面试题与答案

Customer Information Control System (CICS) is a transaction processing system designed for online processing.

Basic Mapping Support (BMS) map is used to define the layout of screens and messages in CICS applications.

A CICS task represents the execution of a transaction from start to finish, including the processing of one or more units of work.

The Execution Interface Block (EIB) contains information about the current task, including transaction ID and terminal details.

Resource definitions in CICS include files, transactions, queues, and other system objects that programs may access.

A CICS terminal is a device used for user interaction. Terminal Control Program (TCP) manages the flow of control between terminals and CICS programs.

CEMT (CICS Execution Management Transaction) is used for monitoring and managing CICS resources, transactions, and tasks during runtime.

The COMMAREA (Communication Area) is a reserved area for passing data between cooperating programs in a CICS transaction.

EXEC CICS RETURN is used to explicitly terminate a CICS program and return control to the calling program or transaction.

DFHRESP in the EIB contains the response code indicating the success or failure of the last CICS command executed in the program.

Transient data queues (TDQ) are used for temporary storage of data within a CICS region and are typically used for communication between tasks.

The RESP field in CICS contains the response code returned by the last CICS command, indicating the success or failure of the operation.

The CICS EIB contains information about the current execution environment, including transaction ID, program name, and other system-related details.

XCTL transfers control to another program and does not return, while LINK transfers control and returns after execution.

A CICS transaction is defined using a PCT (Program Control Table) entry, specifying program and transaction ID.

Pseudo-conversational programs simulate a conversational style by using the XCTL command to transfer control between transactions.

Errors are often handled by checking the RESP code after CICS commands and taking appropriate actions, such as rolling back the transaction.

SYNCPOINT is used to synchronize resource updates, ensuring that changes are either committed or rolled back together.

DFHCOMMAREA is a CICS reserved area used for communication between programs within the same task. It allows passing data between program invocations.

HANDLE CONDITION is used to define exception-handling conditions, specifying actions to take when certain conditions occur during program execution.

File control entries define file-related information in the File Control Table (FCT), specifying attributes like file name, organization, and access mode.

The XCTL and LINK parameters in the program definition specify whether a program is to be executed using XCTL or LINK when called from another program.

Transient data queues hold data within a task and are deleted when the task ends. Temporary storage queues persist data even after the task terminates.

A CICS symbolic map is a map generated at runtime based on the mapset and containing symbolic field names defined in the mapset.

CICS Journaling is used to capture and log changes made to recoverable resources, providing a means for recovery in case of failures.

A CICS program entry in the PCT includes information such as program name, load module location, and language compiler options.

ENABLE and DISABLE commands are used to control the processing of interrupts in a CICS region, allowing or preventing certain events.

Dynamic memory allocation in CICS is often handled using commands like GETMAIN and FREEMAIN to allocate and free storage during program execution.

XCTL is used to transfer control to another program or transaction and does not return, while LINK transfers control and returns after execution.

Deadlocks can be handled by defining proper timeouts, using SYNCPOINT and HANDLE CONDITION, or implementing deadlock detection and resolution mechanisms.