I am learning mainframe. I have done all the training modules from an institute. However I managed to Learn COBOL, JCL, VSAM and DB2 on my own(inst. was not good). Now My problem is I can not co relate All these modules in Mainframe real-environment. Can anyone help?
My prob. is
1. If we talk about Banking project : what COBOL does?, all programs are written so what programmers actually do with COBOL? If we access VSAM or DB2 by COBOL, how in real-time?
3. Do we schedule a job with JCL or tools like CA-7, Endevor, how to check the success or failure of job and where(region, screen etc)?
3. VSAM is an access method and what is DB2, If i create table in DB2 where does it stores and where data resides?
Is there any chance that it will be stored in VSAM env. under KSDS or any other format as I learned Keys and Indexes in both (sorry if question is vague)?
If any one can explain this with a good example of basic workflow, it will be a great help. I am aware of Technical Terms, just need some direction regarding real-world scenarios?
There is lot more to fire but These are the basic ones.
If it is available on-line please tell me.
Thanks, hope someone will reply, I admire Mainframe Tech., and need some help to start my career.
Joined: 06 Jun 2008 Posts: 8154 Location: East Dubuque, Illinois, USA
1. COBOL implements the business logic as coded by the programmers. Once the program is coded and tested, it normally runs as part of a batch job stream or online environment with no further changes until a bug is found or there is a change in the business requirements. At that time, the programmer will change the COBOL code to implement the changes. "Real-time" is normally used to reference embedded or manufacturing systems where a change in a value requires an immediate response. Banking systems are not "real-time" but usually a combination of online and batch programs. CICS is frequently (but not exclusively) used for online coding and there are a full set of manuals for CICS, which you would need to study for a while.
2. The job scheduler generally has built in monitoring tools -- CA-7 even allows emails to be sent when jobs it monitors abend, for example. This is more a site-specific question since it depends upon the specific tools being used. CA-7 has its own set of screen accessed from a terminal that allows review of jobs, changes to queued JCL, and so forth.
3. DB2 is a data base. It is implemented through VSAM files but you do not use VSAM tools with it -- DB2, like all data bases, has its own tools to define tables, load data, access data, and so forth.