User regulations:

  • Users must abide by the Computer Use Policies at UNL.
  • One user account is allowed per person.
  • Two factor authentication (i.e. Duo) is required for access to all HCC resources.
  • Users are not allowed to access cluster nodes directly, unless permission has been granted by HCC. Instead, all work to be performed on the clusters must be submitted via the jobs scheduler(s). If you want more information on using them, please refer to the HCC Documentation.
  • You may not run your programs in the background, or run large CPU/memory intensive programs on logon or head nodes. Your tasks will be terminated and your account may potentially be locked. The login node is shared among all users and it should be used only for light tasks, such as moving and editing files, compiling programs, and submitting and monitoring jobs.
  • HCC depends on the good citizenship of researchers to collectively provide a positive user experience on shared resources. Users are expected to follow best practices when using HCC resources to collectively help prevent excessive load and degraded performance, which can be harmful to the larger community. In order to curtail problematic use, HCC reserves the right to take action with no prior warning to protect the integrity of the systems. This may include, but is not limited to, such measures as limiting job numbers, pausing jobs, canceling jobs, and account locking. HCC will make a reasonable effort to contact any users affected by these measures within one (1) business day.
  • Account holders must have an association (student, faculty, or staff) with either an NU campus, Nebraska state college, or other Nebraska-based higher education institution. Exceptions to this requirement for outside collaborators can be made, subject to the following conditions:
    • A non-NU user must be a member of a group headed by a current NU faculty member. An active research or creative activity collaboration between the non-NU user and the NU faculty is required. Proof of collaboration includes, but is not limited to, active grants and/or co-authored papers within 2 years (subjected to annual re-evaluation).
    • Non-NU users need to acknowledge collaborations and HCC resource usage in their publications.

Class groups:

User accounts created for the purpose of coursework (belonging to a class group) will be removed one week after the course end date. All files remaining in the user's class group directories will be deleted at that time. Users who also belong to a primary research group will also be removed from the class group, and their class group files deleted at that time. Files located in the user's primary (and any supplemental) research groups will not be affected. Full details on how class accounts/groups are treated is available in class-guidelines.docx.

Account/Group 'ownership':

All accounts on HCC machines are to be 'owned' by the research advisor or owner of the group. Upon request, a group owner will be granted access to any data within their group not otherwise immediately accessible. Further, all files on HCC systems may be accessed by HCC administrative staff for purposes of solving system problems (e.g. checking for breaking of policy or trying to find out why the machine is being bogged down) or for system security.

All user account applications must be approved by the group owner prior to creation. The group owner is expected to assist with mediating any issues that occur between members of the group, as well as ensuring group members follow best practices. A group owner is steward of research data and user conduct of the group, and is ultimately responsible to the research sponsor for compliance with applicable research regulatory requirements. [1] [2]

Storage and Disk Space Use:

By default every user account on an HCC machine belongs to a research group. The leader of this group is commonly a faculty member directing undergraduate or graduate research, and other arrangements are possible. Each group is given access to three filesystems: $HOME, $WORK, and $COMMON. Files for a given user ultimately belong to the research group owner, although the privacy of each user by default is protected with standard file permissions. Quotas are enforced on all three filesystems; see this link for details and amounts of each quota. Users may use the command "hcc-du" to check their current storage and quota status. HCC currently has no storage that is suitable for HIPAA, PHI, PID, classified or other data sets for which access is legally restricted. Users are not permitted to store such data on HCC machines.


Quotas are enforced per individual user on $HOME. The $HOME filesystem is only to be used for small files that are necessary for functioning on HCC systems, such as code, difficult to recreate input files, and so on. The $HOME filesystem is not to be used for active job I/O (input/output), large output files, etc. A best-effort backup is maintained for $HOME, but this is not meant to be used as an archive. HCC provides Attic for this purpose. However, if a user accidentally deletes a file, in a best-case scenario HCC may be able to recover it, and will do so when possible.


The $COMMON filesystem is uniformly available on all HCC cluster resources. Quotas on $COMMON are enforced at a group level. Data on $COMMON is not subject to a purge policy at this time, and is also not backed up. It is the researcher's responsibility to back up any valuable data on $COMMON to a more secure location (such as HCC's Attic system).


The $WORK directory should be used for temporary storage of active job I/O (input/output), large output files, and so on. The $WORK fileystem is subject to a per-group quota. If $WORK becomes too full, HCC staff may delete existing files as needed to maintain system functionality. Whenever practical, users will be notified before files are removed for this reason. Users should never store precious data long-term on $WORK. All users should remove files from $WORK as soon as possible. Old files from $WORK will be removed on a regular basis. Data on $WORK is not backed up. It is the researcher's responsibility to back up any valuable data on $WORK to a more secure location (such as HCC's Attic system).

Researchers who have storage needs beyond their default allotment may purchase additional storage. For details concerning this, please contact


HCC asks to be notified of any presentation or publication that results in entirely or in part from use of HCC.

Users are asked to include the following line in any publications resulting from the use of HCC within the Acknowledgements section:

This work was completed utilizing the Holland Computing Center of the University of Nebraska,
which receives support from the UNL Office of Research and Economic Development, and the Nebraska Research Initiative.

Effective January 1, 2017, HCC has established a system of improved scheduling priority for individuals who acknowledge the use of HCC resources in related publications. This will not be a dedicated resource as in priority access, but will improve your position waiting for shared resources with respect to the normal fair share policy. Researchers who acknowledge HCC in publications, proposals, or related work will be entitled to improved priority in the scheduling queue. This priority change will have no affect on current priority access on leased or owned equipment.

Priority increases will be allotted in units of core-years (i.e. the use of one core for a calendar year) according to the following classifications:

Class A: 2 core-years (17,520 core hours)
Awarded for acknowledgements within reviewed publications, dissertations and master theses. Funded grant applications will also receive Class A increases if HCC will be used significantly in the proposed research, or played a role in landing the award (as determined by the PI).

Class B: 1 core-year (8,760 core hours)
Awarded for acknowledgements within undergraduate theses and any reviewed presentations.

Class C: 0.5 core-years (4,380 core hours)
Awarded for acknowledgements in unreviewed presentations, unfunded grant proposals and any published news articles or videos which highlight HCC services.

To submit an acknowledgement, please complete the acknowledgement submission form. If a URL to a digital version of the publication is not available, a PDF version can be emailed to upon completion of the form.

If a digital copy is not available, if possible please mail a hard copy of any publications to Hongfeng Yu, SHOR 118K, UNL 68588-0150.

Support questions

Contact HCC Support at