---
title: "Goals, need of transparency, challenges"
subject: "Distributed System"
chapter: 1
key: "semester_7/distributed_system:goals-transparency-challenges"
source: https://www.bctengineer.com/q/semester_7/distributed_system/goals-transparency-challenges
site: BCT Engineering
---

# Goals, need of transparency, challenges

Distributed System · Chapter 1: Introduction

- Asked in: 2069 Chaitra, 4+4 marks
- Video: [Distributed System Challenge : Transparency Explained in Hindi](https://www.youtube.com/watch?v=dysSzForgRA) — 5 Minutes Engineering
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/distributed_system/goals-transparency-challenges
- Whole chapter: https://www.bctengineer.com/md/semester_7/distributed_system/chapter-1

## Question

What are the major goals of a distributed system? Explain the need of transparency in distributed system along with the challenges in achieving that.

## Short answer

Goals include resource sharing, transparency, openness, scalability, concurrency and fault tolerance. Transparency hides location, replication, failure and concurrency, making the system easy to use and reducing development cost. Challenges are network latency, partial failure, performance cost, concurrency control, heterogeneity, geographic distance, and trade-offs with location-aware services.

## Answer

#### Goals of a distributed system
- **Resource sharing:** users and programs share printers, files, data, storage and compute power across the network (for example the web, cloud storage).
- **Transparency:** hide the fact that processes and resources are physically spread over many machines.
- **Openness:** the system offers services through standard, published interfaces so that parts from different vendors can interoperate and be extended.
- **Scalability:** the system keeps working well as users, resources and geographic spread grow.
- **Concurrency and fault tolerance:** many users work at once, and the system keeps running when some component fails.

#### Need of transparency
Users and application programmers should not have to know where data is stored, how many copies exist, or how a failure is handled. Without transparency each application would need code for networking, location, failure and concurrency, which is complex and error prone. Transparency:

- makes the system easy to use (one system image);
- lets the system move, copy and reorganise resources without changing applications;
- reduces development cost, since programmers work as if on a single computer;
- helps resource sharing and scalability.

The main forms are access, location, migration, relocation, replication, concurrency, failure and persistence transparency.

#### Challenges in achieving transparency
- **Network latency and unreliability:** a remote call cannot be made identical to a local call. Hiding delay completely is impossible.
- **Partial failure:** it is hard to tell whether a server has crashed or the network is only slow, so failure transparency is hard.
- **Performance cost:** full replication transparency needs consistency protocols, and hiding location needs lookups.
- **Concurrency:** keeping replicated and shared data consistent requires locks or transactions, which reduce speed.
- **Heterogeneity:** different data representations need conversion for access transparency.
- **Geographic distance:** a user in Nepal and a server abroad will always see differences in delay.
- **Trade-off:** in some cases (location-aware services, mobile apps) users prefer to know the location, so full transparency is not always desirable.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Why is transparency needed in a distributed system?
   A. Otherwise every application would need its own code for networking, location, failure and concurrency
   B. To make applications slower but safer
   C. To force users to know where data is stored
   D. To remove the need for a network
   Answer: A. Transparency lets programmers work as on a single computer and lets the system move or copy resources without changing applications. (Key point: Need of transparency)

2. Why can transparency not be fully achieved for remote access?
   A. Remote calls are always faster than local calls
   B. Networks have no delay
   C. Network latency and unreliability make a remote call impossible to equal a local call
   D. Remote calls never fail
   Answer: C. Delay cannot be hidden completely, so a remote call differs from a local one. (Key point: Latency challenge)

3. What makes failure transparency hard?
   A. Failures always crash the whole system visibly
   B. It is hard to tell whether a server crashed or the network is merely slow
   C. Servers never fail
   D. Clients always know which component failed
   Answer: B. Partial failure makes slow and failed indistinguishable, so a client cannot be sure what happened. (Key point: Partial failure)

4. What is the performance cost of full replication transparency?
   A. Copies need no synchronisation
   B. Replication reduces the number of copies
   C. Lookups are never needed
   D. Consistency protocols are needed to keep copies in step, adding overhead
   Answer: D. Replication transparency requires consistency protocols, and hiding location requires lookups, both costing performance. (Key point: Replication cost)

## Related in Distributed System

- [Transparency: importance and challenges](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Atransparency-importance-challenges) — Distributed System, chapter 1
- [Goals and design challenges of DS](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Ads-goals-challenges) — Distributed System, chapter 1, asked 3×
- [Concurrency control goals and mechanisms](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Acc-goals-mechanisms) — Distributed System, chapter 8
- [Challenges of DS with example](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Ads-challenges-example) — Distributed System, chapter 1
- [Transparency properties of DS](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Ads-transparency-types) — Distributed System, chapter 1
- [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

## Related in other subjects

- [Distributed parameters and current along a long line](https://www.bctengineer.com/question.md?key=semester_4%2Fpower_system_analysis_i%3Adistributed-parameters-long-line-current) — Power System Analysis I, chapter 5
- [Need and challenges of irrigation in Nepal](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Anepal-irrigation-need-challenges) — Irrigation and Drainage Engineering, chapter 1, asked 9×
- [Need for FACTS and major FACTS devices](https://www.bctengineer.com/question.md?key=semester_8%2Fhigh_voltage_engineering%3Afacts-devices-need-types) — High Voltage Engineering, chapter 1
- [Challenges of modeling a physical system](https://www.bctengineer.com/question.md?key=semester_6%2Fembedded_system%3Amodeling-physical-system-challenges) — Embedded System, chapter 7