TSO ID Becomes Password Suspended After Hitting ENTER Twice Quickly with Wrong Password

Document ID : KB000117505
Last Modified Date : 12/10/2018
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After some testing, entering one (1) incorrect password in TSO and if the ENTER KEY is depressed twice while the TSS7100E INCORRECT PASSWORD is displayed before the "***' appears , the incorrect password is submitted thereby suspending the ID.

Are you aware of any changes with TSS or the z/OS operating system where this is now functioning differently? 
This is really not a TSS problem.

TSO is taking your input from the TSO signon screen then issuing a RACROUTE VERIFY which processes the signon request.

TSO is queuing your keystrokes. Just like hitting any key.

The first ENTER processes the signon request which fails because you entered an incorrect password.

Then the TSO brings you back to the signon screen again to enter the correct password.

Because you hit the ENTER key twice, the second ENTER will be done and since you didnt get a chance to correct the password, a second password violations will occur.

You would get the same results if you hit ENTER once with the incorrect password and waited for the signon screen to re-appear again and hit ENTER again without entering the correct password.

Some TN3270 emulators have a feature that disables the buffering of keystrokes. If you disable the keyboard buffer, the problem will not occur.

But the drawback is not being able to hold down a key and having it automatically repeat.