OS

  1#include <stdio.h>
  2
  3int main() {
  4    int n = 5; // Number of processes
  5    int m = 3; // Number of resource types
  6    int i, j, k;
  7
  8    int alloc[5][3] = {
  9        { 0, 1, 0 }, // P0
 10        { 2, 0, 0 }, // P1
 11        { 3, 0, 2 }, // P2
 12        { 2, 1, 1 }, // P3
 13        { 0, 0, 2 }  // P4
 14    };
 15
 16    int max[5][3] = {
 17        { 7, 5, 3 }, // P0
 18        { 3, 2, 2 }, // P1
 19        { 9, 0, 2 }, // P2
 20        { 2, 2, 2 }, // P3
 21        { 4, 3, 3 }  // P4
 22    };
 23
 24    int avail[3] = { 3, 3, 2 }; // Available Resources
 25
 26    int newRequest[5][3] = {0}, ProNo;
 27
 28    printf("Banker's Algorithm\n");
 29
 30    printf("For the new request: enter process number (0 to 4)\n");
 31    scanf("%d", &ProNo);
 32
 33    printf("Enter the new request of process P%d in the order resources [A B C]\n", ProNo);
 34    scanf("%d", &newRequest[ProNo][0]);
 35    scanf("%d", &newRequest[ProNo][1]);
 36    scanf("%d", &newRequest[ProNo][2]);
 37
 38    // Check if request is less than or equal to available
 39    if (newRequest[ProNo][0] > avail[0] || 
 40        newRequest[ProNo][1] > avail[1] || 
 41        newRequest[ProNo][2] > avail[2]) {
 42        printf("Request cannot be granted now as it exceeds available resources.\n");
 43        printf("Process must wait.\n");
 44        return 0;
 45    }
 46
 47    // Pretend allocation
 48    avail[0] -= newRequest[ProNo][0];
 49    avail[1] -= newRequest[ProNo][1];
 50    avail[2] -= newRequest[ProNo][2];
 51
 52    alloc[ProNo][0] += newRequest[ProNo][0];
 53    alloc[ProNo][1] += newRequest[ProNo][1];
 54    alloc[ProNo][2] += newRequest[ProNo][2];
 55
 56    // Calculate need matrix
 57    int need[n][m];
 58    for (i = 0; i < n; i++) {
 59        for (j = 0; j < m; j++) {
 60            need[i][j] = max[i][j] - alloc[i][j];
 61        }
 62    }
 63
 64    int f[n], ans[n], ind = 0;
 65    for (k = 0; k < n; k++) {
 66        f[k] = 0;
 67    }
 68
 69    int flag;
 70    int y = 0;
 71
 72    for (k = 0; k < 5; k++) {
 73        for (i = 0; i < n; i++) {
 74            if (f[i] == 0) {
 75                flag = 0;
 76                for (j = 0; j < m; j++) {
 77                    if (need[i][j] > avail[j]) {
 78                        flag = 1;
 79                        break;
 80                    }
 81                }
 82                if (flag == 0) {
 83                    ans[ind++] = i; // Safe sequence
 84                    for (y = 0; y < m; y++) {
 85                        avail[y] += alloc[i][y];
 86                    }
 87                    f[i] = 1;
 88                }
 89            }
 90        }
 91    }
 92
 93    int safe = 1;
 94    for (i = 0; i < n; i++) {
 95        if (f[i] == 0) {
 96            safe = 0;
 97            break;
 98        }
 99    }
100
101    if (safe == 0) {
102        printf("Request cannot be granted now, as it may lead to Deadlock.\n");
103        printf("There is no safe sequence.\n");
104        printf("Your request is not granted to avoid Deadlock.\n");
105        printf("Process has to wait.\n");
106    } else {
107        printf("Request can be granted, as a safe sequence is present.\n");
108        printf("There will be no deadlock.\n");
109        printf("Following is the SAFE Sequence:\n");
110        for (i = 0; i < n - 1; i++)
111            printf("P%d -> ", ans[i]);
112        printf("P%d\n", ans[n - 1]);
113    }
114
115    return 0;
116}

 1#include<unistd.h> 
 2#include<stdio.h> 
 3#include<pthread.h> 
 4#include<semaphore.h> 
 5int buf[5],  f,   r;  //Circular queue 
 6sem_t  mutex,  full,  empty; 
 7void *produce(void *arg)
 8{ 
 9    int i; 
10    for(i=0;i<10;i++) 
11    { 
12        sem_wait(&empty);//Wait of empty slot and decrement the empty   
13        sem_wait(&mutex); //Wait if consumer is comsuming a item 
14 
15        printf("produced item is %d\n",i); 
16        buf[(++r)%5]=i; 
17        sleep(1); 
18 
19        sem_post(&mutex); // signal the consumer to consume the item mutex=0 
20        sem_post(&full); // full will be increamented 
21 
22    } 
23} 
24void *consume(void *arg) 
25{ 
26        int item,i; 
27        for(i=0;i<10;i++) 
28        { 
29                sem_wait(&full); //Wait for item  and decrement the full 
30                sem_wait(&mutex); // Wait if producer s producing a item 
31 
32                item=buf[(++f)%5]; 
33                printf("consumed item is %d\n",item); 
34                sleep(1); 
35 
36                sem_post(&mutex); // signal the producer  to produce the item mutex=0 
37                sem_post(&empty); // incrementing the empty variable 
38        } 
39} 
40int main() 
41{ 
42    pthread_t tid1,tid2; 
43    sem_init(&mutex,  0,  1); 
44    sem_init(&full,  0,  0); 
45    sem_init(&empty, 0,  5); 
46    pthread_create(&tid1, NULL, produce, NULL); 
47    pthread_create(&tid2,NULL, consume, NULL); 
48     pthread_join(tid1,NULL); 
49    pthread_join(tid2,NULL); 
50 
51    return 0; 
52}

 1#include<stdio.h> 
 2int main() 
 3{ 
 4int ms, Fsize, NoFrames, NoProcess, RemFrames, i, j, x, y, pa, offset; 
 5int NoPages, PageTable[10]; 
 6printf("\nEnter the memory size -- "); 
 7scanf("%d", &ms); 
 8printf("\nEnter the Frame size -- "); 
 9scanf("%d", &Fsize); 
10NoFrames = ms/Fsize; 
11printf("\n The no. of Frames available in memory are -- %d ", NoFrames); 
12    RemFrames = NoFrames; 
13 
14       printf("\n Enter no. of pages required : "); 
15       scanf("%d", &NoPages); 
16         
17        if(NoPages >RemFrames) 
18        { 
19            printf("\n Memory is Full"); 
20            return (0); 
21        } 
22        RemFrames = RemFrames - NoPages; 
23        printf("\n ---Enter page table --- "); 
24        for(j=0;j<NoPages;j++) 
25            scanf("%d", &PageTable[j]); 
26             
27        printf("\n ---page table --- "); 
28        printf(" \n| PNo || FNo |"); 
29        for(j=0;j<NoPages;j++) 
30            printf(" \n| %d || %d |",j,PageTable[j]); 
31      
32    int yes=1; 
33    do 
34    { 
35    printf("\nEnter Logical Address to find Physical Address "); 
36    printf("\nEnter page number and offset -- "); 
37    scanf(" %d %d",&y, &offset); 
38    if( y>=NoPages || offset>=Fsize) 
39 { 
40        printf("\n trap: Page Number or offset illegal"); 
41   return(0); 
42 } 
43    else 
44    { 
45        pa = (PageTable[y]*Fsize) + offset; 
46         
47        printf("Fsize=%d,offset=%d\n,frame no=%d",Fsize,offset,PageTable[y]); 
48        printf("\n The Physical Address is -- %d", pa); 
49    } 
50        printf("\nContinue : yes=1,no=0\n"); 
51        scanf("%d",&yes); 
52         
53    }while(yes==1); 
54     
55    return 0; 
56} 

 1#include<stdio.h> 
 2int main() 
 3{ 
 4    int i, y, PhyAddre, offset; 
 5    int NoSeg, SegmentTable[10][10]; 
 6 
 7    printf("\nEnter number segments -- "); 
 8    scanf("%d", &NoSeg); 
 9    printf("\nEnter the Segmentation Table data: Base value & Limit Value\n -- "); 
10    for(i=0;i<NoSeg;i++) 
11    scanf("%d%d", &SegmentTable[i][0],&SegmentTable[i][1]); 
12 
13    printf("\n----Enter the Segmentation Table data---\n"); 
14    printf("Segment NO || Base || Limit || \n"); 
15    for(i=0;i<NoSeg;i++) 
16    printf("||   %d    ||  %d  ||  %d   || \n",i,SegmentTable[i][0],SegmentTable[i][1]); 
17 
18     int yes=1; 
19     
20do 
21    { 
22    printf("\nEnter Logical Address to find Physical Address "); 
23    printf("\nEnter segment number and offset\n "); 
24    scanf(" %d %d",&y, &offset); 
25     
26    if(offset>SegmentTable[y][1]) 
27    { 
28        printf("Trap : Addressing Error\n");  
29    } 
30    else 
31    { 
32    PhyAddre=SegmentTable[y][0]+offset; 
33    printf("\n The Physical Address is -- %d", PhyAddre); 
34    printf("\nContinue : yes=1,no=0\n"); 
35        scanf("%d",&yes); 
36    } 
37    }while(yes==1); 
38     
39    return 0; 
40} 

 1#include<stdio.h> 
 2int main() 
 3{ 
 4    int i,j,n,a[50],frame[10],no,k,avail,count=0; 
 5    printf("\n ENTER THE NUMBER OF PAGES:\n"); 
 6    scanf("%d",&n); 
 7    printf("\n ENTER THE PAGE NUMBER :\n"); 
 8    for(i=1;i<=n;i++) 
 9        scanf("%d",&a[i]); 
10         
11    printf("\n ENTER THE NUMBER OF FRAMES :"); 
12        scanf("%d",&no); 
13         
14    for(i=0;i<no;i++) 
15        frame[i]= -1; 
16    j=0; 
17    printf("\tref string\t page frames\n"); 
18     
19    for(i=1;i<=n;i++) 
20    { 
21        printf("%d\t\t",a[i]); 
22        avail=0; 
23        for(k=0;k<no;k++) 
24            if(frame[k]==a[i]) 
25                avail=1; 
26            if (avail==0) 
27            { 
28                frame[j]=a[i]; 
29                j=(j+1)%no; 
30                count++; 
31                for(k=0;k<no;k++) 
32                    printf("%d\t",frame[k]); 
33            } 
34        printf("\n"); 
35    } 
36    printf("Page Fault Is %d",count); 
37    return 0; 
38}