An emergency for help. I have to submit the exam questions at six o'clock P.M.. Please help me. Thank you.

An emergency for help. I have to submit the exam questions at six o'clock P.M.. Please help me. Thank you. -- Linux general technology-Linux programming and kernel information. The following is a detailed description. Operating System Structure Analysis and Application Programming Examination Paper
1. the following commands are available:
Grep computer file3> flist &
Sort flist &
Rm flist &
Each Command is followed by the "&" symbol executed in the background, and these three commands are executed in parallel. Why are they not equivalent to the following commands?
Grep computer file3 | sort


2. In the brelse algorithm, if the content in a buffer zone is invalid, the core places the buffer zone in the header of the idle linked list. Should this buffer still appear in the hash queue?


3. If the core is not the "least recently used" scheme, but the "first-in-first-out" scheme, what modifications should be made to the algorithm getblk?


4. According to the C language habits, the subscript of the array starts from 0. Why does the index node number start from 1 instead of 0?


5. What determines the maximum number of files that a file system can contain? What is the impact of the maximum number on the directory structure of a fixed-length directory?


6. List the reference count of an active I node in at least two cases.


7. If a process continuously reads data from a file, the kernel records the block number of the pre-read block in the active I node. What happens if several processes continuously read from the same file?


8. If the core needs to wake up all the processes sleeping at a certain time and no process is sleeping at this time, what will happen?