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

Schedulers on Mainframes


IBM Mainframe Forums -> JCL & VSAM
Post new topic   Reply to topic
View previous topic :: View next topic  
Author Message
Manu SK

New User


Joined: 20 Mar 2020
Posts: 3
Location: India

PostPosted: Fri Mar 20, 2020 10:55 pm
Reply with quote

Hi All,

We have a number of workload automation solutions available, on Mainframe platform, from various vendors. I would like to understand how these products/solutions get notified about various events like start of job, end of job, start/end of a job step, new dataset cataloged etc.

Thanks
Back to top
View user's profile Send private message
enrico-sorichetti

Superior Member


Joined: 14 Mar 2007
Posts: 10888
Location: italy

PostPosted: Sat Mar 21, 2020 12:10 am
Reply with quote

quoting the IBM manual

Quote:
IBM Tivoli Workload Scheduler for z/OS tracks the progress of jobs and started
tasks through the z/OS system by using JES and SMF exit points. Add all these
exits on each z/OS system where you will start IBM Tivoli Workload Scheduler for z/OS


the other products behave in the same way
Back to top
View user's profile Send private message
Apoorva

New User


Joined: 28 Jan 2020
Posts: 49
Location: India

PostPosted: Sat Mar 21, 2020 8:37 am
Reply with quote

Manu SK wrote:
Hi All,

We have a number of workload automation solutions available, on Mainframe platform, from various vendors. I would like to understand how these products/solutions get notified about various events like start of job, end of job, start/end of a job step, new dataset cataloged etc.

Thanks


Yes as @enrico-sorichetti told us, vendors normally use exits (mainly SMF's IEFU83/IEFU84) to get notified about various events occurring in the system. They might also use ENF exits (Event notification facility), JES exits, Sub-system interfaces (SSI interfaces) depending on events they want to be notified to.
Though exits are widely used, sometimes they might modify IBM modules/control blocks as well in order to intercept certain events for which IBM hasn't provided an exit. For example if a Scheduler has to trigger a job when a new record with particular key gets inserted into a DB2 table (This is just an example, and I am taking DB2 example here because many people are familiar with DB2) then vendors may have to modify DB2 modules/programs in order to accomplish this as DB2 doesn't provide an exit for this. Moreover it's impossible to provide an exit for each and every event occurring in the system. Modifying IBM modules to intercept certain functions is normally called hooking/front-ending/ZAPing. Though this is not the preferred approach, vendors still do it if they don't find any exits.

Another example from CICS perspective is if a batch job needs to be triggered if a transaction, fired by a particular user ends with a particular RC. CICS may not have an exit (as far as I know) for this.

So, in general schedulers use exits if one available otherwise they try to hook IBM code (least preferred approach).
Back to top
View user's profile Send private message
vasanthz

Global Moderator


Joined: 28 Aug 2007
Posts: 1744
Location: Tirupur, India

PostPosted: Sat Mar 21, 2020 11:30 am
Reply with quote

Very informative, Thanks
Back to top
View user's profile Send private message
Joerg.Findeisen

Senior Member


Joined: 15 Aug 2015
Posts: 1337
Location: Bamberg, Germany

PostPosted: Sat Mar 21, 2020 11:58 am
Reply with quote

Here you can find some information about possible involved SMF Exits from Cheryl Watson http://enterprisesystemsmedia.com/article/smf-exits-and-the-life-of-a-job#&ts=undefined
Back to top
View user's profile Send private message
Manu SK

New User


Joined: 20 Mar 2020
Posts: 3
Location: India

PostPosted: Sat Mar 21, 2020 1:19 pm
Reply with quote

Joerg.Findeisen wrote:
Here you can find some information about possible involved SMF Exits from Cheryl Watson http://enterprisesystemsmedia.com/article/smf-exits-and-the-life-of-a-job#&ts=undefined


Thanks everyone for all the information! Really appreciate your time and effort on this. One additional question if you don't mind please. When you say "Vendors may change IBM/DB2/CICS modules if they don't find any exits" does that mean non-IBM Mainframe Software vendors will have access to IBM/DB2/CICS source code?
Back to top
View user's profile Send private message
Apoorva

New User


Joined: 28 Jan 2020
Posts: 49
Location: India

PostPosted: Sat Mar 21, 2020 1:40 pm
Reply with quote

Manu SK wrote:
Joerg.Findeisen wrote:
Here you can find some information about possible involved SMF Exits from Cheryl Watson http://enterprisesystemsmedia.com/article/smf-exits-and-the-life-of-a-job#&ts=undefined


Thanks everyone for all the information! Really appreciate your time and effort on this. One additional question if you don't mind please. When you say "Vendors may change IBM/DB2/CICS modules if they don't find any exits" does that mean non-IBM Mainframe Software vendors will have access to IBM/DB2/CICS source code?


I just know that non-IBM software vendors buy special logic manuals from IBM (that's not available on public domain) under non-disclosure agreement. These logic manuals may include module/program flow of specific functions that vendors are interested in but I don't think so they will also include source code. Nevertheless non-IBM vendors do lot of reverse engineering of DB2/IMS/JES/CICS/SMS etc modules/programs to accomplish what they want to do. The tools that they normally use for such reverse engineering are SLIPs, GTF traces (Generalized trace facilities), PER SLIPs (PER ==> Program event recording) etc. Please Google if you want more info on this.
Back to top
View user's profile Send private message
Manu SK

New User


Joined: 20 Mar 2020
Posts: 3
Location: India

PostPosted: Sun Mar 22, 2020 8:13 am
Reply with quote

Apoorva wrote:
Manu SK wrote:
Joerg.Findeisen wrote:
Here you can find some information about possible involved SMF Exits from Cheryl Watson http://enterprisesystemsmedia.com/article/smf-exits-and-the-life-of-a-job#&ts=undefined


Thanks everyone for all the information! Really appreciate your time and effort on this. One additional question if you don't mind please. When you say "Vendors may change IBM/DB2/CICS modules if they don't find any exits" does that mean non-IBM Mainframe Software vendors will have access to IBM/DB2/CICS source code?


I just know that non-IBM software vendors buy special logic manuals from IBM (that's not available on public domain) under non-disclosure agreement. These logic manuals may include module/program flow of specific functions that vendors are interested in but I don't think so they will also include source code. Nevertheless non-IBM vendors do lot of reverse engineering of DB2/IMS/JES/CICS/SMS etc modules/programs to accomplish what they want to do. The tools that they normally use for such reverse engineering are SLIPs, GTF traces (Generalized trace facilities), PER SLIPs (PER ==> Program event recording) etc. Please Google if you want more info on this.


Thanks for the explanation.
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 -> JCL & VSAM

 


Similar Topics
Topic Forum Replies
No new posts NAK is getting added FTP from Mainframes JCL & VSAM 6
No new posts SH256/MD5 Checksum in Mainframes JCL JCL & VSAM 14
No new posts After hours quick-fix support for IBM... Mainframe Jobs 0
No new posts Mainframes Job opportunity-Full time Mainframe Jobs 0
No new posts IBM z15 mainframes All Other Mainframe Topics 1
Search our Forums:

Back to Top