A Lab Activity 1 – Operating Systems Tasks and Programming a) Future of operating systems. [Report on the future of operating systems here] b) Programming activity C++ #include
out.print(name.charAt(i)); //print character counter++; //increment counter if (counter == id[-1]) { //when counter is last character of ID System.out.println(); //new line counter = 0; //reset counter } } } } PYTHON name = “Salman Mohammed Fazal” id = “6669447” for i in range (0, len(name), int(id[-1])): #for every n characters print(name[i:i+ int(id[-1]))]) #slice and print string Code Outcome (same for all) A Lab Activity 2 – Linux Command Line (Commands and outcomes from a series of small tasks that require use of a number of Linux commands) How made Portfolio1 directory read/write/executable only for you and your group.
That is, not for others.A‚A Show evidence of this with ls command. How downloaded the script http://www.centerkey.com/tree/tree.
sh to your home directory using wget and make it executable. Making Directories How created a 207se directory in your Portfolio1 directory. How created numbered directories for the labs. i.e. lab1 and lab2 etc.
Evidence of transferring lab1 activity into appropriate directory Evidence of make directory activities using tree.sh Display todays date and using the cal command show the month that you were born. Move into the lab1 directory and use the appropriate command to show the current directory What is talk, write and wall are for The Talk command is used for exchanging messages with other users who are logged on the same network. The Write command is used to send messages to users in the same network. This one-way only. The Wall command is used to send messages to all the users in the entire network.
This is limited to the admins only. A‚A What command prevents the effects of those three commands from interrupting you. To prevent users from interrupting you, you can use the Mesg command. This command basically enables or disables users from writing to your terminal.
‘Mesg y’ to Allow access and ‘Mesg n’ to deny access. The song in song.txt. Using wc the number of words and lines in the file. Using grep to get the lines containing “and” and the number of the lines contain “and” in the document Use cat to show the contents of the file. Appropriate Linux command to see if the two files differ and how they differ.
Use sort to sort the file and redirect the output to a new file called song2.txt Use sort and rev to reverse the sorted contents of song.txt and append the output to song2.txt Total memory used and the total memory available Find out how you can display your username on the screen.
List the processes that are running. What are the differences between the Linux commands less, more and most. The ‘more’ command works similarly to the cat command by displaying contents of a file, however the more command, you view bits of the text (a screenful), and is in a forward-scrollable manner. The ‘less’ command is similar to the more command, however with this it is possible to scroll both, forward and backward. The ‘most’ command is more like the less command, but the only difference is, it is possible to view several files at once with this command.
The basic syntax for these commands are: more 4 2 7 7 5 6 3 9 3 2 2 Page Entry 0 4 4 4 4 5 5 5 9 9 9 9 Page Entry 1 2 2 2 2 6 6 6 6 2 2 Page Entry 2 7 7 7 7 3 3 3 3 3 Page Fault F F F H F F F F H F H Page Fault Total: 8 4 2 7 7 5 6 3 9 3 2 2 Page Entry 0 4 4 4 4 4 6 6 6 6 6 6 Page Entry 1 2 2 2 2 2 3 3 3 3 3 Page Entry 2 7 7 7 7 7 9 9 9 9 Page Entry 3 5 5 5 5 5 2 2 Page Fault F F F H F F F F H F H Page Fault Total: 8 RANDOM 4 2 7 7 5 6 3 9 3 2 2 Page Entry 0 4 4 4 4 5 6 6 6 6 2 2 Page Entry 1 2 2 2 2 2 2 9 9 9 9 Page Entry 2 7 7 7 7 3 3 3 3 3 Page Fault F F F H F F F F H F H Page Faults Total: 8 4 2 7 7 5 6 3 9 3 2 2 Page Entry 0 4 4 4 4 4 4 4 9 9 9 9 Page Entry 1 2 2 2 2 2 2 2 2 2 2 Page Entry 2 7 7 7 7 3 3 3 3 3 Page Entry 3 5 6 6 6 6 6 6 Page Fault F F F H F F F F H H H Page Fault Total: 7 The random algorithm did not give me the same result as the way I solved it.
This is because There is no specific rule/method on what memory block to be replaced. Each time a process needs to be moved to a memory block, a random memory block is chosen in order to swap the process. Evidence of running code A Lab Activity 7 Buffer Brief description of the Buffer Activity This weeks task involved using buffers in terms of reading and writing from a file Commented Buffer.c code #include h> //header file #include h> //library for file control options #include ”); exit(3); //exit if cannot write to the file } while (rd_size > 0) { //while characters (in file) still exist: rd_size = read(in_fd, buf, BUF_SIZE); //read the file into buffer if (rd_size < 0) { printf(“Error: Can’t read from file.”); exit(4); //exit if error while reading } wr_size = write(out_fd, buf, rd_size); //write from buffer into file if (wr_size <= 0) { close(in_fd); close(out_fd); //close both of the files if error found exit(5); //exit if error while writing } } printf(“Operation Successful!”); } After compiling and running the code, the hamlet.txt file contained the exact same text that was in the main review.txt file Evidence: Updated buffer.c code to show how many character are read to buffer, how many character read at a time into the buffer, how many words in the document and how many times the buffer is filled #include h> //library for general purpose tools #include ”); exit(3); //exit if cannot write to the file } while (rd_size > 0) { //while characters (in file) still exist: rd_size = read(in_fd, buf, BUF_SIZE); //read the file into buffer if (rd_size < 0) { printf(“Error: Can’t read from file.”); exit(4); //exit if error while reading } if (rd_size == 500){ //if read, rd_count += 500; buf_count += 1; //increment character and buffer counter } else{ rd_count += rd_size; } for (int i=0; i What I noticed was as the buffer size increases, the amount of times the buffer is filled decreases as the buffer is able to fill in more characters each time. Below is a screen shot of when the buffer size was set to 2000: We can see the buffer at this time was filled 0 times, meaning the entire text was placed into the buffer. Updated buffer.c code to compare if two files are the same #include h> //library for file control options #include ”); exit(2); //exit if file’s empty } in_fd2 = open(argv[2], O_RDONLY); //open second file to read from //if file isn’t found, variable will have a negative number if (in_fd2 < 0) { printf(“Error: File not found.”); exit(3); //exit if file’s empty } while (rd_size > 0 && rd_size2 > 0) { //while characters (in file) still exist: rd_size = read(in_fd, buf, BUF_SIZE); //read file 1 to buffer rd_size2 = read(in_fd2, buf2, BUF_SIZE); //read file 2 to buffer if (rd_size < 0 || rd_size2 < 0) { //error if any file is empty printf(“Error: Can’t read from file.”); exit(4); } for (int i=0; i txt Comparison of hamlet.txt and review_observer.txt A Lab Activity 8 Cache Buffer Brief Description of Cache Buffer Activity This weeks task was to alter the cache_reader.c file and complete the cr_read_byte function. Additionally, we also had to add a count of the total number of bytes and the number of times the buffer was filled. Commented implementation of the cr_read_byte function char cr_read_byte(cr_file* f){ /* 1. check if buffer needs refilling 2. return currently pointed character 3. move pointer to next character */ if(f->usedbuffer >= f->bufferlength){ refill(f); } char currentChar = f->buffer[f->usedbuffer]; f->usedbuffer++; return currentChar; } Comment updated code to show that each byte is being read, and when the buffer is being refilled. To show that the buffer is being refilled, I added a print statement each time the buffer refills in the cr_read_byte() function. Also the next part of the question will show that the buffer is being refilled and the bytes are being read by keeping a count each time that happens. *The code for this part of the question is combined with the next part (cache_reader.c). (I set the buffer to 200) Commented updated code showing to show how many bytes were read in total, and how many times the buffer was refilled In this part, I had to update the code in 3 different files, below are the screenshots of every update I made: cache_reader.h In this section, I initialized two variables, one to keep count of the number of times the buffer was refilled and the second to keep count of the total number of bytes. cache_reader.c For the second section, I incremented the buffer (filled) count each time the buffer was refilled. cache_example.c Lastly, each time a byte is printed to the screen, a byte count is incremented. And at the end, before closing the files, I printed both the counts. Cache_reader. h #include c #include “cache_reader.h” //http://www.phim.unibe.ch/comp_doc/c_manual/C/SYNTAX/struct. html //http://vergil.chemistry.gatech.edu/resources/programming/c-tutorial/structs.html int refill(cr_file* buff) { //Refills a buffer //Only works when completely used buffer if (buff->usedbuffer != buff->bufferlength) return 0; else { buff->usedbuffer = 0; int len = fread(buff->buffer, sizeof (char), buff->bufferlength, buff->file); //If we didn’t fill the buffer, fill up with EOF if (len < buff->bufferlength) for (int i = len; i < buff->bufferlength; i++) buff->buffer[i] = EOF; //Accessing like an array! return len; } } void cr_close(cr_file* f) { free(f->buffer); fclose(f->file); } cr_file* cr_open(char * filename, int buffersize) { FILE* f; if ((f = fopen(filename, “r”)) == NULL) { fprintf(stderr, “Cannot open %sn”, filename); return 0; } cr_file* a = (cr_file*) malloc(sizeof (cr_file)); a->file = f; a->bufferlength = buffersize; a->usedbuffer = buffersize; //Start off with no characters, so refill will work as expected a->buffer = (char*) malloc(sizeof (char)*buffersize); refill(a); return a; } //—————————————————————— char cr_read_byte(cr_file* f) { /* 1. check if buffer needs refilling -if refilled, increase buffer count. 2. return currently pointed character 3. move pointer to next character */ if (f->usedbuffer >= f->bufferlength) { refill(f); f->buffer_count++; printf(“nnBuffer Refilled. .nn”); } char currentChar = f->buffer[f->usedbuffer]; f->usedbuffer++; return currentChar; } Cache_example.c #include “cache_reader.h” #import “cache_reader. h” //Simple file display to show how easy it is to use the cached reader functions int main() { char c; //Open a file cr_file* f = cr_open(“text”, 200); //While there are useful bytes coming from it while ((c = cr_read_byte(f)) != EOF) { //Print them f->byte_count++; //increase count for every char printf(“%c”, c); } //Then close the file printf(“nnTotal number of bytes: %d”, f->byte_count); printf(“Buffer filled %d times.”, f->buffer_count); cr_close(f); //And finish return 0; } A Lab 10: The Cache Buffer from week 8 with system calls Brief description of the activity This weeks task involved changing the library to use system calls (open(), close(), read()) instead of fopen, fread and fclose. Changes the cache_reader library from using the fopen, fread, fclose functions to the system call versions open, read, close The changes I made to the code are: Firstly, I added the includes to all the codes. cache_reader.c Changed the commented code to the second one A Cache_reader. h RUNNING CODE Changes cache_reader library to remove (as far as possible) the effects of caching on the library. [Commented code outlining your changes to the .h and .c files here] [Output from running code here and if possible prove not using cache here] References
