What is architecture?

Navigation: Introduction to ABACUS >

Architecture is an abstract concept - not a physical thing. It's a rich and comprehensive description or understanding of the structure of a system - capturing the components and how they're connected (interact). Because the notion of architecture is so all-encompassing, it is fundamental to the cost, availability, evolvability, and performance of the system. A sound architecture is a pre-requisite of a sound system.

In ABACUS, you model your architecture. For simplicity, we call this architectural model an architecture.

The diagram below illustrates a typical architecture of 5 components (in a hierarchy) connected by 2 connections. The labels indicate the names given the various parts of the architecture in ABACUS.

A simple architecture

ABACUS considers all of these things to be part of the architecture:

•Components represent the entities of your architecture which you could describe as "things". For an insurance company, the components might be the systems for processing policies, claims, payments, and receipts.

•Connections represent the relationships between these components. For example, in an insurance company, receipts are generated for valid policies, claims are made against valid policies, and valid claims result in payments. When thinking architecturally - particularly when using ABACUS - connections are as important as components, and they are dealt with in an almost identical way.

•Everything in the tree can have Properties. Properties are things like the way you require your system to perform, the number of lines of code it has, the percentage of these lines that are comments, etc. ABACUS considers all of these things to be part of the architecture.

•By using hierarchies (i.e. sub-components and sub-connections), you can hide information and de-compose your architecture. The ABACUS architectural model is extremely flexible. Any component at any level can be related to any other component at any other level by any connection at any level.

•Attachment is the operation by which components ports are bound to connection roles. Ports and Roles are the interfaces between components and connections. They are used to attach connections to components. Connections have a Source and a Sink role (facilitating data flow from the source component to the sink component) and conceptually, components have ports. For simplicity, however, in ABACUS component ports are not shown and the connection roles are directly attached to the components themselves.

•Components and connections are of a certain Type. This is mainly for classification purposes. For example the policies, claims, payments, and receipts are components of the type 'System'. The valid policies, valid claims, etc. are connections of the type 'Transaction'. The Type assigned to a component or connection provides a template for the properties and standards it has. For example, a Server component type might have 'Make & Model' standard and an IP Address property. Unlike other rigid tools with a basic relational data-base (RDB) back-end, in ABACUS you can freely create your own new Types and assign your own combinations of properties and standards to them.

•Standard libraries of properties can be specified and assigned to anything else in the architecture. These libraries are known as Standards. By using Standards, you only need to gather specific systems properties - the standard properties are already there. For example the standard performance characteristics of Microsoft Windows 2000 can be assigned to whatever components are using the Microsoft Windows 2000 operating system.