Question type III ： Mixed index
Number of blocks that can be indicated per block = Disk block size / Block number size
Number of indirect index blocks = Number of blocks that can be indicated per block ^n Order power
Maximum total file blocks = Number of direct indexes + Number of L1 indirect index blocks + Number of secondary indirect index blocks +……
Maximum file bytes = Maximum total file blocks * Disk block size
Direct example ：
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The file directory entry of a file system contains 6 An array of tables is used to describe the physical structure of the file , Before the array 4 Entries used as direct indexes , Section 5 Entries are first level indirect indexes , The last entry is used as a secondary indirect index , The size of the disk block is 512 byte , Block number 2 byte . Please answer the following questions ：
(1) How many bytes can the file system construct ?
(2) A file file have 268KB, Please draw the index structure of the file data block .
answer ：
(1) Each piece 512 byte , Block number 2 byte , Then each data block can indicate 256 block ,
Then the total number of blocks of the maximum file ：4+256^1+256^2=65796,
(4 Before representation 4 Entries used as direct indexes , Except direct index , Number of indirect index blocks = Number of blocks that can be indicated per block ^n Order power )
Number of bytes is ：65796*512.
(2) 268K Required occupation 268K/512=523 block ,（512 Is the disk block size ）
523=4+256^1+263,523 stay 4+256^1 and 4+256^1+256^2 between , So the secondary index is used .
Index structure diagram ： Box is the logical block number of the file , from 0 Start number
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