Siemens SM2 monitoring system manual Excp, Expanded storage ES, firmware service time DCS

Glossary

4.Further time spent in Q4 except for boursing, ITC, PASS/VPASS and waiting for response to console message.

5.Wait for activation (time spent in Q5).

6.Wait for admission (time spent in queue Q6).

7.Wait in Q7 for hardware error recovery (HERS).

8.Further time spent in Q12 except for boursing and waiting for response to console message.

9.Hardware duration of I/O operations for paging page transfers.

EXCP

Macro on the physical I/O level which initiates a channel program (see “counting of I/O operations and their duration” on page 445).

expanded storage (ES)

In BS2000/OSD V3.0 or earlier, expanded storage was a volatile, semiconductor-based expanded memory which could only be activated on systems of type H120. Support for this system type is discontinued in versions of BS2000/OSD later than V3.0.

In future extensions, main memory over 2 GBytes must be available for caching on SR2000 systems. This additional memory will be used in the same way as the previous expanded storage space. As a result, the definition of expanded storage has been changed as of BS2000/OSD V4.0:

Expanded storage (ES) is a volatile memory that can be used by DAB as a cache.

As with main memory, the data in expanded storage is lost following a system crash. Expanded storage is therefore primarily intended for read caching. If it is to be used as a write or read/write cache, the following files are recommended:

–files that require enhanced failsafe performance (temporary work files, SYSEAM)

–files whose write data is backed up by some additional mechanism (e.g. logging)

–files that can be restored after a system crash with relative ease without loss of data

firmware service time (DCS)

This comprises both the hardware service time and the I/O housekeeping time. It is caused not only while waiting for I/O initiation at the device (FPT = Function Pending Time) but also after channel activities have been terminated until the I/O interrupt has been accepted by the CPU (RST = Remaining Service Time). For DCS systems, this is therefore the time between "Start subchannel" and "Interrupt accept" (see “service times definition (DCS, I/O operations)” on page 455).

448 U3585-J-Z125-8-76