Computer System Architecture

Summary

This lecture delves into computer system architecture, focusing on categorizing systems by the number of general-purpose processors. It introduces single processor systems with a main CPU and optional special purpose processors for device-specific tasks. Multiprocessor systems, offering increased throughput and reliability, are explained, highlighting symmetric and asymmetric multiprocessing. Lastly, clustered systems, composed of multiple interconnected systems for high availability, are discussed, contrasting symmetric and asymmetric clustering approaches.

Takeaways

• 📚 The lecture focuses on computer system architecture, specifically categorizing computer systems based on the number of general-purpose processors.
• 💻 Single processor systems have one main CPU capable of executing a general-purpose instruction set, including user process instructions, and may also include special-purpose processors for device-specific tasks.
• 🔗 Multiprocessor systems contain two or more processors that are closely communicating and sharing resources like the computer bus, memory, and peripheral devices.
• 🚀 Multiprocessor systems offer advantages such as increased throughput, allowing for more data to be processed in parallel, and thus improving system performance.
• 💰 The economy of scale is a benefit of multiprocessor systems, as multiple processors can share resources, making them more cost-effective than multiple single-processor systems with separate resources.
• 🛡️ Multiprocessor systems are more reliable than single-processor systems because if one processor fails, the others can continue to operate, preventing a total system failure.
• 🔄 There are two types of multiprocessor systems: symmetric multiprocessing, where all processors are the same and share tasks, and asymmetric multiprocessing, which has a master-slave approach with a designated master processor.
• 🌐 Clustered systems are composed of two or more individual systems coupled together, providing high availability by allowing other systems to take over tasks if one fails.
• 🔄 Like multiprocessor systems, clustered systems can be structured either symmetrically or asymmetrically, with symmetric structures allowing for more efficient resource sharing.
• 🛑 In asymmetric clustered systems, one machine operates in hot-standby mode, ready to take over if another system fails, while in symmetric systems, all systems monitor each other and share tasks.
• 🔑 The choice between symmetric and asymmetric structures often leans towards symmetric for better resource utilization and efficiency.

Q & A

What are the main types of computer systems based on the number of general purpose processors?

The main types of computer systems based on the number of general purpose processors are single processor systems, multiprocessor systems, and clustered systems.

What is a single processor system?

A single processor system is a computer system that contains one main CPU capable of executing a general purpose instruction set, including instructions from user processes, along with special purpose processors for device-specific tasks.

What is the difference between a general purpose processor and a special purpose processor?

A general purpose processor is capable of executing a wide range of instructions and handling various tasks, while a special purpose processor is designed to perform specific tasks related to a particular device or function.

What are the advantages of a multiprocessor system over a single processor system?

The advantages of a multiprocessor system include increased throughput, economy of scale, and increased reliability due to the presence of multiple processors that can share workload and provide backup in case of failure.

What is the meaning of 'throughput' in the context of computer systems?

In the context of computer systems, 'throughput' refers to the measure of the performance of the system, often defined as the amount of data that can be transferred from one location to another.

What is the concept of 'economy of scale' in relation to multiprocessor systems?

'Economy of scale' in relation to multiprocessor systems refers to the cost efficiency gained from sharing resources among multiple processors, as opposed to having separate single processor systems with individual resources.

How does a multiprocessor system provide increased reliability?

A multiprocessor system provides increased reliability because if one processor fails, the remaining processors can continue to operate and share the workload, preventing a total system failure.

What are the two types of multiprocessing systems?

The two types of multiprocessing systems are symmetric multiprocessing (SMP) and asymmetric multiprocessing (AMP).

What is the key difference between symmetric and asymmetric multiprocessing?

In symmetric multiprocessing, all processors are similar and participate equally in task execution, whereas in asymmetric multiprocessing, there is a master-slave approach where one processor acts as a master and the others as slaves with specific tasks assigned by the master.

What is a clustered system, and how does it differ from a multiprocessor system?

A clustered system is a computer system that couples two or more individual systems together to accomplish computational work. Unlike a multiprocessor system, which consists of multiple processors, a cluster system involves complete systems working in unison, providing high availability and redundancy.

How does a clustered system provide high availability?

A clustered system provides high availability because multiple systems are working together; if one system fails, the others can take over the tasks, minimizing the chance of a complete system failure.

What are the symmetric and asymmetric structures in a clustered system?

In a symmetric clustered system, all hosts run applications and monitor each other, sharing resources efficiently. In an asymmetric clustered system, one machine operates in hot-standby mode while the others run applications, with the standby machine ready to take over if another fails.