--- title: "Transparency properties of DS" subject: "Distributed System" chapter: 1 key: "semester_7/distributed_system:ds-transparency-types" source: https://www.bctengineer.com/q/semester_7/distributed_system/ds-transparency-types site: BCT Engineering --- # Transparency properties of DS Distributed System · Chapter 1: Introduction - Asked in: 2075 Asoj, 2+6 marks - Video: [Types of transparencies in distributed system](https://www.youtube.com/watch?v=QVjGRxvzQqM) — Engineering Digest - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/distributed_system/ds-transparency-types - Whole chapter: https://www.bctengineer.com/md/semester_7/distributed_system/chapter-1 ## Question Define distributed system. Explain the transparency properties of a distributed system. ## Short answer A distributed system is a collection of independent computers connected by a network and middleware appearing as one coherent system. Transparency types hide access, location, migration, relocation, replication, concurrency, failure, persistence, and performance/scaling differences, so users see a single system. ## Answer #### Distributed system 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). #### Transparency properties Transparency means hiding the separation of components so that the system is seen as a whole. ISO's RM-ODP and Coulouris define the following types. | Transparency | What is hidden | Example | |---|---|---| | Access | Differences in data representation and how a resource is accessed | Same call to read a local or remote file | | Location | Where the resource is physically located | URL does not show the server's place | | Migration | A resource may move to another location | A process moved to another host without the user noticing | | Relocation | Movement of a resource while it is in use | Mobile user keeps a call while moving between cells | | Replication | Existence of several copies | Many mirror servers behind one name | | Concurrency | Sharing of a resource by several users | Two users editing a database safely | | Failure | Failure and recovery of a component | Request is served by a backup when a server crashes | | Persistence | Whether the resource is in memory or on disk | Object is loaded from disk when needed | | Performance / scaling | System reconfigures to keep performance or grow | Load balancer adds servers | Access and location transparency are together called **network transparency**, and are the most important. Complete transparency is costly, so designers balance it against performance. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What does transparency mean in a distributed system? A. Hiding the separation of components so the system is seen as a whole B. Showing users every component's location C. Making all components identical D. Removing communication between components Answer: A. Transparency conceals the distribution of components from users and programmers. (Key point: Transparency definition) 2. Which example illustrates access transparency? A. A process moves to another host without notice B. The same call is used to read a local or a remote file C. A backup serves requests when a server crashes D. Mirror servers appear behind one name Answer: B. Access transparency hides differences in representation and how a resource is accessed. (Key point: Access transparency) 3. Which type of transparency lets a mobile user keep a call going while moving between cells? A. Replication transparency B. Persistence transparency C. Relocation transparency D. Concurrency transparency Answer: C. Relocation transparency hides the movement of a resource while it is in use; migration hides movement when not in use. (Key point: Relocation vs migration) 4. Which two types together form network transparency? A. Failure and persistence transparency B. Concurrency and replication transparency C. Migration and scaling transparency D. Access and location transparency Answer: D. Access and location transparency are together called network transparency and are the most important. (Key point: Network transparency) ## Related in Distributed System - [DS vs centralized; layers of transparency](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Ads-over-centralized-transparency) — Distributed System, chapter 1 - [DS properties and interaction model](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Ads-properties-interaction-model) — Distributed System, chapter 1 - [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× - [Goals, need of transparency, challenges](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Agoals-transparency-challenges) — Distributed System, chapter 1 - [Transparency: importance and challenges](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Atransparency-importance-challenges) — Distributed System, chapter 1 - [RPC vs RMI; modern RPC transparency](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Adifferentiate-rpc-modern-rpc) — Distributed System, chapter 2 ## 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 - [Describe LTI system properties](https://www.bctengineer.com/question.md?key=semester_4%2Fsignals_and_systems%3Alti-properties-describe) — Signals and Systems, chapter 5, asked 3×