1. Say you have a transaction code that must be locked down so no one can use it. How can you lock and unlock this...
a) Use R3trans and tp utilities with tp unlck
b) Use transaction sm01 to find the transaction and lock/unlock it.
c) Run report rslocktrans from se38 and enter the variant value for the desired transaction and the lock/unlock checkbox.
d) Always use the ABAP workbench to lock transactions.
sm01 is a very useful transaction. Not only can you lock transactions from being used at all in the system, but as a general SAP use it can also be used to look up transaction codes, whether for functional information or simply because you forgot which code you need!