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Ôîðìàò ôàéëà UDI ( Ultra Disk Image )Âåðñèÿ 1.0 (Alex Makeev, Ðåäàêöèÿ 24 ìàðòà 2002 ã.)Âåðñèÿ 2 (deathsoft, ñîãëàñîâàíî ñ Alex Makeev)--------------------------------------------------------------------------------Ôîðìàò ôàéëà UDI:Offset Length Comment---------- ------ ----------------------------------------------------0x00000000 0x0004 Èäåíòèôèêàòîð "UDI!", åñëè èäåíòèôèêàòîðçàïèñàí ìàëåíüêèìè áóêâàìè ("udi!"), òîïðèìåíåíî ñæàòèå äàííûõ, àëãîðèòì ñæàòèÿïîêà íå îïðåäåëåí, íî âåðîÿòíî áóäåò àíàëîãè÷åíTELEDISK'óÓïàêîâûâàþòñÿ äàííûå, íà÷èíàÿ ñ îáðàçà ïåðâîéäîðîæêè, ò.å. ñðàçó ïîñëå îñíîâíîãî(è äîïîëíèòåëüíûõ) çàãîëîâêà0x00000004 0x0004 Ðàçìåð ôàéëà ïîñëå ðàñïàêîâêè áåç ó÷åòà CRC(åñëè ôàéë íå óïàêîâàí, òî ïðîñòî ðàçìåð ôàéëà - 4)0x00000008 0x0001 Âåðñèÿ ôîðìàòà, äëÿ UDI 1.0 ñîäåðæèò #00,äëÿ UDI 2 ñîäåðæèò #010x00000009 0x0001 Ìàêñèìàëüíî äîñòóïíûé öèëèíäð (0x00...0xFF),èòîãî ìàêñ. ÷èñëî öèëèíäðîâ = 2560x0000000A 0x0001 Ìàêñèìàëüíûé íîìåð ïîâåðõíîñòè äèñêà:0x01 - DoubleSided, 0x00 - SingleSided(0x02..0xFF -reserved!)0x0000000B 0x0001  ýòîé âåðñèè íå èñïîëüçóåòñÿ ïîýòîìó âñåãäà 0x000x0000000C 0x0004 EXTHDL - Äëèíà äîïîëíèòåëüíîãî çàãîëîâêà(âñåãäà 0, â ïðîòèâíîì ñëó÷àå ñòðóêòóðà äàííûõìîæåò áûòü äðóãàÿ...)Äàëåå ñëåäóþò îáðàçû êàæäîé èç äîðîæåê, â ïîðÿäêå ðàçìåùåíèÿ íà äèñêå(Trk00, Side00; Trk00, Side01; Trk01, Side00; Trk01, Side01; ...):0x00000010 0xXXXX Îáðàç äîðîæêè ñì. íèæå...0xXXXXXXXX 0xXXXX Îáðàç ñëåäóþùåé äîðîæêè0xXXXXXXXX 0xXXXX Îáðàç ñëåäóþùåé äîðîæêè......0xXXXXXXXX 0x0004 CRC ôàéëà (äëÿ âåðñèè 1.0 CRC_UDI, àëãîðèòì ñì. ïðèëîæåíèå 1)(äëÿ âåðñèè 2 CRC32 (ïðàâèëüíûé), àëãîðèòì ñì. ïðèëîæåíèå 2)Îáðàç äîðîæêè:Offset Length Comment---------- ------ ----------------------------------------------------0x00000000 0x0001 Îïðåäåëÿåò ôîðìàò äîðîæêè:0x00 - Decoded MFM (íàïðèìåð TR-DOS-íûé ôîðìàò)0x01 - àíàëîãè÷åí 0x00 íî ñ ïîääåðæêîé îáëàñòåé çàïèñü/÷òåíèåâ êîòîðûå äàåò îøèáêè0x02 - RAW MFM (áèòû â òîì âèäå â êîòîðîì îíè ÷èòàþòñÿ ñ äèñêåòû áåçäåêîäèðîâàíèÿ êîíòðîëëåðîì). Äîðîæêà DD äèñêåòû ñîäåðæèò~50000áèòäðóãèå çíà÷åíèÿ ôîðìàòîâ ïîêà çàïðåùåíû!(ò.ê. åùå íå èçâåñòíî ñêîëüêî äîï. èíôûíóæíî õðàíèòü)***Äëÿ ôîðìàòà äîðîæêè 0x00 (Decoded MFM):0x00000001 0x0002 tlen - Äëèíà äîðîæêè â áàéòàõ (òèïè÷íàÿ äëèíàäîðîæêè 6250 áàéò)ÂÍÈÌÀÍÈÅ! Äëÿ MFM DoubleDensity (ÂÃ93) êðàéíåíå ðåêîìåíäóåòñÿ çàäàâàòü äëèíóäîðîæêè, ñèëüíî îòëè÷àþùóþñÿ îò 6250 áàéò!!!0x00000003 tlen Ïîáàéòîâûé îáðàç äîðîæêè - âêëþ÷àÿ ïðîáåëû,ñèíõðîïðîáåëû, ñèíõðîèìïóëüñû (ìàðêåðû MFM),àäðåñíûå ìàðêåðû, çàãîëîâêè, ìàññèâû äàííûõ, etc.Äðóãèìè ñëîâàìè çäåñü çàïèñàíû òå áàéòû,êîòîðûå áóäóò âûäàíû ÂÃ93 ïî êîìàíäå "÷òåíèå äîðîæêè"0x0003+tlen ñtlen Áèòîâûé ìàññèâ, îïèñûâàþùèé òèï CLK äëÿ êàæäîãîáàéòà îáðàçà äîðîæêè (ñì. ïðèëîæåíèå 1);Îäèí áèò ñîîòâåòñòâóåò îäíîìó áàéòó îáðàçà äîðîæêè:0 - çàïèñàíî ñ îáû÷íûì CLK (îáû÷íûå äàííûå)1 - çàïèñàíî ñ ìàðêåðíûì CLK (ìåòêè #A1 è #C2)Íàïðèìåð èìååì ïîñëåäîâàòåëüíîñòü áàéò:{ 0xA1,0xA1,0x00,0xA1,0xFE,0x00,0x00,0x01 }ãäå 0xA1 - MFM ìàðêåðûòîãäà áàéò áèòîâîãî ìàññèâà áóäåò ðàâåí 0x0B.Äëÿ òèïè÷íîé äëèíû äîðîæêè 6250 áàéò:ctlen = tlen/8 + ((tlen-(tlen/8)*8)? 1:0) = 782 áàéòËèøíèå áèòû - íåçíà÷àùèå, èõ ðåêîìåíäóåòñÿçàïîëíÿòü íóëÿìè.Ïðîãðàììû, ñîçäàþùèå/çàïèñûâàþùèå UDI ôàéëû îáÿçàíûîáåñïå÷èâàòü ïðèñóòñòâèå ðåàëüíûõ CRC êîäîâ äëÿìàññèâîâ äàííûõ è àäðåñíûõ ìàññèâîâ ïî àëãîðèòìóCRC ñ ïîëèíîìîì F = X^16 + X^12 + X^5 + 1Ñèìóëÿöèþ îøèáî÷íîãî CRC ñèíòåòè÷åñêèì ñïîñîáîì,ïðè êîíâåðòèðîâàíèè èç ôàéëîâ FDI, ðåêîìåíäóåòñÿïðîèçâîäèòü ñ ïîìîùüþ âûðàæåíèÿ C = RC^0xFFFF,ãäå C - crc êîòîðóþ íóæíî çàïèñàòü, RC - crcñèíòåòè÷åñêàÿ, êîððåêòíî âû÷èñëåííàÿ ïîàëãîðèòìó CRC... ýòî ÷òîá íàêëàäîê íå âûõîäèëî,çàïèøåøü bad CRC ðàâíûé íóëþ èëè åùå ÷åìó-íèáóäü,ãëÿäèøü, à îí è âïðÿìü îêàæåòñÿ ðàâíûì íóëþ -ïîëó÷àåòñÿ ðåàëüíî bad'îâûé CRC áóäåò îïðåäåëÿòñÿêàê áåçîøèáî÷íûé***Äëÿ ôîðìàòà äîðîæêè 0x01 (Decoded MFM ñî ñáîéíûìè ó÷àñòêàìè):(ïîêà íå ðåàëèçîâàíî)***Äëÿ ôîðìàòà äîðîæêè 0x02 (RAW MFM):(ïîêà íå ðåàëèçîâàíî)***Äëÿ äðóãèõ ôîðìàòîâ äîðîæêè:#0001+tlen 4 MTIL - Äëèíà áëîêà, îïèñûâàþùåãî äîðîæêó#0005+tlen MTIL Áëîê îïèñûâàþùèé ôîðìàò äîðîæêè--------------------------------------------------------------------------------Ïî÷åìó òèïè÷íàÿ äëèíà äîðîæêè 6250 áàéò?Èçó÷èâ ïðîöåäóðó ôîðìàòèðîâàíèÿ ó TR-DOS è óòèëèòû FUT ÿ âûÿñíèë, ÷òîðåàëüíàÿ äëèíà (îíà åñòåñòâåííî çàâèñèò îò àïïàðàòóðû) äîëæíà ëåæàòü âäèàïàçîíå 6208...6464 áàéò, äëÿ äðóãèõ äëèí ïðîèçîéäåò îøèáêà. Îäíàêî,ïðîñ÷èòàâ timing, ó÷èòûâàÿ ÷òî íà îäèí áèò èíôîðìàöèè óõîäèò 4ìêñ - ïîëó÷àåìâðåìÿ 32ìêñ íà áàéò; âðåìÿ îäíîãî ïîëíîãî îáîðîòà äèñêà èçâåñòíî - 200000 ìêñ;äàëåå ïðîñòî ñ÷èòàåì äëèíó äîðîæêè: 200000 / 32 = 6250 áàéò.Âíèìàíèþ ðàçðàáîò÷èêàì ýìóëÿòîðîâ: áîëüøàÿ ïðîñüáà - ñâîèõ êîððåêòèâ âôîðìàò UDI áåç ñîãëàñîâàíèÿ ñ àâòîðîì íå âíîñèòü.-------------------------------------------------------------------------------ÏÐÈËÎÆÅÍÈÅ 1Àëãîðèòì âû÷èñëåíèÿ CRC_UDI äëÿ ôàéëà UDI(âåðñèè 1.0){deathsoft, ðåàëüíî ýòî íå àëãîðèòì CRC32, à îøèáî÷íàÿ ðåàëèçàöèÿ CRC32 äàþùàÿ ñîâåðøåííî äðóãèå ðåçóëüòàòû }Íà÷àëüíîå çíà÷åíèå CRC = 0xFFFFFFFF (-1l).Ôóíêöèÿ îáíîâëåíèÿ CRC32 äëÿ îäíîãî áàéòà Symbol:long CalcCRC32(long CRC, unsigned char Symbol){long temp;CRC ^= -1l ^ Symbol;for(int k = 8; k--;){ temp = -(CRC & 1), CRC >>= 1, CRC ^= 0xEDB88320ul & temp; }CRC ^= -1l;return CRC;}Ýòó ôóíêöèþ íóæíî âûçâàòü äëÿ êàæäîãî áàéòà èç ôàéëà UDI (èñêëþ÷àÿ ïîñëåäíèå4 áàéòà CRC).Ïåðâûé àðãóìåíò ôóíêöèè - òåêóùàÿ CRC, âòîðîé àðãóìåíò - áàéò äàííûõ,ðåçóëüòàò - íîâàÿ CRC.-------------------------------------------------------------------------------ÏÐÈËÎÆÅÍÈÅ 2Àëãîðèòì âû÷èñëåíèÿ CRC32 (UDI 2 è âûøå)static uint32_t crc32(const void *data, unsigned len){const uint8_t *d = (const uint8_t *)data;uint32_t crc = 0xFFFFFFFF;while(len--){uint32_t byte = *d++;crc ^= byte;for(int j = 7; j >= 0; j--){uint32_t mask = -(crc & 1);crc = (crc >> 1) ^ (0xEDB88320 & mask);}}return ~crc;}crc32("The quick brown fox jumps over the lazy dog") == 0x414FA339-------------------------------------------------------------------------------