Please help with a through h$.$ Answer correctly with explanation. Image is better.

Problem $1$ : A bunch of distributed file systems questions.

In this problem you will explore the strengths $($and weaknesses$)$ of two commercially successful dis$-$

tributed file systems $-$ AFS and NFS$.$ Specifically, you will look at the implications of state $($or lack thereof$)$

at the server when several clients are writing to the same file.

Recalling from the lecture the semantics of NFS server $($the original version, i$.$e$.,$ no leases$),$ it does not

know when a client opens a file for writing nor when the client is done writing and closes the file. Because

of that, NFS requires that the client writes thorough all changes i$.$e$.,$ every time a client writes a byte to the

file, the client sends the appropriate block $($e$.$g$.,4$ KB$)$ to the server that writes it synchronously to the disk.

The AFS server, on the other hand, keeps a list of all clients that have a file open. The client modifies

a local copy of a file and only when it closes the file are the dirty blocks sent to the server. The server then

looks up all the clients that have a local copy of the same file and sends them an invalidation message via a

callback. This message lists all the blocks that have been modified. The clients have to contact the server if

they want to get the latest version of the data.

Assume a sequence of system calls $($listed below$)$ at four elients that all open the same file stored on

a file server. The file is initially empty. The time increases such that $fdfdfl{d}_{9}flI{g}_9{t}_6{t}_7{l}_g{t}_4{t}_5{l}_g{t}_4{t}_5{t}_1.$ The syscall

write $(fd,$ data$)$ means that the data $is$ written $to$ the file whose descriptor $isfd.$ Answer the following

questions. Give all scenarios whenever possible and briefly explain your answer.

$(a)$ Assuming file $flis$ stored $onanNFS$ server, what $is$ its content $at{d}_9?$

$(b)$ Assuming file $flis$ stored $onan$ AFS server, what $is$ its content $atI{g}_9?$

Assume a network failure occurred between $t_6$ and $t_7$ and $it$ never recovered$(i.e.,$ the elose system call failed

$on$ client $4).$

$(c)$ What $is$ the content $of$ the file $at{l}_{g}onanNFS$ server?

$(d)$ What $is$ its content $onan$ AFS server?

Assume a network failure occurred between $t_4$ and $t_5$ and $it$ never recovered $(i.e.,$ the write failed $on$ client

$3$ and close failed $on$ clients $1,2,$ and $4).$

$(e)$ What $is$ the content $of$ the file $at{l}_{g}onanNFS$ server?

$(f)$ What $is$ its content $onan$ AFS server?

Now assume that the server went down between $t_4$ and $t_5,$ but everything else was functioning well. $It$ took

sufficiently long for the server $to$ come back $upso$ that all the clients finished their applications $(since$ they

didn't handle a failed write and close system calls$)$ happily believing their data was saved.

$(g)$ What $is$ the content $of$ the file when the $NFS$ server came finally $up?$

$(h)$ When the AFS server came finally $up?$