System information

FUNCTION 30: SET FILE ATTRIBUTES

Entry Parameters:

Registers DE: FCB Address

Returned Value:

The Set File Attributes function allows programmatic manipulation of permanent indicators

attached to files. In particular, the R/O and System attributes (t1' and t2') can be set or reset. The

DE pair addresses an unambiguous filename with the appropriate attributes set or reset. Function

30 searches for a match and changes the matched directory entry to contain the selected

indicators. Indicators f1' through f4' are not currently used, but may be useful for applications

programs, since they are not involved in the matching process during file open and close

operations. Indicators f5' through f8' and t3' are reserved for future system expansion.

FUNCTION31: GETADDR(DISKPARMS)

Entry Parameters:

Returned Value:

Registers HL: DPB Address

The address of the BIOS resident disk parameter block is returned in HL as a result of this

function call. This address can be used for either of two purposes. First, the disk parameter values

can be extracted for display and space computation purposes, or transient programs can

dynamically change the values of current disk parameters when the disk environment changes, if

required. Normally, application programs will not require this facility.

5.2 Call Conventions CP/M Operating System Manual

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