Appendix A — System Access and HPC Login

This appendix provides reference instructions for accessing the Hercules HPC system from macOS and Windows, including optional X11 forwarding for GUI applications. These steps support all CADRE Year‑2 training workflows.

A.1 Login from macOS

  1. Open the Terminal application.

  2. Connect to the Hercules login node using SSH:

    ssh -X <username>@hercules-login.hpc.msstate.edu
    

    The -X option enables X11 forwarding.

  3. (Optional) Install XQuartz for GUI/X11 applications:

    After installation, log out and log back in to activate X11.

A.2 Login from Windows (PuTTY)

  1. Install and open PuTTY.

  2. Enter the hostname:

    hercules-login.hpc.msstate.edu

  3. (Optional) Enable X11 forwarding:

    Connection → SSH → X11 → “Enable X11 forwarding”

PuTTY X11 forwarding settings

PuTTY settings for enabling X11 forwarding.

  1. (Optional) Install Xming to provide the X11 display server:

    Start Xming before launching PuTTY.

A.3 Basic Hercules HPC Environment

After logging in, verify your account and environment:

id
groups
showqos
pwd

Key items:

  • Username

  • Project allocation / Slurm QOS

  • Home directory

  • Work directory (e.g., /work/<project>/<username>)

A.4 Filesystem Overview

Hercules provides several storage locations:

  • Home directory — persistent, backed up

  • Work directory — high‑performance storage for experiments

  • Scratch — temporary, purged regularly

Check available space:

df -h
du -sh .

A.5 Slurm Usage Basics

Submit a batch job:

sbatch job.slurm

Request an interactive compute session:

salloc --qos=<qos> --time=01:00:00 --ntasks=1

Check queue status:

squeue

A.6 X11 Forwarding Notes

Test X11 forwarding:

xclock

If the clock window appears, X11 is working.

Troubleshooting:

  • macOS: ensure XQuartz is installed and running

  • Windows: ensure Xming is running before PuTTY

  • SSH must include -X

  • Check echo $DISPLAY is set

A.7 Summary

This appendix provides reference instructions for accessing Hercules from macOS and Windows, configuring X11 forwarding, and verifying your HPC environment. These steps support all CADRE Year‑2 training workflows.