64 practice sets · Page 3 of 4
In Linux, the subdirectory that contains system configuration files including user passwords:
/usr
/boot
/etc
/proc
Correct Answer: C — /etc
Explanation:
The /etc directory in Linux contains all system-wide configuration files, including the /etc/passwd and /etc/shadow files for user authentication.
Linux partitions are created using the file system:
EXT3
FAT
NTFS
FAT32
Correct Answer: A — EXT3
Explanation:
EXT3 (Third Extended Filesystem) is a native file system specifically designed and widely used for Linux partitions.
Which UNIX/Linux command is used to make all files and sub-directories in the directory "progs" executable by all users?
chmod -R a+x progs
chmod -R 222 progs
chmod ugo+x progs
chmod a+x progs
Correct Answer: A — chmod -R a+x progs
Explanation:
The chmod -R a+x progs command recursively (-R) adds (+) execute (x) permissions for all (a) users to the 'progs' directory and its contents.
Consider the following statements:
Statement I: UNIX provides three types of permissions: Read, Write, and Execute.
Statement II: The command chmod is used to change these permissions.
Which of the statements given above is/are correct?
Only Statement I
Only Statement II
Both Statement I and Statement II
Neither Statement I nor Statement II
Correct Answer: C — Both Statement I and Statement II
Explanation:
UNIX fundamentally provides three file permissions: Read, Write, and Execute. These can be modified using the chmod command.
Match the following WINDOWS system calls and UNIX system calls with reference to process control and file manipulation:
| Windows | UNIX |
|---|---|
| (a) CreateProcess() | (i) read() |
| (b) WaitForSingleObject() | (ii) close() |
| (c) ReadFile() | (iii) fork() |
| (d) CloseHandle() | (iv) wait() |
(a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)
(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)
(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)
(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
Correct Answer: B — (a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)
Explanation:
Windows CreateProcess() corresponds functionally to the UNIX fork() and exec(), WaitForSingleObject() maps to wait(), ReadFile() to read(), and CloseHandle() to close().
In UNIX, which of the following command is used to set the task priority?
nice
ps
kill
init
Correct Answer: A — nice
Explanation:
The nice command executes a program with a specified scheduling priority, effectively setting the task priority in UNIX.
Which of the following flags are set when ‘JMP’ instruction is executed?
SF and CF
No flag is set
All flags
AF and CF
Correct Answer: B — No flag is set
Explanation:
The JMP (unconditional jump) instruction changes the instruction pointer but does not perform an arithmetic or logical operation, so no status flags are affected.
Everything below the system call interface and above the physical hardware is known as ______.
Stub
Shell
Bus
Kernel
Correct Answer: D — Kernel
Explanation:
The Kernel is the core component of the operating system that resides between the hardware and the system call interface, managing system resources.
Linux operating system uses
Hand Shaking
Fair Preemptive Scheduling
Affinity Scheduling
Highest Penalty Ratio Next
Correct Answer: B — Fair Preemptive Scheduling
Explanation:
Linux fundamentally uses a Completely Fair Scheduler (CFS), which is a type of fair preemptive scheduling to allocate CPU time to processes.
In Unix, how do you check that two given strings a and b are equal?
test b
test b
test b
Both A and B
Correct Answer: B — test b
Explanation:
In standard UNIX shells, the test command uses the = operator to compare strings for equality, though -eq is sometimes incorrectly conflated with string comparison despite being strictly for integers.
The directory structure used in Unix file system is called
Graph structured directory
Hierarchical directory
Tree structured directory
Directed acyclic graph
Correct Answer: B — Hierarchical directory
Explanation:
The UNIX file system utilizes a hierarchical directory structure, organizing files and directories into a tree-like hierarchy starting from the root (/).
Which statement is not true about process 0 in the Unix operating system?
Process 0 is not created by fork system call
Process 0 is a special process created when system boots
Process 0 is called init process
After forking process 1, process O becomes swapper process
Correct Answer: C — Process 0 is called init process
Explanation:
Process 0 is typically the sched or swapper process, while Process 1 is the init process. Therefore, stating that Process 0 is the init process is incorrect.
Which of the following commands would return the process_id of the sleep command?
sleep 1 & echo $!
sleep 1 & echo $*
sleep 1 & echo $?
sleep 1 & echo $$
Correct Answer: A — sleep 1 & echo $!
Explanation:
The special variable $! holds the process ID of the most recently executed background pipeline, which would be the sleep command in this case.
What does the following command do?
grep -vn "abc" x
It will print the specific line numbers of file x in which there is a match for the string "abc"
It will print total no of the lines in file x that match the search string "abc"
It will print all of the lines in the file x that match the search string "abc"
It will print all of the lines in file x that do not match the search string "abc", along with their line numbers
Correct Answer: D — It will print all of the lines in file x that do not match the search string "abc", along with their line numbers
Explanation:
The grep command with -v inverts the search to output lines that do not match the pattern, while -n includes the line numbers.
The Unix Kernel maintains two key data structures related to processes, the progress table and the user structure. Which of the following information is not a part of the user structure?
System call state
File descriptor table
Scheduling parameters
Kernel stack
Correct Answer: C — Scheduling parameters
Explanation:
Scheduling parameters (like priority and recent CPU usage) are kept in the process table (proc structure) because they must be accessible even when the process is swapped out, unlike the user structure.
A Unix file may be of the type:
Regular file
Directory file
Device file
All of the above
Correct Answer: D — All of the above
Explanation:
UNIX supports multiple file types, primarily regular files, directories, and special (device) files, adhering to its "everything is a file" philosophy.
Match the following for Unix system calls:
| List – I | List – II |
|---|---|
| (a) exec() | (i) Creates a new process |
| (b) brk() | (ii) Replaces the core image of a process |
| (c) wait() | (iii) Changes data segment size |
| (d) fork() | (iv) Blocks caller until child terminates |
(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
(a)-(iii), (b)-(ii), (c)-(iv), (d)-(i)
(a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)
(a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
Correct Answer: D — (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
Explanation:
UNIX system calls provide direct interfaces to the kernel: exec() replaces the process image, brk() changes the data segment space allocation, wait() pauses execution until a child finishes, and fork() spawns a new process.
WOW32 is a:
Kernel - mode objects accessible through Win 32 API
Win 32 API library for creating processes and threads
Special execution environment used to run 16 bit Windows applications on 32 - bit machines
Special kind of file system to the NT name space
Correct Answer: C — Special execution environment used to run 16 bit Windows applications on 32 - bit machines
Explanation:
WOW32 (Windows on Windows 32-bit) is a subsystem that allows older 16-bit Windows applications to run seamlessly on 32-bit Windows operating systems.
The Unix command:
$ vi file1 file2
Edits file1 and stores the contents of file1 in file2
Both files i.e. file1 and file2 can be edited using 'ex' command to travel between the files
Both files can be edited using 'mv' command to move between the files
Edits file1 first, saves it and then edits file2
Correct Answer: B — Both files i.e. file1 and file2 can be edited using 'ex' command to travel between the files
Explanation:
When multiple files are opened in vi, they are loaded into the buffer array, and 'ex' commands like :n (next) can be used to switch between them.
______ maintains the list of free disk blocks in the Unix file system.
I-node
Super block
File allocation table
Boot block
Correct Answer: B — Super block
Explanation:
The Super block contains critical metadata about the file system, including the size, status, and a list of free disk blocks.
