INT 21 - DOS 2+ - "CHMOD" - SET FILE ATTRIBUTES
	AX = 4301h
	CX = new file attributes (see #01420)
	DS:DX -> ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. filename
Return: CF clear if successful
	    AX destroyed
	CF set on error
	    AX = error code (01h,02h,03h,05h) (see #01680 at AH=59h)
Notes:	will not change volume label or directory attribute bits, but will
	  change the other attribute bits of a directory (the directory
	  bit must be cleared to successfully change the other attributes of a
	  directory, but the directory will not be changed to a normal file as
	  a result)
	MS-DOS 4.01 reportedly closes the file if it is currently open
	for security reasons, the Novell NetWare execute-only bit can never
	  be cleared; the file must be deleted and recreated
	under the FlashTek X-32 DOS extender, the filename pointer is in DS:EDX
	DOS 5.0 SHARE will close the file if it is currently open in sharing-
	  compatibility mode, otherwise a sharing violation critical error is
	  generated if the file is currently open
	DR DOS 3.41/5.0 will silently ignore attempts to change the 'directory'
	  attribute bit
SeeAlso: AX=4300h,AX=4311h,AX=7143h,INT 2F/AX=110Eh


Bitfields for file attributes:
Bit(s)	Description	(Table 01420)
 7	shareable (Novell NetWare)
 7	pending deleted files (Novell DOS, OpenDOS)
 6	unused
 5	archive
 4	directory
 3	volume label
	execute-only (Novell NetWare)
 2	system
 1	hidden
 0	read-only