Version 1
: Received: 7 December 2021 / Approved: 8 December 2021 / Online: 8 December 2021 (14:25:02 CET)
Version 2
: Received: 16 December 2021 / Approved: 21 December 2021 / Online: 21 December 2021 (13:59:45 CET)
Version 3
: Received: 21 January 2022 / Approved: 24 January 2022 / Online: 24 January 2022 (11:43:32 CET)
Haeri, S.H.; Thompson, P.; Davies, N.; Van Roy, P.; Hammond, K.; Chapman, J. Mind Your Outcomes: The ΔQSD Paradigm for Quality-Centric Systems Development and Its Application to a Blockchain Case Study. Computers2022, 11, 45.
Haeri, S.H.; Thompson, P.; Davies, N.; Van Roy, P.; Hammond, K.; Chapman, J. Mind Your Outcomes: The ΔQSD Paradigm for Quality-Centric Systems Development and Its Application to a Blockchain Case Study. Computers 2022, 11, 45.
Haeri, S.H.; Thompson, P.; Davies, N.; Van Roy, P.; Hammond, K.; Chapman, J. Mind Your Outcomes: The ΔQSD Paradigm for Quality-Centric Systems Development and Its Application to a Blockchain Case Study. Computers2022, 11, 45.
Haeri, S.H.; Thompson, P.; Davies, N.; Van Roy, P.; Hammond, K.; Chapman, J. Mind Your Outcomes: The ΔQSD Paradigm for Quality-Centric Systems Development and Its Application to a Blockchain Case Study. Computers 2022, 11, 45.
Abstract
This paper directly addresses a long-standing issue that affects the development of manycomplexdistributedsoftwaresystems:howtoestablishquickly,cheaply,andreliablywhetherthey can deliver their intended performancebeforeexpending significant time, effort and money ondetailed design and implementation.We describe∆QSD, a novelmetrics-basedandquality-centricparadigm that uses formalisedoutcome diagramsto explore the performance consequences of designdecisions, as a performance blueprint of the system. The distinctive feature of outcome diagrams isthat they capture the essentialobservationalproperties of the system, independent of the details ofsystem structure and behaviour. The∆QSD paradigm derives bounds on performance expressed asprobability distributions encompassing all possible executions of the system. The∆QSD paradigmis both effective and generic:it allows values from various sources to be combined in a rigorousway, so that approximate results can be obtained quickly and subsequently refined.∆QSD has beensuccessfully used by Predictable Network Solutions for consultancy on large-scale applications in anumber of industries, including telecommunications, avionics, and space and defence, resulting incumulative savings worth billions of US dollars. The paper outlines the∆QSD paradigm, describesits formal underpinnings, and illustrates its use via a topical real-world example taken from theblockchain/cryptocurrency domain.∆QSD has enabled challenging throughput targets to be met fora globally distributed blockchain operating on the public internet.
Computer Science and Mathematics, Computer Science
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received:
24 January 2022
Commenter:
Peter Thompson
Commenter's Conflict of Interests:
Author
Comment:
Correction to Definition 4 and a variety of improvements to the text including: - The Introduction section has been edited and broken into subsections to improve clarity - A new section has been added referencing recent studies on block propagation analysis - Added missing figure captions - A section has been added discussing limitations of the method - A section has been added discussing practical implications for system designers
,
Commenter: Peter Thompson
Commenter's Conflict of Interests: Author
- The Introduction section has been edited and broken into subsections to improve clarity
- A new section has been added referencing recent studies on block propagation analysis
- Added missing figure captions
- A section has been added discussing limitations of the method
- A section has been added discussing practical implications for system designers