Doing CSC 151 work remotely
There are four primary mechanisms for doing CSC 151 work remotely.
You can run a virtual machine on your laptop. A virtual machine is a simulated computer - it’s like you have a Linux workstation running within your Mac or Windows computer. This ends up being the most straightfoward approach. However, it does mean that you’ll need to spend a little work transferring files back and forth from MathLAN.
You can connect to the workstation using a protocol called
ssh(for “secure shell”). This approach is relatively straightforward for Mac and Linux users, and more complicated for Windows users. Using ssh, all of your files are on the MathLAN, which is convenient. However, the
sshapproach doesn’t always seem to work.
If you run Linux on your workstation, you can install the CSC 151 software on your computer. This requires some understanding of Linux system administration, and is not always reliable. (We do this with Debian and Ubuntu regularly.) Once again, you’ll have to deal with the files residing on your computer, rather than on MathLAN.
You can use an application called VNC to connect to the MathLAN. This approach seems to work well for people who want to work with the MathLAN software and have limited bandwidth. However, it requires a lot of extra work to do securely. It can pollute our workstations with running processes. And our instructions are currently not very good.
The remaining sections of this document describe various OS/mechanism combinations. They currently appear in no particular order. Note that none of the CS faculty use Microsoft Windows, so we are much less familiar with how well any of this works under Windows. Windows users should probably use the virtual machine.
Running a virtual machine on MacOS, Windows, or Linux
Follow the virtual machine instructions
Installing software on your Linux workstation
The instructions we use to set up the virtual machine are at https://github.com/GlimmerLabs/virtual-mediascheme/blob/master/Building.md You should probably do the parts labeled “More Things to Install” and “Install the Mediascript Tools”.
You should also learn how to transfer files between workstations. The
rsync command, described in the
virtual machine instructions will
work well. (You can’t use the shortcuts given in those instructions.)
Using ssh from a Mac or Linux workstation
These steps should work on most modern Macintosh and Linux workstations. If you have a Mac, you will need to download XQuartz first.
The steps below refer to
ssh.cs.grinnell.edu. Note that for the time
being, you should connect to a computer in Science 3813, rather than
ssh.cs.grinnell.edu. You might, for example, use
(All of those should be suffixed with
Open a terminal window.
ssh -X USERNAME@ssh.cs.grinnell.edu. Make sure to fill in your MathLAN username.
When prompted, type your MathLAN password.
gimp &. Yes, you should include the ampersand.
drracket &. Yes, you should include the ampersand.
Wait a little bit.
Both DrRacket and GIMP should appear in new windows on your Mac.
Proceed as normal. (Mac users will need to use the control key rather than the command key for DrRacket and GIMP.)
If DrRacket and GIMP don’t appear, record what message you get and ask your professor.
When you are finished, make sure to quit DrRacket and GIMP. Also, log out in the terminal window and then close the terminal window.
Using ssh from a Microsoft Windows workstation
About a decade ago, a student wrote instructions for connecting from Windows computers using PuTTY and Xming. Those are likely to still work correctly. If someone wants to write a simpler version of those instructions, we’ll put them here.
Using VNC securely on Mac, Windows, or Linux
Follow the poorly written VNC instructions
Using VNC insecurely on Microsoft Windows
Using PuTTY, connect to one of the MathLAN machines mentioned above. (In the future, this should be
ssh.cs.grinnell.edu. For now, it should be
zuse. (All of those should be suffixed with
.cs.grinnell.edu). You may be asked to confirm that you want to connect to that computer. You will be prompted to enter your MathLAN password.
In your PuTTY terminal window, type
vncpasswd. It will prompt you for a new passowrd. This new password is only for VNC. Enter a password that others are unlikely to guess. (Only the first eight characters are significant.) Enter it again when prompted.
In your PuTTY terminal window, type
vncserver. It should start a VNC server and give you a response something like the following
New 'machine:2 (username)' desktop is machine:2 Starting applications specified in /home/username/.vnc/xstartup Log file is /home/username/.vnc/machine:2.log
Make a note of the number after the colon. That’s called your “desktop”. In the example response, the desktop is 2.
Start VNC Viewer. It will prompt you for a machine. Type
MACHINEis the machine name you used with PuTTY and
xis the desktop number. So, if I’d used dahl and had desktop 2, I’d write
dahl.cs.grinnell.edu:5902. If the desktop number is greater than 10, don’t use the 0. If the desktop were 13, I’d write
A MathLAN-like window should appear with one terminal window.
Start GIMP by typing
Start DrRacket by typing
When you are done, quit GIMP, DrRacket, and VNC Viewer.
In terminal, type
vncserver -kill :x, where
xis your desktop number.