File organization and access mode

You can organize your files as sequential, line-sequential, indexed, or relative. The access mode defines how COBOL reads and writes files, but not how files are organized.

You should decide on the file organization and access modes when you design your program.

The following table summarizes file organization and access modes for COBOL files.

Table 1. **File organization and access mode**
File organization	Order of records	Records can be deleted or replaced?	Access mode
Sequential	Order in which they were written	A record cannot be deleted, but its space can be reused for a same-length record.	Sequential only
Line-sequential	Order in which they were written	No	Sequential only
Indexed	Collating sequence by key field	Yes	Sequential, random, or dynamic
Relative	Order of relative record numbers	Yes	Sequential, random, or dynamic

Your file-management system handles the input and output requests and record retrieval from the input-output devices.