The driver interrogates the controller to determine the type of drive attached. The driver recognizes the following drives: 7912, 7914, 7933, 7936, 7937, 7945, 757A/B, 7958A/B, 7959B, 7962, 7963, 9122, 9134, 7912, 7936, and 9122, not all of which have been tested. Special file names begin with ‘
rd' and ‘
rrd' for the block and character files respectively. The second component of the name, a drive unit number in the range of zero to seven, is represented by a ‘
?' in the disk layouts below. The last component of the name is the file system partition and is designated by a letter from ‘
a' to ‘
h' which also corresponds to a minor device number sets: zero to seven, eight to 15, 16 to 23 and so forth for drive zero, drive two and drive three respectively (see
physio(4)). The location and size (in sectors) of the partitions for these drives:
7914CT/P partitions:
rd?f
179648
78400
802-1151
rd?g
56448
201600
252-1151
rd?h
81088
176960
362-1151
7958A partitions:
rd?e
64764
100800
257-656
rd?f
165564
89712
657-1012
rd?g
48636
206640
193-1012
rd?h
64764
190512
257-1012
7957A partitions:
rd?f
113344
46200
736-1035
rd?g
40810
118734
265-1035
rd?h
58520
101024
380-1035
7933H partitions:
rd?e
99866
165646
167-443
rd?f
265512
165646
444-720
rd?g
83720
706238
140-1320
rd?h
431158
358800
721-1320
7936H partitions:
rd?e
100737
120540
117-256
rd?f
220416
120540
256-395
rd?h
341817
259161
397-697
7937H partitions:
rd?e
100737
246246
63-216
rd?f
346983
246246
217-370
rd?g
84747
1031355
53-697
rd?h
593229
522873
371-697
7957B/7961B partitions:
rd?f
115668
44226
918-1268
rd?g
48888
111006
388-1268
rd?h
65268
94626
518-1268
7958B/7962B partitions:
rd?e
65772
121716
174-495
rd?f
187488
109620
496-785
rd?g
49518
247590
131-785
rd?h
65772
231336
174-785
7959B/7963B partitions:
rd?e
82404
303912
218-1021
rd?f
386316
207900
1022-1571
rd?g
65772
528444
174-1571
rd?h
82404
511812
218-1571
The eight partitions as given support four basic, non-overlapping layouts, though not all partitions exist on all drive types.
In the first layout there are three partitions and a ``bootblock'' area. The bootblock area is at the beginning of the disk and holds the standalone disk boot program. The
rd?a partition is for the root file system,
rd?b is a paging/swapping area, and
rd?g is for everything else.
The second layout is the same idea, but has a larger paging/swapping partition (
rd?d) and a smaller ``everything else'' partition (
rd?h). This layout is better for environments which run many large processes.
The third layout is a variation of the second, but breaks the
rd?h partition into two partitions,
rd?e and
rd?f.
The final layout is intended for a large, single file system second disk. It is also used when writing out the boot program since it is the only partition mapping the bootblock area.