Introduction to Cobol – with Mainframe Access

Log into the mainframe by using the logon command with your TSO user ID and password, then press enter to reach the Ispf screen.

Learn how to log off from TSO by using the F3 key to navigate back, delete the SPF trace file if prompted, and enter log off to disconnect.

Learn keyboard-driven navigation inside the mainframe system: manage up to eight screens with the swap bar, use F keys, navigate with cursor, and perform copy, paste, and screen split.

Explore the ISPF menus, including the settings, view, and edit menus, and learn how dataset management, file operations, and utilities streamline Cobol mainframe workflow.

Compare PS files and PDS in the z/OS file system. Learn to browse, view, and edit PS and PDS members in Zeos with the DDS list menu.

Learn to edit a mainframe file for COBOL programming via menu 3.4 and the pre-created user 01 file, using insert, delete, copy, and move lines.

Code your first COBOL program in a mainframe environment by creating a Hello world member in the COBOL PDS, following the four divisions and displaying 'Hello world' before stopping.

Learn to compile cobol programs on z/os by submitting a jcl job, producing a load module in the load library, and preparing to run the program.

Submit the execution JCL to run the compiled load module. Use input data and produce output in the job report; a return code of zero indicates success.

View and interpret a COBOL job execution using SDSF, inspecting job status, JCL, sysout, and compilation reports to debug and verify hello world program results.

Explore the structure of a COBOL line, focusing on margin a and margin b, with columns eight to seventy-two for code; column seven serves as a line indicator.

Explore the COBOL program structure, from divisions to sections, paragraphs, and instructions. Learn about the four divisions and how the working storage section declares data.

The identification division documents a COBOL program and aids maintenance in large environments, with a mandatory program-id and optional paragraphs such as author, date written, date compiled, installation, and security.

Explore how COBOL comments are ignored during execution, how to document code, and how to temporarily disable a line with an asterisk in column seven, then recompile.

Analyze COBOL compilation errors, fix issues like incorrect column placement and missing spaces, and interpret return codes from 0 to 12; use the report to identify severity and address errors.

Learn how to declare variables in Cobol, including the data division structure, file and working storage sections, level numbers, pic x and pic nine, and the value clause for initialization.

Group variables to organize a cobol program, using a main group item at level zero one containing elementary items like user id, user name, and user age.

Learn how the Cobol display instruction in the procedure division outputs strings, numbers, and variables to sysout for debugging and final summaries, with examples like Hello World and city values.

Discover how the move instruction assigns values to variables in COBOL by writing move followed by a value or variable and specifying the destination variable.

Practice writing a COBOL program named Cobb X01 that declares a full name from first name and last name, uses the move and display instructions to show the result.

Learn to purge sdsf jobs by using the p command in the np column, confirm deletions, and perform multiple deletions with double p and double slash.

Explore the COBOL accept instruction to read input from Sysin, assign it to a suitably sized variable, and display the retrieved data, including handling multiple lines and program parameters.

Explore how Cobol filler reserves memory space without naming a field, enables ignoring data and spacing, and uses the same syntax as regular variables, but cannot be used in instructions.

Initialize cobol variables to avoid unexpected behavior by using spaces for alphanumeric and zeros for numeric types. Use the initialize statement with space or zero keywords for group variables.

Explore cobol arithmetic with the add instruction by declaring numeric variables, initializing num1 to five and num2 to ten, and displaying results after adding numbers or literals.

Explore subtraction in Cobol using the subtract instruction, subtract num one from num two, and optionally store the result with the giving keyword, leaving num1 and num2 unchanged.

Explore the Cobol multiply instruction, multiplying num1 by num2, with results stored in a target variable or via the giving keyword, and the importance of sufficient variable size.

Use the COBOL divide instruction to divide num two by num one, store the quotient using the giving keyword, and obtain the remainder in num three.

Master the cobol compute instruction, which writes compute followed by a result variable, equals the expression, and enables complex calculations with add, subtract, multiply, and divide using parentheses.

Learn how to structure COBOL programs with conditional control structures using the if statement, write conditions with operators, test equality, and apply and or logic, else blocks, and nested ifs.

Practice the cob x02 program to determine reduced or full price using an if statement, based on age and student status. Combine conditions with or and and, and display the result.

Learn how the evaluate statement replaces cascading ifs for optimized, readable code, using when clauses and an optional when other to cover all cases, including through ranges.

Practice the Cobol evaluate statement by converting a previous if-based X02 program to X03, demonstrating how to combine when clauses for identical actions without changing behavior.

Explore Cobol loops as core control structures: fixed, conditional, and control-variable loops. See examples using perform and varying, display iteration numbers, and stop until the condition is true.

Learn how the COBOL period acts as a block and scope terminator, when to place or omit periods, and why consistent use after divisions, sections, declarations, and stop run matters.

Define and call reusable COBOL paragraphs to organize code in the procedure division, using perform or through with an ending name to control flow and reuse.

Learn how Cobol sections group paragraphs inside the procedure division, naming sections, and calling them with perform to structure programs.

Explore how condition names use level 88 variables to represent age categories. Use value clauses, ranges, and set instructions to simplify code and improve readability and maintainability.

Build a cobol mainframe program that reads n, validates n is less than 50, computes the sum 1 to n, and prints the result or an error.