Unit 2 Technology Systems BTEC First Diploma in

Unit 2 Technology Systems BTEC First Diploma in Information and Creative Technology

Learning aims A. Understand how the components of technology systems work together. B. Understand how data flows between internal components of a computer and is processed to provide information. C. Understand different types of software. Lesson Aim: Understand the characteristics of high-level and low-level programming Introduction to designing a computer program

High-level programming Most programmers use a high-level programming language to write their programs – e. g. C#, C++, Java, Visual Basic High-level programs have much clearer structures when repeating code or making decisions. High-level programming languages are powerful and easy to understand. Programs written in a high-level language are much closer to spoken language than low-level, as well as being a lot more intuitive to use.

Low-level programming Low-level programs usually have a very large number of lines of code because each instruction only does a small action, so it can be difficult to see the overall structure among so much detail. Low-level programs are written in situations where precise control is needed over the processing and where speed is essential. Although a low-level program will have a large number of lines in the code (written by the programmer) when it gets assembled into machine code this is a lot smaller than an equivalent program written in a high-level language. This is because a line of code written using a high-level language will create a lot of machine code to allow for the many ways the high-level code instruction could be used.

Activity In groups, explain the characteristics: High-level programming languages, including the following: Imperative code Procedural code Event-driven programs Object-orientated programs Low-level programming languages

Characteristics of high-level programming languages Imperative code – this is used in most languages (both older and modern). In this type of code, each program statement is a step towards handling the inputs, processing and outputs. Procedural programs – these have definite start and end points. These languages were normal before GUI operating systems, as they usually have a single starting point then follow a sequence. Modern programs respond to events so can have many start points within the code. Event-driven programs – these respond to events such as a mouse click. These are the current approach for modern programming because they need to produce responses to the great variety of events that GUI operating systems provide. Object-orientated programs (OOP) – these view programs as a collection of objects, such as a database record, and not as a list of tasks in procedural programming. Each object can be viewed as an independent ‘machine’ with a distinct role or responsibility, which is capable of receiving messages, processing data and sending messages to other objects.

Characteristics of low-level programming languages Assembly language is written using an assembler, which helps the programmer by checking for errors in the mnemonics before compiling the program into machine code. Assembly language consists of a number of mnemonics, abbreviations such as MOV – move instruction. Each mnemonic is equivalent to a machine code instruction. Machine code is binary bytes, so could be written without an assembler by typing binary numbers directly into memory. However, this would be difficult, as the programmer would only see the program as numbers. The mnemonic abbreviations in assembly languages make understanding the program much easier.

Designing a computer program Programs need to be designed so they meet the intended requirements and to help ensure they function correctly. The design for the program is used to create a test plan to make sure that every part of the program works as intended. One of the common approaches to designing computer programs is to create a flow chart.

Flow Charts Flow charts are used to help design a program. A flow chart is a diagram that shows how a program works and the routes that can be taken through it. A flow chart shows where the program starts, where decisions are taken, processing operations, inputs and outputs.

Flow chart symbols Symbol Process – used to represent any calculation or general processing operation carried out by the program. Terminator – shows where the program starts and finishes. Decision box – used in any place where the program makes a test to decide on a choice of directions to run the next code. Data (Input/Output) – represents any part of the program that takes data in or shows, prints or outputs data. Connector – also known as a flow line. These lines connect other parts of the flow chart to show the routes the program can take. Flow lines usually have an arrow at one end to show the direction the program takes. If there is no arrow, the direction will be either downwards or to the right.

Activity Create a diagram to show the flow chart symbols

Snake game flow chart

Activity Create a flow chart to show a program could be used to calculate the overall grade for you and other learners completing the BTEC First Award in ICT.

Check! 1. Can you draw the following flow chart symbols: A process Data A decision box A connector A terminator 2. What is the purpose of a flow chart when programming?

Key Terms Solid state Dynamic RAM / DRAM Static RAM / SRAM Flash memory Battery life System on a chip (So. C) Chip Analogue data Digital data Encrypt Bit Byte Word ASCII Binary format Operating system Utility application Command line interface (CLI) GUI Hierarchal structure Mnemonics High-level language Low-level language Machine code