The Modify Host button enables the user to modify any information attached to an already-existing entry in the Host list. To use this button, the user selects a host in the Host list by clicking on the host with the left mouse button. The entry will then be highlighted. The user then selects the Modify Host button. The PADE Add Host window already described above will then appear. This window is the same one as appears when the Add Host button is selected except that the information pertaining to the highlighted host appears in the two text-entry boxes. The user can then modify this text as desired. Choosing the Save button will cause the Add Host window to exit and the modified text will replace the old text in the highlighted entry. As above, if the text in the Host name text-entry box is cleared and the Save button selected, then the highlighted entry remains unchanged. If no host has been selected at the time the Modify Host button is chosen, a message appears in the message box at the bottom of the window indicating that a host must first be chosen. The Modify Host button is most convenient for adding commands to a list of hosts reading in from a PVM hostfile.