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CICS File Control Table (FCT)

Master the CICS File Control Table (FCT), the essential control table that manages file access, VSAM integration, and data file operations in CICS environments.

FCT Overview

The File Control Table (FCT) is a critical CICS control table that contains entries for every file that can be accessed within a CICS region. It defines file characteristics, access methods, and security controls.

File Definitions

Each FCT entry defines a file's characteristics including dataset name, access method, and processing attributes.

  • File name and dataset information
  • Access method (VSAM, QSAM, etc.)
  • File processing options

File Access Control

FCT entries control how files are accessed, shared, and managed within the CICS environment.

  • File sharing and locking
  • Security and authorization
  • Error handling and recovery

FCT Entry Structure

Each FCT entry contains detailed information about a file's characteristics, access requirements, and runtime behavior within the CICS environment.

File Identification

  • File name (8 characters)
  • Dataset name and type
  • Group assignment

Access Method

  • VSAM (KSDS, ESDS, RRDS)
  • QSAM (Sequential)
  • BDAM (Direct)

Processing Attributes

  • File sharing options
  • Security requirements
  • Error handling options

File Types and Access Methods

CICS supports various file types and access methods, each with specific characteristics and processing requirements.

VSAM Files

Key Characteristics:

  • KSDS (Key Sequenced Data Set)
  • ESDS (Entry Sequenced Data Set)
  • RRDS (Relative Record Data Set)

Example FCT Entry:

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FILE = CUSTFILE
DSNAME = USER.CUST.DATA
STATUS = ENABLED
SHARE = YES
SECURITY = YES
ACCESS = VSAM

Sequential Files

Key Characteristics:

  • QSAM (Queued Sequential Access Method)
  • Sequential processing only
  • Limited sharing capabilities

Example FCT Entry:

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FILE = LOGFILE
DSNAME = USER.LOG.DATA
STATUS = ENABLED
SHARE = NO
SECURITY = YES
ACCESS = QSAM

Direct Access Files

Key Characteristics:

  • BDAM (Basic Direct Access Method)
  • Direct record access by RBA
  • High performance for specific applications

Example FCT Entry:

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FILE = INDEXFILE
DSNAME = USER.INDEX.DATA
STATUS = ENABLED
SHARE = YES
SECURITY = YES
ACCESS = BDAM

File Sharing and Locking

Understanding file sharing mechanisms is crucial for data integrity and concurrent access in CICS environments.

S

Shared

Access:

Multiple

Locking:

Record

Multiple tasks can access the file simultaneously with record-level locking.

E

Exclusive

Access:

Single

Locking:

File

Only one task can access the file at a time with file-level locking.

N

No Share

Access:

Single

Locking:

None

No sharing or locking mechanisms, typically for read-only files.

FCT Management

Learn how to manage FCT entries using CICS commands and understand the relationship between FCT and other CICS control tables.

FCT Commands

CEDA ADD FILE:

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CEDA ADD FILE(CUSTFILE) GROUP(CUSTGRP)
DSNAME(USER.CUST.DATA)
STATUS(ENABLED)
SHARE(YES)
SECURITY(YES)
ACCESS(VSAM)

CEDA ALTER FILE:

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CEDA ALTER FILE(CUSTFILE) GROUP(CUSTGRP)
SHARE(YES)
SECURITY(YES)

CEDA DELETE FILE:

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CEDA DELETE FILE(CUSTFILE) GROUP(CUSTGRP)

FCT Relationships

Control Table Dependencies:

  • PPT: Programs may reference FCT entries for file access
  • PCT: Transactions may have file access restrictions
  • TCT: Terminal definitions may reference file access

File Operations:

  • File opening and closing
  • Record locking and sharing
  • Error handling and recovery

FCT Best Practices

Follow these best practices to optimize file access, data integrity, and system performance.

File Design

  • 1Use meaningful file names that reflect their purpose
  • 2Choose appropriate access methods based on usage patterns
  • 3Set appropriate sharing levels for concurrent access
  • 4Group related files together for efficient management

Security and Performance

  • 1Implement proper security controls for all files
  • 2Monitor file access patterns and performance
  • 3Document file dependencies and relationships
  • 4Regularly review and update FCT entries

Quick Quiz

Question 1:

What is the primary purpose of the CICS File Control Table (FCT)?

A) To store transaction definitions

B) To manage file access and VSAM integration

C) To control terminal operations

D) To define program characteristics

Question 2:

Which file sharing option allows multiple tasks to access a file simultaneously?

A) Exclusive

B) Shared

C) No Share

D) Read Only

Question 3:

What command is used to add a new file to the FCT?

A) CEDA ADD PROGRAM

B) CEDA ADD TRANSACTION

C) CEDA ADD FILE

D) CEDA ADD TERMINAL

Related Concepts

CICS Resource Definitions

Learn about CICS Resource Definition Online (RDO) and how FCT entries are managed.

VSAM Integration

Understand how FCT manages VSAM file access and integration.