StorageTek Host Software Component 6 User Manual

1st ed., 6/30/04 - 312579601

The SCP emulates the following MVS GTRACE features: 

 1. The MVS GTRACE macro is supported, without alteration. 

 2. A Monitor Call (MC) program interrupt occurs when the GTRACE function is 

invoked. The SCP program check handler recognizes and handles the Monitor Call 
as a GTRACE event. 

 3. Up to 256 bytes of user data may be traced. 

 4. With most interrupts, the SCP dispatcher does not return to the interrupted task 

immediately, but dispatches the next task in the priority queue. However, after a 
monitor call program interrupt the interrupted task IS returned to immediately. If this 
were not done, program flow would be artificially altered by the act of tracing. 

 5. The Format Id (FID) parameter is supported. It describes the internal format of the 

trace record. The valid (decimal) FID ranges are:

 Actual FIDs used by the SCP are:

The actual FID used by the HSC is passed to the HSC initialization routine 
(SLSBINIT), and is recorded in the ACS SYSPROF file. The default FID is 23. 

 6. The Event ID (EID) parameter is supported. It describes the event as a subtype of the 

Format ID. 

It is specified as a 4-digit hexadecimal number, of which the left-most digit is the 
monitor call class. 

195

x’C3’

c’C’

IUCV event

196

x’C4’

c’D’

Dispatcher event

197

x’C5’

c’E’

External interrupt

201

x’C9’

c’T’

I/O interrupt

212

x’D4’

c’M’

Machine check interrupt

215

x’D7’

c’P’

Program interrupt

217

x’D9’

c’R’

Restart interrupt

226

x’E2’

c’S’

Start I/O

229

x’E5’

c’V’

Supervicor call interrupt

230

x’E6’

c’W’

Return from SVC