Mainframe, MVS and zOS Discussion

Enrico,

Just one more question though, don't TSO(user) address spaces get swapped out, like other jobs? I thought so!

The simple answer to your question is z/OS doesn't maintain versions of datasets.

Before TSO all kind of mainframe processing was batch. You'd send your deck of punched cards and tapes to a central processor complex where an operator would execute the work on your behalf and return you the print out, if you were fortunate and everything ran well. The invention of a batch program ...

Good insight - thanks Anuj!

Hi all, Reading about DB2 internals and performance metrics has always been my favourite topic of interest. I recently read a column on Sequential Prefetch , one of the coolest features of DB2. DB2 can asynchronously read consecutive pages of data, if DB2 thinks you are likely to read pages sequenti...

Maidy, To add here, you not only re-organize tables but also re-organize indexes! As time goes by, insertions and deletions can cause tables, indexes to be dis-organized. In brief, REORG's put table data on the pages in order(clustering sequence). Free-space is reset. DB2 maintains real-time statist...

To add, here's the entire list of DFHBMSCA constants that you can use -

http://publib.boulder.ibm.com/infocente ... stants.htm

We can have this one as a sticky in fact!

HTH,
Quasar

Anuj, I read the article quoted by you. CPU time can be converted to SUs by multiplying DURATION x SU_SEC(the SU_SEC is processor dependent). SU_SEC differs, because different processors have different clock speeds, so one z12 CPU second is not equal to one z10 CPU second. MSU capacity of an LPAR wo...

Hi all, MIPS has never been used as a unit to measure mainframe processing power. Instead, they use SU(Service units). A simple equation one could formulate to calculate capacity would be, Capacity(MSU's) = Duration x SU_SEC(constant published by IBM). I do not understand, why the SU_SEC constant di...

Hi Disha - http://support.sas.com/documentation/cdl/en/acims/59519/HTML/default/images/segrsh.gif Siblings - Segments that share the same parent. Example : B,E1 and E2. C1,C2 and D. F1,F2,G and H. Twins - Multiple segment occurrences that share the same parent occurrence. Example : E1 and E2, C1 and...

The crux of the concept is, on the mainframe data is transferred to/fro between the system and I/O devices in blocks. Assume you had to buy 100 apples from the market place. If you buy just one apple every time, you'd have to make 100 trips. Transportation cost would be too high. Instead, if you bou...

I read his oral interview. Piscopo - the guy when he set out to start a new company, they had a meeting - his uncle knew several wealthy friends and potential investors. He put several ideas on the table. By the end of the meeting, twenty five investors left checks on the table totaling $150,000. Th...