IBM has added some really nice features that are implemented in the system values for i/OS 6.1. Here are two of my favorites.

QPWDCHGBLK – (Password Change Blocking)
This is a new system value that allows you to specify a password change block time. For example, you can set the system value to 24, which tells the system that a user may not change their password again within 24 hours of a successful password change.

The default value is *NONE, which means that there is no password change blocking in effect. However, the system value may be overridden at the user profile level with the new user profile attribute of PWDCHGBLK. You may choose to block additional password changes anywhere from one to 99 hours.

Setting this value is useful to thwart the attempts of those users who repeatedly change their passwords in order to get back to their original password when they have exceeded the password re-use system value.

This system value, like most other password system values, is not considered when the CHGUSRPRF(Change User Profile) command is used to change a user's password. It is in effect only when the CHGPWD(Change Password) command or the QSYCHGPW(Change Password) API is used (as in the case of iSeries Access or Signon Server log-on).

The system value will not affect a profile that has been set as PWDEXP(*YES).

QLMTDEVSSN – (Limit Device Sessions)
This is a changed system value in 6.1. In prior releases, you could allow only one or multiple concurrent display sessions for a user. The change in 6.1 allows you more granular control, because you can now specify the maximum number of concurrent display sessions (from one to nine) allowed for a user.

So, for example, now you can set QLMTDEVSSN to a value of 2 to allow users to have 2 concurrent display sessions(or windows) open to the same system. The main reason for this system value is to keep users from sharing passwords and prohibiting the use of generic profiles like QSYSOPR.

This system value may be overridden at the user profile level with the new support in the Create and Change User Profile commands.