MVS data sets

Table 1 is a summary of MVS™ data sets that contain TSO/E information.

Table 1. MVS data sets
MVS data sets	Description	Reference
Broadcast data set	Contains notices (messages sent to all users of a system), and mail (messages sent to individual users). You can change the amount of space reserved in the broadcast data set for notices using the IKJBCAST macro statement.	Maintaining the UADS, RACF data base, and broadcast data set
SYS1.CMDLIB	Contains service routines, utility programs, and TSO/E command processors. You may want to move TSO/E commands to SYS1.LPALIB, possibly improving the performance of TSO/E.	None
SYS1.HELP	Contains help information about TSO/E commands and messages.
SYS1.LNKLIB	Contains RACF® commands, the data set initialization program, report writer, and utilities.	None
SYS1.LPALIB	Contains some TSO/E commands, such as MVSSERV. It also contains RACF-related information and installation-written exit routines.	None
SYS1.MACLIB	Contains the macro definitions for supervisor and data management macro instructions. It also contains RACF and TSO/E macros, such as IKJBCAST.	None
SYS1.PARMLIB	Contains IBM-supplied and installation-created lists of system parameter values. It contains parameters you can use to tailor the logon process, and the way TSO/E works with VTAM®.	None
SYS1.PROCLIB	Contains the cataloged procedures used to perform system functions. By default, it contains all TSO/E logon procedures. You may want to use your own procedure library. For more information, see Writing a logon procedure.	None
RACF data base	Contains profiles for every entity—users, data sets, and groups—defined to RACF. The profiles describe the attributes and the authorities of each of the entities. If you use RACF to add users, logon information is stored in the user's profile.	Maintaining the UADS, RACF data base, and broadcast data set
SYS1.UADS	If you use the TSO/E ACCOUNT command to add and maintain users, SYS1.UADS contains a list of TSO/E users and information about them, such as account numbers, logon procedures, and commands they can use.	Maintaining the UADS, RACF data base, and broadcast data set