Vocareum Lab Environments (Vocareum Notebook, Visual Studio Code labs, and JupyterLab labs) run student work inside a managed environment with defined limits on processing resources and session duration. These limits keep labs responsive, protect shared infrastructure from runaway processes, and give every student a predictable amount of compute. Some of these limits are managed by Vocareum and cannot be changed in the settings interface, while others are yours to adjust at the course level or for an individual assignment part.

This article explains the two tiers of limits, lists the baseline values relevant to Admins, and clarifies the difference between processor time and wall-clock time, which is the concept that most often determines why a grading job stops before it finishes.

Throughout this article, the term baseline refers to the value that is present when a course is first created, before anyone changes it. Note that "baseline" is a description used in this documentation rather than a label in the platform.

The limits that apply to Vocareum Lab Environments fall into two tiers.

The first tier is managed by Vocareum. These are the ceilings on total compute resources and the maximum processor time and wall-clock time allowed in a course. You cannot change these values in the settings interface. If your course needs higher ceilings, for example to support graphics processing unit (GPU) workloads or longer-running computations, contact Vocareum Support to request an adjustment.

The second tier is controlled by you, a Teacher or an Admin, in the settings interface. These include the course-level fields under Other Settings and the per-part fields on an assignment part. You can change these at any time without contacting Support, as long as the values stay within the ceilings managed by Vocareum.

The reference tables below describe the values in each tier.

The following table lists the Vocareum-managed ceilings that are most relevant to Admins, along with their baseline values and the maximum each can be raised to. To request a change to any of these, contact Vocareum Support.

Additional low-level resource limits, such as file descriptor and process count ceilings, are also managed by Vocareum. These rarely affect typical coursework. If you suspect a low-level limit is affecting your course, contact Vocareum Support.

GPU access is disabled at baseline. Enabling it involves a setup process that begins with Vocareum and includes a course-level step before teachers can activate it for an assignment. For the full process and how to use GPU resources, refer to GPU in Vocareum Notebook.

Within an organization, each user can run a limited number of Vocareum Lab Environments at the same time. The baseline is two.

When a user opens more lab environments than this limit allows, the earliest-opened session ends automatically. Saved work is not lost, because each user's files persist in their home directory and remain available the next time the session is opened. At the baseline of two, opening a third lab environment ends the first session the user opened. To raise this limit for your organization, contact Vocareum Support.

The following limits are yours to adjust, either across the whole course under Other Settings or on an individual assignment part. The table lists each field with its baseline value.

These fields apply to every lab in the course and are found under Course Settings, in the Other Settings section.

These fields apply only to a single assignment part and are found on that part's Grading and Budget pages.

When a Monthly Time or Total Time budget is active for a part, the session timer at launch is set to the lesser of the configured Session Length and the user's remaining budget for that period. Students can check their remaining time budget on the course page. There is no in-session time budget display within the lab environment itself.

The single most important concept for understanding grading timeouts is the difference between processor time and wall-clock time. The two limits are enforced at the same time, and a grading job stops if it exceeds either one.

Processor time measures how much the processor actually worked on a job. It accumulates only while the processor is actively computing. A computation-heavy job consumes processor time quickly, while a job that waits for input or a network response consumes very little.

Wall-clock time measures the real time that passes from the moment a job starts, regardless of whether the processor is busy. A job that waits, blocks, or runs slow student code accumulates wall-clock time even when it is not computing.

For most notebook grading, wall-clock time is the binding limit. Student code is often slow or blocking without being processor-intensive, so a grading job typically reaches the wall-clock time limit before it reaches the processor time limit.

This distinction has a direct, practical consequence for the settings you adjust.

The part-level Max Grading Time setting controls processor time only. It does not control wall-clock time. Raising Max Grading Time alone will not fix grading jobs that stop because they exceeded the wall-clock time limit.

The setting to adjust when grading jobs stop on wall-clock time is the course-level Wall Clock Limit (seconds) under Other Settings. Wall-clock time can be set only at the course level. There is no per-part wall-clock time override, so raising Wall Clock Limit affects every lab in the course.

For the steps to adjust Wall Clock Limit, Max Grading Time, and the other limits you control, refer to Adjusting Resource and Time Limits for Vocareum Labs.