There are several useful techniques for dealing with large jobs that take a lot of time. You can run your jobs in batch mode, rather than interactive. This avoids using any memory that would be necessary for interactive mode. You can run your batch job in the background (by placing an ampersand [&] at the end of the command-line invocation), which allows you to logout while the job finishes, if you wish. (Running a job in the background also allows you to avoid timeout problems associated with long periods of terminal inactivity when you are connected via a micom line or modem.) And you can queue your job to run at a later time, when the system is likely not to be so busy.