On Mon, 2006-12-04 at 17:06 -0500, T wrote:
> On Mon, 04 Dec 2006 15:06:08 -0500, Greg Folkert wrote:
> 
> > On Sun, 2006-12-03 at 21:14 -0800, Carl Johnson wrote:
> >> > 
> >> > I just created a FAT32 partition using Win2k at /dev/sda16.
> >> > 
> >> > But when I tried to mount it under Linux, I get:
> >> > 
> >> > % mount /dev/sda16 /mnt/tmp1/
> >> > mount: special device /dev/sda16 does not exist
> >> > 
> >> > why the device not exist? [...]
> >> 
> >> If you look at the device numbers for sda16 and sdb under linux I
> >> think you will see why. [...]
> 
> 1st of all, thank you both for the reply.
> 
> I'm using Testing (kernel 2.6.17 + udev), I don't see /dev/sdb in my
> system. 
> 
> > It is part of the SCSI Standard. Even if it is an SATA drive which is an
> > IDE drive in Windows, partition 16 is actually partition 0 on the next
> > drive.
> 
> Both of you has hinted that sda16 should have device numbers as sdb. So I
> gave it a try, as follows:
> 
>   $ ls -l /dev/sda /dev/sda1*
>   brw-rw---- 1 root disk 8,  0 12-04 09:28 /dev/sda
>   brw-rw---- 1 root disk 8,  1 12-04 09:28 /dev/sda1
>   brw-rw---- 1 root disk 8, 10 12-04 14:28 /dev/sda10
>   brw-rw---- 1 root disk 8, 11 12-04 14:28 /dev/sda11
>   brw-rw---- 1 root disk 8, 12 12-04 09:28 /dev/sda12
>   brw-rw---- 1 root disk 8, 13 12-04 14:28 /dev/sda13
>   brw-rw---- 1 root disk 8, 14 12-04 14:29 /dev/sda14
>   brw-rw---- 1 root disk 8, 15 12-04 14:29 /dev/sda15
>   brw-rw---- 1 root disk 9,  0 12-04 16:49 /dev/sda16
>                          ^^^^^
> 
> But that does not work:
> 
> $ mount /dev/sda16 /mnt/tmp1/
> mount: /dev/sda16: can't read superblock
> 
> So is there any workaround so that I can access it? How come my Win2k can
> accesse the sda16 without any problem?

Because it uses IDE drives to access the drive. IDE allows 64
partitions. SATA using "libsata" is classified as a SCSI device. SCSI
dunnah work past a minor 15. And "9,0 block" is not sdb it is /dev/md0.
"8,16 block" is sdb, according to the Major and Minor number references
I find (see further down in the message)

Here is my example of my 2 SATA and 2 "USB-Storage" drive setup
everything automagically setup using udev and hotplug:

[EMAIL PROTECTED]:/dev$ ls -l sd*
brw-rw---- 1 root disk   8,  0 2006-11-27 19:45 sda
brw-rw---- 1 root disk   8,  1 2006-11-27 19:45 sda1
brw-rw---- 1 root disk   8, 16 2006-11-27 19:45 sdb
brw-rw---- 1 root disk   8, 17 2006-11-27 19:45 sdb1
brw-rw---- 1 root floppy 8, 32 2006-12-06 08:10 sdc
brw-rw---- 1 root floppy 8, 33 2006-12-06 08:10 sdc1
brw-rw---- 1 root floppy 8, 34 2006-12-06 08:10 sdc2
brw-rw---- 1 root floppy 8, 48 2006-12-06 08:10 sdd

As you can see the minor numbers are as follows:
        sda =   0 (  1 -  15 usable for partions 1-15)
                sda   =   0     sda1  =   1
                sda2  =   2     sda3  =   3
                sda4  =   4     sda5  =   5
                sda6  =   6     sda7  =   7
                sda8  =   8     sda9  =   9
                sda10 =  10     sda11 =  11
                sda12 =  12     sda13 =  13
                sda14 =  14     sda15 =  15

        sdb =  16 ( 17 -  31 usable for partions 1-15)
                sdb   =  16     sdb1  =  17
                sdb2  =  18     sdb3  =  19
                sdb4  =  20     sdb5  =  21
                sdb6  =  22     sdb7  =  23
                sdb8  =  24     sdb9  =  25
                sdb10 =  26     sdb11 =  27
                sdb12 =  28     sdb13 =  29
                sdb14 =  30     sdb15 =  31

        sdc =  32 ( 33 -  47 usable for partions 1-15)
                sdc   =  32     sdc1  =  33
                sdc2  =  34     sdc3  =  35
                sdc4  =  36     sdc5  =  37
                sdc6  =  38     sdc7  =  39
                sdc8  =  40     sdc9  =  41
                sdc10 =  42     sdc11 =  43
                sdc12 =  44     sdc13 =  45
                sdc14 =  46     sdc15 =  47

        sdd =  48 ( 49 -  63 usable for partions 1-15)
                sdd   =  48     sdd1  =  49
                sdd2  =  50     sdd3  =  51
                sdd4  =  52     sdd5  =  53
                sdd6  =  54     sdd7  =  55
                sdd8  =  56     sdd9  =  57
                sdd10 =  58     sdd11 =  59
                sdd12 =  60     sdd13 =  61
                sdd14 =  62     sdd15 =  63

        sde =  64 ( 65 -  79 usable for partions 1-15)
                sde   =  64     sde1  =  65
                sde2  =  66     sde3  =  67
                sde4  =  68     sde5  =  69
                sde6  =  70     sde7  =  71
                sde8  =  72     sde9  =  73
                sde10 =  74     sde11 =  75
                sde12 =  76     sde13 =  77
                sde14 =  78     sde15 =  79

        sdf =  80 ( 81 -  95 usable for partions 1-15)
                sdf   =  80     sdf1  =  81
                sdf2  =  82     sdf3  =  83
                sdf4  =  84     sdf5  =  85
                sdf6  =  86     sdf7  =  87
                sdf8  =  88     sdf9  =  89
                sdf10 =  90     sdf11 =  91
                sdf12 =  92     sdf13 =  93
                sdf14 =  94     sdf15 =  95

        sdg =  96 ( 97 - 111 usable for partions 1-15)
                sdg   =  96     sdg1  =  97
                sdg2  =  98     sdg3  =  98
                sdg4  = 100     sdg5  = 101
                sdg6  = 102     sdg7  = 103
                sdg8  = 104     sdg9  = 105
                sdg10 = 106     sdg11 = 107
                sdg12 = 108     sdg13 = 108
                sdg14 = 110     sdg15 = 111

        sdh = 112 (113 - 127 usable for partions 1-15)
                sdh   = 112     sdh1  = 113
                sdh2  = 114     sdh3  = 115
                sdh4  = 116     sdh5  = 117
                sdh6  = 118     sdh7  = 119
                sdh8  = 120     sdh9  = 121
                sdh10 = 122     sdh11 = 123
                sdh12 = 124     sdh13 = 125
                sdh14 = 126     sdh15 = 127

        sdi = 128 (129 - 143 usable for partions 1-15)
                sdi   = 128     sdi1  = 129
                sdi2  = 130     sdi3  = 131
                sdi4  = 132     sdi5  = 133
                sdi6  = 134     sdi7  = 135
                sdi8  = 136     sdi9  = 137
                sdi10 = 138     sdi11 = 139
                sdi12 = 140     sdi13 = 141
                sdi14 = 142     sdi15 = 143

        sdj = 144 (145 - 159 usable for partions 1-15)
                sdj   = 144     sdj1  = 145
                sdj2  = 146     sdj3  = 147
                sdj4  = 148     sdj5  = 149
                sdj6  = 150     sdj7  = 151
                sdj8  = 152     sdj9  = 153
                sdj10 = 154     sdj11 = 155
                sdj12 = 156     sdj13 = 157
                sdj14 = 158     sdj15 = 159

        sdk = 160 (162 - 175 usable for partions 1-15)
                sdk   = 160     sdk1  = 161
                sdk2  = 162     sdk3  = 163
                sdk4  = 164     sdk5  = 165
                sdk6  = 166     sdk7  = 167
                sdk8  = 168     sdk9  = 169
                sdk10 = 170     sdk11 = 171
                sdk12 = 172     sdk13 = 173
                sdk14 = 174     sdk15 = 175

        sdl = 176 (177 - 191 usable for partions 1-15)
                sdl   = 176     sdl1  = 177
                sdl2  = 178     sdl3  = 179
                sdl4  = 180     sdl5  = 181
                sdl6  = 182     sdl7  = 183
                sdl8  = 184     sdl9  = 185
                sdl10 = 186     sdl11 = 187
                sdl12 = 188     sdl13 = 189
                sdl14 = 190     sdl15 = 191

        sdm = 192 (193 - 207 usable for partions 1-15)
                sdm   = 192     sdm1  = 193
                sdm2  = 194     sdm3  = 195
                sdm4  = 196     sdm5  = 197
                sdm6  = 198     sdm7  = 199
                sdm8  = 200     sdm9  = 201
                sdm10 = 202     sdm11 = 203
                sdm12 = 204     sdm13 = 205
                sdm14 = 206     sdm15 = 207

        sdn = 208 (209 - 223 usable for partions 1-15)
                sdn   = 208     sdn1  = 209
                sdn2  = 210     sdn3  = 211
                sdn4  = 212     sdn5  = 213
                sdn6  = 214     sdn7  = 215
                sdn8  = 216     sdn9  = 217
                sdn10 = 218     sdn11 = 219
                sdn12 = 220     sdn13 = 221
                sdn14 = 222     sdn15 = 223

        sdo = 224 (223 - 239 usable for partions 1-15)
                sdo   = 224     sda1  = 225
                sdo2  = 226     sda3  = 227
                sdo4  = 228     sda5  = 229
                sdo6  = 230     sda7  = 231
                sdo8  = 232     sda9  = 233
                sdo10 = 234     sda11 = 235
                sdo12 = 236     sda13 = 237
                sdo14 = 238     sda15 = 239

        sdp = 240 (241 - 255 usable for partions 1-15)
                sdp   = 240     sdp1  = 241
                sdp2  = 242     sdp3  = 243
                sdp4  = 244     sdp5  = 245
                sdp6  = 246     sdp7  = 247
                sdp8  = 248     sdp9  = 249
                sdp10 = 250     sdp11 = 251
                sdp12 = 252     sdp13 = 253
                sdp14 = 254     sdp15 = 255

Applying the above info to the info below should give you a clue as to
the complexity of defining devices.

Past /dev/sdp  is Major  65 block device or /dev/sdq  --> /dev/sdaf
Past /dev/sdaf is Major  66 block device or /dev/sdag --> /dev/sdav
Past /dev/sdav is Major  67 block device or /dev/sdaw --> /dev/sdbl
Past /dev/sdbl is Major  68 block device or /dev/sdam --> /dev/sdcb
Past /dev/sdcb is Major  69 block device or /dev/sdcc --> /dev/sdcr
Past /dev/sdcr is Major  70 block device or /dev/sdcs --> /dev/sddh
Past /dev/sddh is Major  71 block device or /dev/sddi --> /dev/sddx
Past /dev/sddx is Major 128 block device or /dev/sddy --> /dev/sden
Past /dev/sden is Major 129 block device or /dev/sdeo --> /dev/sdfd
Past /dev/sdfd is Major 130 block device or /dev/sdfe --> /dev/sdft
Past /dev/sdft is Major 131 block device or /dev/sdfu --> /dev/sdgj
Past /dev/sdgj is Major 132 block device or /dev/sdgk --> /dev/sdgz
Past /dev/sdgz is Major 133 block device or /dev/sdha --> /dev/sdhp
Past /dev/sdhp is Major 134 block device or /dev/sdhq --> /dev/sdif
Past /dev/sdif is Major 135 block device or /dev/sdig --> /dev/sdiv

For a total of 255 SCSI Disk Drives in direct control of the kernel.
Each with upto 15 usable partitions gives you a possibility of 3825
device files for SCSI Drives only.

On the IDE stuff:
        major 3  block = hda (minor 0-63) and hdb (64-127)
            Minor numbers for /dev/hda
                hda   =   0     hda1  =   1
                hda2  =   2     hda3  =   3
                hda4  =   4     hda5  =   5
                hda6  =   6     hda7  =   7
                hda8  =   8     hda9  =   9
                hda10 =  10     hda11 =  11
                hda12 =  12     hda13 =  13
                hda14 =  14     hda15 =  15
                hda16 =  16     hda17 =  17
                hda18 =  18     hda19 =  19
                hda20 =  20     hda21 =  21
                hda22 =  22     hda23 =  23
                hda24 =  24     hda25 =  25
                hda26 =  26     hda27 =  27
                hda28 =  28     hda29 =  29
                hda30 =  30     hda31 =  31
                hda32 =  32     hda33 =  33
                hda34 =  34     hda35 =  35
                hda36 =  36     hda37 =  37
                hda38 =  38     hda39 =  39
                hda40 =  40     hda41 =  41
                hda42 =  42     hda43 =  43
                hda44 =  44     hda45 =  45
                hda46 =  46     hda47 =  47
                hda48 =  48     hda49 =  49
                hda50 =  50     hda51 =  51
                hda52 =  52     hda53 =  53
                hda54 =  54     hda55 =  55
                hda56 =  56     hda57 =  57
                hda58 =  58     hda59 =  59
                hda60 =  60     hda61 =  61
                hda62 =  62     hda63 =  63

            Minor numbers for /dev/hdb
                hdb   =  64     hdb1  =  65
                hdb2  =  66     hdb3  =  67
                hdb4  =  68     hdb5  =  69
                hdb6  =  70     hdb7  =  71
                hdb8  =  72     hdb9  =  73
                hdb10 =  74     hdb11 =  75
                hdb12 =  76     hdb13 =  77
                hdb14 =  78     hdb15 =  79
                hdb16 =  80     hdb17 =  81
                hdb18 =  82     hdb19 =  83
                hdb20 =  84     hdb21 =  85
                hdb22 =  86     hdb23 =  87
                hdb24 =  88     hdb25 =  89
                hdb26 =  90     hdb27 =  91
                hdb28 =  92     hdb29 =  93
                hdb30 =  94     hdb31 =  95
                hdb32 =  96     hdb33 =  97
                hdb34 =  98     hdb35 =  99
                hdb36 = 100     hdb37 = 101
                hdb38 = 102     hdb39 = 103
                hdb40 = 104     hdb41 = 105
                hdb42 = 106     hdb43 = 107
                hdb44 = 108     hdb45 = 109
                hdb46 = 110     hdb47 = 111
                hdb48 = 112     hdb49 = 113
                hdb50 = 114     hdb51 = 115
                hdb52 = 116     hdb53 = 117
                hdb54 = 118     hdb55 = 119
                hdb56 = 120     hdb57 = 121
                hdb58 = 122     hdb59 = 123
                hdb60 = 124     hdb61 = 125
                hdb62 = 126     hdb63 = 127

Please apply above logic to the listings below:

        major 22 block = hdc (minor 0-63) and hdd (64-127)
        major 33 block = hde (minor 0-63) and hdf (64-127)
        major 34 block = hdg (minor 0-63) and hdh (64-127)
        major 56 block = hdi (minor 0-63) and hdj (64-127)
        major 57 block = hdk (minor 0-63) and hdl (64-127)
        major 88 block = hdm (minor 0-63) and hdn (64-127)
        major 89 block = hdo (minor 0-63) and hdp (64-127)
        major 90 block = hdq (minor 0-63) and hdr (64-127)
        major 91 block = hds (minor 0-63) and hdt (64-127)

For a total of 10 IDE controllers and 2 drives posible per channel.

20 drives with 63 usable partitions different partitons gives 1260
devices files for IDE Drives only (but not SATA drives which are
classified as SCSI in Linux)


Reference for Major and Minor, Block and Character mode devices:

        http://www.lanana.org/docs/device-list/devices-2.6+.txt

Search for "8 block" and read

Then search for "9 block" (or just scroll down) is for /dev/md* setups


So the lesson here, is one I learned about 12 years ago:

        Allocate the whole disk in 15 partitions. Period.

I know, it sucks. But Dual booting taught me that, years ago. I also
learned that Novell's Netware (through Netware 6 that I know of) only
allows 8 partitions per disk using traditional disk management (not
NSS)... if you don't use it up in 8 you lose it, unless you remove all
data and re-partition.

For the record, now that I am using HUGE drives(300GB+), I use LVM or
EVMS to manage allocations. I know Windows doesn't know how to use LVM
or EVMS. I don't use Windows anymore except in a Virtual machine and I
can't remember the last time I even booted it.
-- 
greg, [EMAIL PROTECTED]

The technology that is
Stronger, better, faster:  Linux

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