Server: A server is generally a relatively large computer that manages a shared resource and provides a set of shared user services to the clients. It runs the server process, which services the client requests for use of the resource managed by the server. A server’s operating system is generally designed to enable it to support a multi-user environment. Servers are generally headless machines, which don’t have monitor, keyboard and mouse attached to them since users don’t directly interact with then, but use them via network.

In the Question:

A central computer that holds collections of data and programs for many PCs, workstations and other computers is a

A server is a computer program or device that provides a service to another computer program and its user, also known as the client.

The Answer is server.

Hence the Option D is Correct.

Mainframes and supercomputers are both high-performance computing systems, but they are designed for different types of tasks and have distinct characteristics. Here are the main differences between mainframes and supercomputers:

1. Purpose:

   • Mainframe: Mainframes are designed for handling large volumes of transaction-oriented tasks and business applications simultaneously. They excel at processing vast amounts of data in batch processing or online transaction processing (OLTP) environments. Common tasks include banking transactions, airline reservations, inventory management, and database processing.
   • Supercomputer: Supercomputers are designed for performing complex scientific, engineering, and research computations that require massive processing power and high-speed calculations. They are used for tasks such as weather forecasting, climate modeling, simulations, computational fluid dynamics (CFD), molecular modeling, and nuclear simulations.

2. Architecture:

   • Mainframe: Mainframes typically use a shared-memory architecture where multiple users or applications access a centralized system with a large amount of memory and processing resources. They emphasize reliability, availability, and scalability for handling concurrent tasks efficiently.
   • Supercomputer: Supercomputers often use a distributed-memory architecture, such as clusters of interconnected nodes or massively parallel processors (MPP). They focus on raw computational power and parallel processing capabilities to solve complex scientific and engineering problems faster.

3. Workload:

   • Mainframe: Mainframes are optimized for handling multiple concurrent tasks from numerous users or applications, emphasizing throughput and response time for transactional processing.
   • Supercomputer: Supercomputers are optimized for executing highly compute-intensive and data-intensive tasks that can be parallelized across multiple processing units. They prioritize raw computational speed and efficiency for solving large-scale scientific and engineering problems.

4. Cost and Maintenance:

   • Mainframe: Mainframes are expensive to acquire and maintain, but they offer high reliability, redundancy, and built-in features for fault tolerance and data integrity. They are typically used by large enterprises and organizations with critical business operations.
   • Supercomputer: Supercomputers are also expensive to build and maintain due to their specialized hardware and cooling requirements. They are often used in research institutions, government labs, and industries requiring advanced computational capabilities.

Hence option C is the correct answer .

In the above question the following statement is incorrect 

(i) Palmtop computer is a type of Supercomputer.

Because ,  Palmtop computer is  a type of Microcomputer. Handheld or Palmtop: -  Computer These are the smallest and are designed to fit into the palm. So, these are also known as Palmtop. They are practical for certain functions such as phone books and calendars. They use the pen for input instead of keyboard. e.g. PDA (Personal Digital Assistant), tablets, etc.

But the statement below is correct .

(ii) Special purpose computers are used in Automatic aircraft landing .

Hence the correct option is A.