Operating Systems Questions and Answers

Answer: B

Organising the contents of each file into contiguous regions and creating larger areas of free space on the disk is called defragmentation, and the process of making files take up less space by reducing their size is compression. Debugging means finding and fixing errors in a program, assembly is the process of translating assembly language, formatting prepares a disk for use, and mirroring keeps a duplicate copy of data on a second disk. None of these pairs fits both blanks.

Answer: D

The exclamation mark (!) is not an input/output redirection symbol. In the Linux shell the symbol < redirects standard input from a file, > redirects standard output to a file overwriting it, and >> appends the output to a file. The '!' is used for history expansion and for negation, not for redirecting input or output. For example, command > file.txt sends the output to a file, command < file.txt takes input from it, and command >> file.txt adds to it.

Answer: A

The commands that search content from files are grep, egrep and fgrep, so i, ii and iii only. All three look for text patterns inside files. The command find searches for files by name or other attributes and not by what is inside them, tail prints the last lines of a file, and tr translates or deletes characters from its input. So the options with find, tail or tr are wrong. For example, grep pattern file prints the lines of the file that contain the pattern, and egrep and fgrep are variants for extended expressions and for fixed strings.

Answer: C

The commands that create files in Linux are touch and cat, so i and ii only. The touch command creates an empty file, and cat can create a file with redirection, as in cat > file. The head command shows the first lines of a file and finger shows information about users, so iii and iv do not create files. The options with them, or with only one command, are wrong. For example touch notes.txt creates an empty file, and cat > notes.txt lets the user type text into a new file.

Answer: D

'Data Compilation' is not a system call category. The usual categories are process control, file manipulation, device manipulation, information maintenance and communication. Process control, device manipulation and file manipulation are named in the options, so the fourth option is the odd one out. The system calls of an operating system let programs request services such as creating a process, opening a file or reading from a device.