StorageTek Host Software Component 6 User Manual

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Chapter 2. Host Software Component Functions   21
1st ed., 6/30/04 - 312579601
 
Initialization/Termination Functions 
Initialization/termination functions control initialization and termination of HSC 
components. This section describes the major initialization/termination functions. 
HSC Service Levels 
To provide you with a more flexible, dynamic, automated cartridge mounting execution 
environment, the HSC has a service level strategy. Operation at either of the two service 
levels impacts the HSC subsystem. Operation flexibility is provided at a base service level 
to tolerate failures in certain isolated areas without impacting the functions of other 
sections of the HSC or your entire data center. Overall, this fault-tolerant HSC gives you 
greater availability of your automated library and lessens the need to shutdown and 
reinitialize. The HSC subsystem operates at two service levels:
Base service level
provides minimal functionality keeping the HSC running while having the capability 
of applying software maintenance or altering the subsystem parameters at the same 
time. This level is the lower level of functionality. 
Full service level 
provides full functionality of the HSC. 
Normally the HSC initializes to the full service level when started. HSC can be started at 
the base service level by specifying the BASE parameter in the startup SLKJCL file. Refer 
to “Initializing the HSC to the Base Service Level” on page 129 for more information 
about HSC startup.
Description of Base Service Level 
The base service level is the nucleus of the HSC subsystem. It involves the functions 
necessary to execute as an extension of the operating system. The service level and its 
functions satisfy the requirements defined by the operating environment in place at the 
time of execution. Base service level functions include the capabilities to: 
• issue subsystem commands
• execute certain utilities 
• access the control data sets 
• support the operating system interfaces and front-ends and maintain HSC 
host-to-host communications. 
All operator commands can be issued with the HSC executing at the base service level. 
However, the commands which involve library hardware cannot perform their function 
completely. Table 1 on page 21 indicates which commands have complete functionality at 
the base service level. 
Table 2 on page 22 indicates which utilities can be executed at the base service level.