File: Drobo.py

package info (click to toggle)
drobo-utils 0.6.1+repack-2
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid, stretch
  • size: 1,000 kB
  • ctags: 172
  • sloc: python: 1,705; sh: 229; makefile: 65
file content (1389 lines) | stat: -rwxr-xr-x 45,103 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
"""
The Drobo module is used to get configuration data 
from a Data Robotics Inc. "Drobo" storage unit.
  
The ways of querying the unit are derived mostly from:
        DROBO Management Protocol Specification Rev. A.0 03/08

referred herein as 'DMP Spec'.  Another source of data was the
droboprotocoldefs.h file (referred to as dmp.h).  The last source 
of information is what the device actually does.  Many inconsistencies 
were identified.  ERRATA is used to identify when a conflict was apparent.

tested with firmware: 1.0.3 and later...

( Drobo is a trademark of Data Robotics Inc. )

copyright:
Drobo Utils Copyright (C) 2008,2009  Peter Silva (Peter.A.Silva@gmail.com)
Drobo Utils comes with ABSOLUTELY NO WARRANTY; For details type see the file
named COPYING in the root of the source directory tree.

"""

import fcntl, struct, socket, array, commands, time
import exceptions
import os, sys, re
import types

#only for fw download...
import os.path
import urllib2
import zipfile,zlib

#only for simulation mode...
import random

# maximum transaction ID before wrapping...
MAX_TRANSACTION = 250

# obviously need to update this with every release.
VERSION = '0.6.1'


# set to non-zero to increase verbosity of library functions.
DEBUG = 0
# It's a bit field, 
DBG_Chatty = 0x01 
DBG_HWDialog = 0x02
DBG_Instantiation = 0x04
#DBG_DMP = 0x08 # C-layer...  not used here...
DBG_Detection = 0x10
DBG_General = 0x20 

# This isn't entirely simulation mode.  It is to aid development
# when no drobo is available.  You can format random disks, including 
# non-drobos.  So do not activate unless you read what the code does first.
# in simulation mode, can run non-root, best for GUI work.
DBG_Simulation = 0x80

#for generic SCSI IO details...
import DroboIOctl


class DroboException(exceptions.Exception):
  """  If there is a problem accessing the Drobo, this exception is raised.
  """
  def __init__(self, msg="Unknown"):
      self.msg = msg

  def __str__(self):
     print "Problem accessing a Drobo: " + self.msg

def _ledstatus(n):
    """ return colors decoded, given numeric slot status 
            goal: match what the lights are doing on the unit.

        STATUS: working with ERRATA:
        Developer Notes:
        The spec says: status is high order 3 bits, and starting from 0, goes:
		green, yellow, Red, ( Green Yellow )

        dmp.h says:
        forget the high order 3 bits, it's the whole byte.
        off is supposed to be 0, but doesn't match when flashing red green..
           off, red, yellow, green, yellow-green, red-green, red-off, red-yellow 

        my drobo says: 
                high order bits always 0. status seems to use whole byte.
		green is 3,  
		flashing red-green is 4...  which dmp.h says is yellow green
                flashing red-black is 6...  agrees with dmp.h
		0x80 is indeed an empty slot, as per dmp.h
                unknown-- yellow-green...
        matches neither... hmm...        
    """
    colourstats=[ 'black', 'red', 'yellow', 'green', ['red', 'green'], 
      [ 'red', 'yellow' ], ['red', 'black'] ] 
    if DEBUG & DBG_General:
         print 'colourstats, argument n is: ', n
    if ( n == 0x80 ):  # empty
       return 'gray'
    return colourstats[n & 0x0f ]


def _unitstatus(n):
    """ return string, given numeric unit status 
   
    STATUS: working with ERRATA:
        here is what the spec says should work (integers...):
    ust = [ 'Normal', 'Red Threshold Exceeded', 'Yellow Threshold Exceeded',
      'No Disks',  'Bad Disk',  'Multiple Disks Removed', 'No Redundancy', 
      'No Magic Hotspare', 'Unit Full', 'Relay Out in Progress', 
      'Format in Progress' ]
    return ust[n]   

    the .h files says... no stupid... it's bit fields.  I don't much care
    as long as folks make up their mind. I have a higher regard for the .h
    so that implementation is active.
    """
    f = []
    if ( n & 0x0002 ):
       f.append( 'Red alert' )
    if ( n & 0x0004 ):
       f.append( 'Yellow alert' )
    if ( n & 0x0008 ):
       f.append( 'No disks' )
    if ( n & 0x0010 ):
       f.append( 'Bad disk' )
    if ( n & 0x0020 ):
       f.append( 'Too many missing disks' )
    if ( n & 0x0040 ):
       f.append( 'No redundancy' )
    if ( n & 0x0080 ):
       f.append( 'No magic hotspare' )
    if ( n & 0x0100 ):
       f.append( 'no space left' )
    if ( n & 0x0200 ):
       f.append( 'Relay out in progress' )
    if ( n & 0x0400 ):
       f.append( 'Format in progress' )
    if ( n & 0x0800 ):
       f.append( 'Mismatched disks' )
    if ( n & 0x1000 ):
       f.append( 'Unknown version' )
    if ( n & 0x2000 ):
       f.append( 'New firmware installed' )
    if ( n & 0x4000 ):
       f.append( 'New LUN available after reboot' )
    if ( n & 0x10000000):# was going to say 'Let us pray...', but no need to alarm people.
       f.append( 'Unknown error' ) 

    return f

def _partformat(n):
    """ return Drobo's idea of what the partition type is

        STATUS: working with ERRATA: 
           the codes are wonky...

           dmp.h says 0x08 for EXT3, but my Drobo says, 0x80 
                 says 0x01 is 'no format', but my Drobo says that is NTFS.
           tried added >>4 but that

	   says only one bit is supposed to be set, but, I dunno if I trust it.

           returning a tuple for now.
    """
    f = []
    
    if ( n & 0x01 ):
       f.append( 'NTFS' )
    if ( n & 0x02 ):
       f.append( 'NO FORMAT' )
    if ( n & 0x04 ):
       f.append( 'HFS' )
    if ( n & 0x80 ): # on Peter's...
       f.append( 'EXT3' )
    #if ( n & 0x08 ): # on Matthew Mastracci's
    #   f.append( 'EXT3' )
    if ( n & 0xFF ) == 0:
       f.append( 'FAT32' )

    if (len(f) != 1):
      print 'hoho! multiple partition types! Brave are we not?' 

    return f


def _partscheme(n):
   """ return what drobo thinks the partition scheme is

       STATUS: working, no issues.
       Have set all of them on my drobo using parted, was detected correctly.
   """
   if (n == 0):
     return "No Partitions"
   if (n == 1):
     return "MBR"
   if (n == 2):
     return "APM"
   if (n == 3):
     return "GPT"
   
def _unitfeatures(norig):
    """ return a list of features supported by a unit
    
        STATUS: working.
        this comes straight from dmp.h.. what they mean isn't documented.
        stuff that looks wrong:	
		-- USED_CAPACITY... should be USE_CAPACITY ... no 'D'
		-- all the 'SUPPORTS' texts are redundant. every bit is about
                   what is supported.  It should be just LUNINFO2
         etc...			
         feature x0800 and 0x2000 show up on my Drobo v1 running 1.3.0...
         of course, do not know what they are...
    """
    n=norig
    feature_map = [ ( 0x001, 'NO_AUTO_REBOOT' ), ( 0x0002, 'NO_FAT32_FORMAT' ),
       ( 0x0004, 'USED_CAPACITY_FROM_HOST' ), ( 0x0008, 'DISKPACKSTATUS' ),
       ( 0x0010, 'ENCRYPT_NOHEADER' ), ( 0x0020, 'CMD_STATUS_QUERIABLE' ),
       ( 0x0040, 'VARIABLE_LUN_SIZE_1_16' ), ( 0x0080, 'PARTITION_LUN_GPT_MBR' ),
       ( 0x0100, 'FAT32_FORMAT_VOLNAME' ), ( 0x0200, 'SUPPORTS_DROBOSHARE' ),
       ( 0x0400, 'SUPPORTS_NEW_LUNINFO2' ), ( 0x0800, 'feature x0800' ),
       ( 0x1000, 'LUN_MANAGEMENT' ), ( 0x2000, 'feature x2000 ' ), 
       ( 0x4000, 'SUPPORTS_OPTIONS2' ), ( 0x8000, 'SUPPORTS_SHUTDOWN' ), 
       ( 0x80000000, 'SUPPORTS_SINGLE_LUN_FORMAT' ), ( 0x40000000, 'SUPPORTS_VOLUME_RENAME' ) ]
    f = []
    for feature in feature_map:
        #print "checking for %s %04x in %04x: " % ( feature[1], feature[0], n )
        if n & feature[0] :
          n = n & ~ feature[0]
          f.append( feature[1] )
    if n != 0:
        f.append( "leftovers (%04x)" % n )

    return f

class Drobo:
  """
  Drobo the class for data exchange with the storage units.
  
  briefly, communicates using SCSI sub_page blocks. 
  There are member functions for each page type...

  See the DMP Spec for details.

  All capacity returned are in bytes.

  the rest of this comment is destined only for Drobo.py developers, not users:
  DMP Spec ERRATA, by subpage:
         - in config, last Q is capacity, manual says bytes, sample code 
           says *512, which works better... so actual quantity is 512 byte blocks.
         - in slotinfo, 
            'managed capacity' is always 0, is that OK? 

         - in version, seems to want an extra byte. BB fails, but BBB works... returns  
         - in settings, the 32 byte name starts with a null byte before 
            'TRUSTED DATA', is that normal?
  """


  def __init__(self,chardevs,debugflags=0):
     """ chardev is /dev/sdX... 
         the character device associated with the drobo unit
     """   
     global DEBUG

     DEBUG=debugflags

     if DEBUG & DBG_Instantiation :
        print '__init__ '

     self.fd=None

     if type(chardevs) is types.ListType:
        self.char_dev_file = chardevs[0]
        self.char_devs = chardevs
     else:
        self.char_dev_file = chardevs
        self.char_devs = [ chardevs ]

     self.features = []    
     self.transactionID=random.randint(1,MAX_TRANSACTION)

     self.relaystart=0
 
     if DEBUG & DBG_Simulation == 0:
        self.fd=DroboIOctl.DroboIOctl(self.char_dev_file,0,debugflags)
        if self.fd == None :
            raise DroboException

        # more thorough checks for Drobohood...
        # for some reason under ubuntu intrepid, start getting responses of all bits set.
        # need some ways to spot a real drobo.  
        cfg = self.GetSubPageConfig()

        #Side effect: Config, sets self.slot_count...

        if DEBUG & DBG_Detection:
            print "cfg: ", cfg

        if ( len(cfg) != 3 ): # We ask this page to return three fields...
            if DEBUG & DBG_Detection:
              print "%s length of cfg is: %d, should be 3" % (self.char_dev_file, len(cfg))
	    raise DroboException 

        if ( self.slot_count < 4 ): 
            if DEBUG & DBG_Detection:
              print "%s cfg[0] = %s, should >= 4. All Drobos have at least 4 slots" % (self.char_dev_file, cfg[0])
	    raise DroboException # Assert: All Drobo have 4 slots.
 
        set=self.GetSubPageSettings()
        if DEBUG & DBG_Detection:
            print "settings: ", set

        fw=self.GetSubPageFirmware()
        if ( len(fw) < 8 ) and (len(fw[7]) < 5):
            if DEBUG & DBG_Detection:
              print "%s length of fw query: is %d, should be < 8." % (self.char_dev_file, len(fw))
              print "%s len(fw[7]) query: is %d, should be < 5." % (self.char_dev_file, len(fw[7]))
            raise DroboException

        if ( fw[6].lower() != 'armmarvell' ):
            if DEBUG & DBG_Detection:
              print "%s fw[6] is not armmarvell." % self.char_dev_file
            raise DroboException
        
 
  def __del__(self):

     if DEBUG & DBG_Instantiation :
        print '__del__ '

     if self.fd != None :
           self.fd.closefd()

     self.fd=None


  def format_script(self,fstype='ext3'):
     """ return a shell script giving the code to commands required to 
     format the single LUN represented by a given drobo...
     
     pscheme is one of: mbr, apt, gpt,  
          gpt - >= 2 TB, linux or windows...
          mbr <= 2 TB good for FAT32

     fstype is one of:  fat32, ext3, ntfs (HPS+ is not supported on linux)
     sizes in terabytes

     not implemented yet...
     each lun is formatted as a single primary partition.
     partitions are never marked bootable.

     need to detect each lun...

     algorithm:
	do discoverLUNs()
        figure out which LUNs belong to the current Drobo... How?
          -- do not want to partition LUNS on another Drobo!
             That would be bad!

        for l in LUN:
            parted /dev/sd?? mklabel gpt mkpart pri ext2 0 -1
            mke2fs -j ... /dev/sd??

     """    

     format_script='/tmp/fmtscript'
     fd=open(format_script, 'w')
     fd.write( "#!/bin/sh\n" )

     if fstype == 'FAT32' or fstype == 'msdos':
         ptype='msdos'
     else:
         ptype='gpt' 

     for cd in self.char_devs:
        fd.write( "parted -s %s mklabel %s\n" % (cd, ptype) )

        # there is a bit of a race condition creating the partition special file.
        # the parted print gives a little time before starting the mkfs, to ensure
        # file is there...

        if fstype == 'ext3': 
            # -m 0 -- Drobo takes care of complaining when near the size limit.
            #         little point in complaining early, pretending you have less space.
            # ^resize_inode -- Drobo makes the file system much bigger than the actual space
            #       available ( >= 2TB ) , so it doesn't make sense to allow space for future
            #       inode expansion beyond that.  only makes sense in LVM, that's why this
            #       option is 'off' (the '^' at the beginning.)
            # sparse_super -- there are lots too many superblock copies made by default.
            #       safe enough with fewer.
            fd.write( "parted -s %s mkpart ext2 0 100%%\n" % cd )
            fd.write( "parted -s %s print; sleep 5\n" % cd )
            fd.write( 'mke2fs -j -i 262144 -L Drobo01 -m 0 -O sparse_super,^resize_inode %s1\n' % cd )
        elif fstype == 'ntfs':
            fd.write( "parted -s %s mkpart ntfs 0 100%%\n" % cd )
            fd.write( "parted -s %s print; sleep 5\n" % cd )
            fd.write( 'mkntfs -f -L Drobo01  %s1\n' % cd )
        elif fstype == 'FAT32' or fstype == 'msdos':
            fd.write( "parted -s %s mkpart primary fat32 0 100%%\n" % cd )
            fd.write( "parted -s %s print; sleep 5\n" % cd )
            fd.write( 'mkdosfs -v -v -F 32 -S 4096 -n Drobo01 %s1\n' % cd )
        else:
            print 'unsupported  partition type %s, sorry...' % fstype

     fd.close()
     os.chmod(format_script,0700)

     #if DEBUG & DBG_Simulation !=0:
     return format_script 
     #fmt_process = subprocess.Popen( format_script, close_fds=True )
     #pid, sts = os.waitpid(fmt_process.pid, 0)
     

  def __getsubpage(self,sub_page,pack): 
    """Retrieve Sub page from drobo block device.
       Uses DroboIOctl class to run the raw ioctl.

       sub_page: selection code from DMP Spec...
       pack: the pattern of fields in the subpage...

       returns: a list unpacked according to the  structure 

       Each sub_page has a standard header:
           pack is prepended with a standard header '>BBH'
       Drobo is bigendian.
       first byte has some flags and a vendor code.
       second byte is the sub-page code.
       following two bytes have the length of the record (max: 65535)
    """
    if DEBUG & DBG_HWDialog:
       print 'getsubpage'

    if DEBUG & DBG_Simulation:
       return ()

    mypack = '>BBH' + pack
    paklen=struct.calcsize(mypack)

    modepageblock=struct.pack( ">BBBBBBBHB", 
         0x5a, 0, 0x3a, sub_page, 0, 0, 0, paklen, 0 )

    cmdout = self.fd.get_sub_page(paklen, modepageblock,0, DEBUG)

    if len(cmdout) != paklen:
      raise DroboException("cmdout is unexpected length")

    result = struct.unpack(mypack, cmdout)
    if DEBUG & DBG_HWDialog :
        print '4 byte returned sense buffer header: 0x%x, 0x%x, 0x%x' % result[:3]
    return result[3:]

  def __transactionNext(self):
    """ Increment the transaction member for some modeSelect pages.
    """
    if (self.transactionID > MAX_TRANSACTION):
       self.transactionID=0
    self.transactionID=self.transactionID+1


  def __issueCommand(self,command):
    """ issue a command to a Drobo...
     0x06 - blink.
     0x0d - Standby

     returns nothing, look at the drobo to see if it worked.
     note: command is asynchronous, returns before operation is complete.
    """

    if DEBUG & DBG_HWDialog:
        print 'issuecommand...'

    if DEBUG & DBG_Simulation:
        self.__transactionNext()
        return

    modepageblock=struct.pack( ">BBBBBBBHB", 
         0xea, 0x10, 0x00, command, 0x00, self.transactionID, 0x01 <<5, 0x01, 0x00 )

    try:
       cmdout = self.fd.get_sub_page(1, modepageblock,1,DEBUG)

    except:
       print 'IF you see, "bad address", it is because you need to be the super user...'
       print " try sudo or su ...       "
       sys.exit()

    self.__transactionNext()

    if ( len(cmdout) != 1 ):
       raise DroboException
    # only way to verify success is to look at the Drobo...

  def Sync(self,NewName=None):
    """  Set the Drobo's current time to the host's time,
	 and the name to selected value.

     STATUS: works, maybe...
        DRI claims Drobos are all in California time.  afaict, it ignores TZ completely.
        I feed it UTC, and when I read the time, normal routines convert to local time.
        so it looks perfect.  but diagnostics might not agree.
    """
    if DEBUG & DBG_Simulation:
       return
 
    now=int(time.time())
    payload="LH32s"
    payloadlen=struct.calcsize(payload)
    if NewName==None:
    	NewName=self.GetSubPageSettings()[2]

    buffer=struct.pack( ">BBH" + payload , 0x7a, 0x05, payloadlen, now, 0 , NewName )
    sblen=len(buffer)

    # mode select CDB. 
    modepageblock=struct.pack( ">BBBBBBBHB", 0x55, 0x01, 0x7a, 0x05, 0, 0, 0, sblen, 0)
    self.fd.put_sub_page( modepageblock, buffer, DEBUG )

  def SetOptions(self,options):
    """ Set Options.
        accepts a set of options as returned by GetSubPageOptions

    STATUS:  UNTESTED!
         basic thresholds work on Drobo v1.
         OPTIONS2 is just a guess, have no Pro, cannot test.

    """
    # v1 Options first...
    fmt = 'BBBLBB'
    payloadlen=struct.calcsize(fmt)
    buffer = struct.pack(">BBH" + fmt, 0x7a, 0x30, payloadlen, options["YellowThreshold"], options["RedThreshold"], 0, 0, 0, 0 )
    sblen=len(buffer)
    modepageblock=struct.pack( ">BBBBBBBHB", 0x55, 0x01, 0x7a, 0x30, 0, 0, 0, sblen, 0)
    self.fd.put_sub_page( modepageblock, buffer, DEBUG )

    # These are for the DroboPro.  UNTESTED.
    if ( 'SUPPORTS_OPTIONS2' in self.features ):
      fmt = 'QHLL490B' 
      payloadlen=struct.calcsize(fmt)
      rawip = struct.unpack('I', socket.inet_aton(options['IPAddress']))
      rawnm = struct.unpack('I',socket.inet_aton(options['NetMask']))
      flags=0
      if (d["DualDiskRedundancy"]):
        flags |= 0x0001
      if (d["SpinDownDelay"]):
        flags |= 0x0002
      if (d["UseManualVolumeManagement"]):
        flags |= 0x0004
      if (d["UseStaticIPAddress"]):
        flags |= 0x0008

      buffer = struct.pack(">BBH" + fmt, 0x7a, 0x31, payloadlen, \
        flags, options["SpinDownDelayMinutes"], \
        rawip, rawnm, "" )
      sblen=len(buffer)
      modepageblock=struct.pack( ">BBBBBBBHB", 0x55, 0x01, 0x7a, \
        0x31, 0, 0, 0, sblen, 0)
      self.fd.put_sub_page( modepageblock, buffer, DEBUG )

    return


  def SetLunSize(self,tb):
    """
       SetLunSize - Sets the maximum LUN size to 'tb' terabytes

       status:  works with no issues!
    """
    if (DEBUG & DBG_Chatty):
       print 'set lunsize to %d TiB' % tb

    if not self.umount():
       if (DEBUG & DBG_Chatty):
          print 'cannot free up Drobo to set lunsize'
       return

    buffer=struct.pack( ">l", tb )
    sblen=len(buffer)

    # mode select CDB. 
    modepageblock=struct.pack( ">BBBBBBBHB", 
      0xea, 0x10, 0x0, 0x0f, 0, self.transactionID, (0x01 <<5)|0x01, sblen, 0x00 )

    self.fd.put_sub_page( modepageblock, buffer, DEBUG )
    self.__transactionNext()


  def SlotCount(self):
    self.GetSubPageConfig()
    return self.slot_count

  def Blink(self):
    """ asks the Drobo nicely to blink it's lights. aka. Identification 
        If you happen to have five in a row (drool), you can know which is which.

        STATUS: works, no issues.
    """
    self.__issueCommand(6)


  def Standby(self):
    """ asks the Drobo nicely to shutdown, flushing all manner of caches.

        STATUS: command itself works, no issues.... only light tests so far.
                still testing umount code.
    """
    if self.umount():
      self.__issueCommand(0x0d)


  def GetDiagRecord(self,diagcode,decrypt=0):
    """ returns diagnostics as a string...
        diagcodes are either 4 or 7 for the two different Records available.

	STATUS: works fine.

        decryption done in drobom (look at diagprint)
    """
    if DEBUG & DBG_Chatty:
      print "Dumping Diagnostics..."

    # tried 32000 ... it only returned 5K, so try something small.
    buflen=4096

    modepageblock=struct.pack( ">BBBBBBBHB", 
      0xea, 0x10, 0x80, diagcode, 0x00, self.transactionID, (0x01 <<5)|0x01, buflen, 0x00 )

    todev=0

    if DEBUG & DBG_General:
        print "Page 0..."

    cmdout = self.fd.get_sub_page( buflen, modepageblock, todev, DEBUG )
    diags=cmdout
    i=0
    while len(cmdout) == buflen:
        modepageblock=struct.pack( ">BBBBBBBHB", 
            0xea, 0x10, 0x80, diagcode, 0x00, self.transactionID, 0x01, buflen, 0x00 )

        cmdout = self.fd.get_sub_page( buflen, modepageblock, todev, DEBUG )
        i=i+1
	diags=diags+cmdout

        if DEBUG & DBG_General:
            print "diags ", i, ", cmdlen=", len(cmdout), " diagslen=", len(diags)
       
    return diags


  def dumpDiagnostics(self):

    n=time.gmtime()

    dfname="/tmp/DroboDiag_%d_%02d%02d_%02d%02d%02d.log" % ( n[0:6] )
    df=open(dfname, "w")
    d=self.GetDiagRecord(4)
    df.write(d)
    d=self.GetDiagRecord(7)
    self.__transactionNext()
    df.write(d)
    df.close()
    return dfname

  def decodeDiagnostics(self,diagfilename):
    try:
      f=open( diagfilename )
      data = f.read()
      f.close()
    except:
      return ''

    key = ord(data[0]) ^ 0x2d
    datam = ''.join(map( lambda x: chr(ord(x)^key), data ))
    return datam



  #
  # constants for use with firmware operations
  #

  fwsite="ftp://updates.drobo.com/"
  localfwrepository= os.path.expanduser("~") + "/.drobo-utils"

  def localFirmwareRepository(self):
     return Drobo.localfwrepository

  def PickFirmware(self,name):
    """
       read in a given firmware from disk.

       sets self.fwdata

    """
    if (DEBUG & DBG_Chatty):
       print 'Reading Firmware from = %s' % name

    if ( name[-1] == 'z' ): # data is zipped...
       inqw=self.inquire()
       hwlevel=inqw[10] 
       z=zipfile.ZipFile(name,'r')
       for f in z.namelist():
           if (DEBUG & DBG_General):
              print f , ' ? '
              print 'firmware for hw rev ', f[-5] , ' this drobo is rev ', hwlevel[0]
	   if f[-5] == hwlevel[0]:
              self.fwdata = z.read(f) 
    else: # old file...
       f = open(name,'r')
       self.fwdata = f.read()
       f.close()

    good = self.validateFirmware()
    return good

  def inquire(self):
    """ 
     issue a standard SCSI INQUIRY command, return standard response as tuple.

     STATUS: works.

     trying to understand how to send an INQUIRY:
     SCSI version 2 protocol  INQUIRY...
     protocol : T10/1236-D Revision 20

     byte:  0 - descriptor code.                0x12 -- INQUIRY
            1 - 00 peripheral dev. type code    0x0, 4, 5, 7, e .. 
            2 - reserved
            3 - reserved.
            4-27   target descriptor parameters.
                 0 - target descriptor type code: 0x04 - Identification.

            28-31  dev. type params.

    """
    mypack = '>BBBBBBBB8s16s4s20sBB8HH'
    paklen=struct.calcsize(mypack)

    modepageblock=struct.pack( "BBBBBB", 0x12 , 0, 0, 0, paklen, 0 )

    cmdout = self.fd.get_sub_page(paklen, modepageblock,0, DEBUG)
    if ( len(cmdout) == paklen ):
      return struct.unpack(mypack, cmdout)
    else:
      raise DroboException


    
  def PickLatestFirmware(self):
    """
       fetch firmware from web site. ... should be a .tdf file.
       validate firmware from header...
 
       sets self.fwdata

       go to fwsite
       download index.txt
       figure out which one to download.
       return arch and version of firmware running, and the download file name.
       SCSI INQUIRY is supposed to respond with 'VERSION' 1.0 or 2.0 to tell which to use.
       tdz support: zip file containing two .tdf's.  one for rev1, another for rev2.

     status: works 


    """
    if DEBUG & DBG_Simulation:
       return ('fwarch', 'fwv', 'hwlevel', 'value')

    inqw=self.inquire()
    hwlevel=inqw[10] 
    fwi=self.GetSubPageFirmware()
    fwv= str(fwi[0]) + '.' + str(fwi[1]) + '.' + str(fwi[2])

    #FIXME ugly hack to force v1 to get onto the v2 firmware stream
    #  current dri index.txt file says v1's should run 1.1.2, but win/Mac dashboards upgrade
    #  to 1.2.4 anyways...  so I guess linux should too.
    #  if a v1 is running 1.1.2, then just claim to be an early v2 firmware, all should work.
    #if fwv == "1.200.11177": 
    #   fwv="1.201.12942"     

    fwarch = fwi[6].lower()

    if (DEBUG & DBG_Chatty):
      print 'looking for firmware for:', fwarch, fwv, 'hw version:', hwlevel
    listing_file=urllib2.urlopen( Drobo.fwsite + "index.txt")
    list_of_firmware_string=listing_file.read().strip("\t\r")
    list_of_firmware=list_of_firmware_string.split("|") 
    i=1
    p = re.compile('\[(.*)\]')
    while i < len(list_of_firmware):
      key=list_of_firmware[i-1].split()[1]
      value=list_of_firmware[i].split()[1]

      k=key.split('/')
      
      # profits oblige...
      if k[2] == "licensed" : 
        k = k[0:2] + k[3:]
        #print k
   
      # these If's are now nested for ease of debugging, insert a print to taste...
      # the algorithm is wrong wrt, other platforms...
      if k[2] == "firmware" :
        #print '    match firmware'
        if k[3] == fwarch :
          #print '    match k[3] = ', fwarch
          #if we are on a line that lists the fwversion in [] fixup k[4]
          m=p.search(list_of_firmware[i-1])
          if m :
              k[4]=m.group(1);
          if k[4] == fwv:
              if len(k) > 4: 
                if (DEBUG & DBG_Chatty):
                   print 'This Drobo should be running: ', value
                return (fwarch, fwv, hwlevel, value)
      i=i+2
    if (DEBUG & DBG_Chatty):
       print 'no matching firmware found, must be the latest and greatest!'
    return ( '','','','' )

  def downloadFirmware( self, fwname, localfw ):
    """
      download given fw file from network repository.
      load self.fwdata with the data from it

      STATUS: works.
    """
    if (DEBUG & DBG_Chatty):
      print 'downloading firmware ', fwname, '...'
    self.fwdata=None
    firmware_url=urllib2.urlopen( Drobo.fwsite + fwname )
    filedata = firmware_url.read()
    f = open(localfw,'w+')
    f.write(filedata)
    f.close()
    if (DEBUG & DBG_Chatty ) :
        print 'local copy written'

    if ( fwname[-1] == 'z' ): # data is zipped...
       self.PickFirmware(localfw)
    else: 
       self.fwdata=filedata

    if (DEBUG & DBG_Chatty ) :
       print 'downloading done '
    return self.fwdata

  def validateFirmware(self):
    """
       requires self.fwdata to be initialized before calling.
       read in the header of the firmware from self.fwdata.

       check the information in the header to confirm that it is a valid firmware image.

       status:
            works for length, and body CRC.  something wrong with header CRC.

       according to dpd.h:
       (hdrlength, hdrVersion, magic, imageVersion, targetName, sequenceNum, bootFailureCount, imageFlashAddress, imageLength, imageCrc32, about, hdrCrc32 ) = struct.unpack('llll16slllll256sl', self.fwdata[0:304])

       & 0xffffffffL is a kludge to work around CRC32 returning different values on 32 vs. 64 bit platforms.
       can remove once py3k arrives.  (see: http://bugs.python.org/issue1202)
       STATUS: working.

    """
    if (DEBUG & DBG_Chatty):
      print 'validateFirmware start...'
    self.fwhdr = struct.unpack('>ll4sl16slllll256sl', self.fwdata[0:312])

    if  len(self.fwdata) != ( self.fwhdr[0] + self.fwhdr[8] ) :
	print 'header corrupt... Length does not validate.'
	return 0

    if (DEBUG & DBG_Chatty):
      print 'header+body lengths validated.  Good.'
    #print self.fwhdr

    if  self.fwhdr[2] != 'TDIH' :
        print 'bad Magic, not a valid firmware'
        return 0

    if (DEBUG & DBG_Chatty):
      print 'Magic number validated. Good.'
      print '%d + %d = %d length validated. Good.' % ( self.fwhdr[0], self.fwhdr[8], len(self.fwdata) )

    # http://bugs.python.org/issue1202
    # doesn't work on 64 bit, only on 32bit... weird...
    blank = struct.pack('i',0)
    hdrcrc = zlib.crc32( self.fwdata[0:308] + blank + self.fwdata[312:self.fwhdr[0]] ) & 0xffffffffL
    r = self.fwhdr[11] & 0xffffffffL

    if (DEBUG & DBG_Chatty):
      print 'CRC from header: %d, calculated using python zlib crc32: %d ' % ( r, hdrcrc)
    if r != hdrcrc :
        print 'file corrupt, header checksum wrong'
        return 0
    bodycrc = zlib.crc32( self.fwdata[self.fwhdr[0]:] ) & 0xffffffffL
    q = self.fwhdr[9] & 0xffffffffL
 
    if (DEBUG & DBG_Chatty):
      print 'CRC for body from header: %d, calculated: %d ' % ( q, bodycrc)
    if q != bodycrc :
        print 'file corrupt, payload checksum wrong'
        return 0
    
    if (DEBUG & DBG_Chatty):
      print '32 bit Cyclic Redundancy Check correct. Good.'
      print 'validateFirmware successful...'

    return 1 
    

  def updateFirmwareRepository(self):
    """
      put the best firmware in self.fwdata.
            return 1 if successful, 0 if not.

      determine currently running firmware and most current from web site.

      check if the most current one has already been downloaded.
      if not, then download it into a local repository.

      Compare the current running firmware against the appropriate file 
      in the local repository

      STATUS: working...

    """
    (fwarch, fwversion, hwlevel, fwpath ) = self.PickLatestFirmware()
    if fwarch == '' : # already at latest version...
        return 0

    if not os.path.exists(Drobo.localfwrepository) :
         os.mkdir(Drobo.localfwrepository)

    fwname = fwpath.split('/')
    localfw = Drobo.localfwrepository + '/' + fwarch + '_' + hwlevel + '_' + fwname[-1] 
    if (DEBUG & DBG_Chatty):
       print 'looking for: %s' % localfw
    if not os.path.exists(localfw):
       if (DEBUG & DBG_Chatty):
          print 'not present, fetching from drobo.com'
       self.fwdata = self.downloadFirmware(fwpath,localfw)
       good = self.validateFirmware()
       if not good:
          print 'downloaded firmware did not validate.' 
          return 0
    else:
       if (DEBUG & DBG_Chatty):
          print 'local copy already present:', localfw
       good = self.PickFirmware(localfw)

    if good:
      if (DEBUG & DBG_Chatty):
         print 'correct fw available'
      return 1
 
    print 'no valid firmware found'
    return 0
   

  def writeFirmware(self,function):
    """
        given good firmware data, upload it to the Drobo...

	1_README_*.txt from the resource kit is followed here.

        function -- a callback that accepts a single argument, an integer in the range 0-100.
           indicates % done.  the function is called after each write in the loop.

        STATUS: works.

    """ 

    totallength = len(self.fwdata)
    buffer = struct.pack( ">L" , totallength ) + self.fwdata[0:self.fwhdr[0]]

    modepageblock=struct.pack( ">BBBBBBBHB", 
      0xea, 0x10, 0x00, 0x70, 0x00, self.transactionID, (0x01<<5)|0x01, len(buffer), 0x00 )
    
    written = self.fd.put_sub_page( modepageblock, buffer, DEBUG )

    if DEBUG & DBG_General:
      print "Page 0..."

    buflen=32768
    written=buflen
    i=self.fwhdr[0]
    j=i+buflen 
    moretocome=0x01

    if (DEBUG & DBG_General ) :
      print 'writeFirmware: i=%d, start=%d, last=%d fw length= %d\n' % \
         ( i, self.fwhdr[0], totallength, len(buffer) )

    while (written == buflen) and ( i < len(self.fwdata)) :

        if ( i + buflen ) > totallength :  # writing the last record.
        	buflen= totallength - i
                moretocome=0

        modepageblock=struct.pack( ">BBBBBBBHB", 
            0xea, 0x10, 0x00, 0x70, 0x00, self.transactionID, moretocome, 
            buflen, 0x00 )

        j=i+buflen
        written = self.fd.put_sub_page( modepageblock, self.fwdata[i:j], DEBUG )
        i=j

        function(i*100/totallength)

        if (DEBUG & DBG_General ) :
            print 'wrote ',written, ' bytes.  Cumulative: ',  i, ' of', totallength

    if (DEBUG & DBG_General ) :
       print 'writeFirmware Done.  i=%d, len=%d' % ( i, totallength )

    self.__transactionNext()
    
    paklen=1 
    modepageblock=struct.pack( ">BBBBBBBHB",
         0xea, 0x10, 0x80, 0x71, 0, self.transactionID, 0x01 << 5 , paklen, 0 )

    cmdout = self.fd.get_sub_page(paklen, modepageblock,0, DEBUG)
    status = struct.unpack( '>B', cmdout )

    if DEBUG & DBG_General : 
      print 'Drobo thinks write status is: ', status[0]

        


  def GetCharDev(self):
     return self.char_dev_file

  def GetSubPageConfig(self):
     """ returns: ( MaxNumberOfSlots, MaxNumLUNS, MaxLunSize )
     """ 
     # SlotCount, Reserved, MaxLuns, MaxLunSz, Reserved, unused, unused 

     if DEBUG & DBG_Simulation:
        self.slot_count = 8
	return (8, 16, 2199023250944)

     result=self.__getsubpage( 0x01, 'BBBQ'  )
     self.slot_count = result[0]
     return ( result[0], result[2], result[3]*512 )

  def GetSubPageCapacity(self):
     """ returns: ( Free, Used, Virtual, Unprotected ) 
     """
     if DEBUG & DBG_Simulation:
        capacity = 495452160000
        used = random.randint(0,capacity)
	return (capacity-used, used, capacity, 125184245760)

     return self.__getsubpage(0x02, 'QQQQ' )

  def GetSubPageSlotInfo(self):
     """  returns list of slot info, each slot is:
       ( slotId, PhysicalCapacity, ManagedCapacity, leds, Manufacturer, Model ) ... )
       
       leds - indicates what the lights on the front panel are doing.
              returns one colour if one colour is constant, set of
              colours if there is flashing going on.
     """
     if DEBUG & DBG_Simulation:
       return ( 
             (0, 500107862016, 0, 'green', 'ST3500830AS', 'ST3500830AS'), 
             (1, 750156374016, 0, 'green', 'WDC WD7500AAKS-00RBA0', 'WDC WD7500AAKS-0'), 
             (2, 0, 0, _ledstatus(random.randint(0,6)), '', ''), 
             (3, 0, 0, 'gray', '', ''),
             (0, 500107862016, 0, 'green', 'ST3500830AS', 'ST3500830AS'), 
             (1, 750156374016, 0, 'green', 'WDC WD7500AAKS-00RBA0', 'WDC WD7500AAKS-0'), 
             (2, 0, 0, _ledstatus(random.randint(0,6)), '', ''), 
             (3, 0, 0, 'gray', '', '')
       )

     slotrec='HBQQB32s16sL'

     i = 0
     pattern='B'
     while ( i < self.slot_count ): 
        pattern += slotrec
        i +=1
 
     r = self.__getsubpage( 0x03, pattern )

     l=[]
     j=0
     while (j < r[0] ):
       i=j*8
       s = ( r[i+2], r[i+3], r[i+4], _ledstatus( r[i+5] ), r[i+6].strip(" \0"),
		r[i+7].strip(" \0") )
       l.append( s ) 
       j=j+1

     return l


  def GetSubPageLUNs(self):
     """
         returns  for each LUN  returns detailed info:
             ( LUNID, LUN total Capacity, LUN Used Capacity, PartitionScheme*, Partition Count*, Format* )

         *only returned if firmware: SUPPORTS_NEW_LUNINFO2 (essentially >=1.1.0)

      N.B. must run getSubPageFirmware before the first time you
         calling this routine, or it will fail by returning the empty set.


      STATUS: works, with ERRATA:

         report from matthew mastracci that this doesn't work for him... should be +6,
         and the value for ext3 should be 0.0x8, and not 0x80...
         haven't understood it yet...

      question: is it correct to mix 'used capacity' from luninfo, with 
      total capacity from luninfo2?

      for old luninfo, the spec and dmp.h agree... 
      spec says:   
      dmp.h says:  len ( 8* H-len, B-id, Q-cap, Q-used ) 

         returns  for each LUN  returns detailed info:
             ( LUNID, LUN total Capacity, PartitionScheme, PartitionCount, Format )

      for Luninfo2.. works, but 'PartCount' is odd.

      my guess after much experiments: PartitionCount and format are
      inverted vs. dmp.h. the count is last(6th), and the format is 5th..

      even that doesn't work right, because I get partcount=1 when there
      are none, and it stays 1 when I add one.  now there are 8 when there is
      only one... unless 8 is ext2 fs. and I guessed wrong about part types...

      See also ERRATA for _partscheme

      dmp.h says
      8 x H-length, B-LunID, Q-TotalCapacity, B-PartScheme, B-PartCount, B-Format, 5B-rsvd 
     
     """
     if DEBUG & DBG_Simulation:
       return [(0, 2199023251456, 5092651008, 'GPT', ['EXT3'])]

     lp="HBQQ"
     l = self.__getsubpage( 0x04, 'B'+lp+lp+lp+lp+lp+lp+lp+lp )

     if ( 'SUPPORTS_NEW_LUNINFO2' in self.features ):
        li2="HBQBBB5B"
        l2= self.__getsubpage( 0x07, "B"+ li2+li2+li2+li2+li2+li2+li2+li2 )

     i=0
     li=[]
     while ( i < l[0] ):
        j=i*4
        if ( 'SUPPORTS_NEW_LUNINFO2' in self.features ):
           k=i*7
           li.append( (l[j+2], l2[k+3], l[j+4], _partscheme(l2[k+4]), _partformat(l2[k+5]) ) )
        else:
           li.append( (l[j+2], l[j+3], l[j+4]) )
        i=i+1

     return li


  def GetSubPageSettings(self):
     """
        returns: ( currentUTCtime, UTCoffset, DroboName )

        STATUS: works with... 
        ERRATA:
		-- dpd.h and other sources say offset is two bytes.
                -- DMP Spec says it is only one byte.
		-- other sources say it is always set to 'California Time'... 8.
		-- California time is UTC - 8... +8 would be China.
		-- structures returned are supposed to be in network byte order (MSB)
                   when two byte value read in network byte order, result is 2048.
                   they stuff it in LSB order, so the 8 ended up in the higher order byte.
		-- so I just claim it says 8 and shut up.

     """
     if DEBUG & DBG_Simulation:
        return (1220112079, 8, 'TRUSTED DATA')

     ( utc, offset, name ) = self.__getsubpage(0x05, 'LH32s' )
     name=name.strip(" \0")
     offset=8 # offset is screwed up returned by Drobo, just set it to what they claim it should be.
     return ( utc, offset, name )

  def GetSubPageProtocol(self):
     """ 
        returns ( Major, Minor )

        STATUS: working... 
            soupcon: at firmware 1.0.3, seemed to demand an additional byte.
              might be a confused artifact of dev.
            at 1.1.1 the additional byte leads to resid > 0 in the C call, 
            so matches docs. 
     """
     if DEBUG & DBG_Simulation:
         return (0, 10)

     return self.__getsubpage( 0x06, 'BB' )

  def GetSubPageFirmware(self):
     """

        STATUS:  working with ERRATA:

        returns ( majorVer, MinorVer, Build, UpgMajorVer, UpgMinorVer, 
		BuildDate, Arch, )
        above is what the spec says...

	dpd.h says byte 128 has a feature
	    agrees on the first four, but says the date is a 32 char string, and
            is followed by Arch[16], and Extra[256],  

            Drobo has a version string after arch, guessed at 16 chars.
            I shortened Extra for that.
	    byte 0x80 is supposed to be feature flags, found it a 0x73...
     """
     if DEBUG & DBG_Simulation:
        return (1, 201, 12942, 12, 6, 'May 13 2008,15:29:32', 'ArmMarvell', '1.1.2', ['NO_AUTO_REBOOT', 'NO_FAT32_FORMAT', 'USED_CAPACITY_FROM_HOST', 'DISKPACKSTATUS', 'ENCRYPT_NOHEADER', 'CMD_STATUS_QUERIABLE', 'VARIABLE_LUN_SIZE_1_16', 'PARTITION_LUN_GPT_MBR', 'FAT32_FORMAT_VOLNAME', 'SUPPORTS_DROBOSHARE', 'SUPPORTS_NEW_LUNINFO2'])

     raw=self.__getsubpage(0x08, 'BBHBB32s16s16s240s' )
     result = struct.unpack('>112sL32sH90s', raw[8])
     self.features = _unitfeatures(result[1])
     return (raw[0], raw[1], raw[2], raw[3], raw[4], raw[5].strip(" \0"), 
         raw[6].strip(" \0"), raw[7].strip(" \0"), self.features )

  def GetSubPageStatus(self):
     """
     return _unitstatus

     STATUS: works a bit, 
        relayoutcount stuff completely untested...
      Errata: 
      spec says a single byte.
      dmp.h says two longs:  (Status, RelayOutCount)
      Drobo always returns 0 for second Long.
      when I remove a disk, I get [ 'No Redundancy', 'Relay out in progress'],
      but when I format, it stays empty...
     """
     if DEBUG & DBG_Simulation:
         return _unitstatus(random.randint(0,16535))       

     ss=self.__getsubpage(0x09, 'LL' )
     s=_unitstatus(ss[0])

     if ss[1] > 0 : # relay out in progress
        if self.relaystart == 0:
           self.relaystart=time.time()
           self.relayinitialcount=ss[1]
           s.append( 'no estimate yet ' )
        else: 
           now=time.time()
           runningtime=(now - self.relaystart)/60.0
           amtdone= self.relayinitialcount - ss[1]
           amtleft= ss[1]
           pctleft= 100.0 * amtleft / self.relayinitialcount 
           pctdone= 100 - pctleft
           
           if amtdone == 0:
              s.append( 'gathering stats, no estimate yet ' )
           else:
              rate=  pctdone / runningtime 
              timeleft = pctleft*rate  # timeleft in minutes...
              s.append( '%d blocks left ' % ss[1] )
     else:
        if self.relaystart > 0:
           self.relaystart == 0

     return ( s, ss[1] )

  def GetSubPageOptions(self): 
     """
        different fw/hw combinations will return different results.
        return one of:
           None 
               - this drobo does not support Options ( fw < 1.11 )
           ( YellowThresh, RedThresh, AutoDelSnapshot, LowYel, LowRed )
               - drobo supports first version of options ( fw >= 1.11)
  	   ( above + FeatureOnOffStates, SpinDownDelay, IPAddress, Subnetmask ) 
               - DroboPro only ? my v1's don't support it.
	
        STATUS: untested, seems to agree with dmp.h for Options
            Options2 (only on Drobo Pro) completely un-tested.


        DMIP spec says:
           B-YelThresh, B-RedThresh, 5B-Rsvd, 1bit-AutoDel, B-Rsvd

        dmp.h (published 2007 and summer 2009) says:
           B-YelThresh, B-RedThresh, B-Flags, L-DataCheckParam, B-LowYelThresh, B-LowRedThresh.
        
        later firmware version and dmp published in 2009 adds OPTIONS2 with
        hmm...
     """
     if DEBUG & DBG_Simulation:
        return {"YellowThreshold":85, "RedThreshold":95 }

     try: # insert try/except for compatibility with firmware <= 1.1.0  
         #o = self.__getsubpage(0x07, 'BB5BBB' )
         #return ( o[0], o[1], o[4] >>7 )
         #return ( o[0], o[1], o[2], )

         o = self.__getsubpage(0x30, 'BBBLBB' )
         d = { "YellowThreshold": o[0], "RedThreshold": o[1] }
         if ( 'SUPPORTS_OPTIONS2' in self.features ):
             ( pagelen, flags, d['SpinDownDelayMinutes'], \
               rawip, rawnm, reserved ) = \
               self.__getsubpage(0x31, 'QHLL490B' )
             d["DualDiskRedundancy"] = ( flags & 0x0001 ) > 0 
             d["SpinDownDelay"] = ( flags & 0x0002 ) > 0 
             d["UseManualVolumeManagement"] = ( flags & 0x0004 ) > 0 
             d["UseStaticIPAddress"] = ( flags & 0x0008 ) > 0 

             d["IPAddress"]=socket.inet_ntoa(struct.pack('I',rawip))
             d["NetMask"]=socket.inet_ntoa(struct.pack('I',rawnm))
         return d
     except:
         return None

  def umount(self):
    """
       umount all file systems using the given Drobo.
       return true on success, false on failure.
    """

    if DEBUG & DBG_Simulation:
       return True

    toumount = self.DiscoverMounts()
    if len(toumount) > 0:
       for i in toumount:
           if DEBUG & DBG_Chatty:
              print "unmounting: ", i
           umresult=os.system("umount " + i )
           if umresult != 0:
                return False
    return True

  def DiscoverMounts(self):
    """
        return the list of mounted file systems using the unit.
    """

    if DEBUG & DBG_Simulation:
       return [ "/drmnt0", "/drmnt2" ]
    
    mounts=open("/etc/mtab")
    dlen=len(self.char_dev_file)
    filesystems=[]
    for l in mounts.readlines():
       fields=l.split()
       for i in self.char_devs:
          if fields[0][0:dlen] == i:
             filesystems.append(fields[1])
    mounts.close()
    return filesystems

def DiscoverLUNs(debugflags=0):
    """ find all Drobo LUNs accessible to this user on this system. 
	returns a list of list of character device files 
              samples: [ [ "/dev/sdf", "/dev/sdg" ], [ "/dev/sdh" ] ] 
    """
    global DEBUG
    DEBUG=debugflags

    if DEBUG & DBG_Simulation:
       return [ [ "/dev/sdb", "/dev/sdc" ], [ "/dev/sdd" ] ]

    devices=[]

    for potential in DroboIOctl.drobolunlist(DEBUG):
       if ( DEBUG & DBG_Detection ):
             print "trying: ", potential

       try: 
              d = Drobo( potential, DEBUG )
              devices.append(potential)
       except:
 	      pass
              
    return devices