INT 21 - DOS 5+ - SET EXECUTION STATE                                           
	AX = 4B05h
	DS:DX -> execution state structure (see #01625)
Return: CF clear if successful
	    AX = 0000h
	CF set on error
	    AX = error code (see #01680 at AH=59h/BX=0000h)
Note:	used by programs which intercept AX=4B00h to prepare new programs for
	  execution (including setting the DOS version number).	 No DOS, BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly.
	  or other software interrupt may be called after return from this call
	  before commencement of the child process.  If DOS is running in the
	  HMAsee High Memory Area, A20(Address line 20) The 80286 and higher CPUs allow addresses in real mode to extend slightly beyond the one megabyte mark, which causes an incompatibility with some older programs which expect such addresses to wrap back to the beginning of the address space.  For complete compatibility with the 8088, newer machines thus contain circuitry which permits the twenty-first address line (A20) to be disabled.  The CPU then effectively has only twenty address lines in real mode, just as the 8088 does, and addresses which would extend beyond the one megabyte mark wrap to the beginning of the address space.  See also High Memory Area, Real Mode. is turned off on return from this call.
SeeAlso: AH=4Bh


Format of execution state structure:
Offset	Size	Description	(Table 01625)
 00h	WORD	reserved (00h)
 02h	WORD	type flags
		bit 0: program is an .EXE
		bit 1: program is an overlay
 04h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	pointer to 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. name of program file
 08h	WORD	PSPsee Program Segment Prefix segment of new program
 0Ah	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	starting CS:IP(Internet Protocol) The lower level (transport layer) of the TCP/IP protocol suite.	See also TCP, TCP/IP. of new program
 0Eh	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	program size including PSPsee Program Segment Prefix