FIFO algorithm, the whole program. Get another 300 points!

FIFO? Isn't it just a queue?

*I know the principle of the FIFO algorithm, but I still don't understand this**, which master finger teaches the meaning of each program segment? Much appreciated! */

#include

#include

define msize 3 allocates three memory page boxes define psize 12 total of 12 processes static int memery[msize] = ;

static int process[psize] = ;Page visit sequence.

void fifo();

int main()

get() The sequence of resources that need to be accessed.

int i,n;

for(i=0;i<12;i++) output sequence }void fifo().

The assigned three page boxes are initialized to 0

int i = 0, j = 0;

int m = -1, n = -1;

int max = -1,maxtime = 0;

int count = 0;

for(i = 0;imaxtime) } if(n == -1) A page missing break occurs because the required resource is not found in the page box and the table is also full.

m = -1;

elsemax = -1;

maxtime = 0;

count++;

elsen = -1;

for(j = 0 ;j < msize; j++)printf("\t%d",count);

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public class lru ;;

Hahaha, who the hell are you, I'm going to tell Mr. Summer.

The principle of calculating the minimum depth of asynchronous FIFO.

If the data stream is continuous, no matter how deep the FIFO is, as long as the read and write clocks are of different sources and the same frequency, the number will be lost.

FIFO is used to buffer block data streams, and is generally used when writing fast and reading slow, following the following rules:

That is, make sure that there is no overflow when writing data to the FIFO and no underflow when reading data from the FIFO

For example, if a D sample rate is 50 MHz and DSP reads A D read at 40 MHz, if you want to send 100,000 sample data to DSP without loss, how much FIFO of at least a large capacity (depth) should be added between A D and DSP?

100,000 / 50mhz = 1/500 s = 2ms

50MHz - 40MHz) *1 500 = 20k is both FIFO depth.

A wrong algorithm (I also made the same mistake):

100,000 / 40mhz= 1/400s =

50m - 400m)*1/400 =25k.Then the data that goes in this way is not 100k, but 100k+50m*(, 000bit, the error in the calculation of time.

FIFO is a first-in-first-out algorithm, when the page that the CPU needs to access is not in memory, a page missing interrupt is a program that calls the pages in the external memory into the memory, and the original pages in the memory need to be put back into the external memory. The page missing interruption rate is the number of missing pages during the execution of a process divided by the total number of pages to be accessed to obtain the missing page interruption rate, the lower the value, the better.

Don't get me wrong.

Page replacement! = Number of missing pages Page replacements Both are 6 times f i.e. Number of missing pages Number of failed page visits = Number of page replacements (respectively) + Number of times to fill in physical blocks at the beginning (respectively

s is the number of hits and the number of successful page visits = respectively, so the page missing rate f is and respectively.

In a request paging system, when using a simple clock algorithm, suppose the page direction of a job is page buffering algorithm (PBA) [I don't know if it's your PBA] and an improved clock algorithm as for the C program.

m=3.

Dial In Recall Replace Replace Replace Replace Hit Hit Replace Replace Hit.

Missing page rate = 9 12 = 75% m = 4.

Dial In Recall Recall Hit Hit Replace Replace Replace Replace Replace Replace Replace

Page Missing Rate = 10 12=

The missing page rate is first of all, to know what is called missing pages, the simplest explanation is that there is no hit page, that is, the page is replaced.

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