IBM Mainframe Forum Index
 
Log In
 
IBM Mainframe Forum Index Mainframe: Search IBM Mainframe Forum: FAQ Register
 

Error in a large file


IBM Mainframe Forums -> Mainframe Interview Questions
Post new topic   Reply to topic
View previous topic :: View next topic  
Author Message
suraaj

New User


Joined: 16 Apr 2009
Posts: 69
Location: Canada

PostPosted: Fri Nov 13, 2015 8:23 pm
Reply with quote

How do you find an error in a large file without using a debugger tool? This is an interview question that was posed to me.
Back to top
View user's profile Send private message
Akatsukami

Global Moderator


Joined: 03 Oct 2009
Posts: 1788
Location: Bloomington, IL

PostPosted: Fri Nov 13, 2015 8:49 pm
Reply with quote

What is meant here by "error"?
Back to top
View user's profile Send private message
suraaj

New User


Joined: 16 Apr 2009
Posts: 69
Location: Canada

PostPosted: Fri Nov 13, 2015 8:52 pm
Reply with quote

Bad data.
Back to top
View user's profile Send private message
Akatsukami

Global Moderator


Joined: 03 Oct 2009
Posts: 1788
Location: Bloomington, IL

PostPosted: Fri Nov 13, 2015 9:08 pm
Reply with quote

OK, if the data cause the program to abend, it can be found in the dump. Otherwise, you will have to deduce from the erroneous output what the bad data are, and search the data set with some utility. The program should then edits and/or sanity checks added to it so that this situation does not recur.
Back to top
View user's profile Send private message
RahulG31

Active User


Joined: 20 Dec 2014
Posts: 446
Location: USA

PostPosted: Fri Nov 13, 2015 9:31 pm
Reply with quote

I think this is a vague question.

1. What is a large file? 10000 records or over a million records ?

2. How do you find the error in 'a large file' using debugger ? Do you already know the record in question ?

a. If you don't know the record then do you really plan to go through each record one by one until you find error in 'a large file'?

b. And if you already know the error then why don't you use File mapping utilities like File Aid/ File Manager and see the field having bad data.

3. You can also use displays (depends on how large is the file and If you know the field to display)

.
Back to top
View user's profile Send private message
RahulG31

Active User


Joined: 20 Dec 2014
Posts: 446
Location: USA

PostPosted: Fri Nov 13, 2015 9:34 pm
Reply with quote

And Why put it in a JCL & VSAM section of the forum ?
Back to top
View user's profile Send private message
Rohit Umarjikar

Global Moderator


Joined: 21 Sep 2010
Posts: 3051
Location: NYC,USA

PostPosted: Fri Nov 13, 2015 9:39 pm
Reply with quote

Have you looked at ICETOOL VERIFY?
Back to top
View user's profile Send private message
suraaj

New User


Joined: 16 Apr 2009
Posts: 69
Location: Canada

PostPosted: Fri Nov 13, 2015 9:58 pm
Reply with quote

Thanks Rohit. This will help me identify decimal values.

Do you know of any other ways which will tell me of bad data?
Back to top
View user's profile Send private message
Bill Woodger

Moderator Emeritus


Joined: 09 Mar 2011
Posts: 7309
Location: Inside the Matrix

PostPosted: Fri Nov 13, 2015 10:01 pm
Reply with quote

"Bad data" can mean anything. Data which must appear on a keyed file/db table can look quite normal, but be "bad" because it does not match.

To find bad data, you have to know what you're looking for.
Back to top
View user's profile Send private message
suraaj

New User


Joined: 16 Apr 2009
Posts: 69
Location: Canada

PostPosted: Fri Nov 13, 2015 10:06 pm
Reply with quote

You are exactly right Bill. That was the sole reason of me asking for different methods.
Back to top
View user's profile Send private message
Rohit Umarjikar

Global Moderator


Joined: 21 Sep 2010
Posts: 3051
Location: NYC,USA

PostPosted: Fri Nov 13, 2015 11:12 pm
Reply with quote

Quote:
Do you know of any other ways which will tell me of bad data?


Suraaj, If any interviewer asks you such questions next time what you should answer is,
a. What do you mean by bad data?
b. Bad data is for numerics, so I told you the way.
c. No one wants to spend time looking just for a bad data in a file unless some jobs abends hence you should ask them about specifics about the abend and the dump.
d.So S0C7 is abend you should see for bad data.

So if you tell this to them then I don't think they will have anymore questions for you on this. They sometimes wants to run some fool tests and we shouldn't get trapped by looking at "Other Methods" which doesn't exist.
Quote:
That was the sole reason of me asking for different methods.

There is no other method than adding display's or look for an offset and investigate.
Back to top
View user's profile Send private message
Robert Sample

Global Moderator


Joined: 06 Jun 2008
Posts: 8696
Location: Dubuque, Iowa, USA

PostPosted: Fri Nov 13, 2015 11:59 pm
Reply with quote

Quote:
Do you know of any other ways which will tell me of bad data?
I think your basic problem is that "bad data" is ALWAYS context-related. Packed decimal data can cause S0C7 abends but may or may not cause abends.
Back to top
View user's profile Send private message
suraaj

New User


Joined: 16 Apr 2009
Posts: 69
Location: Canada

PostPosted: Sat Nov 14, 2015 12:43 am
Reply with quote

Thanks Rohit and all others for all your help.
Back to top
View user's profile Send private message
Pandora-Box

Global Moderator


Joined: 07 Sep 2006
Posts: 1592
Location: Andromeda Galaxy

PostPosted: Sat Nov 14, 2015 12:50 am
Reply with quote

CEEMSG output helps as well in identifying the record in case of S0C7
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic View Bookmarks
All times are GMT + 6 Hours
Forum Index -> Mainframe Interview Questions

 


Similar Topics
Topic Forum Replies
No new posts FTP VB File from Mainframe retaining ... JCL & VSAM 1
No new posts Extract the file name from another fi... DFSORT/ICETOOL 6
No new posts How to split large record length file... DFSORT/ICETOOL 10
No new posts Error to read log with rexx CLIST & REXX 11
No new posts Extracting Variable decimal numbers f... DFSORT/ICETOOL 17
Search our Forums:

Back to Top