Certain operations within SIP display their results on the sip plot. These fall into two categories, termed temporary and permanent. Permanent results are plotted on the sip plot and are also maintained in memory. This allows the data to be interrogated. Temporary results are plotted straight to the sip plot and are not maintained in memory. Any changes to the sip plot, for example, plotting new data, will destroy these results. The distinction has been made primarily to deal with operations and parameters that yield a lot of results. It is therefore possible to view these results but without the overhead of allocating a large amount of memory.