Difference between SST and DST

SST is available when the OS is started. The OS is required for accessing SST. SST is used to manage firmware & hardware. It is not used to manage OS.

DST is available even when the system has limited capabilities. DST is available even if OS is not installed. LIC is required for accessing DST.  

Accessing DST

We can access DST in 2 different ways
1. From Control Panel
2. Through manual IPL

Accessing DST from the control panel:
To access service tools using DST from the control panel, complete the following steps:

• Put the control panel in manual mode.
• Use the control panel to select function 21 and press Enter. The DST Sign On display appears on the console.
• Sign on to DST using your service tools user ID and password. The Use dedicated service tools (DST) display appears.
• Select the appropriate option from the list and press Enter.
• Select option 5 (Work with DST environment) to get to additional options for working with service tools user IDs.
• Select option 7 (Start a service tool) to start any of the service tools available from DST.
• Select any of the other options, as appropriate.

Accessing service tools using DST from a manual IPL:
To access service tools using DST from a manual initial program load (IPL), complete the following steps:

• Put the control panel in manual mode.
• Take either of the following actions:
• If the system is powered off, turn the system on.
• If the system is powered on, enter the Power Down System (PWRDWNSYS) command, PWRDWNSYS *IMMED RESTART(*YES), on a command line to turn off the system and restart it.
• Sign on to DST using your service tools user ID and password. The Use dedicated service tools (DST) display is shown.
• Select the appropriate option from the list and press Enter.
• Select option 5 (Work with DST environment) to get additional options for working with service tools user IDs.
• Select option 7 (Start a service tool) to start any of the service tools available from DST.
• Select any of the other options, as appropriate.

Service Tools

Service tools are used to perform various system functions including diagnosing system problems, managing disk units, and managing system security. 

Dedicated Service Tools (DST) or System Service Tools (SST) are used to access service tools functions.  The following are the few functions we can perform with DST or SST.

• Add hardware resources to the system.
• Diagnose system problems.
• Manage disk units.
• Manage logical partition (LPAR) activities, including memory.
• Manage or view main storage dumps.
• Manage other service tools user IDs.
• Manage system security.
• Review the Licensed Internal Code and product activity logs.

Service tools user IDs are user IDs that are required for accessing service functions through DST, SST, i series navigator (for disk unit management), and Operations Console. 

Service tools user IDs are created through DST or SST and are separate from IBM i (OS/400) user profiles. It is possible to have a service tools user ID and operating system user profile with the same name.

You can create a maximum of 100 service tools user IDs (including the four IBM-supplied user IDs).