ALLOCATE

This TSO command can help you with allocating data sets on the system

you can use the ALLOCATE command to associate a particular data set with a ddname.

Although many data sets will be automatically allocated when a TSO session is started, others can be allocated manually with this command.

An existing data set is usually allocated for use by a program.

When reading or writing data most users will use a symbolic name called a ddname

ALLOCATE DATASET('data set name') FILE(ddname) will allocate a data set with the provided name.
Multiple names can be provided by separating them with commas.

UNIT is also a valid parameter to this command~!

You can also allocate a data set that does not exist yet

If an asterisk is coded instaed of a dsname, the input will be taken from the keyboard and the output will be sent to the screen, depending on if it was an input or an output.