Format of DOS 4.00 (pre UR 25066) disk buffer info:
Offset	Size	Description	)
 00h	DWORD	pointer to array of disk buffer hash chain heads (see #01654)
 04h	WORD	number of disk buffer hash chains (referred to as NDBCH below)
 06h	DWORD	pointer to lookahead buffer, zero if not present
 0Ah	WORD	number of lookahead sectors, else zero (the y in BUFFERS=x,y)
 0Ch	BYTE	00h if buffers in EMS (/X), FFh if not
 0Dh	WORD	EMS handle for buffers, zero if not in EMS
 0Fh	WORD	EMS physical page number used for buffers (usually 255)
 11h	WORD	??? seems always to be 0001h
 13h	WORD	segment of EMS physical page frame
 15h	WORD	??? seems always to be zero
 17h  4 WORDs	EMS partial page mapping information???
SeeAlso: #01649,#01650,#01653,#01657