Microsoft KB Archive/10692
Maximum Number of INDEXED Files that Can Be OPENed (MS-DOS)
PSS ID Number: Q10692 Article last modified on 11-16-1992
2.00 2.10 2.20 MS-DOS
Summary: The maximum number of Indexed files that can be opened at one time is reduced when the CHAIN command is used. The maximum number of files that a process can have open at one time is 20. This limitation is set by MS-DOS via the FILES= statement in the CONFIG.SYS file. Of the 20 file handles available, three are used by DOS and two are used by the COBOL product. This leaves 15 file handles for the COBOL application. The number of open files, ISAM or otherwise, is affected by the CHAIN verb because COBOL has to open a file (i.e., a program loader) to load the CHAIN program. Because of this requirement, one of the 15 available file handles is used up, leaving 14 file handles available. Please note that for each ISAM file opened, two of the 20 files are used; one for the key file and another for the data file.
Copyright Microsoft Corporation 1992.