What Is Systems Architecture? Key Traits and Building Blocks

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What Is Systems Architecture? Key Traits and Building Blocks

System Analysis and Design · Chapter 5: Interface Design and Systems ArchitectureSection 5.4 · lesson 37 of 698 min · free with a free account

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In this lesson

5 building blocks, 3 quality attributes, and where a system runs.

  • Define systems architecture and its 5 building blocks
  • Explain scalability, reliability, and maintainability
  • Distinguish monolithic from distributed architecture
  • Compare on-premises deployment with IaaS, PaaS, and SaaS

Transcript

Everything said in the video, section by section (1,048 words). Read along, or search it.

Interface Design and Systems Architecture

What Is Systems Architecture?

So far in this chapter, we have looked at the surface of a system, its interface. Now we step back, to look at the whole structure underneath. This section defines systems architecture, and its five building blocks. Then three quality attributes that every architecture is judged on. The choice between monolithic and distributed systems. And the options for where a system actually runs, from on-premises to the cloud.

The Big Picture

Architecture vs. Design

Systems architecture is the overall structure of a system. It is how the system's hardware, software, data, network, and people are organized, and how they work together to meet its requirements. How does that differ from systems design? Systems design works out the detailed blueprint for one part of a system at a time. Architecture is the bigger picture those detailed designs have to fit inside. It is the arrangement that determines how well the whole system will actually perform, scale, and hold up over time. A brilliant design for one part cannot rescue an architecture that is wrong for the whole.

Figure 5.1

The 5 Building Blocks

Every system's architecture can be described in terms of five building blocks. Hardware. The physical devices a system runs on. Servers, client devices, storage, and network equipment. Software. The programs that run on the hardware. Operating systems, application software, and database management software. Data. The information the system stores, processes, and provides, and how and where it is kept. Network. The communication infrastructure connecting the hardware, from a local office network to the internet. And people. The users, administrators, and support staff who operate the system, and interact with it day to day. A single architecture decision usually involves more than one of these at once. Choosing a network layout has consequences for hardware. And a data storage decision has consequences for the people who will administer it.

Holding Up in the Real World

3 Quality Attributes

Beyond simply working, a well-architected system has to hold up under real-world conditions. Three quality attributes come up constantly. Scalability is the ability to handle growth in users, data, or transaction volume, without a serious drop in performance. For example, a retail site's checkout still responds quickly during a holiday sales spike, not just on an ordinary day. Reliability means the system performs correctly and consistently, is available when needed, and recovers well from failure. For example, a hospital's patient records system stays available through a server failure, because a backup server takes over automatically. Maintainability is how easily the system can be modified, fixed, or extended over time, as needs change. For example, a clearly organized, well-documented system lets a new developer add a feature, without untangling the whole codebase first.

Figure 5.2

Monolithic vs. Distributed

One of the most fundamental architecture decisions is whether a system's components are bundled together, or spread apart. On the left is a monolithic architecture. The user interface, business logic, and data access are built and deployed as a single unit. They are built, deployed, and scaled together. On the right is a distributed architecture. The same layers are split across independent systems. A U I server, an application server, and a database server. They communicate with one another over a network. Each layer can be scaled, updated, or replaced on its own.

Comparing the Two

The Trade-Offs

Each approach has its trade-offs. A monolith is simpler to build at first, because everything lives in one place. A distributed system is more complex, because its components must be coordinated across a network. On scalability, a monolith must be scaled as a whole, even if only one layer needs it. A distributed system can scale each layer independently, based on where the demand actually is. On fault isolation, a serious failure in one layer of a monolith can bring the whole application down. In a distributed system, a failure in one component does not necessarily affect the others. And on deployment, a monolith must be redeployed entirely for any change, however small. A distributed system can update or replace individual components, without redeploying everything.

Where the System Runs

On-Premises vs. Cloud

Architecture decisions also cover where a system actually runs. With on-premises deployment, the organization owns and maintains its own hardware, in its own facility. That means full control over every layer, but also full responsibility for every layer. Cloud deployment instead rents computing resources from a vendor, in a few common tiers. With infrastructure as a service, or I a a S, the vendor provides virtual servers, storage, and networking. The organization still installs and manages its own operating system, runtime, and applications. With platform as a service, or P a a S, the vendor also manages the operating system and runtime. The organization focuses on building and managing its own application and data. And with software as a service, or S a a S, as introduced earlier, the vendor manages everything, including the application. The organization simply uses the finished software, over the internet.

The Pattern

A Steady Handoff of Responsibility

Look at those four options in order, and a pattern appears. Moving from on-premises toward S a a S is a steady handoff of responsibility to the vendor. On-premises, the organization manages every layer. With I a a S, the vendor takes the hardware. With P a a S, the vendor also takes the operating system and runtime. And with S a a S, the vendor takes the application itself. At each step, the organization manages less of the technical stack. And it depends more on the vendor to keep that layer running, patched, and available.

Key Terms

The Vocabulary of This Section

Let's lock in the key terms. Systems architecture is how a system's hardware, software, data, network, and people fit together. Scalability is handling growth. Reliability is staying correct and available. Maintainability is being easy to change. A monolithic architecture bundles all layers into one unit. A distributed architecture spreads them across networked systems. And I a a S, P a a S, and S a a S are infrastructure, platform, and software as a service.

Key Takeaways

What to Carry Forward

To pull this together. Systems architecture is the overall structure of a system, how its hardware, software, data, network, and people fit together. Scalability, reliability, and maintainability describe how well an architecture holds up under growth, failure, and change. A monolithic architecture bundles all layers into one deployable unit. A distributed architecture spreads them across network-connected components. And on-premises, I a a S, P a a S, and S a a S represent a steady handoff of responsibility, from the organization to the vendor.

About System Analysis and Design at UPI Study

System Analysis and Design (Computer Science 390) is a self-paced online course of 69 video lessons in 9 chapters, from the analyst's role and requirements to UML modeling, interface and database design, testing, maintenance and project management. It carries a NCCRS credit recommendation for 3 semester credits.

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Why students take System Analysis and Design with UPI Study

From business problem to working systemSystem Analysis and Design teaches how analysts study a business need and turn it into a system design: requirements, UML and data-flow models, interface and database design, implementation and project management. It is a core course in information systems and IT degrees.
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130,000+students helped with college creditsACE and NCCRS have over 2,100 cooperating colleges that will consider accepting credits; the final decision is with the universities.

Where the credit goes

Universities that work with NCCRS

System Analysis and Design carries a NCCRS credit recommendation. These universities work with NCCRS; some are UPI Study's signed partners. ACE and NCCRS have over 2,100 cooperating colleges that will consider accepting credits; the final decision is with the universities.

Thomas Edison State UniversityThomas Edison State UniversitySigned partnerUniversity of the PeopleUniversity of the PeopleSigned partnerCharter Oak State CollegeCharter Oak State CollegeSigned partnerStrayer UniversityStrayer UniversitySigned partnerColumbia Southern UniversityColumbia Southern UniversitySigned partnerIndiana TechIndiana TechSigned partnerPenn StatePenn StateWorks with NCCRSSouthern New Hampshire UniversitySouthern New Hampshire UniversityWorks with NCCRSSUNYSUNYWorks with NCCRS +many more cooperating universitiesFind my college →

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FAQ

Questions students ask us

About What Is Systems Architecture? Key Traits and Building Blocks

What are the five building blocks of systems architecture?
The five building blocks of systems architecture are hardware, software, data, network, and people. Hardware covers servers, client devices, and storage; software covers operating systems, applications, and database management software; data is the information stored and processed; the network connects the hardware; and people are the users, administrators, and support staff. A single architecture decision usually affects more than one block at once.
What do scalability, reliability, and maintainability mean in system architecture?
Scalability is handling growth in users, data, or transactions without a serious drop in performance, reliability is performing correctly, staying available, and recovering well from failure, and maintainability is how easily a system can be modified, fixed, or extended. Examples include a checkout that stays fast during a holiday spike, a records system that fails over to a backup server, and a well-documented codebase a new developer can extend.
What is the difference between monolithic and distributed architecture?
A monolithic architecture builds and deploys the user interface, business logic, and data access as a single unit, while a distributed architecture splits those layers across independent systems that communicate over a network. A monolith is simpler to build at first but must be scaled and redeployed as a whole. A distributed system is more complex but can scale, update, or replace each component independently and better isolate failures.
What is the difference between IaaS, PaaS, and SaaS?
IaaS, PaaS, and SaaS differ in how much of the technical stack the cloud vendor manages. With infrastructure as a service, the vendor provides virtual servers, storage, and networking, while the organization manages the operating system, runtime, and applications. With platform as a service, the vendor also manages the operating system and runtime. With software as a service, the vendor manages everything, including the application itself.

About the System Analysis and Design course

How many college credits is System Analysis and Design?
System Analysis and Design (Computer Science 390) carries a NCCRS credit recommendation for 3 semester credits. ACE and NCCRS have over 2,100 cooperating colleges that will consider accepting credits; the final decision is with the universities.
How much does System Analysis and Design cost and what is included?
$250, paid once, with lifetime access: all 69 video lessons, a practice quiz after each, the graded work and final exam, and an official transcript when you finish. Students who want several courses choose UPI Study PRO instead.
Which universities accept UPI Study credits?
UPI Study has signed partner agreements with universities such as Thomas Edison State University, University of the People and Charter Oak State College, and works with universities such as Penn State, SNHU and SUNY. ACE and NCCRS have over 2,100 cooperating colleges that will consider accepting credits; the final decision is with the universities. Use "Find my college" on this page to check yours.
How long does System Analysis and Design take?
It is self-paced with no deadlines. The 69 lessons total about 9 hours of video; most students add reading and practice time and finish in a few weeks to a few months, on their own schedule.
How are the exams done?
Quizzes and assignments are online in the course. The final exam is taken online with proctoring; a person on the UPI Study team checks assignments, usually within two days.
How do my credits reach my college?
When the course shows 100% complete, request the official transcript from your dashboard. It is sent to the college you name, and you can send it to more than one. Check your college first with "Find my college" on this page, or ask Athena.

Ready for the full course? Earn 3 credits in System Analysis and Design.

69 video lessons, a quiz after each one, and the graded work that earns the credit. Recommended for credit by NCCRS.

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