In VSAM, what does a RETURN-CODE value of 28 generally indicate during a read operation on a data set?

Introduction / Context:
VSAM (Virtual Storage Access Method) is a file access method used on IBM mainframe systems. It returns specific codes to indicate the outcome of operations such as OPEN, READ, WRITE, and CLOSE. Understanding these return codes is important for diagnosing problems in batch jobs and online programs. This question focuses on the meaning of a VSAM RETURN-CODE value of 28 during a read operation.

Given Data / Assumptions:

• The environment involves VSAM data sets on a mainframe.
• The operation of interest is a read request.
• The RETURN-CODE value is 28.
• We assume normal application level interpretation of VSAM codes.

Concept / Approach:
Many VSAM return codes correspond to logical or physical conditions encountered when accessing data sets. A common situation is attempting to read beyond available records, which produces an end of file condition. When a program calls VSAM to read the next record and there are no more records, the returned code signals this state so that the program can stop reading gracefully. Therefore, an answer that describes reading beyond the last record and end of file semantics is the most appropriate, rather than answers about network, backups, or compile time errors.

Step-by-Step Solution:
1. Recall that VSAM distinguishes between successful reads and conditions such as end of file or record not found. 2. Understand that when the last record has already been read, a subsequent read attempts to move past the end of the data set. 3. This results in a special return code that tells the program there are no more records. 4. Examine the options and choose the one that states an attempt to read beyond the last record and signals an end of file condition. 5. Confirm that other options describe situations unrelated to VSAM record access, such as network failures or compile time syntax errors.

Verification / Alternative check:
You can verify by thinking of a typical COBOL program that reads a VSAM file in a loop. The loop continues as long as the read operation returns a success or non end of file status. When the program reaches the last record, the next read returns a code indicating the end of file, and the program exits the loop. No network, backup, or compile time activity is involved in this runtime condition. This confirms that record exhaustion and end of file semantics are the key ideas for the return code in question.

Why Other Options Are Wrong:

• Option B is wrong because a VSAM return code does not directly describe network connection status; network issues are handled at different layers.
• Option C is wrong because VSAM return codes are not used to indicate automatic backups that permanently block access to data sets.
• Option D is wrong because compiler syntax errors are discovered before runtime and are not signaled by VSAM during file operations.

Common Pitfalls:
A common pitfall is treating all non zero return codes as general errors without understanding their specific meaning. For example, an end of file condition is not necessarily an error; it is a normal part of controlled sequential processing. Another mistake is confusing VSAM file status codes and other system return codes, which may have different numbering and interpretation. Reading and interpreting VSAM documentation carefully helps avoid misdiagnosing conditions like end of file as hardware or network failures.

Final Answer:
The correct answer is That an attempt was made to read beyond the last record in the VSAM data set, indicating an end of file condition, because this describes the logical situation that VSAM signals with this return code during read operations.