File System & Security, Unix

It is a sequence of characters organized into lines.

• object file

• text file

• source file

The records are accessed in some sequence, i.e., the information in the file is processed in order, one record after the other. This access method is the most primitive one.

• Sequential access

• Indexed sequential access

• Direct/Random access

Files are allocated disk spaces by operating system. Operating systems deploy three main ways to allocate disk space to files. What are these?

In this one, an index block is created having all pointers to files. Each file has its own index block which stores the addresses of disk space occupied by the file. What method of space allocation is used here?

It refers to identifying each user of the system and associating the executing programs with those users.

In this system, a unique password is required every time user tries to login into the system. Once this password is used, then it cannot be used again.

It can replicate itself on the computer system. It is highly dangerous and can modify/delete user files, crash systems. It is generally a small code embedded in a program.

• Logic Bomb

• Trojan Horse

• Virus

• Trap Door

Such program traps user login credentials and stores them to send to malicious user who can later on login to computer and can access system resources.

• Logic Bomb

• Trojan Horse

• Virus

• Trap Door

It is a mechanism or means by which a hacker can detect system vulnerabilities to make an attack on the system.

• Worm

• Denial of Service

• Port Scanning

• Phishing

As per the U.S. Department of Defense Trusted Computer System's Evaluation Criteria there are four security classifications in computer systems.

What classification is the lowest level? It has the minimum protection.

• A

• B

• C

• D