Computer Science/IT MCQs
Topic Notes: Computer Science/IT
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
4481
Why is it generally a bad security practice to give "write" permission to "everyone" for important system files?
Answer:
Any user on the system could potentially modify or delete those files, which could damage the operating system.
Granting universal write access to critical system files is a major security risk. It would allow any user, including malicious software, to make changes that could render the system unstable or unusable.
4482
In a directory with the "sticky bit" permission set, what is the special behavior?
Answer:
A user can only delete files that they themselves own
The sticky bit is often used on public directories like `/tmp`. Even with full write access to the directory, a user cannot delete another user's files, preventing mischief.
4483
What is the main disadvantage of lossy compression?
Answer:
The loss of data is permanent and cannot be recovered
Once a file has been saved with lossy compression, the discarded data is gone forever. You cannot decompress it to get the original, perfect-quality file back.
4484
If you have write permission on a directory but not on a file inside it, can you delete that file?
Answer:
Yes, because deleting a file is a modification of the directory that contains it
Deleting a file removes its entry from the directory's list. Therefore, to delete a file, you need write permission on the *directory*, not necessarily on the file itself.
4485
Which is a first-generation cellular phone system?
Answer:
AMPS
Advanced Mobile Phone System (AMPS) was the analog mobile phone system standard developed in the 1980s, representing 1G technology.
4486
What is the main advantage of end-to-end encryption for email communication?
Answer:
It ensures that only the sender and intended recipient can read the message.
End-to-end encryption guarantees that the message is encrypted from the moment it leaves the sender's device until it reaches the recipient's device, making it unreadable to any intermediaries, including email providers.
4487
What is the common term for the practice of sending emails with the intention of spreading false information or rumors?
Answer:
Hoax
A hoax, in the context of email, refers to a deceptive message that aims to mislead or trick recipients, often by spreading false alarms, chain letters, or urban legends. Spam is unsolicited commercial mail, phishing seeks data, and spoofing fakes identities.
4488
The carrier for intra-LATA services is:
Answer:
LEC
A Local Exchange Carrier (LEC) is a telephone company that provides services within a LATA.
4489
Which switch type combines space-division and time-division technologies for optimal performance?
Answer:
TST
A Time-Space-Time (TST) switch combines time-division and space-division switching to create a highly efficient, non-blocking switching fabric.
4490
Which term describes emails that deliver advertisements to a user's inbox without their explicit consent?
Answer:
Spam
Spam is specifically defined as unsolicited and often commercial email, sent in bulk. Newsletters and opt-in mails are usually consensual, and transactional emails are responses to user actions.