to be on the school network (via an on-campus connection or VPN) to apply for an account or connect to skew.

  • Skew accounts are not to be shared with any other person. Every user must have his/her own ID.

  • Disk quotas and scratch space: Your quota is the amount of space that your files are allowed to take up on the server. Each new user receives a standard 5GB quota when the account is created. If a user goes above his/her quota, the operating system will issue a warning and allow work to continue, but many processes like SAS will not be allowed to run. If the space used reaches the quota, no further data will be written to disk. This will typically prevent the user from logging into the account. To unlock the account, the user must contact research computing. If a user needs to increase the quota, please submit to research computing staff a written request that states the purpose, the amount of space needed and the length of time for the increase. Research computing staff will then discuss with the user about the appropriate size of increase. Upon approval, the quota will be increased within 48 hours. External colleagues and RA's must submit such request through their sponsoring faculty member at Kellogg. The home directory is for storing critical files only, such as program codes and final results. For storing intermediate files generated by SAS, Stata, MATLAB and other programs, /scratch or /scratch2 are more appropriate. There are no user quota limits on the /scratch and /scratch2 directories, but files in /scratch that have not been modified in 15 days are deleted automatically by the operating system every night and cannot be restored. The policy for /scratch2 is similar, except files can be stored up to 30 days. Every night, scripts run to clean the files in both scratch directories according to the rules mentioned. Neither directory is backed up. If one needs to continue working with a file in /scratch or /scratch2 beyond these time limits, one can use a UNIX command touch to refresh the modification date, e.g.
    touch /scratch2/users/xxx123/mydata/*
    Note: user files that are uploaded to skew via SFTP may, depending on the settings in your SFTP program, retain their original modification dates. If these files are stored in /scratch or /scratch2, such a date may be already in the past, and hence such files could be subject to immediate deletion. To refresh the date, you can either use the touch command as above, or, if such an option is available, modify the settings in your SFTP software to refresh the dates of such files. For "SSH Secure Shell for Windows" users, the relevant setting is under Edit -> Settings -> Global Settings -> File Transfer -> Advanced -> UNCHECK "Preserve original file time".

  • Job monitoring: Jobs are monitored on a daily basis. Jobs set to run in the background will have their priority dropped below other jobs. Multiple concurrent jobs, which are particularly resource-intensive in nature, must not be run without prior approval of a Research Computing staff member. More specifically, SAS, SPSS, Matlab, Gauss, etc. applications should not have more than one running copy per user at any one time. Users should refrain from running jobs that will use 100% of an available resource (for example, RAM memory).

  • Backups: Backups of user data on Skew (except in the temporary directories /scratch and /scratch2) are carried out on a nightly basis.

  • Backup restoration:: Data restorations are provided as quickly as possible, but in general they will be done within two to three business days of the request. The speed of the recovery depends on the extent of the data being restored and the complexity of the data retrieval process.

  • Skew account will be deactivated if the users is no longer afilliated with Kellogg School. The user will be given an email notice one month ahead prior to deactivation. It is user's responsibility to transfer files from the SKEW server to other machines. The account will be permanently deleted from the server after deactivation. The user can only keep the UNIX account if she/he meets the standards listed in the following sections.

  • License of Skew resources: Software and data sets on Skew are licensed for research and instructional use at Kellogg.

Faculty Policies

  • Eligibility: Kellogg faculty members (including visiting faculty) are entitled to a Skew account upon request, assuming that the request is based on research needs.

  • Account expiration: Access to a skew account is tied to affiliation to the school. Accounts are disabled when the netid expires.

PhD Student Accounts

  • Eligibility: Kellogg PhD students are entitled to a Skew account upon request, assuming that the request is based on research needs, coursework needs, or Kellogg instructional needs.

  • Account expiration: Access to a skew account is tied to affiliation to the school. Accounts are disabled when the netid expires. Verification of degree status and student status will be done through the Kellogg Doctoral Office.

  • Under certain rare circumstances, graduated PhD students may be granted an extension on their Skew account. These circumstances may include, for example, that the person is co-authoring with a current Kellogg faculty member or revising work that was a significant part of the graduate�s dissertation. A written request including an explanation from the graduated PhD student and a desired extension date must be submitted, along with approvals from a sponsoring faculty member, the Department Chair and the Associate Dean for Academic Affairs. If approved, these accounts will be given a job priority level and support level that is equal to that of External Faculty Colleagues (see below). Extensions of access to a Skew account will not exceed 12 months; the account cannot be used for purposes other than the one specified in the request.

  • If the reason for requesting a Skew account extension is on-going research with a current faculty member, the same rules will be applied to the former PhD student as are applied to External Faculty Colleagues or Research Assistants, depending on the nature of their on-going relationship with the current faculty member.

  • Non Northwestern PhD students who move to Northwestern along with their dissertation advisor who is a new tenured or tenure-track faculty member at Kellogg may request a Skew account in the same way as described above for graduated PhD students.

Accounts for Research Assistants and Visiting Scholars

  • Eligibility: Kellogg Research Assistants, who are enrolled as Northwestern students, and Kellogg Visiting Scholars, who are officially registered with the Academic Affairs Office and have a Northwestern netid, may be granted a Skew account.

  • For Research Assistants, sponsoring faculty, the Department Chair, and the Associate Dean for Academic Affairs must approve the account request. A letter from the sponsoring faculty member must be submitted along with the Skew account application.the letter must detail the nature of the relationship and its expected duration. Approved Research Assistant accounts will be granted full computing support.

  • Visiting Scholars need to have a Northwestern netid before requesting a Skew account. Approved Visiting Scholar accounts will be granted limited computing support. Their accounts will expire with their appointments.

  • Quota: If disk space beyond the standard quota is requested for people in either of these categories, the sponsoring faculty member must request the additional space through the aforementioned channels.

  • Account expiration: These Skew accounts will be disabled, and all contents erased, 3 months after the end date indicated on the letter requesting the account. A one-month advance notification will be sent prior to disabling the account.

Accounts for External Faculty Colleagues

  • Eligibility: External faculty colleagues are normally expected to use the computing resources provided and the datasets licenses by their own home depatment/university. In exceptional cases, Skew accounts may be granted to external faculty colleagues who are working with Kellogg faculty on joint research that is likely to lead to joint publication. These Kellogg Skew accounts are to be used exclusively for working on the joint research project.

  • Sponsoring faculty, the Department Chair, and the Associate Dean for Academic Affairs must approve these Skew account requests. A letter must accompany these requests from the sponsoring faculty member detailing (a) the nature of the research, (b) the expected duration of the research, and (c) the reason that Kellogg computing resources are necessary for the external faculty colleague.

  • Priority: These accounts will be given a lower priority level than other accounts to insure that the immediate Kellogg community has the most direct access to our computing resources. These individuals may not make support requests beyond basic account maintenance. All other support requests must be made directly by the sponsoring Kellogg faculty member.

  • Quota: If disk space beyond the standard quota is requested for an external faculty colleague, the sponsoring faculty member must request the additional space through the aforementioned channels.

  • Account expiration: These accounts will be available for a term of one quarter to one year. No account may continue for more than one year without being re-approved through the aforementioned channels.

  • Unless a renewal letter is received and approved by the appropriate individuals prior to the end of the Skew account term, the account will be disabled, and all contents erased, three months after the end of the term.

Sharing Files

  • It is responsibility of the user to make sure that his netid and password are not shared with anyone within or outside Kellogg, as well as that his files have appropriate access permissions.
  • Researchers who need to collaborate on projects and share files and directories with other specific users are encouraged to use ACL to set permissions on individual level. There is a nice tutorial available from, also see an example of using ACL's on skew.

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