What is Mainframe?
Mainframes are one among the most legacy systems started almost in the 1940s. The major vendors of mainframe systems are IBM, Amdahl, and Hitachi. A couple of mainframe technologies are considered to be obsolete.
Mainframe computers act as a key entity across fortune 1000 companies. Even another format of technologies plays decent role mainframe systems hold a stable position for themselves in the current e-business environment. Mainframes spread its arms in the following fields,
- Banking
- Finance
- Health care
- Insurance
- Public Activities
When it comes to handling large volume mainframes are very much preferable than supercomputers. Usually floating point operation such as subtraction, addition and multiplication can be excelled using supercomputers setup. In the consideration of stability, security and compatibility mainframe computers definitely play a great role. Even now the latest version can handle extremely high customer loads and also run applications that are formulated and built a decade ago.
Understanding Mainframe
The major components of mainframe environments are below,
- JCL
- COBOL
1. JCL:
Job Control language is the expansion for JCL, Processing data in batches is the key principle behind JCL. JCL is an authoritative and stretchy language that facilitate in operating and customizing remote resources for the computers.
| Batch processing | Interactive processing |
| Jobs submitted are executed at a later time | Jobs submitted are executed immediately |
| Non-interaction between the available users | Flexible interaction between the associated users |
| Debugging is archived through snapshot | Debugging in a much more interactive manner |
Stages of JCL execution,
- Input – Job number is exclusively been tagged for each job
- Conversion – Job listed in JES spool, preparing it for execution
- Initiator – Job will be triggered for execution from the spool
- Execution – Actual running of the job
- Output – All associated devices receive the output
- Purge – Purging the job is the last step which takes place after the completion in the execution of the job
Ex:-
//LMSBCE5D JOB 'Q868144,TSSS,D','USER Q868144',
//CLASS=K,MSGCLASS=X,MSGLEVEL=(1,1),REGION=0M, REGION=900M
//NOTIFY=Q868144 TYPRUN=SCAN
//********************************************************************
//S010 EXEC PGM=DFSRRC00,
//PARM=(DLI,LMSBCE5D,GDMINQU,8,0000,,0,,N,0,T,,,Y,Y,IRLT,N,),
//REGION=8M
//STEPLIB DD DSN=IMS.TEST.SDFSRESL,DISP=SHR
//DD DSN=IMS.TEST.DYNALLO,DISP=SHR
//DD DSN=KADSCM.STGE.#010308.LDB,DISP=SHR
//DFSRESLB DD DSN=IMS.TEST.SDFSRESL,DISP=SHR
//DFSVSAMP DD DSN=KADSCM.PROD.UTILLIB(DFSVKRMS),DISP=SHR
//IMS DD DSN=IMS.TEST.PSBLIB,DISP=SHR
/DD DSN=IMS.TEST.DBDLIB,DISP=SHR
//PARMFILE DD *
20171120 20171125 U
/*
//OUTFILE DD DSN=TESTKRMS.KRMS.LMSBCE5D.DT120617,
//UNIT=SYSDA,SPACE=(CYL,(1,1),RLSE),
//DISP=(NEW,CATLG,DELETE),
//LRECL=180,RECFM=FB,BLKSIZE=0
//IEFRDER DD DUMMY
//ERRFILE DD SYSOUT=*
//REPORT DD SYSOUT=*
//DUMPER DD SYSOUT=*
//SYSLST DD SYSOUT=*
//SYSOUT DD SYSOUT=*
//SYSPRINT DD SYSOUT=*
//SYSABEND DD SYSOUT=*
//SYSDUMP DD SYSOUT=*
//SYSUDUMP DD SYSOUT=*
//SYSDBOUT DD SYSOUT=*
//SYSABOUT DD SYSOUT=*
//SYSDTERM DD SYSOUT=*
//*****************************************************************
//* OSAM BUFFER CONTROL
//DFSCTL DD DSN=KADSCM.PROD.UTILLIB(KRMSBUFF),DISP=SHR
//DFSSTAT DD SYSOUT=*
2. COBOL:
In the 1950s, Utilized majorly for data processing in business sectors as a high-level language.US Department of Defence assemble a discussion in 1958 May and the new language was designed by three major groups. Cobol was the name associated to it which expands as (COmmon Business Oriented Language) in 1959 Sep. May 1961 was the date when COBOL was officially announced. When it comes to the compiler perspective it was designed initially in 1962 users started Cobol programs. At 1965 the superior version released. The standard version of a language, approved by ANSI (American National Standards Institute) was introduced in Aug 1968. Next revised official standard was introduced in 1974 and is known as ANSI-74 Cobol or Cobol-74.
Structure of Cobol:
- Program
- Division
- Section
- Paragraph
- Sentences
- Statements
- Words
- Characters
Character Set,
- 0 – 9: 10 numerals
- A to Z: 26 English alphabets
- or b Space or blank
- – + * / = : Minus or hyphen, plus, asterisk, slash, equal
- $ or £: Currency sign
- ,;. “ ( ) < > ‘: Other special characters
Properties of Cobol,
- The key characters in a Cobol word are as below,
- 0 – 9: 10 numerals
- AZ:26 English alphabets
- -: Hyphen
- Alphabet must be placed in at least one of the characters; on some compilers, the first letter has to be an alphabet.
- Cannot contain any special character the only allowed special character is a hyphen.
- Cannot contain a blank.
Coding Format by position-
- 1 to 6: Sequence
- 7: Indicator
- 8 to 11: Area A/margin A
- 12 to 72: Area B / margin B
- 73 to 80: Identification
What Mainframe can Do?
- Software Application Development
- E-Business and E-commerce
- Healthcare application development
- Analystics using Mainframe SAS
Advantages
- High availability of the systems
- Extreme reliability of the systems
- Systems of extreme high availability to handle large volumes of data
- English-like constructs.
- Self-documenting systems.
Required Skills
- Virtualization
- Troubleshooting
- Programming capability
- Storage Management Part
- Escalation management
An audience for Mainframe
- Audience with interest to learn
- Individual who aspire to Mainframe Administrator and Architect, developer, Analyst, Tester also relative professional roles.
- Helps to move forward the professional aspects and technical skillset of professionals who are intended to do the same.
- Candidates with mainframe application development
Career growth
- Mainframe Application developer
- Mainframe system administrator
- Mainframe Storage Administrator
- Mainframe Application Architect
- Mainframe Support Engineer
Conclusion
Definitely, this is one among the most versatile and stable systems over a decade. We could confidently put a statement mainframe will hold its position for any period of time. Security over the substances which mainframe handles is also a key reason for the position which mainframe holds. Availing a solution for almost all requirements in the market, a mainframe is hardly non-replaceable.
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