There is an overlooked command in TSO called PROFILE and therefore it is seldom used. You use TSO PROFILE to set up a lot of different things in TSO, but I will only cover three of these things, which I consider to be the most important. First of all you can decide which prefix TSO will use when you type in dataset names without putting them in quotes ('). The second thing is to decide whether you want to receive notify messages from batch jobs or other users or not. The third thing is to decide whether messages should be prefixed with a message id or not.
Dataset names without quotes will be default prefixed with your TSO userid. By issuing the command TSO PROFILE NOPREFIX you remove the prefix and all dataset names will be considered as fully qualified whether in quotes or not. You can also change the prefix by issuing the command TSO PROFILE PREFIX(ANOTHER). Now all dataset names without quotes will be prefixed with ANOTHER until you change it again. It is nice to know how to change the prefix, although you seldom need to do it.
By issuing the command TSO PROFILE NOINTERCOM you effectively prevent your TSO session form being interrupted by notify messages from batch jobs or other users. This is a very nice feature, if you don't want to be interrupted all the time, because you have a lot of notifying batch jobs running. Messages from HSM are very irritating, especially if you have submitted a batch job that issues a lot of HSM commands, because HSM will send the notify for each command to your TSO session. Fortunately TSO PROFILE NOINTERCOM prevents HSM messages as well. When you want to have notify messages again you just issue a TSO PROFILE INTERCOM.
TSO PROFILE NOMSGID removes the message id, that usually prefixes the messages returned by several TSO commands. TSO PROFILE MSGID will put them back on again. This is a nice feature if you need a more in depth explanation of a message by looking it up in book manager.
If you just issue a TSO PROFILE command, TSO will list the current values of all the different parameter you can adjust by using the PROFILE command. Issuing TSO PROFILE is a good start because the parameters described in this tip can be set up in different ways depending on your installation. Any change of a PROFILE parameter will work instantly and keep its value for all your future TSO sessions until you change them again. This is not the case for TSO batch jobs. The changes works only for the current batch jobstep and disappears when the jobstep terminates.