X clock: Host or terminal busy, wait

What it means

The clock is the time indicator in the 3270 operator information area. With the X in front of it, it says the keyboard is locked because a function is in progress. On a terminal emulator you usually see it right after you press Enter or a PF key, while the screen travels to the host and the application works on it.

The keyboard is released when the application writes back with keyboard restore set in its write control character. Until then anything you type is refused. A short flash of the clock is normal. A clock that stays for a long time means the host or the application is slow, waiting on something, or not going to answer.

Some emulators show the clock in some situations and X SYSTEM in others. For the person at the keyboard they mean the same thing. The host has the next move.

Common causes

• Normal processing. Every Enter or PF key locks the keyboard with the clock until the reply arrives.
• The transaction is doing heavy work, such as a large search or a report run from the screen.
• The application is waiting on a lock, a database, a queue or another region before it can answer.
• The host system is busy, so every transaction is slow.
• The response was lost because the connection dropped. In that case a COMM indicator usually takes the place of the clock soon after.

How to find the problem

1. Time it. If the clock always clears in a few seconds, it is response time, not an error.
2. Ask colleagues on the same application. If they see the same delay, the problem is in the host or application.
3. Watch the status line. If the clock gives way to COMM and a number, or the emulator shows the session as disconnected, the network or the TN3270 server is the problem instead.
4. The CICS team can check the task with CEMT INQUIRE TASK. The IMS team can check the transaction and region with /DISPLAY commands. Both show whether the work is running, queued or suspended.
5. If one screen always ends with the clock stuck even though the application has finished, a programmer should trace the data stream and check whether the final write sets keyboard restore in the WCC.

How to fix it

• Wait for the reply. Typing ahead doesn't help, because the keys are refused while the clock shows.
• If you have waited far longer than usual, interrupt with Attn or PA1 if the application supports it, or ask support to cancel the task.
• If the session is dead, disconnect and reconnect. Check whether your last update was applied before you enter it again.
• For a programmer, make sure the last output of every transaction sets keyboard restore. In CICS BMS use FREEKB. In a raw 3270 data stream set bit 6 of the WCC.
• If the slowdown is general, report the time and transaction to the operations team so they can look at system load.

Technical reviewer: Albert Joseph, WND Software.

Last reviewed 2026-10-18 by the WND Software team. Written in our own words. For the full reference, check IBM’s 3270 or 5250 display documentation.