--- title: "Advantages and disadvantages of DS" subject: "Distributed System" chapter: 1 key: "semester_7/distributed_system:ds-advantages-disadvantages" source: https://www.bctengineer.com/q/semester_7/distributed_system/ds-advantages-disadvantages site: BCT Engineering --- # Advantages and disadvantages of DS Distributed System · Chapter 1: Introduction - Asked in: 2070 Chaitra, 2+6 marks; Model question (asked 2 times) - Video: [Distributed System Lecture #1 - Introduction, Advantages, Disadvantages, Architecture, Need](https://www.youtube.com/watch?v=6kzoZF3Kyso) — Easy Engineering Classes - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/distributed_system/ds-advantages-disadvantages - Whole chapter: https://www.bctengineer.com/md/semester_7/distributed_system/chapter-1 ## Question Define Distributed System. What are the advantages and disadvantages of distributed system? ## Short answer A distributed system is a collection of independent computers connected by a network and middleware appearing as one coherent system. Advantages include economics, performance, reliability, resource sharing, scalability, and openness. Disadvantages include complexity, network problems, security risks, partial failure, no global clock, and higher management cost. ## Answer #### Definition A **distributed system** is a collection of independent computers, connected by a network and running distribution middleware, that appears to its users as a single coherent system. Its components communicate and coordinate their actions only by passing messages (Tanenbaum; Coulouris). #### Advantages - **Economics:** many cheap computers give a better price/performance ratio than one mainframe. - **Performance and speed:** work is shared among processors (parallel processing, load balancing). - **Inherent distribution:** applications such as banking, e-mail and the web are naturally spread over many places. - **Reliability and availability:** if one machine fails the others continue, particularly with replication. - **Resource sharing:** hardware, software and data are shared by remote users. - **Incremental growth (scalability):** capacity is added by adding machines. - **Flexibility and openness:** parts from different vendors can be combined. #### Disadvantages - **Complexity:** design, development and debugging are harder than for a single machine. - **Software:** little general-purpose distributed software exists; middleware adds overhead. - **Network problems:** the network may be slow, saturated or fail, and lost messages hurt the system. - **Security:** open networks and shared resources raise the risk of attacks and data leakage. - **Partial failure:** parts fail independently, so the state is hard to know and keep consistent. - **No global clock or shared memory:** synchronisation and agreement are difficult. - **Higher management cost:** many machines need to be administered, upgraded and kept consistent. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Why does a distributed system give a better price/performance ratio? A. Many cheap computers together cost less than one mainframe for the same performance B. A single mainframe is always cheaper C. It needs no network hardware D. It needs fewer administrators Answer: A. Commodity machines in combination are more economical than a mainframe. (Key point: Economics) 2. What gives a distributed system higher reliability and availability? A. All machines fail together B. It has one central machine C. If one machine fails the others continue, especially with replication D. Messages are never lost Answer: C. Independent nodes and replication mask single failures. (Key point: Reliability) 3. Why does partial failure make a distributed system hard to manage? A. Failures are always total and obvious B. Parts fail independently, so the overall state is hard to know and keep consistent C. There is no network involved D. It only affects one user Answer: B. Independent failures leave an uncertain, possibly inconsistent state. (Key point: Partial failure disadvantage) 4. What is the effect of having no global clock or shared memory? A. Synchronisation becomes trivial B. Nodes need no communication C. All events have a known exact order D. Synchronisation and agreement between nodes become difficult Answer: D. Without shared time or memory, nodes must coordinate through messages, making agreement hard. (Key point: No global clock) ## Related in Distributed System - [DS as a single coherent system](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Asingle-coherent-system) — Distributed System, chapter 1, asked 2× - [Autonomous vs distributed system](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Aautonomous-vs-distributed) — Distributed System, chapter 1 - [Models of distributed system](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Amodels-of-ds) — Distributed System, chapter 1 - [True distributed system; middleware organisation](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Atrue-ds-middleware) — Distributed System, chapter 3 - [Define DS and its requirements](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Adefine-ds-requirements) — Distributed System, chapter 1, asked 3× - [Applications, advantages of DS](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Ads-applications-advantages) — Distributed System, chapter 1 ## Related in other subjects - [Distributed system in big data example](https://www.bctengineer.com/question.md?key=semester_8%2Fbig_data_technologies%3Adistributed-system-example) — Big Data Technologies, chapter 1 - [Short note: Distributed system implementation](https://www.bctengineer.com/question.md?key=semester_6%2Fobject_oriented_analysis_and_design%3Ashort-note-distributed-implementation-issues) — Object Oriented Analysis and Design, chapter 4 - [Distributed system and Hadoop](https://www.bctengineer.com/question.md?key=semester_8%2Finformation_system%3Adistributed-system-hadoop-voluminous-data) — Information System, chapter 8 - [Voltage drop and loss with uniformly distributed load](https://www.bctengineer.com/question.md?key=semester_8%2Ftransmission_and_distribution_system_design%3Avoltage-drop-loss-uniform-load) — Transmission and Distribution System Design, chapter 7, asked 2×