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idk if this figure is needed for the question but it was on top of it Byte Range Description Essential 0-0 First character of file
idk if this figure is needed for the question but it was on top of it
Byte Range Description Essential 0-0 First character of file name in ASCII and allocation status Yes (Oxe5 or 0x00 if unallocated) 1-10 Characters 2 to 11 of file name in ASCII Yes 11-11 File Attributes (see Table 10.6) Yes 12-12 Reserved No 1313 Created time (tenths of second) No 14-15 Created time (hours, minutes, seconds) No 16-17 Created day No 18-19 No Accessed day High 2 bytes of first cluster address (0 for FAT12 and FAT16) 20-21 Yes 22-23 Written time (hours, minutes, seconds) No 24-25 Written day No 26-27 Low 2 bytes of first cluster address Yes 28-31 Size of file (o for directories) Yes Table 10.5 Data structure for a basic FAT directory entry. 2. According Table 10.5, the creation date/time stamp is stored in a word sized, little endian data structure at offsets 16-17 in a file's 32B directory entry structure that begins at absolute offset 10105936. (Hint: The Data parsing & endianness example (sample case) help video will help you with this question.) a. What are the two absolute offset values containing this word? b. Being told this is a little endian data structure, what is the number stored in this data structure for savedfile.txt in hexadecimal? C. What is this value in binary? d. This conversion to binary is critical, because in FAT, the word data structure for its creation date/time stamp must be broken into sub-parts using the binary data stream. The first 7 bits indicate the year; the next four bits indicate the month; and the last 5 bits indicate the day. Using this information, what year, month, and day was this file created? e. This year probably doesn't make sense to you until you add it to epoch for a FAT file system, which is 1980. Add the year you got above to 1980 and report the real year this file was created. f. Putting this all together, what was the date samplefile.txt was created? 1015920 1015936 1015952 1015968 1015984 1016000 49 00 40 00 45 00 2E 00 54 00 00 00 58 00 54 00 I LE. I X T 53 41 56 45 44 46 7E 31 54 58 54 02 00 12 29 90 SAVEDF1TXT ) 66 41 45 45 00 00 49 90 66 41 03 00 12 00 00 00 fAEE I fA E5 58 00 54 00 00 00 FF FF FF FF OF 00 A7 FF FF X T yyyy Syy FF FF FF FF FF FF FF FF FF FF 00 00 FF FF FF FF yyyyyyyyyy E5 44 00 45 00 4C 00 45 00 54 00 OF 00 A7 45 00 D E LET SE Figure 1. FAT Directory Entry Structure Table from a Thumb Drive
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