added first page from section 8 and testing google's svn

pages/e08-01

@@ -0,0 +1,54 @@
+/ u8 -- unix
+
+rtap: / read from the dec tape
+	asr	r1 / divide the i-number by 2
+	sub	$4.,r1 / (i-number/2)-r r1
+	mov	r1,cdev / cdev now has device number
+	jsr	r0,bread; 578. / read in block thats in *u.fofp
+wtap:
+	asr	r1 / divide i-number by 2
+	sub	$4.,r1 / r1 = i-number minus 4
+	mov	r1,cdev / this is used as the device number
+	jsr	r0,bwrite; 578. / write block (u.fofp) on dec tape
+				/ Maximum
+
+rrk0:
+	mov	$1,cdev / set current device to 1., disk
+	jsr	r0,bread; 4872. / read block from disk (maximum block
+				/ number allowed on device is 4872.)
+				/ - (u.fofp) contains block number
+
+wrk0:
+	mov	$1,cdev / set current device to 1; disk
+	jsr	r0,bwrite; 4872. / write block (u.fofp) on disk
+
+rrf0:
+	clr	cdev / set current device to 0., fixed head disk
+	jsr	r0,bread; 1024. / read block (u.fofp) from fixed head
+				/ disk (max. block number allowed on
+				/ device is 1024.)
+
+wrf0:
+	clr	cdev / set current device to 0., fixed head disk
+	jsr	r0,bwrite; 1024. / write block '(u.fofp)' on fixed head
+				 / disk
+
+bread: / read a block from a block structured device
+	jsr	r0,tstdeve / error on special file I/O (only works on
+			   / tape
+	mov	*u.fofp,r1 / move block number to r1
+	mov	$2.-cold,-(sp) / "2-cold" to stack
+1:
+	cpm	r1,(r0)	/ is this block # greater than or equal to
+			/ maximum block # allowed on device
+	bhis	if / yes, if (error)
+	mov	r1,-(sp) / no, put block # on stack
+	jsr	r0,preread / read in the block into an I/O buffer
+	mov	(sp)+,r1 / return block # to r1
+	inc	r1 / bump block # to next consecutive block
+	dec	(sp) / "2-1-cold" on stack
+	bgt	1b / 2-1-cold = 0?  No, go back and read in next block
+1:
+	tst	(sp)+ / yes, pop stack to clear off cold calculation
+	mov	*u.fofp,r1 / restore r1 to initial value of the
+			   / block #