Saturday, March 30, 2013

Performance tuning points for Mainframe applications

May be as they worry the Moores law have saturated, May be the chips used to get smarter at a better rate. 

The more fancy and much demanded work at many instances these days as I see is to scale up the business critical software applications. The resource rich legacy Mainframe applications which rarely worry about the performance also appears to be shifting focus towards this front.

Below is the list of usual tactics to attack the mainframe performance problems - Am going to try and keep this unsorted by any order list updated as when there is a new entrant I learn about.

JCL Techniques

1) The buf no which is signifies the buffers used to read is installation specific and is usually defined one or two - Override this to of more value like 20 to 50. 
[DCB=BUFNO=50 ] - Should be done with carefull because over allocating buffers is as bad as not allocating. 
2) If feasible migrate away from tape - this doesnt improve considerably at many instances due to the advancements in the tapes storage managements - but I think it is worth verifying this dimension.
3) Shift the region size and time parameters from step level to the job level if possible.
4) Try allocating sortwork files when dealing with sort.
5) Reasonable amount of secondary space to the data sets.
6) Scratch with IDCAMS rather than IEFBR14.
7) Replace IEBGENERS with DFsort/Syncsort to copy. IEBGENER is simply old timer and these sort utilities are optimized to the max level possible. 

Cobol Techniques

1) Verify for too many open and close of the files. Open once and close as minimal as possible. 
2) Initialize copybooks - This is a killer- Its safe not to initialize entire copybooks because it creates too many assembly statements. Try moving than initializing. 
3) Compiler options - SSRANGE consumes lot - If possible override and use NOSSRANGE
4) Whenever possible try to exploit the utilities like DFsort/Easytrieve/SAS available for sorting/joining/Reformatting/reporting instead of homegrown cobol elements. They are tested and proven for performance. 
5) Cobol Sorts ? Inefficient sorting method.
6) Binary search - Search all is preferred over search. 
7) Make it like block contains 0 records on FD
8) Using NoDYNAM
9) Using Indexes over subscripts 
10) Occurs depending is another thing that can be eliminated to miprove a bit 

DB2 Techniques 

1)  Table scan usage prohibits the usage of the indexes, and also not using all the cols indexed in case of composite index would also not make use of the index - So Dummy or force use all the cols that are indexed. Make the query use index. 
2)  Many a times the SQL query in a element as such wouldn't consume more resources but the too many execution of that query would be a killer for performance and would create hot spots  Try caching the results in a cobol table. 
3) Avoid session tables - Instead go for the declared temporary tables. 
4) Try and Reduce the level of queries 
5)  If possible try to take away the exist clause in the query into a separate query. 
6) Multi row fetch 
7) Use of optimize for n rows or fetch first 
8) Of course - Introduce indexes on frequently used cols. 

Indeed Last but not the least - Its good to verify the job scheduling timings and strategies such that when the job gets active it gets all it want and doesn't wait for something midway of their execution. 

Of course not this list neither any list on this topic could be finite to list all of the options and there is always one more interesting way. 

Tuesday, February 05, 2013

Why Weekdays are named so ?

I kind of instructed myself not to write something online which wouldn't be useful to read for someone else, To satisfy that - I made it a point that I should write only the solutions to interesting problems. 

But I am choosing to bend the rule which I set to myself, which is just sticking to interesting and so a post need not be necessarily a solution to a problem but an identification or a collection or perspectives or their combinations at times - should be fine too. This is primarily because I probably not finding enough or searching enough interesting problems, and urge to say something I see interesting to other is very tempting. 

This is one such, definitely not useful,definitely not a solution but because I thought - hey this is interesting I should probably tell it to others.

Getting to the point at last - whats behind the names of weekdays ? In other words Etymology of weekdays 
Sunday - Pretty easy it is suns day. an awesome day definitely.What it reminds is church and holiness
Monday - Moon's day - Interesting. Probably those days every one liked what they did on monday unlike the current scenario - so they appear to have the day named after something cool like moon. 
Tuesday - Pro- Germanic god - Tîwaz who Considered to be god of war , law, Justice or in many other languages - Mars the god of war.Ares is another name. The man day. 
 Wednesday - Basically named after planet, Mercury - Ask me what is the relation here ? Woden or Odin is none but a gods name who is represented as Mercury.
Thursday - Purely Thor's day. That god with the hammer, Its after him. Where is the planet you ask - Am not very sure - some say he is the owner or resident or both of Jupiter
Friday - very aptly named day - the meaning is intact and is very visible - The awesome day - The frigg - the Venus - The goddess of love & beauty- She they say spins cloud. The Girl day.
Saturday - The Saturn's day, the planet with the ring. Saturn is considered to be god for agriculture, wealth and liberation. 
This kind of convention or pattern of naming days after a god who is represented as a planet seems to be in practice very wide i.e - Almost in every language.So if you kind of know all the famous planets name in a language - you have a better chance of deriving weekdays in that same language or intrestingly vice versa.

Interesting you say ? I say - I know I know 

Hmm, Boring you say? I wasted your time ? Sorry not intended! 

See you or myself or both in the next post. ;-)

Update 12/11:
Tangentially to this line of thought - weekdays have not always been 7 days long, and I read something very interesting on Quora about calendars - would like to link to it for further reading Click here  

Saturday, November 10, 2012

How to Wake up Early ?

Waking up early is one of a thing at which I have failed at many occurences. 

So, I got online Googled, binged spent time reading about it, researching it, devising strategies, experimenting it..alas equally spent time failing at it again too..

Intresting Things I have tried - the things which they claim as tricks and never worked are 

  1. Use multiple alarms - Definetly doesnt work. sometimes none of it ring.. Sad thing is who could you blame for it, If you didnt hear them ringing? I tried the max of 7 alarms.It Just doesnt work.
  2. Drink a tank - You wouldnt even sleep before before you are back in square one.
  3. Make the sleep comfortable - Like it wasnt and I am tying hard for it :P.Once Followed this and made the Room more airy like they said by opening up all windows for more fresh oxygen and next day I woke up full of cold and fever. 
  4. Sleep early - Bwhaha, This just gives you more personal time with your device or network like laptop/mobile phone/twitter/Facebook/Reader
  5. Get a pet ? - Seriously? Not a wise move IMHO. 
  6. Do not go to bed if you arent sleepy - and it becomes morning and sun pops up and smiles. 
  7. Advertise you are going to wake up early - People laugh and after little more occurences they just ignore.BTW am even feeling foolish to have tried this. 
  8. Use wake up call service - I want to wake up early, not to be woken up early by a third party. 
  9. Avoid Caffenie - Just not works.The point is with loads of Caffeine I was able to wake up at times with *spoiler alert*
  10. Use a Random alarm tone - you think it is some one else's alarm. you are just wise to derive reasons. 
  11. Use your favourite music as alarm tone - another funny trick. Wakes you up. you dont hit snooze and it times out. you wake up after some very long time and smile :)
  12. Hide your alarm clock - So that you would search for it, like hitting the snooze or dismiss the alarm is the first thing I need, there are times I had it close to my head and didnt even hear it ringing. I didnt even try this and it is just not my cup of idea. 
  13. Gradually sleep early and you will wake up early - Gradually ? Let me not waste time explainig why it doesnt work. Just know it doesnt work either. 
  14. Get someone wake you up - Again, defeats the purpose.I - I repeat _I_ want to wake up early and not to be woken up. But you know what ? This works and Moms are good at this.

Failing all these tricks doesnt mean I have never woke up early, I just couldnt wake up for the sake of waking up. and touch wood - I havent missed anything so important sleeping over it. 

Trying all this, There are some things which I find working 

  1. Do not sleep. awesomely perfect and simple. Just makes you lil tierd the next day. But it will be all ok. 
  2. Just do not rely on any method/trick/device/people, Belive - If you want to wake up you will wake up. Philosphical but truth. 
  3. Smell of breakfast - It just works :)

Though I feel exhausted of attempts, I would try if there is any intresting strategy which works or atleast would like to know if any tricks works for you.. Let me know.Drop a note. 

and Stay good.Sleep good. 

</rant off>

Saturday, October 27, 2012

How to Renew your Employment card(Tamilnadu Governments) online

Yes, Many of us have registered at employment offices.Few because of that bleak hope and didn't just want to take a chance and miss out the big opportunity just because you missed to register and others due to the enforcement from wise and few others due to the demand of well wishers.

Ok, To get to the point quick. I was registered and have the employment card too, and I wanted to renew it but couldnt because I was missing an information and I figured it luckily and the purpose of this post is to make it clear so that it could probably help.

Good news is - employment card can be renewed online.To renew it online you just got to go to and login and follow the angels and click renew and you are done.

The interesting part is you do not have the login details and the log in instructions at the portal are not very clear like they always were. Foolish me spent some worthy time hit at his place.

Login ID to this portal as mentioned - is exchange code suffixed with the registration number.Easy part is you have the exchange code from here
so lets say your exchange code is CHP and the registration ID as printed in your employement slip/card is 2009M13322 your user ID is not CHP2009M13322 as I thought and wasted my time but CHP2009M00013322. Just make sure you add up zeroes after M or F in your registration number so that the string length of the userid you cook up is 17  and the login the password is clearly DOB like DD/MM/YYY, sadly no easter eggs for password.

I think I can bet that I know how to write a bad post.and yeah, bye and have a good day!

Thursday, December 09, 2010

How to get E-Mails delivered to your Mobile as text message/SMS ?

SMS has always been my fav concept.
I love to get the latest happening say news/weather/technology updates/ friends status updates in my mobile phone.So when i came to know about this Google SMS channel, i said Wow at Google one more time & I loved it.

Some time back I was just in need of service from Yahoo mail/GMail which could send me my mails, at least basic details of my mail like from who and what is the subject of my new mail to my mobile as SMS. I hoped they would be having one, But pity me after some serious Goggling all i found is just few other mortals wishing like me in vain. So If you are one, read further I got a solution.

Here is my approach,
  1. Get your mails converted into RSS feeds, There are few apps out there.My fav one for this is Feed flip (because this is secure and very easy configuration & also as it runs on Google appspot more reliable).All you need to do is login to your mailbox and follow the angels :P
  2. Get yourself registered in the Google SMS channel using your mobile number & Create an Invite only SMS Channel in Google SMS channel
  3. Make the source to this SMS channel as the feed from Feed flip.
  4. Read your mails as SMS in your mobile.

Should you receive mail as SMS from more than one Mailbox ?? you don't have to create SMS channels for each Mailbox. you can club them(RSS feeds) into one using any feed aggregation tool (my choice is Yahoo pipes )

You like this ?? Trick is not working ?? Got an Idea to do more ?? Do drop me a note.

I am not affiliated with yahoo/Google/ Feed flip. This is just a hack, by trying this you are agreeing to use it at your own risk.

Monday, April 09, 2007

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