INT E0 - DR Multiuser DOS - "A_READBLK" - READ STRING FROM AUX DEVICE
	CL = ACh
	DS:DX -> character control block (CHCB) (see #04051,#04052)
Return: AX = number of characters read
Desc:	read characters from the default auxiliary (AUXn:) device into a buffer
	  until the buffer is full or the device is no longer ready
Notes:	if the device is initially not ready, blocks until at least one
	  character has been read
	if another process owns AUX, this call blocks until the device becomes
	  available
	also supported by REAL/32
SeeAlso: INT E0/CL=03h,INT E0/CL=A5h,INT E0/CL=ADh


Format of DR Multiuser DOS character control block (CHCB):
Offset	Size	Description	(Table 04051)
 00h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	pointer to character buffer
 04h	WORD	length of character buffer
Note:	this version of the structure is used by REAL/32 in real mode
SeeAlso: #04059


Format of REAL/32 protected-mode Character Control Block (CHCB):
Offset	Size	Description	(Table 04052)
 00h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	32-bit offset of character buffer
 04h	WORD	selector for character buffer
 06h	WORD	length of character buffer
SeeAlso: #04051