Virtual Workbenches Richard Anthony The University of Greenwich

Overview Three virtual workbenches facilitate practical experimentation and simulation of technical and dynamic aspects of the computer science curriculum.

Design method / philosophy Don’t water down difficult aspects of courses → instead, find better ways to teach these aspects! Ways to simulate / demonstrate / emulate are devised to facilitate understanding by capturing the dynamic behaviour of systems. Design is focussed on: * clear presentation of technical / dynamic concepts, * ensuring that the user interface is highly intuitive, * enabling full user configuration control, * providing clear instrumentation and instant feedback, * facilitating a wide range of progressive experimentation, * keeping the general look-and-feel consistent.

Mature, yet still growing Progressively developed since 2002.

Versatile Teaching and Learning The workbenches can be used in many ways: lectures and tutorials, laboratory tasks, coursework, unsupervised learning (structured - with the student activities provided, or unstructured - free experimentation).

Integrated Environments Each workbench focuses on a particular discipline within computer science. Dynamic aspects of systems are brought to life through user-configurable, repeatable, simulations and experiments. No programming required.

Engaging Activities Student activity guides provide progressive challenges and encourage evaluation and reflection.

Evaluation Used by an increasing number of lecturers since Evaluation in the form of: Feedback via student critique in coursework, Student and staff responses to questionnaires, Personal teaching experience, Requests for modifications and additional features.

Lab Activity example: Real-Time Scheduling: Introductory: DL 2 Fairness between two processes 1. Configure the simulation as follows: Process 1: Task inter-arrival time = 33 milliseconds, Computation time = 16. Process 2: Task inter-arrival time = 20 milliseconds, Computation time = 10. Scheduler Configuration = Deadline. 2. Press the Free Run button and pay attention to the dynamic graph in the Runtime State Display window. 3. When the timestep reaches about 100, press the pause button. Note the System Statistics and Runtime Statistics. Questions Q1. Do the tasks always seem to meet their deadlines? Q2. Do you think the Deadline algorithm is ‘fair’ to both processes ? (In the context of real-time scheduling, how do you interpret the term ‘fair’ ?). Q3. Can the amount of CPU Idle time be determined from the configuration of the processes, or is a simulation experiment needed in each case ?

Summary – Key Features Replacement of static representations with dynamic, interactive, user-configured simulations (showing how components interact and also the temporal relationships within those interactions). Students learn at their own pace, with repeatable experiments. The tools can be used at any location / time. Works on a laptop - no network connection needed. The tools can be used in lectures and tutorials to demonstrate concepts as well as in the laboratory and unsupervised. Progressive laboratory exercises; designed to encourage analysis and critical thinking. In house → Custom material, No licences.

Observations and Lessons learnt Do not underestimate the time needed to develop e-learning materials. (the single biggest problem, far more significant than technical hurdles, in my case certainly). An incremental approach is encouraged: Enables early pay-back with some working functionality, whilst allowing reflection before the next phase. Promotes continuity, rather than inefficient stop-start fragmented effort. So design for extensibility and easy upgrade (Workbenches developed over a period of 5 years, but used 6 months in). The development of the tools is a form of CPD, in terms of developing teaching materials and also in actual software design and development.