How to access a VSAM?



IBM's Command List programming language & Restructured Extended Executor

Re: How to access a VSAM?

Postby Jikesh Patel » Mon Dec 14, 2009 1:00 pm

Thanks dick,

The fileaid did it may be because of the second second reason you gave.

But the fileaid is also working the same way as DFDss and IDCAMS working? Is it safe to use fileaid because it took almost 70 I/O count (I used fileaid online copy option).
Jikesh Patel
 
Posts: 23
Joined: Mon Apr 06, 2009 12:41 pm
Has thanked: 0 time
Been thanked: 0 time

Re: Re: How to access a VSAM?

 

Re: How to access a VSAM?

Postby dick scherrer » Tue Dec 15, 2009 12:20 am

Hello,

Internally all 3 work differently. . . This is not an issue as they all work as their vendor intend.

Is it safe to use fileaid because it took almost 70 I/O count (I used fileaid online copy option).
I don't understand the question? How is safety involved? Why is "almost 70 i/o" a concern?

In general, online copies should be avoided - regardless of the copy tool. A copy is most often best done in batch.
Hope this helps,
d.sch.
User avatar
dick scherrer
Global moderator
 
Posts: 6304
Joined: Sat Jun 09, 2007 8:58 am
Has thanked: 3 times
Been thanked: 91 times

Re: How to access a VSAM?

Postby Jikesh Patel » Tue Dec 15, 2009 11:09 am

Thanks dick,

I meant 70 I/O CPU count. Actually MIPS is measured based on I/O CPU count. So i meant that fileaid took much more MIPS as compare to DFDss(I copied the sized file using dfdss and it took only 1 I/O CPU count).
Jikesh Patel
 
Posts: 23
Joined: Mon Apr 06, 2009 12:41 pm
Has thanked: 0 time
Been thanked: 0 time

Re: How to access a VSAM?

Postby dick scherrer » Wed Dec 16, 2009 12:34 am

Hello,

Actually MIPS is measured based on I/O CPU count
This contains multiple misunderstandings. . .

MIPS is a rating - it is not a measurement. I/O and CPU are completely different resources and are measured completely differently. The one thing they have in common is that when the number goes up, more has been used.

FileAid will take more i/o than dfdss. This is normal.
Hope this helps,
d.sch.
User avatar
dick scherrer
Global moderator
 
Posts: 6304
Joined: Sat Jun 09, 2007 8:58 am
Has thanked: 3 times
Been thanked: 91 times

Re: How to access a VSAM?

Postby Jikesh Patel » Mon Dec 21, 2009 4:44 pm

Thanks Dick,

If I understood correctly then the MIPS can be high even if I/O count is less and MIPS can be low even if I/O counts are very high.
And If I understood correctly then the measurment for MIPS is different for different applications like online, batch and the usage of mainframe machines. :?
Jikesh Patel
 
Posts: 23
Joined: Mon Apr 06, 2009 12:41 pm
Has thanked: 0 time
Been thanked: 0 time

Re: How to access a VSAM?

Postby expat » Mon Dec 21, 2009 4:54 pm

No, MIPS is the capacity rating of the mainframe.
i.e. the mainframe has the capacity to process instructions at x MIPS
expat
 
Posts: 382
Joined: Sat Jun 09, 2007 3:21 pm
Has thanked: 0 time
Been thanked: 1 time

Re: How to access a VSAM?

Postby dick scherrer » Tue Dec 22, 2009 1:19 am

Hello,

CPU usage may be high(er) or low(er), but MIPS is a constant. . .
Hope this helps,
d.sch.
User avatar
dick scherrer
Global moderator
 
Posts: 6304
Joined: Sat Jun 09, 2007 8:58 am
Has thanked: 3 times
Been thanked: 91 times

Re: How to access a VSAM?

Postby Jikesh Patel » Thu Dec 24, 2009 6:18 pm

Thanks Expat and DIck,

If I understood correctly then MIPS is measured based on the capacity of mainframe machine to process no of instructions per second and it is then fixed for all the tasks performed on that machine. And it is used to calculate rating for a particular task performed on that mainframe machine.

dick scherrer wrote:CPU usage may be high(er) or low(er), but MIPS is a constant. . .

Dick do you mean the mainframe machine CPU?

Thanks a lot for all your kind help. :)
Jikesh Patel
 
Posts: 23
Joined: Mon Apr 06, 2009 12:41 pm
Has thanked: 0 time
Been thanked: 0 time

Re: How to access a VSAM?

Postby Robert Sample » Thu Dec 24, 2009 11:59 pm

If I understood correctly then MIPS is measured based on the capacity of mainframe machine to process no of instructions per second and it is then fixed for all the tasks performed on that machine
You misunderstand. IBM used to give out MIPS ratings on their machines when they were announced to be available, but stopped doing so because MIPS was a misleading number -- with instruction caches, multiple processors per machine, and so forth a MIPS number could be measured many different ways, giving many different values, and all could be considered "correct" for some value of "correct". They now announce MSU (million service units) for each machine. This value is not calculated nor measured -- it is provided by the vendor as a way to measure relative throughput of two machines.

If you are measuring a number, it is not MIPS as that term is generally used in the industry.
Robert Sample
Global moderator
 
Posts: 3367
Joined: Sat Dec 19, 2009 8:32 pm
Location: Dubuque, Iowa, USA
Has thanked: 1 time
Been thanked: 222 times

Re: How to access a VSAM?

Postby Jikesh Patel » Mon Dec 28, 2009 3:07 pm

Thanks Robert,

Thats a very useful information you shared. :o

So you mean the MSU is a term used by vendor and MIPS is the term still used by users of vendor mainframe machine but users are charged based on MSU only.
Can you please suggest me that which factors I should consider while coding to reduce the use of MSU.
And why industries are still measuring MIPS to save money instead of considering MSU?
Jikesh Patel
 
Posts: 23
Joined: Mon Apr 06, 2009 12:41 pm
Has thanked: 0 time
Been thanked: 0 time

PreviousNext

Return to CLIST & REXX

 


  • Related topics
    Replies
    Views
    Last post