diff --git a/sys/arch/pmax/pmax/disksubr.c b/sys/arch/pmax/pmax/disksubr.c
index d5eff63a948d..0db5dc476a4c 100644
--- a/sys/arch/pmax/pmax/disksubr.c
+++ b/sys/arch/pmax/pmax/disksubr.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: disksubr.c,v 1.5 1995/07/14 01:05:22 jonathan Exp $	*/
+/*	$NetBSD: disksubr.c,v 1.6 1995/08/04 02:34:24 jonathan Exp $	*/
 
 /*
  * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
@@ -149,7 +149,9 @@ compat_label(dev, strat, lp, osdep)
 			goto done;
 		}
 
-/*XXX*/		printf("Ultrix label loop\n");
+#ifdef DIAGNOSTIC
+/*XXX*/		printf("Interpreting Ultrix label\n");
+#endif
 
 		lp->d_magic = DEC_LABEL_MAGIC;
 		lp->d_npartitions = 0;
@@ -164,7 +166,7 @@ compat_label(dev, strat, lp, osdep)
 			  (part==1) ? FS_SWAP : FS_BSDFFS;
 			lp->d_npartitions += 1;
 
-#ifdef DEBUG
+#ifdef DIAGNOSTIC
 			printf(" Ultrix label rz%d%c: start %d len %d\n",
 			       DISKUNIT(dev), "abcdefgh"[part],
 			       lp->d_partitions[part].p_offset,
@@ -274,3 +276,68 @@ done:
 	brelse(bp);
 	return (error);
 }
+
+
+/*
+ * was this the boot device ?
+ */
+int
+dk_establish(dk, dev)
+	struct dkdevice *dk;
+	struct device *dev;
+{
+	/* see also arch/alpha/alpha/disksubr.c */
+	printf("Warning: boot path unknown\n");
+	return 1;
+}
+
+/* 
+ * UNTESTED !!
+ *
+ * Determine the size of the transfer, and make sure it is
+ * within the boundaries of the partition. Adjust transfer
+ * if needed, and signal errors or early completion.
+ */
+int
+bounds_check_with_label(bp, lp, wlabel)
+	struct buf *bp;
+	struct disklabel *lp;
+	int wlabel;
+{
+
+	struct partition *p = lp->d_partitions + dkpart(bp->b_dev);
+	int labelsect = lp->d_partitions[0].p_offset;
+	int maxsz = p->p_size;
+	int sz = (bp->b_bcount + DEV_BSIZE - 1) >> DEV_BSHIFT;
+
+	/* overwriting disk label ? */
+	/* XXX should also protect bootstrap in first 8K */ 
+	if (bp->b_blkno + p->p_offset <= LABELSECTOR + labelsect &&
+	    (bp->b_flags & B_READ) == 0 && wlabel == 0) {
+		bp->b_error = EROFS;
+		goto bad;
+	}
+
+	/* beyond partition? */ 
+	if (bp->b_blkno < 0 || bp->b_blkno + sz > maxsz) {
+		/* if exactly at end of disk, return an EOF */
+		if (bp->b_blkno == maxsz) {
+			bp->b_resid = bp->b_bcount;
+			return(0);
+		}
+		/* or truncate if part of it fits */
+		sz = maxsz - bp->b_blkno;
+		if (sz <= 0) {
+			bp->b_error = EINVAL;
+			goto bad;
+		}
+		bp->b_bcount = sz << DEV_BSHIFT;
+	}               
+
+	/* calculate cylinder for disksort to order transfers with */
+	bp->b_resid = (bp->b_blkno + p->p_offset) / lp->d_secpercyl;
+	return(1);
+bad:
+	bp->b_flags |= B_ERROR;
+	return(-1);
+}