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    Guided lesson
    06 / 06About 30 minutesdata handling

    Place Euler Data And Freeze Run Inputs

    Choose how a fictional beam run preserves exact inputs and useful results. The current assessment checks decisions, not a real recoverable run record.

    Where you will workOn this web page
    1. 1Understand
    2. 2Try it yourself
    3. 3Check and submit

    Before you start#

    Names beginning with $ are shell variables that resolve to paths. Follow one fictional project through its run; locations must still be owner-approved.

    Stage Fictional item Decision
    Before submission Reviewed code, measurements and configuration Identify the commit, environment and unchanged input snapshot
    During computation Rebuildable mesh and intermediate files Use $SCRATCH or job-local $TMPDIR, never the only important copy
    After computation Result, useful logs and run metadata Verify the copy in approved durable project storage before cleanup

    $HOME is small private storage; /cluster/work/fuge is approved shared working storage. Neither a temporary directory nor a Slurm script replaces a run record. A reproducible run records code, environment, inputs, configuration and command so someone can identify what produced its result.

    The job is pending while a collaborator edits its input. What must be stable before it starts? Make that decision before reading the explanation.

    Why the pending job needs unchanged referenced files

    The submitted batch script is captured, but external code/configuration/input files can still change. Use an immutable reviewed run snapshot and retain its identifiers. Copy useful results and metadata back to approved durable storage and verify them. A matching checksum establishes copy equality, not permission, backup or retention. The optional GitHub code-sync guide is extra practice after this lesson; it introduces no completion requirement.

    Keeping the only result in temporary storage, or assuming that a commit ID freezes every file in a live working directory.

    Start the practice

    Practice

    Work through the decisions

    Follow in order

    Steps

    Names such as $HOME and $SCRATCH are shell variables: short names that resolve to paths on Euler. High input/output (high-I/O) work repeatedly reads or writes a large amount of data. Use the fictional scenario. Choose locations by ownership and durability, not convenience.

    1. 01

      Know the Euler storage areas

      Read and answer on this web page

      Follow the fictional beam run in the table above. $HOME holds small private code/configuration; approved shared work storage holds the main inputs and outputs. Temporary copies need a rebuild or copy-back rule.

      Open the Euler storage reference

      Look forYou can identify which locations survive, which are shared, and which are temporary.

      Explanation and help
      What this means
      Record the code revision for the fictional run.
      Safe recovery
      Do not place the only copy of a result in scratch or TMPDIR.
    2. 02

      Record the code revision

      Read and answer on this web page

      For this fictional run, choose the reviewed commit before submission. Its identifier records a version; a separate clean, immutable run snapshot prevents later working-tree edits from changing what the job reads.

      Look forThe run plan names one exact commit and a clean or explicitly described source state.

      Explanation and help
      What this means
      Choose the exact input location for this run.
      Safe recovery
      Do not call an uncommitted changing checkout reproducible.
    3. 03

      Freeze input identity

      Read and answer on this web page

      The approved beam measurements have a known version/checksum. Decide whether a job may point to a file still edited by a collaborator. A checksum detects a changed file; it does not approve its contents or freeze it.

      Look forThe inputs used by the job can be identified later.

      Explanation and help
      What this means
      Choose temporary working storage.
      Safe recovery
      Stop if a pending job points to files that collaborators may overwrite.
    4. 04

      Use scratch only for replaceable work

      Read and answer on this web page

      Use Euler scratch for high-throughput temporary files that can be rebuilt. Do not leave the only checkpoint or result there.

      Look forEvery scratch item has a rebuild or copy-back rule.

      Explanation and help
      What this means
      Choose the durable output destination.
      Safe recovery
      Copy and verify irreplaceable output in approved durable storage.
    5. 05

      Name durable outputs and ownership

      Read and answer on this web page

      After computation, verify the result in the owner-approved durable location and retain its metadata. Only then follow the approved cleanup/retention rule. No actual copy or deletion is required in this lesson.

      Look forThe main durable result location and its owner are stated explicitly.

      Explanation and help
      What this means
      Record the software environment.
      Safe recovery
      Ask the project owner before inventing a durable location.
    6. 06

      Record the environment

      Read and answer on this web page

      Record modules, environment definition, application version, configuration, and the exact command or script used.

      Look forAnother authorized user can reconstruct the software context.

      Explanation and help
      What this means
      Keep run-specific logs with the run record.
      Safe recovery
      Do not rely on an undocumented interactive shell history.
    7. 07

      Keep identifiable logs

      Read and answer on this web page

      Use run-specific log names containing the job ID and retain the useful logs with the run metadata.

      Look forEach log maps to one submitted job and configuration.

      Explanation and help
      What this means
      Complete the placement questions.
      Safe recovery
      Correct colliding or ambiguous log paths first.
    8. 08

      Complete the run plan

      Read and answer on this web page

      Answer the six fictional decisions. Use the table as a lookup; this assessment does not create or check a free-form run plan. Optional code synchronization after completion is separate from progress.

      Look forGit, durable storage, scratch, environment metadata, and logs have distinct roles.

      Explanation and help
      What this means
      Run Check my work.
      Safe recovery
      Return to the first file or result whose owner or durability is unclear.

    Practise

    One practice question. It does not affect your progress.

    01A job is pending. Its batch script names a configuration file that a collaborator replaces. Has the submitted script frozen that configuration?
    See an explanation

    Slurm captures the submitted script, not every external file it references. A run-specific unchanged snapshot and its identifiers keep the intended configuration identifiable. A filename alone cannot do that.

    Finish the lesson

    Questions to submit

    Answer these 6 questions, then confirm the work you checked.

    To pass: 80% and every safety question. Completion appears after the automatic GitHub check passes.

    01What is Euler scratch for?Safety-critical
    02What must a reproducible run identify?
    03A pending job points to an input file that collaborators still edit. What should happen?Safety-critical
    04How should a high-I/O Euler job use data whose durable source is on the NAS?Safety-critical
    05A required checkpoint currently exists only in scratch. What is the next safe action?
    06What makes Slurm logs traceable to one run?
    Before submitting
    Open my real passport first

    You can check sample answers here. Open your local Passport to check your practice files and submit the lesson.

    Preview onlyYou can try the questions here. This page does not store or submit your answers.
    Need help?Open recovery steps and AI-review guidance

    If Blocked#

    Do not invent permissions or recursively change a shared folder. Ask the data owner which approved location holds the main durable copy, and use Euler storage for lifecycle and collaboration recovery.

    Useful references:

    Understand Before Accepting AI Output#

    Inspect every source and destination before copying or deleting. An agent must not assume a temporary path is backed up or that a successful transfer is a backup.