Admin Alert: Starting DST Without an IPL

by Joe Hertvik

The DST menu is, of course, an integral part of OS/400, where, among other things, you can set and reset DST user IDs, reset the QSECOFR user profile password, work with disk units and storage configurations, and start an iSeries or AS/400 system IPL. Some of the functionality of DTS is duplicated in the System Service Tools (STRSST) command that can be called from an OS/400 green screen, but because there are several items in DST that IBM doesn't want activated by the casual user, you have to explicitly put your system into manual mode to enter DST. You also have to bring up the DST menu from the system console, which seals it away from any crackers who may be able to Telnet into your machine.

To further complicate matters, there are two different ways to enter DST from the system console without performing an IPL. The first way is by using the physical buttons on the iSeries or AS/400 system panel, which can be used for non-partitioned machines as well as for the primary (controlling) partition on a partitioned machine. The second way is used for all iSeries and AS/400 primary and secondary partitions, some of which are logical iSeries boxes with no physical buttons or system panels. The method you choose depends on whether you're working with a stand-alone non-partitioned machine, a primary partition, or a secondary partition in a multi-partition environment. Here's how to enter DST without an IPL for each of these configurations.

For non-partitioned machines, entering DST without an IPL is simply a matter of performing two manual tasks from your iSeries or AS/400 system panel. The first task is to put the system keylock in manual mode. This can be accomplished by either turning the key on the front of your AS/400 to the manual position or (for some AS/400s) pushing a button that changes an indicator light on the front of the system panel from the Automatic or Normal position to Manual. The second task is--while the keylock is in manual mode--to press the OS/400 indicator buttons until the system panel LCD status indicator reads "21," and then press the Enter button. This will automatically bring up the sign-on for the DST menu on your system console. After signing in with your DST user ID and password, you can perform whatever DST commands you want. When finished, you exit DST and the menu will close, returning you to the system console sign-on screen. (Be sure to return the system keylock to its previous position.)

Note that this physical technique can be used to invoke DST for the primary partition of a multi-partitioned iSeries or AS/400, since option 21 can be invoked in that partition through the system keylock and indicator buttons.

For partitioned machines, the DST drill is a little different because there are no physical buttons or system panels on your secondary partitions; although, this technique can also be used for the primary partition. Here you have to perform the software equivalent of putting your system into manual mode and selecting option 21. You do this by starting the System Service Tools menu on your primary--or controlling--partition. (Enter System Service Tools by typing the STRSST command on your controlling partition's system console command line.) After signing on to SST with a valid DST user ID, select the following functions on an OS/400 V5R1 machine, and the DST menu will automatically appear on your target partition's system console:

1. Select option 5 (Work with System Partitions) from the main STRSST menu.

2. Select option 3 (Work with Partition Configuration) from the Work with System Partitions menu. The Work with Partition Configuration screen shows you all the logical OS/400 partitions that are set up on your physical box.

3. Press F11 (Work with Partition Status). The Work with Partition Status screen shows the current status (IPL Source, IPL Mode, State, Sys IPL action) of each partition on your machine.

4. Tab down to the partition entry you want to enter DST for and type "10" in front of that partition. Press Enter. This will change the IPL mode for that partition to Manual.

5. To start DST on your partition's system console, now type a "21" (Force Dedicated Service Tools) in front of your target partition entry on the Work with Partition Status screen. This will automatically start the DST menu on your target partition's system console. Sign on to DST from the system console and use it to perform whatever tasks you wish. When you press F3 to exit DST, a second screen will appear that asks you to confirm whether you want to exit DST (option 1) or resume using DST (option 2). After entering option 1, the DST menu will disappear and--for most partitions--the system sign-on screen will reappear on your target partition's system console.

6. Reset your OS/400 partition IPL mode back to Normal or Automatic mode by once again entering the Work with Partition Status screen and entering "9" (Normal mode) or "11" (Mode auto) next to the OS/400 partition that you were using DST on. This entry should match the IPL mode your box was in before you started DST. If you don't reset the partition to Normal or Automatic, your partition will restart in manual mode the next time you perform an IPL.

For this article, I tested the non-partitioned technique on an OS/400 V4R5 machine, as well as on several V5R1 boxes. I tested the partitioned technique on an OS/40 V5R1 machine using the instructions listed above (be aware, however, that the partitioned machine instructions may be slightly different on a V4R5 box). Both systems brought up DST as advertised. I also received independent configuration from some of our readers that this technique works very well.