门| GATE-CS-2004 |第49章

Unix样式的i节点具有10个直接指针和一个单，一个双和一个三重间接指针。磁盘块大小为1 KB，磁盘块地址为32位，并使用48位整数。可能的最大文件大小是多少?
(A) 2 ²⁴字节
(B) 2 ³²字节
(C) 2 ³⁴字节
(D) 2 ⁴⁸字节答案： (C)
解释：
图片来源：Wiki

Size of Disk Block = 1Kbyte

Disk Blocks address = 32bits, 
but 48 bit integers are used for address
Therefore address size = 6 bytes
                    

No of addresses per block = 1024/6  = 170.66 
Therefore 170 ≈ 2^8 addresses per block can be stored

Maximum File Size = 10 Direct + 1 Single Indirect + 
                    1 Double Indirect + 1 Triple Indirect
                 = 10 + 28 + 28*28 + 28*28*28
                 ≈ 224 Blocks

Since each block is of size 210                 

Maximum files size = 224 * 210     
                   = 234    

这个问题的测验