INT 21 - DOS 2.11+ - GET OR SET MEMORY ALLOCATION STRATEGY                      
	AH = 58h
	AL = subfunction
	    00h get allocation strategy
		Return: AX = current strategy (see #01679)
	    01h set allocation strategy
		BL = new allocation strategy (see #01679)
		BH = 00h (DOS 5+)
Return: CF clear if successful
	CF set on error
	    AX = error code (01h) (see #01680)
Notes:	the Set subfunction accepts any value in BL for DOS 3.x and 4.x;
	  2 or greater means last fit
	the Get subfunction returns the last value set
	setting an allocation strategy involving high memory does not
	  automatically link in the UMBsee Upper Memory Block memory chain; this must be done
	  explicitly with AX=5803h in order to actually allocate high memory
	a program which changes the allocation strategy should restore it
	  before terminating
	Toshiba MS-DOS v2.11 supports subfunctions 00h and 01h, as does the
	  TI Professional MS-DOS v2.13
	DR DOS 3.41 reportedly reverses subfunctions 00h and 01h
SeeAlso: AH=48h,AH=49h,AH=4Ah,INT 2F/AX=4310h"XMSsee Extended Memory Specification",INT 67/AH=3Fh


(Table 01679)
Values for DOS memory allocation strategy:
 00h low memory first fit
 01h low memory best fit
 02h low memory last fit
---DOS 5+ ---
 40h high memory first fit
 41h high memory best fit
 42h high memory last fit
 80h first fit, try high then low memory
 81h best fit, try high then low memory
 82h last fit, try high then low memory
                                                                                

INT 21 - DOS 5+ - GET OR SET UMBsee Upper Memory Block LINK STATE
	AH = 58h
	AL = subfunction
	    02h get UMBsee Upper Memory Block link state
		Return: AL = current link state
			    00h UMBs not part of DOS memory chain
			    01h UMBs in DOS memory chain
	    03h set UMBsee Upper Memory Block link state
		BX = new link state
		    0000h remove UMBs from DOS memory chain
		    0001h add UMBs to DOS memory chain
Return: CF clear if successful
	CF set on error
	    AX = error code (01h) (see #01680)
Notes:	a program which changes the UMBsee Upper Memory Block link state should restore it before
	  terminating
	UMBs will only be available if CONFIG.SYS contains the line DOS=UMBsee Upper Memory Block,
	  the UMBs have been linked into the memory chain with AX=5803h, and
	  the allocation strategy has been set to include high memory with
	  AX=5801h
SeeAlso: #01687,#02766 at INT 2F/AX=4310h