As of 2025-03-20:

1. The servers must be accessed with new SSH port numbers. See details below.
2. An additional terabyte of storage has been added to the aarch64-002 server, accessible via ~/aux – See details below.
3. An additional 500 GiB of storage has been added to the home directories on the x86-001 server.

In order to gain access to these computers, you must send an SSH key to your professor using the instructions on the SPO600 Communication Tools page.

Accounts are created in batches and should be ready within a week of submitting your keys.

This machine is a Honeycomb LX2K system. It has a large number of moderate cores (16 x Cortex-A72), an NVME SSD storage system, and 32GiB RAM. Note that it is running an older version of both Linux and the GCC compiler. This system is capable of compiling GCC in about 100 minutes.

You can access this system at the hostname aarch64-002.spo600.cdot.systems at port 2202; using OpenSSH from the command line, you can use these arguments:

ssh -p 2202 username@aarch64-002.spo600.cdot.systems

On March 20, 2025, an additional terabyte of storage was added to this system. The additional storage is available through the symlink ~/aux in each user's directory. To be fair to other users, please limit your use of this additional storage to 30 GiB.

You can see your current disk usage and available space in both your home and aux directories with the command: storage

This x86_64 system is a workstation/server class system (x86-64-v4 architectural level) with 64GiB RAM. It has the hostname x86-001.spo600.cdot.systems and is accessible on port 2201. It can be accessed using OpenSSH with these arguments:

ssh -p 2201 username@x86-001.spo600.cdot.systems

If you're using OpenSSH (the ssh client used on most Linux systems and other platforms), you can simplify ssh command lines by placing host connection details in the file ~/.ssh/config>, something like this:

         
 Host "aa2"
         hostname "aarch64-002.spo600.cdot.systems"
         port 2202
         user "YourUserID"

 Host "x86"
         hostname "x86-001.spo600.cdot.systems"
         port 2201
         user "YourUserID"

Once you have added these lines (inserting your user ID where appropriate) and set the permission on that file (chmod 0600 ~/.ssh/config) you can use these simplified commands to access the servers:

 ssh aa2

 ssh x86

You can similarly configure simplified access in most other SSH client programs.

Remember that these machines are multi-user systems. Use the w or who commands to see who else is using them; you can also try using the write command to communicate with another user if required.

Your password on each of these systems has been set to a random string (different on each host). You can find out the original random password by viewing the file ~/password.txt and you can change the password with the passwd command.

If you wish to access the servers from additional computers, you can append the SSH public keys from those computers to the ~/.ssh/authorized_keys file on the target system. Alternately, you can copy the private key from one client system to another (e.g., your laptop to your desktop).

The current servers are both running Fedora and will be updated from time to time. The machines may not be updated at the same time, so the versions of software may vary slightly. The kernel versions may also vary between the systems because of kernel hardware support.

These accounts are never backed up, and the machines may fail, lose data, or be reinstalled without warning at any time. Please back up your work frequently by copying it to another system or storage device.

With the OpenSSH client:

1. Your ssh private key must be in your ~/.ssh directory (which must have 0700 permission) and the private key file must have 0600 permissions – no more and no less.
2. If your SSH public key is not named ~/.ssh/id_rsa, your SSH client may not automatically find it. You can specify the identity (private key) file using the -i argument to the SSH command.}}

The passphrase is the one you provided when you created your SSH keys. You must remember this passphrase in order to successfully unlock your private key. If you do not remember your passphrase, you will need to create a new pair of keys and re-send the public key to your professor:

1. Create the keys with ssh-keygen -t ed25591
2. Copy the public key (which by default will be named ~/.ssh/id_ed25519.pub) to a file named UserId.pub where UserId is your Seneca User ID.
3. Attach that file to an e-mail message and send it to your professor.

The password is for the remote system, but the SSH client will only ask you for a password if it is unable to authenticate using your keys. If that is the case, then one of your keys is corrupted, missing, has the wrong permission, or can't be found by the SSH client.

1. If you're using OpenSSH, try using the -i argument to tell the client which private key identity file to use: ssh -i /path/to/ssh/PrivateKey …
2. Check the permissions on the private key and the directory holding the private key.
3. If necessary, generate a new key and send it to your professor (see the previous section).

To see what the OpenSSH client program is doing, you can use the -v (verbose) argument, up to three times: ssh -vvv …

By reading through the output carefully, you can see what the OpenSSH client program is doing, and address any problems that arise (such as permission or file naming issues).

The screen utility provides disconnect/reconnect capability, which is very useful for unstable network connections, long interactive operations, and changing your work location.

Other programs such as tmux provide similar capability.

For graphical disconnect/reconnect capability, consider using VNC.