More notes on UNIX Systems. See other article here: Unix System Program Layout in Memory Program versus process A program is an executable file containing a sequence of instructions A process is a program in execution For reasons of technology today A program is usually stored on disk or other non-volatile secondary storage A […]
Some notes regarding UNIX Systems. More notes can be found here: UNIX Program Execution, CPU, Memory and Virtualization Operating System UNIX began 1970s ATT Bell Labs. Many variations of Unix today. UNIX Architecture: Kernel System Calls Shell and Library routines Applications UNIX documentation part of OS – man pages. (manual pages). Man page […]
Sequence diagram = represents an interaction; can only show interactions so model element type: interaction; in form: sd [Interaction] interaction name [diagram name] [1] What is the diagram kind for a sequence diagram, and which type of model element does it represent? A = sd / interaction only; [2] What is the context for an […]
Parametric Diagrams (par) = used to express information about system’s constraints. Recall that a constraint block = special kind of block that encapsulates constraint expression; equation or inequality. This enables the following abilities: – Specify assertions of valid system values (thereby detecting exceptional conditions) – Provides inputs and outputs for engineering analysis and simulation during […]
State Machine (stm) = behavior diagram, how a structure within system changes state in response to event occurrences over time. This is not the same as state machine diagram (can have multiple diagrams for single state machine). State machine is the namespace, a set of named elements. Classifier behavior = behavior that begins executing […]
Sequence diagrams (sd) = used to express information about system’s dynamic behavior, by using elements called lifelines to model participants in the system behavior and use messages between lifelines to model the interactions. This view expresses sequences of behaviors and events over time. This is an ideal diagram when wanting to display how blocks interacts […]
Requirement = capability or condition that must be met by a system, or a performance condition the system must achieve; similar requirements are grouped into a specification; requirements can be shown graphically or tabular, or in compact graphical notations in any SysML diagram. Uses <<requirement>> model element; [1] What is the abbreviation for a requirement […]
Package Diagrams Package diagram (pkg) = displays the organization of the system model based on package hierarchy where packages could be nested within each other. Namespace = model element that is allowed to contain other named elements, included nested elements. A model = one of four specialized kind of packages, this serves as the root […]
Activity Diagram = frame represents an activity; [1]What is the diagram kind of the activity diagram?diagram kind of “act” for activity; has following form: act [Activity] activity name [diagram name] Activity name = name to represent the activity; Diagram name = user defined name to describe purpose of diagram; [2]How are an action and […]
Activity Diagram (act) = one of three ways to express information about system’s dynamic behavior (activity, sequence, state machine), it’s a dynamic view of the system that expresses sequences of behaviors and event occurrences over time. (whereas a structure diagram like BDD, IBD and parametric diagrams show static views that convey no sense of time […]
Interruptible region = subset of actions within activity that can interrupt execution of activity via interrupting edge; noted by dashed line around activity nodes; an interrupting edge is noted by lightning bolt symbol; [21] interrupting edge node is within the interruptible region and this has to be triggered to exit the interruptible region; […]
IBD = similar to BDD except it is to specify the internal structure of a single block. It is static (structural) view of the system or one of its parts. Unlike BDD the IBD does not display blocks, but the usages of blocks. IBD shows how the block must be assembled to create a valid […]
The most common SysML diagram is BDD, which includes elements such as blocks, actors, value types, constraint blocks, flow specifications and interfces. Elements of Definition = the elements of a BDD, which are the foundation of everything else, contains the structural relationships, associations, generalizations and dependencies BDD should be created often = created when stakeholder […]
SysML language concepts are described in 3 parts: – abstract syntax = or schema, described by metamodel – concrete syntax = or notation, described by notation tables – semantics = meaning Architecture of SysML There are 3 levels of concept relevant to modeling language: – Domain concepts – the domain being modeled – […]
SysML = broad and richly expressive graphical language with aspects of system’s design: structure, behavior, requirements, parametrics (mathematical models) SysML grammar and notations are defined by OMG (Object Management Group) SysML is extension of UML and as such, some SysML rules are actually defined in UML specification document (ie ValueType is derivative of DataType) Nine […]
The Systems Modeling Language (SysML)[1] is a general-purpose modeling language for systems engineering applications. It supports the specification, analysis, design, verification and validation of a broad range of systems and systems-of-systems. SysML was originally developed by an open source specification project, and includes an open source license for distribution and use.[2] SysML is defined as an extension of a subset of the Unified Modeling Language (UML) using UML’s profile mechanism. The language’s extensions […]
Systems Engineering Overview SysML = System Modeling Language INCOSE = International Council of Systems Engineering SysML = Object Management Group’s (OMG) SysML = general purpose graphical modeling language for representing systems that may include hardware, software, data, people, facilities and natural objects. Supports practice of model-based system engineering (MBSE). Systems engineering = multidisciplinary approach to […]