13
A Checklist for Migrating Big Iron Cobol Applications Migrating common business oriented language (Cobol) applications from HP NonStop Tandem systems to IBM z/OS mainframes requires detailed analysis of program structuring, variable declaration and keywords and a methodical conversion approach. Executive Summary CIOs facing the rising challenges of higher total cost of operations (TCO) of HP NonStop Tandem systems need to find alternatives. 1 The bulk of applications created for these HP systems use the Cobol programming language. IBM z/OS mainframes provide an alternative with stability and reliability similar to the HP NonStop Tandem systems. However, migrating Cobol applications written for HP Tandem to IBM mainframes is fraught with complexity and is often time-consuming. This white paper delves into recent versions of Cobol on both systems and provides a comprehensive listing of code differences and similarities. The aim is to provide all the relevant information CIOs and application developers need when considering migrating from HP Tandem to the IBM z/OS mainframe. The differences and similarities covered include: Program organization and format. Identification division. Environment division. Data division. Procedure division. Also included is a case study that offers insights into compilation issues found when recompiling an HP Tandem COBOL program on the IBM z/ OS mainframe COBOL Enterprise compiler. The paper concludes by assessing various conversion approaches and tools. Not covered is the use of Screen COBOL (SCOBOL) language to find differences. The SCO- BOL language on HP Tandem is similar to Cobol and is used to generate graphical user-based interfaces. In addition, we do not tackle embed- ded SQL programming. Program Organization and Format Figure 1 (on next page) illustrates the difference between the HP Tandem and IBM Cobol reference format. cognizant 20-20 insights | june 2013 Cognizant 20-20 Insights

A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

Embed Size (px)

Citation preview

Page 1: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

A Checklist for Migrating Big Iron Cobol Applications Migrating common business oriented language (Cobol) applications from HP NonStop Tandem systems to IBM z/OS mainframes requires detailed analysis of program structuring, variable declaration and keywords and a methodical conversion approach.

Executive SummaryCIOs facing the rising challenges of higher total cost of operations (TCO) of HP NonStop Tandem systems need to find alternatives.1 The bulk of applications created for these HP systems use the Cobol programming language. IBM z/OS mainframes provide an alternative with stability and reliability similar to the HP NonStop Tandem systems. However, migrating Cobol applications written for HP Tandem to IBM mainframes is fraught with complexity and is often time-consuming.

This white paper delves into recent versions of Cobol on both systems and provides a comprehensive listing of code differences and similarities. The aim is to provide all the relevant information CIOs and application developers need when considering migrating from HP Tandem to the IBM z/OS mainframe.

The differences and similarities covered include:

• Program organization and format.

• Identification division.

• Environment division.

• Data division.

• Procedure division.

Also included is a case study that offers insights into compilation issues found when recompiling an HP Tandem COBOL program on the IBM z/OS mainframe COBOL Enterprise compiler. The paper concludes by assessing various conversion approaches and tools.

Not covered is the use of Screen COBOL (SCOBOL) language to find differences. The SCO-BOL language on HP Tandem is similar to Cobol and is used to generate graphical user-based interfaces. In addition, we do not tackle embed-ded SQL programming.

Program Organization and Format Figure 1 (on next page) illustrates the difference between the HP Tandem and IBM Cobol reference format.

cognizant 20-20 insights | june 2013

• Cognizant 20-20 Insights

Page 2: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

cognizant 20-20 insights 2

Configuration Section

This optional section can be used to describe the computer environment on which the program is compiled and executed. Figure 4 (on next page) compares the paragraph of the configuration section.

Input-Output Section

Figure 5 (on page 4) compares the paragraph of the input-output section.

The function of the FILE-CONTROL paragraph is described in detail below.

The differences can be summarized as shown in Figure 2.

Identification DivisionIdentification division must be the first division in each Cobol source program. It names the pro-gram, the date of compilation and other docu-mentary information (see Figure 3, on next page).

Environment DivisionEnvironment division is optional. It contains two sections, namely CONFIGURATION and INPUT-OUTPUT.

Organization of the Two Reference Formats

Figure 1

Tandem Reference Format IBM Reference Format

Margin: C A

1 2

Area AIndicator Area

Area B

Line

3 4 5 6 7 8 9 10 … nx xn<= 132

B R 1Sequence Area

Indicator Area

2 3 4 5 6 7 8 9 1110 12 13 …Area BArea A

71 72

Column:

Summary of Differences in the Two Formats

Figure 2

HP Tandem COBOL IBM z/OS Enterprise COBOL

Number of columns where code lines are accepted is 132.

Number of columns where code lines are accepted is 72.

There is no area known as “Sequence Number Area.”

The first six columns are taken as “Sequence Number Area” which is used to label a source statement line.

The indicator area begins at column 1. It can be empty or it can contain a single character that describes the type of information on the line.? Compiler directive* Ordinary comment/ Comment for top of next pageD Debugging lined Debugging line- Continuation line

Space Text line

The indicator area begins at column 7. It can be empty or it can contain a single character that describes the type of information on the line.* Ordinary comment/ Comment for top of next pageD Debugging lined Debugging line- Continuation line

Space Text line

There is no distinction made between Area A and Area B.

Specific items must begin in Area A.• Division headers• Section headers• Paragraph headers or paragraph names• Level indicators (FD and SD) or level-numbers (01 and 77)• DECLARATIVES and END DECLARATIVES

Specific items must begin in Area B.• Entries, sentences, statements and clauses• Continuation lines

Page 3: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

cognizant 20-20 insights 3

The Paragraph uses the SELECT clause to connect an operating system file name to Cobol file name. The various files possible along with the detailed clause such as ASSIGN, ORGANIZATION, ACCESS MODE, RECORD KEY, etc. are described.

The ASSIGN clause associates the name of a file in a program with the actual external name of the data file. The #DYNAMIC used in Tandem COBOL cannot be used in Enterprise COBOL; instead an alphanumeric literal must be men-tioned. During the execution of the program, a job control language (JCL) assignment by the use of data dictionary (DD) and data source name (DSN) commands takes care of assigning the external name of the file. The PASSWORD clause is present only in Enterprise COBOL which controls access to files.

Figure 6 (on page 5) summarizes the File-Entry clause for both HP Tandem COBOL and IBM z/OS Enterprise COBOL. As seen, the requirement is the same in both versions; wherever differences are present on Enterprise COBOL, they have been marked with a dark gray background.

The SORT-MERGE file is not mentioned here as the handling for them is the same in both versions of Cobol dialect.

Data Division The Data division is the place where all variables to be used in the program are defined at various levels, namely from 01-49, 66, 77 and 88. The level has similar meaning in both the HP Tandem COBOL and IBM z/OS Enterprise COBOL.

Identification Divisions: Defined and Compared

Figure 3

PARAGRAPH HP Tandem COBOL IBM z/OS Enterprise COBOL

PROGRAM-ID The paragraph specifies the name by which the program is known and assigns selected program attributes to that program.

Present. Provides an optional clause of RECURSIVE to recursively enter a program while previous invocation is still active.

AUTHORName of the author of the program.

Present and similar in both versions.

INSTALLATIONName of the company or location.

DATE-WRITTENDate the program was written.

DATE-COMPILEDDate the program was compiled.

SECURITYLevel of confidentiality of the program.

Configuration Section Paragraphs: Defined and Compared

Figure 4

PARAGRAPH HP Tandem COBOL IBM z/OS Enterprise COBOL

SOURCE-COMPUTER The paragraph describes the computer on which the source text is to be compiled.

The syntax is similar in both the versions of Cobol.

OBJECT-COMPUTERThe paragraph specifies the system for which the object program is designated.

An additional clause of “CHARACTER-SET” is present which enables it to specify the national character set defining the ALPHABETIC data class.

The syntax is similar to HP Tandem COBOL with the absence of “CHARACTER- SET” clause.

SPECIAL-NAMESThe paragraph assigns user- defined names to certain system-name parameters.

An additional “SYSTEM-NAME” clause having values of CONSOLE, MYTERM, CHANNEL-1 through CHANNEL-2 is available.

“SYSTEM-NAME” clause is absent.More options available to aid in object-oriented program development.

Page 4: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

cognizant 20-20 insights 4

The Data division is optional. It contains four optional sections on HP Tandem COBOL.

• FILE.

• WORKING-STORAGE.

• EXTENDED-STORAGE.

• LINKAGE.

The EXTENDED-STORAGE section is specific to HP Tandem COBOL, wherein variables will exceed the 64KB boundary. This section is completely absent in IBM z/OS Enterprise COBOL which has a section named LOCAL-STORAGE which is not a replace-ment of the EXTENDED-STORAGE. Figure 7 (on page 6) describes more of the Cobol sections.

The data-types of NATIVE-2, NATIVE-4 and NATIVE-8 available on HP Tandem COBOL are not available on IBM z/OS Enterprise COBOL. These data types will be replaced by corresponding signed numeric data types on IBM z/OS Enter-prise COBOL. In addition, there are options for double byte character set (DBCS) type literals which are specific to IBM z/OS Enterprise COBOL.

Procedure Division Procedure division is the place where Cobol verbs and statements carry out the business logic determined for the program. This section details the verbs and word names only; a detailed syntax

can be found in the respective COBOL manuals (mentioned in the reference section).

Declarative Section

Declaratives provide one or more special-purpose sections that are executed when an exceptional condition occurs on a program file. Each declara-tive section starts with a USE statement that identifies the section's function. The series of procedures that follow specify the actions that are to be taken when an exception occurs. Each declarative section ends with another section-name followed by a USE statement or with the keywords END DECLARATIVES.

The USE statement has three formats in which the EXCEPTION/ERROR and DEBUGGING declara-tives are similar in both HP Tandem COBOL and IBM z/OS Enterprise COBOL. The LABEL declara-tive is present only in Enterprise COBOL.

Statements

There are many statements present in HP Tandem COBOL but not on IBM z/OS Enterprise COBOL, and vice versa. They are divided into imperative and conditional types.

• Imperative statements: This either specifies an unconditional action to be taken by the

Input-Output Section Paragraphs: Defined and Compared

Figure 5

PARAGRAPH HP Tandem COBOL IBM z/OS Enterprise COBOL

FILE-CONTROLA file-control entry connects an operating system file name to a Cobol file name, specifies the file’s organization and keys and provides additional information needed for input and output.

The Paragraph is present in both versions and is described in detail in the text on pages 2 and 3.

I-O-CONTROLThe optional I-O-CONTROL paragraph specifies positioning information for a tape file or the sharing of a memory area by more than one file.

The Paragraph is similar in both versions. The one difference is that Enterprise COBOL contains APPLY WRITE-ONLY Clause.

RECEIVE-CONTROL The Paragraph is specific to HP Tandem COBOL by which the inter-process message (IPM) communica-tion known as $RECEIVE is enabled. The reading of $RECEIVE is not mandatory for the batch category of programs whereas it’s mandatory for the online category of programs that deal with user interaction.

The Paragraph is absent as the $RECEIVE concept is not available. An alternative to the online category of programs is possible by use of customer information control system (CICS) calls and IBM’s message queue (MQ) mechanism.

Page 5: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

cognizant 20-20 insights 5

> ACCEPT> ADD> ALTER> CALL> CANCEL> CLOSE> COMPUTE> CONTINUE> COPY > DELETE> DISPLAY> DIVIDE> ENTER> EVALUATE> EXIT> GOTO> IF

The statements present only on HP Tandem COBOL are shown in Figure 8 (on page 7).

The statements present only in Enterprise COBOL:

> ENTRY > EXIT PROGRAM> GOBACK> INVOKE> XML GENERATE> XML PARSE

• Conditional statements: The conditional statement specifies that the truth value of a condition is to be determined and that the subsequent action of the object program is dependent on this truth value.

All the conditional statements present on HP Tandem COBOL are present on Enterprise COBOL. The additional ones on Enterprise COBOL are noted below.

File-Entry Clauses

Figure 6

Note: QSAM = Queue Sequenced Access Method, VSAM = Virtual Sequenced Access Method

CLAUSE SEQUEN-TIAL

QSAM/ VSAM

LINE SE-QUENTIAL

LINE SE-QUENTIAL

RELATIVE VSAM INDEXED VSAM

SELECT Required Required Required Required

ASSIGN Required Required Required Required

RESERVE Optional Optional NA Optional Optional

ORGANIZATION(Default SEQUENTIAL)

Optional Optional - LineSequential

Required - Relative

Required - Indexed

PADDINGCHARACTER

Optional NANot applicable

NA NA

RECORDDELIMITER

Optional NA NA NA

ACCESS MODE Sequential Sequential SequentialRandomDynamic

SequentialRandomDynamic

RECORD KEY NA NA NA Required

RELATIVE KEY NA NA Optional if access mode is sequential.Required for Ran-dom and Dynamic access modes.

NA

ALTERNATERECORD KEY

Optional NA NA Optional NA Optional

PASSWORD Optional NA Optional Optional

FILE STATUS Optional Optional Optional Optional

program or is a conditional statement termi-nated by its explicit scope terminator.

The following statements are available in both HP Tandem COBOL and Enterprise COBOL:

> INITIALIZE> INSPECT> MERGE> MOVE> MULTIPLY> OPEN> PERFORM> READ> RELEASE

> REPLACE

> RETURN> REWRITE> SEARCH> SET> SORT> START> STOP> STRING

> SUBTRACT> UNSTRING

> USE> WRITE

Page 6: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

cognizant 20-20 insights 6

> XML GENERATE ... ON EXCEPTION > XML GENERATE ... NOT ON EXCEPTION > XML PARSE ... ON EXCEPTION > XML PARSE ... NOT ON EXCEPTION > INVOKE ... ON EXCEPTION > INVOKE ... NOT ON EXCEPTION

Reserved Words

A reserved word is a character string with a predefined meaning in a Cobol source unit. In addition to the similar keywords, there are some keywords that are specific to HP Tandem COBOL and Enterprise COBOL which are mentioned in Figure 9 (on page 8). It needs to be checked in programs for conversion planning.

Figurative Constants

Figurative constants are reserved words that name and refer to specific constant values. The constants NULL and NULLS are available only in Enterprise COBOL and not in Tandem COBOL. All other constants are the same in both versions.

Common Phrases

The following phrases common to arithmetic and data manipulation statements are used similarly in both HP Tandem COBOL and Enterprise COBOL:

> CORRESPONDING > GIVING > ROUNDED > SIZE ERROR > FROM > INTO

Data Division Sections: Defined and Compared

Figure 7

SECTION HP Tandem COBOL IBM z/OS Enterprise COBOL

FILEThe section identifies a file and the various layouts by which the file can be accessed.

The section syntax is similar in both versions, with an additional clause of “REPORT” which is not present in Enterprise COBOL.It is also possible to ASSIGN a file to the DEFINE name parameter which is passed onto the program.

Syntax is similar.An additional clause of “RECORDING MODE” having value of F (Fixed), V (Variable), U (Fixed/Variable) or S (Spanned) for a QSAM file.Assigning a file to the DEFINE name parameter is not possible.

WORKING-STORAGEThe various variables used to perform the business functionality in the program are declared and, if required, defined as well.

Usage of the section is similar in both versions.HP limits the size of variable in the section to 63,400 bytes, above which the variables must be declared in the EXTENDED-STORAGE section, which has a limit of up to 133,693,440 bytes.There’s also a binder limit of 32767 words on the total WORKING-STOR-AGE memory of all bound COBOL programs.

IBM z/OS allows a limit of 134,217,727 bytes which is higher than the total of WORKING-STORAGE and EXTENDED-STORAGE sections on HP Tandem COBOL.

EXTENDED-STORAGEThe section is required in case the variable size is too big to fit in the WORKING-STORAGE section.

The section is used when variables cannot be fit in the WORKING-STOR-AGE section.

The section is absent.

LINKAGE The section is used in case the program is going to call and pass on parameters to other modules.

The section usage is similar in both the versions.

LOCAL STORAGEThe section is used to create recursive programs.

Not present. The section is used to create recur-sive programs. The data-variables declared in this section are initialized on each invocation of the recursion, thereby insulating different instances. A program not containing this section can’t be recursive and an attempt leads to run-time system error.

Page 7: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

cognizant 20-20 insights 7

Intrinsic Functions

An intrinsic function is a function that a program can use without needing to declare or code it explicitly in the program. It returns a value that is computed at the time of reference during the execution of the object program.

The following intrinsic functions are available both in Enterprise COBOL and in Tandem COBOL. The functions themselves are explained in detail in their respective manuals listed under the reference:

The following intrinsic functions are present only on Enterprise COBOL:

> DATE-TO-YYYYMMDD> DATEVAL > DAY-TO-YYYYDDD > DISPLAY-OF > NATIONAL-OF> UNDATE> YEAR-TO-YYYY> YEARWINDOW

Availability Statistics and Performance

HP NonStop Tandem’s availability statistics and performance (ASAP) product monitors the HP Tandem operating system and application resources. The related calls can be coded in programs to gain insights into critical applica-tions running on HP NonStop Tandem systems. This investigation enables users to plan for the infrastructure growth as required.

Tivoli software can be used to measure current response times of programs running on IBM z/OS for good and bad transactions, the use of resources, amount of MQ messages and DB2 calls.

Based on further investigations, a product similar to ASAP – Application Performance Analyzer2 – exists on the IBM platform. Transaction Management Facility

The HP NonStop Tandem transaction manage-ment facility (TMF) product furnishes transac-tion protection, database consistency and data-

HP-Only Imperative Statements

Figure 8

Statements HP Tandem COBOL IBM z/OS Enterprise COBOL

CHECKPOINTSTARTBACKUPSYNCDEPTH phrase of OPEN FREEALLOCATE

The statements are used to develop fault-tolerant programs known as Nonstop Process pairs.

Such fault-tolerant programming is not available.

LOCKFILEUNLOCKFILEUNLOCKRECORD

The statements are used to LOCK and UNLOCK the accessibility of a file during the program execution.

The option to LOCK/UNLOCK a file exists by use of JCL statements. But the locking is applicable throughout the execution of the program and not on an as-needed basis, which is available on HP Tandem COBOL.

USING and GIVING Phrase of ENTER statement

The statement is used to perform mixed-language programming wherein sources in languages other than Cobol are called within Cobol programs.

The statement is not available. The CALL statement is used to perform the mixed-language programming.

> ACOS> ANNUITY> ASIN> ATAN> CHAR> COS> CURRENT-DATE> DATE-OF-INTEGER> DAY-OF-INTEGER> FACTORIAL> INTEGER> INTEGER-OF-DATE> INTEGER-OF-DAY> INTEGER-PART> LENGTH> WHEN-COMPILED> LOG> LOG10> LOWER-CASE> MAX> MEAN> MEDIAN

> MIDRANGE> MIN> MOD> NUMVAL> NUMVAL-C> ORD> ORD-MAX> ORD-MIN> PRESENT-VALUE> RANDOM> RANGE> REM> REVERSE> SIN> SQRT> STANDARD-

DEVIATION> SUM> TAN> UPPER-CASE> VARIANCE

Page 8: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

cognizant 20-20 insights 8

Key Words Specific to Respective COBOL Versions

Figure 9

Key words present only in HP Tandem COBOL

Key words present only in Enterprise COBOL

APPROXIMATE BASIS

CD BEGINNING

CF CBL

CH CLASS-ID

CHARACTER-SET COM-REG

CHECKPOINT COMP-1

CLOCK-UNITS COMP-2

COLLATING COMP-4

COLUMN COMPUTATIONAL-1

COMMUNICATION COMPUTATIONAL-2

CONTROL COMPUTATIONAL-4

CONTROLS DBCS

DE DISPLAY-1

DESTINATION EGCS

DETAIL EJECT

DISABLE FUNCTION-POINTER

EGI GOBACK

EMI GROUP-USAGE

ENABLE ID

EXCLUSIVE INHERITS

EXTENDED-STORAGE INVOKE

FINAL JNIENVPTR

GENERIC KANJI

GROUP LOCAL-STORAGE

GUARDIAN-ERR METHOD

HEADING METHOD-ID

INDICATE MORE-LABELS

INITIATE OBJECT

LAST OVERRIDE

LIMIT PROCEDURE-POINTER

LIMITS PROCESSING

LINE-COUNTER READY

LOCKFILE RECORDING

MESSAGE RELOAD

NUMBER RETURN-CODE

PAGE-COUNTER RETURNING

PF SELF

PH SERVICE

Key words present only in HP Tandem COBOL

Key words present only in Enterprise COBOL

PLUS SHIFT-IN

PRINTING SHIFT-OUT

PROGRAM-STATUS SKIP1

PROGRAM-STATUS-1 SKIP2

PROGRAM-STATUS-2 SKIP3

PROMPT SORT-CONTROL

PROTECTED SORT-CORE-SIZE

PURGE SORT-FILE-SIZE

QUEUE SQL

RD TITLE

RECEIVE TRACE

RECEIVE-CONTROL WHEN-COMPILED

REPLY WRITE-ONLY

REPORT ZEROS

REPORTING XML

REPORTS XML-CODE

RF XML-EVENT

RH XML-NAMESPACE

SEGMENT XML-NAMESPACE-PREFIX

SEND XML-NNAMESPACE

SHARED XML-NNAMESPACE-PREFIX

SOURCE XML-NTEXT

STARTBACKUP XML-SCHEMA

SUB-QUEUE-1 XML-TEXT

SUB-QUEUE-2

SUB-QUEUE-3

SUM

SYNCDEPTH

TAL

TERMINAL

TERMINATE

TEXT

UNLOCK

UNLOCKFILE

UNLOCKRECORD

base recovery critical in high-volume transaction processing. It sustains high performance for online transaction processing (OLTP) applica-tions, as well as online query processing (OLQP) activities, batch processing applications and decision-support systems.

• Database consistency: On the IBM z/OS Enterprise COBOL, an invocation of a pro-gram unit containing DB2 leads to a starting

of a DB2 thread which encapsulates all the transactions till a COMMIT statement is used to finalize the transaction onto the database. The similar action is available on the HP Tandem COBOL by the use of TMF-based calls of BEGINTRANSACTION, ENDTRANSACTION and ABORTTRANSACTION.

• Restart mechanism: This mechanism is a methodology to ensure transactions in a large

Page 9: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

cognizant 20-20 insights 9

data file are processed only once when a pro-cess failure is identified. This is possible in both HP Tandem COBOL and IBM z/OS Enterprise COBOL by use of appropriate programming.

Compiler Directives

The compiler directive is the word that directs the compiler to perform a certain action when the program is being compiled to create the final runnable object. Both Cobol versions provide the option to enable this action in different manners.

The directive “?SOURCE” is heavily used in HP Tandem COBOL to source-in different modules or a data dictionary. An alternative for “?SOURCE” is achieved by entering “BASIS” on the IBM z/OS Enterprise COBOL.

The directives “?LIST ?NOLIST ?PAGE” have similar meanings on both HP Tandem COBOL and IBM z/OS Enterprise COBOL.

The processing accomplished by directives of “?CONSULT” and “?SEARCH” is possible on IBM z/OS Enterprise COBOL by use of JCL scripting statement of STEPLIB which enables a program to use information from a library of load modules.

The directives listed below have no alternative on IBM z/OS Enterprise COBOL:

HEADING, SAVE, INSPECT, SYMBOLS, ICODE, HEAP, SAVEABEND, ANSI, TANDEM, IF, ENDIF, IFNOT, SETOG PORT, NONSTOP, SECTION, NOB-LANK

ConclusionBased on the investigations using a sample HP Tandem COBOL program converted into Enter-prise COBOL by the use of Cobol and CICS/VS Command Level Conversion Aid (CCCA) tool, the following conclusions were reached:

• Application with online programs only: Such an application is heavily driven by use of SCOBOL requestor programs interact-ing with a Cobol server which provides the business logic.

The suggested option is to create the speci-fications of the business logic which need to be migrated to IBM and then do the develop-ment of the necessary logic on IBM z/OS from scratch by use of CICS and Cobol by using MQ as the message tunnel between the user GUI and COBOL program.

The rationale behind the suggested option:

> The SCOBOL code is very different than CICS and hardly any similarities can be found.

> The handling of user interaction in SCOBOL is very different than CICS and automated conversion is not feasible.

• Application with batch programs only: This approach works with systems heavily driven by the use of Cobol programs that provide the business logic in batch mode and where the concept of IPM is rarely used. The suggested option is to create the conversion specifica-tions known as language conversion program (LCP) and use the CCCA tool for automated conversion. A certain minimum level of manual conversion may still be required.

The rationale behind the suggested option:

> A lot of similarities exist which can be lever-aged to have an automated conversion of batch programs.

> An automated approach will enable enter-prises to reduce the development cost.

• Application with a combination of both types of programs: The conversion approach depends on the ratio of online to batch programs present in the application.

The more online programs present in the application, the more the option suggested for online-only programs should be used. The same rationale also applies when the application is laden with batch programs and fewer online programs are present.

Page 10: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

cognizant 20-20 insights 10

Quick Take

Cobol Compilation at a Global Banking Major

At a Netherlands-based financial institution with worldwide operations, an exercise to check the feasi-bility of migrating Cobol applications from HP to IBM was performed to select a future IT platform for building current account and payment engine applications.

Business SituationTo identify the modifications required for ensuring correct compilation of HP Tandem COBOL on the IBM z/OS system.

Challenges and Actions Taken• Creating a sample Cobol program on the

HP Tandem system using many of the Cobol functions, statements, etc.

• Ensuring correct compilation on the HP Tandem system and then aligning the code correctly for compilation using the IBM z/OS Enterprise COBOL compiler.

• Compile the code on the IBM z/OS system and identify the errors received and actions to overcome them.

Benefits

The following is a comprehensive table indicating the actions to be taken on treating the possible compi-lation errors that can occur on compiling a HP Tandem Cobol program on an IBM z/OS system.

HP Tandem COBOL Code Snippet

Errors Received Replacement in Enterprise COBOL

SELECT FILE1 ASSIGN TO #DYNAMICENTER "COBOLASSIGN" USING

Non-COBOL character(s) were found starting with "#" in column 44. The characters were discarded. "DYNAMIC" was found in the "ASSIGN" clause. The clause was dis-carded.

The #DYNAMIC is not used in Enterprise COBOL; instead, an alpha-numeric literal must be mentioned. During the execution of the program, a JCL assignment by use of DD and DSN commands takes care of assign-ing the external name of the file. The ENTER "COBOLASSIGN" statement is not required.

?NOLIST A character other than "*", "D", "/" or "-" was found in column 7. A blank was assumed. "NOLIST" should not begin in area "A". It was processed as if found in area "B". "NOLIST" was invalid. Scan-ning was resumed at the next area "A" item, level-number or the start of the next clause.

The compiler directives must not start with “?”.

02 Y NATIVE-2 "NATIVE-2" was invalid. Scan-ning was resumed at the next area "A" item, level-number, or the start of the next clause.

Replace the NATIVE-2 with picture clause PIC S9(4).

Page 11: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

cognizant 20-20 insights 11

SELECT FILE5 ASSIGN TO FILE5 ORGANIZATION IS SEQUENTIALACCESS MODE IS SEQUENTIAL FILE STATUS IS FST-FILE5.FD FILE5. 01 FILE5-REC.03 FILE5-ID.05 FIELD-5 PIC X(06).05 TEST-9 PIC X(35).05 TEST-10 PIC X(80).

A "RECORDING MODE" of "F" was assumed for file "FILE5".

The “RECORDING MODE” clause is mandatory option for Sequential/QSAM files.

SELECT FILE1 ASSIGN TO FILE1 ORGANIZATION IS RELA-TIVE ACCESS MODE IS RANDOMRELATIVE KEY IS KEY-FILE1FILE STATUS IS FST-FILE1.01 KEY-FILE1 PIC S9(6) COMP.

"RELATIVE KEY" "KEY-FILE1" was not defined as an unsigned integer data item. The key was discarded.

The Relative Key must not be a signed integer.

MOVE FUNCTION ACOS (-1) TO MF-A

Numeric function "NUMERIC FUNCTION ACOS" was not allowed in this context. The statement was discarded.

For Numeric and Integer Intrinsic functions, MOVE is not allowed. A COMPUTE statement must be mentioned.

MOVE CORRESPONDING W-ADD-GR-1 TO W-ADD-GR-2ADD CORRESPONDING W-ADD-GR-1 TO W-ADD-GR-2 01 W-ADD-GR-1.03 W-GR1 PIC 9(02).03 W-GR2 PIC 9(02).01 W-ADD-GR-2.03 W-GR3 PIC 9(02).03 W-GR4 PIC 9(02).

No "CORRESPONDING" operands were found. The statement had no effect.

The subordinate data items present in the group data items must be of the same name.

OPEN INPUT FILE1 SHARED "SHARED" was not defined as a file-name. The statement was discarded.

The options of SHARED/PROTECTED/EXCLUSIVE are not available in Enter-prise COBOL. It needs to be taken care by use of JCL statements.

START FILE4 KEY = TEST-8 OF FILE4-ID OF FILE4-RECGENERIC

"GENERIC" was invalid. Skipped to the next verb, period or procedure-name definition.

The options of GENERIC, EXACT, APPROX mode to position a key to read a record are not available.

Further Steps

A more complicated program containing all the elements possible in an HP Tandem COBOL Program to be compiled on both the systems to find ways to overcome more compiler errors on the IBM z/OS system.

Page 12: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

cognizant 20-20 insights 12

About the AuthorsAmeen Abbas is an Associate within Cognizant’s Banking and Financial Services Business Unit. He has over five years of application-building experience with Cobol and the C programming language across the complete SDLC lifecycle. His areas of expertise include requirements rationalization and designing, building and deploying banking applications for European financial institutions. He holds a bachelor of engineering degree in computer science from Anna University affiliated college in India. Ameen can be reached at [email protected]. Linkedin http://www.linkedin.com/in/ameenabbas.

Janani Karunanithi is an Associate within Cognizant’s Banking and Financial Services Business Unit. She has over five years of application-building experience with Cobol and the C programming language for European banks across the complete SDLC lifecycle. Her areas of expertise include current account engine enhancement, functional requirements gathering and designing, building and deploying banking applications for European financial institutions. She holds a bachelor of engineering degree in elec-tronics and communication from Anna University affiliated college in India. Janani can be reached at [email protected]. Linkedin http://in.linkedin.com/pub/janani-karunanithi/17/23b/991.

Thilakam Ponnuraj is an Associate within Cognizant’s Banking and Financial Services Business Unit. She has over five years of application-building experience using the Cobol programming language for European banks and has been involved in the complete SDLC lifecycle. Her areas of expertise include payment engine enhancement, functional requirements rationalization and designing, building, deploy-ing and providing third-line support of banking applications for European banks. She holds a bache-lor of engineering degree in electronics and communication from Anna University affiliated college in India. Thilakam can be reached at [email protected]. Linkedin http://www.linkedin.com/pub/thilakam-ponnuraj/50/a23/502.

Meenakshi Sundaram Arunachalam is a Senior Manager within Cognizant’s Banking and Financial Services Business Unit. He has 13-plus years of experience as solution architect and HP Tandem NonStop technical architect for domestic and cross-border payments projects. His areas of expertise involve pre-sales, payment engine application designing, building, deploying and large scale project management. He holds a master of computer applications degree from Madurai Kamaraj University in India. Meenakshi can be reached at [email protected]. Linkedin http://www. linkedin.com/pub/meenakshi-sundaram-arunachalam/4/116/193.

Rammurthy Mudaliar is a Senior Associate within Cognizant’s Banking and Financial Services Business Unit. He has eight-plus years of experience in application building with Cobol, TAL and C languages for European banks using Wallstreet Systems’ Atlas/GBS product suite. His areas of expertise involve designing, building, deploying, third-line support and project management for FX, money-market, treasury and cross-border payments applications involving a globally distributed team. He holds a bach-elor of engineering degree in electronics from Mumbai University. He can be reached at [email protected]. Linkedin http://www.linkedin.com/pub/rammurthy-mudaliar/19/2a2/27b.

References

• HP Nonstop Tandem COBOL Reference manuals, http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02121195/c02121195.pdf.

• IBM z/OS Enterprise COBOL Reference manuals, http://pic.dhe.ibm.com/infocenter/pdthelp/v1r1/topic/com.ibm.entcobol.doc_4.2/PGandLR/igy3pg50.pdf.

Footnotes1 Ian Bramley, “Declining HP Integrity NonStop Far Outclassed by IBM System z10 Mainframe,”

Enterprise e-Infrastructure Analysis, September 2009, ftp://public.dhe.ibm.com/common/ssi/rep_wh/n/ZSL03066USEN/ZSL03066USEN.PDF.

2 Product information, IBM site, http://www-03.ibm.com/software/products/fr/fr/apa/.

Page 13: A Checklist for Migrating Big Iron Cobol Applications · A Checklist for Migrating Big Iron Cobol ... of the data file. The #DYNAMIC used in Tandem COBOL ... The SORT-MERGE file is

About Cognizant

Cognizant (NASDAQ: CTSH) is a leading provider of information technology, consulting, and business process outsourcing services, dedicated to helping the world’s leading companies build stronger businesses. Headquartered in Teaneck, New Jersey (U.S.), Cognizant combines a passion for client satisfaction, technology innovation, deep industry and business process expertise, and a global, collaborative workforce that embodies the future of work. With over 50 delivery centers worldwide and approximately 162,700 employees as of March 31, 2013, Cognizant is a member of the NASDAQ-100, the S&P 500, the Forbes Global 2000, and the Fortune 500 and is ranked among the top performing and fastest growing companies in the world.

Visit us online at www.cognizant.com for more information.

World Headquarters

500 Frank W. Burr Blvd.Teaneck, NJ 07666 USAPhone: +1 201 801 0233Fax: +1 201 801 0243Toll Free: +1 888 937 3277Email: [email protected]

European Headquarters

1 Kingdom StreetPaddington CentralLondon W2 6BDPhone: +44 (0) 207 297 7600Fax: +44 (0) 207 121 0102Email: [email protected]

India Operations Headquarters

#5/535, Old Mahabalipuram RoadOkkiyam Pettai, ThoraipakkamChennai, 600 096 IndiaPhone: +91 (0) 44 4209 6000Fax: +91 (0) 44 4209 6060Email: [email protected]

© Copyright 2013, Cognizant. All rights reserved. No part of this document may be reproduced, stored in a retrieval system, transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the express written permission from Cognizant. The information contained herein is subject to change without notice. All other trademarks mentioned herein are the property of their respective owners.