Running Logisim Directly on ITS machines

However, even with ssh'ing into separate CS machines, the X-forwarding of logisim can be a bit slow. And, if you just can't stand it, you can avoid the lag by temporarily installing logisim on the ITS machine and use logisim locally (saving your work periodically as you go). If you do this it is VERY IMPORTANT that you copy your .circ file back to your CS account BEFORE logging out of the ITS machine, otherwise you will lose all your work.

Installing Logisim on an ITS machine and copying files between CS and ITS machines:

1. Go to the Logisim web page, choose download, and download the logisim software on the ITS machine you are logged into. We are using version 2.7.

2. If you have an existing .circ file in your CS account that you want to edit on the ITS machine, scp the file over from your CS account to the ITS machine. scp is secure copy between two machines connected by a network. scp takes a source and a destination argument just like local copy, cp, but the source or desitnation may specify a file from an account on a remote machine, and thus needs to specify user name, machine, and path name to the file.

   For example, from a shell on the ITS machine you can copy over files from your CS account by doing the following:

   cd Desktop    # let's just copy stuff to Desktop
   
   # copy the alu.circ file from your CS account to the ITS machine
   scp your_user_name@cs.swarthmore.edu:./cs31/labs/02/alu.circ .
   
   # you can use the -r flag to scp to copy over an entire subdirectory contents:
   scp -r your_user_name@cs.swarthmore.edu:./cs31/labs/02 .
   
   open alu.circ  # should start logisim on this file
   

3. open alu.circ with logisim on the ITS machine, edit and test it, save it on the ITS machine periodically as you go.

4. Very Important Step: anything you save on the ITS machine (including logisim and your .circ files) is wiped-out as soon as you log out of the ITS machine. Therefore, make sure to scp your .circ file back to your CS account before logging out of an ITS machine:

   # copy the alu.circ file from the ITS machine back to your CS account
   scp alu.circ your_user_name@cs.swarthmore.edu:./cs31/labs/02/alu.circ 
   

   If you forget this step, you will lose all the work you saved on the ITS machine, which may be reason enough to endure the X-forwarding lag of ssh'ing into your CS machine and running logisim there.

   You can (and I'd suggest that you do) periodically scp the changes to your .circ file back to your CS account as you work on an ITS machine.