① 为什么NAND Block中坏一个Page就要丢弃整个Block
您好，很高兴为您解答。
上图是NAND内部结构，WL是若干个Page，一组（64）WL是一个block，从左边的电路看，如果一个page的WL坏了，那么就不能正常地使用这个WL来控制栅极电压，这样就不能对其他WL下的cell进行Read, Program, Erase的操作了。所以对其他page的操作也有可能产生问题。
Inside NAND Flash Memories一书中这么说：
Due to their particular structure, NAND memories haven't row rendancy. When a wordlines short occurs, the block containing those wordlines is marked as bad.
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② md5算法在delphi中的应用
具体使用方法如下,另外还附有源代码:/*1、 MD5String、MD5File、MD5Print、MD5Match这四个函数是供调用的。其他是用来辅助这几个函数的子函数。2、MD5String为加密字符串。3、MD5File为加密这个文件。4、MD5Print是将加密后的密文转换成字符串。5、MD5Match是用来比较密文是否一致。加密字符串aaa MD5String('aaa')将加密后的aaa显示出来 MD5Print(MD5String('aaa'))比较两次密文是否一致： MD5Match(MD5String('第一次明文'),MD5String('第二次输入的明文')) */MD5加密算法(DELPHI)unit md5; // ———————————————————————————————–INTERFACE// ———————————————————————————————–usesWindows;typeMD5Count = array[0..1] of DWORD;MD5State = array[0..3] of DWORD;MD5Block = array[0..15] of DWORD;MD5CBits = array[0..7] of byte;MD5Digest = array[0..15] of byte;MD5Buffer = array[0..63] of byte;MD5Context = recordState: MD5State;Count: MD5Count;Buffer: MD5Buffer;end;procere MD5Init(var Context: MD5Context);procere MD5Update(var Context: MD5Context; Input: pChar; Length: longword);procere MD5Final(var Context: MD5Context; var Digest: MD5Digest);function MD5String(M: string): MD5Digest;function MD5File(N: string): MD5Digest;function MD5Print(D: MD5Digest): string;function MD5Match(D1, D2: MD5Digest): boolean;// ———————————————————————————————–IMPLEMENTATION// ———————————————————————————————–varPADDING: MD5Buffer = ($80, $00, $00, $00, $00, $00, $00, $00,$00, $00, $00, $00, $00, $00, $00, $00,$00, $00, $00, $00, $00, $00, $00, $00,$00, $00, $00, $00, $00, $00, $00, $00,$00, $00, $00, $00, $00, $00, $00, $00,$00, $00, $00, $00, $00, $00, $00, $00,$00, $00, $00, $00, $00, $00, $00, $00,$00, $00, $00, $00, $00, $00, $00, $00);function F(x, y, z: DWORD): DWORD;beginResult := (x and y) or ((not x) and z);end;function G(x, y, z: DWORD): DWORD;beginResult := (x and z) or (y and (not z));end;function H(x, y, z: DWORD): DWORD;beginResult := x xor y xor z;end;function I(x, y, z: DWORD): DWORD;beginResult := y xor (x or (not z));end;procere rot(var x: DWORD; n: BYTE);beginx := (x shl n) or (x shr (32 – n));end;procere FF(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD);begininc(a, F(b, c, d) + x + ac);rot(a, s);inc(a, b);end;procere GG(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD);begininc(a, G(b, c, d) + x + ac);rot(a, s);inc(a, b);end;procere HH(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD);begininc(a, H(b, c, d) + x + ac);rot(a, s);inc(a, b);end;procere II(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD);begininc(a, I(b, c, d) + x + ac);rot(a, s);inc(a, b);end;// ———————————————————————————————–// Encode Count bytes at Source into (Count / 4) DWORDs at Targetprocere Encode(Source, Target: pointer; Count: longword);varS: PByte;T: PDWORD;I: longword;beginS := Source;T := Target;for I := 1 to Count div 4 do beginT^ := S^;inc(S);T^ := T^ or (S^ shl 8);inc(S);T^ := T^ or (S^ shl 16);inc(S);T^ := T^ or (S^ shl 24);inc(S);inc(T);end;end;// Decode Count DWORDs at Source into (Count * 4) Bytes at Targetprocere Decode(Source, Target: pointer; Count: longword);varS: PDWORD;T: PByte;I: longword;beginS := Source;T := Target;for I := 1 to Count do beginT^ := S^ and $ff;inc(T);T^ := (S^ shr 8) and $ff;inc(T);T^ := (S^ shr 16) and $ff;inc(T);T^ := (S^ shr 24) and $ff;inc(T);inc(S);end;end;// Transform State according to first 64 bytes at Bufferprocere Transform(Buffer: pointer; var State: MD5State);vara, b, c, d: DWORD;Block: MD5Block;beginEncode(Buffer, @Block, 64);a := State[0];b := State[1];c := State[2];d := State[3];FF (a, b, c, d, Block[ 0], 7, $d76aa478);FF (d, a, b, c, Block[ 1], 12, $e8c7b756);FF (c, d, a, b, Block[ 2], 17, $242070db);FF (b, c, d, a, Block[ 3], 22, $c1bdceee);FF (a, b, c, d, Block[ 4], 7, $f57c0faf);FF (d, a, b, c, Block[ 5], 12, $4787c62a);FF (c, d, a, b, Block[ 6], 17, $a8304613);FF (b, c, d, a, Block[ 7], 22, $fd469501);FF (a, b, c, d, Block[ 8], 7, $698098d8);FF (d, a, b, c, Block[ 9], 12, $8b44f7af);FF (c, d, a, b, Block[10], 17, $ffff5bb1);FF (b, c, d, a, Block[11], 22, $895cd7be);FF (a, b, c, d, Block[12], 7, $6b901122);FF (d, a, b, c, Block[13], 12, $fd987193);FF (c, d, a, b, Block[14], 17, $a679438e);FF (b, c, d, a, Block[15], 22, $49b40821);GG (a, b, c, d, Block[ 1], 5, $f61e2562);GG (d, a, b, c, Block[ 6], 9, $c040b340);GG (c, d, a, b, Block[11], 14, $265e5a51);GG (b, c, d, a, Block[ 0], 20, $e9b6c7aa);GG (a, b, c, d, Block[ 5], 5, $d62f105d);GG (d, a, b, c, Block[10], 9, $2441453);GG (c, d, a, b, Block[15], 14, $d8a1e681);GG (b, c, d, a, Block[ 4], 20, $e7d3fbc8);GG (a, b, c, d, Block[ 9], 5, $21e1cde6);GG (d, a, b, c, Block[14], 9, $c33707d6);GG (c, d, a, b, Block[ 3], 14, $f4d50d87);GG (b, c, d, a, Block[ 8], 20, $455a14ed);GG (a, b, c, d, Block[13], 5, $a9e3e905);GG (d, a, b, c, Block[ 2], 9, $fcefa3f8);GG (c, d, a, b, Block[ 7], 14, $676f02d9);GG (b, c, d, a, Block[12], 20, $8d2a4c8a);HH (a, b, c, d, Block[ 5], 4, $fffa3942);HH (d, a, b, c, Block[ 8], 11, $8771f681);HH (c, d, a, b, Block[11], 16, $6d9d6122);HH (b, c, d, a, Block[14], 23, $fde5380c);HH (a, b, c, d, Block[ 1], 4, $a4beea44);HH (d, a, b, c, Block[ 4], 11, $4bdecfa9);HH (c, d, a, b, Block[ 7], 16, $f6bb4b60);HH (b, c, d, a, Block[10], 23, $bebfbc70);HH (a, b, c, d, Block[13], 4, $289b7ec6);HH (d, a, b, c, Block[ 0], 11, $eaa127fa);HH (c, d, a, b, Block[ 3], 16, $d4ef3085);HH (b, c, d, a, Block[ 6], 23, $4881d05);HH (a, b, c, d, Block[ 9], 4, $d9d4d039);HH (d, a, b, c, Block[12], 11, $e6db99e5);HH (c, d, a, b, Block[15], 16, $1fa27cf8);HH (b, c, d, a, Block[ 2], 23, $c4ac5665);II (a, b, c, d, Block[ 0], 6, $f4292244);II (d, a, b, c, Block[ 7], 10, $432aff97);II (c, d, a, b, Block[14], 15, $ab9423a7);II (b, c, d, a, Block[ 5], 21, $fc93a039);II (a, b, c, d, Block[12], 6, $655b59c3);II (d, a, b, c, Block[ 3], 10, $8f0ccc92);II (c, d, a, b, Block[10], 15, $ffeff47d);II (b, c, d, a, Block[ 1], 21, $85845dd1);II (a, b, c, d, Block[ 8], 6, $6fa87e4f);II (d, a, b, c, Block[15], 10, $fe2ce6e0);II (c, d, a, b, Block[ 6], 15, $a3014314);II (b, c, d, a, Block[13], 21, $4e0811a1);II (a, b, c, d, Block[ 4], 6, $f7537e82);II (d, a, b, c, Block[11], 10, $bd3af235);II (c, d, a, b, Block[ 2], 15, $2ad7d2bb);II (b, c, d, a, Block[ 9], 21, $eb86d391);inc(State[0], a);inc(State[1], b);inc(State[2], c);inc(State[3], d);end;// ———————————————————————————————–// Initialize given Contextprocere MD5Init(var Context: MD5Context);beginwith Context do beginState[0] := $67452301;State[1] := $efcdab89;State[2] := $98badcfe;State[3] := $10325476;Count[0] := 0;Count[1] := 0;ZeroMemory(@Buffer, SizeOf(MD5Buffer));end;end;// Update given Context to include Length bytes of Inputprocere MD5Update(var Context: MD5Context; Input: pChar; Length: longword);varIndex: longword;PartLen: longword;I: longword;beginwith Context do beginIndex := (Count[0] shr 3) and $3f;inc(Count[0], Length shl 3);if Count[0] < (Length shl 3) then inc(Count[1]);inc(Count[1], Length shr 29);end;PartLen := 64 – Index;if Length >= PartLen then beginCopyMemory(@Context.Buffer[Index], Input, PartLen);Transform(@Context.Buffer, Context.State);I := PartLen;while I + 63 < Length do beginTransform(@Input[I], Context.State);inc(I, 64);end;Index := 0;end else I := 0;CopyMemory(@Context.Buffer[Index], @Input[I], Length – I);end;// Finalize given Context, create Digest and zeroize Contextprocere MD5Final(var Context: MD5Context; var Digest: MD5Digest);varBits: MD5CBits;Index: longword;PadLen: longword;beginDecode(@Context.Count, @Bits, 2);Index := (Context.Count[0] shr 3) and $3f;if Index < 56 then PadLen := 56 – Index else PadLen := 120 – Index;MD5Update(Context, @PADDING, PadLen);MD5Update(Context, @Bits, 8);Decode(@Context.State, @Digest, 4);ZeroMemory(@Context, SizeOf(MD5Context));end;// ———————————————————————————————–// Create digest of given Messagefunction MD5String(M: string): MD5Digest;varContext: MD5Context;beginMD5Init(Context);MD5Update(Context, pChar(M), length(M));MD5Final(Context, Result);end;// Create digest of file with given Namefunction MD5File(N: string): MD5Digest;varFileHandle: THandle;MapHandle: THandle;ViewPointer: pointer;Context: MD5Context;beginMD5Init(Context);FileHandle := CreateFile(pChar(N), GENERIC_READ, FILE_SHARE_READ or FILE_SHARE_WRITE,nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL or FILE_FLAG_SEQUENTIAL_SCAN, 0);if FileHandle <> INVALID_HANDLE_value then tryMapHandle := CreateFileMapping(FileHandle, nil, PAGE_READONLY, 0, 0, nil);if MapHandle <> 0 then tryViewPointer := MapViewOfFile(MapHandle, FILE_MAP_READ, 0, 0, 0);if ViewPointer <> nil then tryMD5Update(Context, ViewPointer, GetFileSize(FileHandle, nil));finallyUnmapViewOfFile(ViewPointer);end;finallyCloseHandle(MapHandle);end;finallyCloseHandle(FileHandle);end;MD5Final(Context, Result);end;// Create hex representation of given Digestfunction MD5Print(D: MD5Digest): string;varI: byte;constDigits: array[0..15] of char =('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f');beginResult := '';for I := 0 to 15 do Result := Result + Digits[(D[I] shr 4) and $0f] + Digits[D[I] and $0f];end;// ———————————————————————————————–// Compare two Digestsfunction MD5Match(D1, D2: MD5Digest): boolean;varI: byte;beginI := 0;Result := TRUE;while Result and (I < 16) do beginResult := D1[I] = D2[I];inc(I);end;end;end.
③ 为什么NAND Block中坏一个Page就要丢弃整个Block
NAND内部结构，WL是若干个Page，一组（64）WL是一个block，从左边的电路看，如果一个page的WL坏了，那么就不能正常地使用这个WL来控制栅极电压，这样就不能对其他WL下的cell进行Read, Program, Erase的操作了。所以对其他page的操作也有可能产生问题。Inside NAND Flash Memories一书中这么说：Due to their particular structure, NAND memories haven't row rendancy. When a wordlines short occurs, the block containing those wordlines is marked as bad.
