====Logging In====
AHPCC clusters are available on several ''ssh'' hosts and from [[ https://openondemand.org | OpenOnDemand ]] web portal [[ https://pinnacle-portal.uark.edu ]].

''ssh'' common account text login hosts are **pinnacle.uark.edu**, **trestles.uark.edu**, and **razor.uark.edu**.  **trestles** and **razor** login hosts are deprecated and will be shut down as those clusters are integrated into the **pinnacle** Slurm scheduler.  Each login host presents the same view of your files but has a different job scheduler and job queue (**pinnacle** Slurm, **trestles** Torque, **razor** Torque).  The CSCE cluster has an ''ssh'' login host **karpinski.uark.edu** with separate accounts and files and a Slurm scheduler.  The CSCE cluster is also available through [[ https://pinnacle-portal.uark.edu ]].

An ''ssh'' client is needed on your workstation to access the **ssh** login hosts, and a web browser is needed for **pinnacle-portal**.  

''ssh'' clients (and file-transfer ''scp,sftp'') are usually installed by default on linux and Mac workstations. On Windows 7 or 10 we recommend the stand-alone program [[ https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html | PuTTY ]].  With the PuTTY ssh client ''putty.exe'' you will probably also need a file-transfer program from the same site, either ''pscp.exe'' or ''psftp.exe''. Windows 10 can install a near-complete clone of Linux including ''ssh,scp,sftp'' called [[ https://docs.microsoft.com/en-us/windows/wsl/wsl2-install | WSL ]]. If you want an explorer-like GUI for ssh and file transfer, there is a free installable download  
[[ https://downloads.uark.edu/ssh/sshwinsecureshell-3.2.9.exe | sshwinsecureshell-3.2.9.exe ]]. If workstation disk space is a consideration, PuTTY is small, sshwinsecureshell medium, WSL large.

Login to ''ssh'' hosts using your UArk email name (without @uark.edu) and authenticate with your UArk password.  If you don't have a Uark account, we will send you alternate login instructions. In PuTTY and sshwinsecureshell you may need to set the host port on the configuration screen to 22, not 23. 

AHPCC doesn't know and can't change UArk passwords, use [[ https://account.uark.edu ]] or ITS support. If you fail UArk authentication three times, you won't be able to login for half an hour.  If an AHPCC login host fails to answer or fails to login, contact hpc-support@listserv.uark.edu . It is helpful to first try the other two login hosts and/or a protected ITS host such as [[ https://account.uark.edu ]] to help determine if it is a host, network, or account/password issue.