.NLIST
	.TITLE	VD     - VIRTUAL DISK PREFIX FILE
;
;	GET UCB OFFSETS.
;
	.MCALL	UCBDF$		;DEFINE UCB OFFSETS
	UCBDF$
;
; DEFINE ADDITIONAL UCB OFFSET.
;

	.IF	NDF,R$$MPL	;FOR RSX11M --------------------------
U.NXT	= U.VCB+2		;EXTENSION BLOCK ADDRESS
	.IFF			;FOR RSX11M+ -------------------------
U.NXT	= U.VCB+14		;EXTENSION BLOCK ADDRESS
	.ENDC			; ------------------------------------

;
; DEFINE EXTENSION BLOCK OFFSETS.
;
X.OFF	= 0			;DISK FILE OFFSETS
X.UCB	= X.OFF+4		;NEXT UCB ADDRESS
X.FLG	= X.UCB+2		;EXTENSION FLAGS
X.FNB	= X.FLG+2		;FILENAME BLOCK
X.LGTH	= X.FNB+36		;LENGTH OF EXTENSION BLOCK
;
; DEFINE EXTENSION FLAG BITS
;
XF.RON	= 1			;ALLOW ONLY READ ACCESS
;
; DEFINE VD: AS LOADABLE
LD$VD=0
;
; DEFINE NUMBER OF VD: UNITS    (#UCBs)
V$$D11=2

	.LIST