新品のSDカードには何が記録されているのか？

まっさらなメディアには何が記録されているのか？

関連: 新品のSSDには何が記録されているのか？

今回はアマゾンで買ったSundiskのmicroSDカード32GB SDSDQUL-032G-EPK UHS-Iだが30MB/sで少し遅いタイプ。ddでの表示では24MB/sくらいだった。たぶん国内版正規品。

・sgdiskの結果

***************************************************************
Found invalid GPT and valid MBR; converting MBR to GPT format
in memory. 
***************************************************************


Warning! Secondary partition table overlaps the last partition by
33 blocks!
You will need to delete this partition or resize it in another utility.
Disk /dev/mmcblk1: 62333952 sectors, 29.7 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): ADDB84C9-13AE-44F1-BCAC-xxxxxxxxxxxx
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 62333918
Partitions will be aligned on 2048-sector boundaries
Total free space is 8158 sectors (4.0 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            8192        62333951   29.7 GiB    0700  Microsoft basic data

なんかワーニングが出ているが、セカンダリパーティションテーブルなんて無いし何かの間違い？

・全領域ダンプ

00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000001b0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 82  |................|
000001c0  03 00 0c fe ff ff 00 20  00 00 00 04 b7 03 00 00  |....... ........|
000001d0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000001f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 55 aa  |..............U.|
00000200  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00400000  eb 00 90 20 20 20 20 20  20 20 20 00 02 40 92 04  |...        ..@..|
00400010  02 00 00 00 00 f8 00 00  3f 00 ff 00 00 20 00 00  |........?.... ..|
00400020  00 04 b7 03 b7 1d 00 00  00 00 00 00 02 00 00 00  |................|
00400030  01 00 06 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00400040  80 00 29 32 36 65 39 4e  4f 20 4e 41 4d 45 20 20  |..)26e9NO NAME  |
00400050  20 20 46 41 54 33 32 20  20 20 00 00 00 00 00 00  |  FAT32   ......|
00400060  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
004001f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 55 aa  |..............U.|
00400200  52 52 61 41 00 00 00 00  00 00 00 00 00 00 00 00  |RRaA............|
00400210  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
004003e0  00 00 00 00 72 72 41 61  ff ff ff ff 02 00 00 00  |....rrAa........|
004003f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 55 aa  |..............U.|
00400400  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
004005f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 55 aa  |..............U.|
00400600  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00400c00  eb 00 90 20 20 20 20 20  20 20 20 00 02 40 92 04  |...        ..@..|
00400c10  02 00 00 00 00 f8 00 00  3f 00 ff 00 00 20 00 00  |........?.... ..|
00400c20  00 04 b7 03 b7 1d 00 00  00 00 00 00 02 00 00 00  |................|
00400c30  01 00 06 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00400c40  80 00 29 32 36 65 39 4e  4f 20 4e 41 4d 45 20 20  |..)26e9NO NAME  |
00400c50  20 20 46 41 54 33 32 20  20 20 00 00 00 00 00 00  |  FAT32   ......|
00400c60  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00400df0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 55 aa  |..............U.|
00400e00  52 52 61 41 00 00 00 00  00 00 00 00 00 00 00 00  |RRaA............|
00400e10  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00400fe0  00 00 00 00 72 72 41 61  ff ff ff ff 02 00 00 00  |....rrAa........|
00400ff0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 55 aa  |..............U.|
00401000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
004011f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 55 aa  |..............U.|
00401200  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00492400  f8 ff ff 0f ff ff ff 0f  ff ff ff 0f 00 00 00 00  |................|
00492410  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00849200  f8 ff ff 0f ff ff ff 0f  ff ff ff 0f 00 00 00 00  |................|
00849210  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
76e47fe00  b0 42 15 cb 40 43 62 91  bf 70 33 35 96 b7 d2 73  |.B..@Cb..p35...s|
76e47fe10  0c 95 0a 17 1e 7b a9 d8  5a 09 6c d1 e3 e5 71 6f  |.....{..Z.l...qo|
76e47fe20  c7 67 97 fa 14 a2 ac 89  3b 1d 66 5d f2 8d 39 99  |.g......;.f]..9.|
76e47fe30  a9 22 87 b2 e4 7c da 93  83 a5 e1 43 e7 dd 23 f7  |."...|.....C..#.|
76e47fe40  79 5a 5a e0 e3 47 d0 4f  8e 3b 7b 4d 46 b3 ca 21  |yZZ..G.O.;{MF..!|
76e47fe50  21 f8 98 ac 79 36 27 91  ab 6b 64 1d c1 83 57 5f  |!...y6'..kd...W_|
76e47fe60  df 14 70 8c 1e 20 da 86  17 c6 08 8e dd f5 9d f2  |..p.. ..........|
76e47fe70  f7 50 8d 40 27 34 cf c9  0d 51 8c 31 78 58 7d 66  |.P.@'4...Q.1xX}f|
76e47fe80  4a 99 13 aa 21 e7 6a af  58 26 34 85 2e 55 66 af  |J...!.j.X&4..Uf.|
76e47fe90  21 f2 69 e7 d3 d7 27 1e  2f d6 86 0c 37 7f 1e 05  |!.i...'./...7...|
76e47fea0  0d 16 83 18 6c 76 37 71  d9 27 78 8b 9e 55 31 99  |....lv7q.'x..U1.|
76e47feb0  63 fa 44 44 82 8c 92 01  0b b1 4e 9c 1e b0 16 47  |c.DD......N....G|
76e47fec0  bd 90 2f dd 55 1c 5e 96  47 1e 64 45 1b 6a 14 c2  |../.U.^.G.dE.j..|
76e47fed0  f1 81 1b 10 4b fe b0 fa  55 aa 44 7a 31 af ee 0a  |....K...U.Dz1...|
76e47fee0  c6 c2 2a b6 ed 24 65 0c  e5 4d 30 64 38 80 cd 14  |..*..$e..M0d8...|
76e47fef0  86 0a 21 e6 6d 94 89 83  52 94 d0 14 06 52 1e 50  |..!.m...R....R.P|
76e47ff00  c7 28 90 68 a9 3f d5 00  d1 bf 81 55 e2 2a a2 75  |.(.h.?.....U.*.u|
76e47ff10  7c 68 59 14 37 c6 0d 93  83 5c 8f 83 c1 34 80 55  ||hY.7....\...4.U|
76e47ff20  fa 30 b0 35 72 82 35 1b  fb 90 a9 e1 fb 04 c1 c4  |.0.5r.5.........|
76e47ff30  c8 22 94 d2 c9 64 1c 7d  11 e3 ae 2b 0e 3f a1 e6  |."...d.}...+.?..|
76e47ff40  bd da 24 8c 47 12 fd 80  2d a2 4a a3 2d 00 87 f1  |..$.G...-.J.-...|
76e47ff50  cf 27 7d f8 b8 d0 9f 92  87 53 2a ff a1 71 d1 f2  |.'}......S*..q..|
76e47ff60  c7 21 9b 91 2e cc 15 53  c5 b5 54 4b 36 43 64 f1  |.!.....S..TK6Cd.|
76e47ff70  61 90 45 63 b3 b0 24 a4  1a 63 7e aa 78 3f 97 82  |a.Ec..$..c~.x?..|
76e47ff80  25 cc 80 aa 50 b6 61 2a  80 1b c8 03 ed 5a 19 6b  |%...P.a*.....Z.k|
76e47ff90  0a b7 05 a2 88 ef 8f 84  dd 68 06 df 52 5d 7a ae  |.........h..R]z.|
76e47ffa0  31 c4 cf f8 24 a6 73 4a  f6 62 ab 0b 4c 84 aa 0b  |1...$.sJ.b..L...|
76e47ffb0  b7 0d df 29 72 a4 ce 86  c1 60 7b 4b d5 c3 ca a5  |...)r....`{K....|
76e47ffc0  ec 01 29 12 dc 63 8a 5a  7b 0e 40 25 7d 8a ff 51  |..)..c.Z{.@%}..Q|
76e47ffd0  c8 27 ae b5 b5 17 3b f1  04 74 3c cd eb bd e5 d4  |.'....;..t<.....|
76e47ffe0  ca 88 40 2e a0 38 44 a3  f1 0c 00 85 0d da a7 17  |..@..8D.........|
76e47fff0  f1 56 28 97 02 83 97 00  3a 72 a1 9b ff fc 3b dd  |.V(.....:r....;.|
76e480000

基本的にはMBR形式パーティションで、普通にWindowsでパーティショニング、フォーマットしたのと違ってブートコードが無し。パーティションテーブルのみでパーティション1にFAT32で全領域割り当て。

領域内は大半00で埋められているが、一部データが残っている。パーティションをFAT32でフォーマットした痕跡が二か所にある。他はaa55とか、f8ff…f0とかメモリテストパターンっぽいものが点在。

0x76e47fe00以降に謎のデータが。