Establishing access

The next two steps make the service provider's services available to a user. The instructions used for these two steps must be issued from the user's address space by a program running in supervisor state or with a PKM value of 0-7. If the user is a problem state program, the service provider must provide code that executes on behalf of the user with the user's address space as the home address space. The service provider must repeat these two steps for each user.

Set the PT and SSAR authority in the user's authority table entry that corresponds to the service provider's AX value. This action allows the service provider to issue a PT or SSAR instruction with the user's address space as the instruction target.
```
SETAT  ATSET  AX=AXVALUE,PT=YES,SSAR=YES,RELATED=RESETAT
```
Connect the service provider's entry table to the user's linkage table at the entry that corresponds to the service provider's LX. After the system completes the connection, the linkage table entry points to the service provider's entry table.
```
          LA      2,1
          ST      2,TKCOUNT    SET COUNT OF ETS TO BE CONNECTED
CONET     ETCON   TKLIST=TKL,LXLIST=LXL,RELATED=DISET1
```
Or connect the service provider's entry table to the linkage tables at the entry that corresponds to the service provider's extended LX values. After the system completes the connection, the linkage table entry points to the service provider's entry table.
```
          LA      2,1
          ST      2,TKCOUNT    SET COUNT OF ETS TO BE CONNECTED
CONETX    ETCON   TKLIST=TKL,ELXLIST=ELXL,RELATED=DISETX
```

To invoke a PC routine, the user still needs a PC number. The service provider and the user must have previously agreed on a method the service provider will use to provide a PC number. For example, the service provider could provide a macro that the user issues to find the PC number that the service provider has stored in a table in commonly addressable storage. In addition, if a reusable LX was reserved by the service provider, the LX sequence number associated with the LX/PC number must also be provided to the user. The service provider could use the same macro that the user issued to find the PC number, to provide the LX sequence number.

At this point in the example, the service provider has provided two services that the user can access using PC instructions. The service provider has also established authority to issue PT and SSAR instructions to the user's address space. The user's linkage table is connected to the service provider's entry table as shown in Figure 1.

Figure 1. Linkage table and entry table connection