Operating system or hardware configurations and parameter settings directly constrain a COBOL application. Check your operating system and hardware for any limits. You might need to consider the following:
| Item | Limit |
|---|---|
| Environment variables | Limited to a maximum of 64 Kilobytes (or the machine's free space, whichever is smaller) of written environment variables at any one time during the run of an application. |
| Record locks | Operating system dependent |
| File locks | Operating system dependent |
| CALL nesting | Limited by stack space allocated by the operating system |
| Length of contents of DD_ environment variables | Up to the maximum operating system size for each path |
| Total data and procedure size | Limited by available free memory |
| Simultaneously loaded subprograms | Limited by available free memory |
| File and record sizes | Limited by operating system environment |
| Files open simultaneously | Limited by operating system environment. |
| Filename size and format | Operating system dependent |
| Index key size and number | Might be limited if a non-standard file handler is used |
| Sort key size and number | Might be limited if a non-standard SORT support routine is used |