Phil Harker & Norman Green What is a Computer? Phil Harker & Norman Green

What is a Computer? It is a device that can carryout instructions very, very quickly and very accurately. Computers have become more powerful and cheaper which means they have become part of everyone’s life, (that’s unless you are a member of a tribe living in a remote area). Fast Repetitive Processing Vast Storage Capabilities Ability to search and combine data in different ways Response Times

Benefits of Computers Fast Repetitive Processing Utility Companies (Gas & Electric) On-line Order Processing Vast Storage Capabilities Banks Accounts Tax Records

Benefits of Computers Ability to search and combine data in different ways Medical records can be searched very quickly to find patients who need to be called for a particular procedure. Police use computers to search through records of evidence looking for ways of combining and presenting information in a way that is useful to the investigating team. Credit card companies use computers to search through the transaction records in order to identify unusual transactions which may indicate fraud. Response Times Flight Control System on an Aeroplane

What is in a Computer? There are five main features Operating System - Windows 10 Home 64 Processor – Intel Core i5 Screen Size – 35.6cm Memory (RAM or Random Access Memory) 8GB Hard Disk and / or SSD (Solid State Drive - 256 GB) This laptop costs £629.

Processor A Processor execute or carries out instructions given in binary: 000001010100101011 010100101010101010 100100101010100000 Each make of processor has its own set of instructions that it can understand. The instructions include: Add, Subtract, Multiple, Divide Compare (Bigger, Smaller, Equal) Moving Data Instructions This is all hidden from you by the operating system which is usually Windows.

Processor Computer Programmers no longer write programs in binary. Most programs are written in a high level language such as C, Visual Basic, COBOL and they use English type commands These programs are then converted into Machine Code – the equivalent binary instructions. How many instructions do you think a processor can execute in a second? Public Class frmIf1 REM This program shows the three forms of an If Statement Private Sub btnDisplay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplay.Click Dim Age As Integer Dim Message As String   Age = InputBox("Enter Your Age", "Driver") If Age < 17 Then Message = "You are too young to drive." Else Message = "You are old enough to drive." End If If Age = 17 Then Message &= vbNewLine & "You can apply for your provision license." If Age >= 80 Then Message = "Consider taking the bus." lblDisplay.Text = Message End Sub End Class

Processor Who makes processors for Personal Computers? Intel AMD 10th Gen Intel® Core™ processors Intel Core i9 Intel Core i7 Intel Core i5 AMD AMD Ryzen™ AMD Athlon AMD A-Series Processors The most expensive PCs at the moment tend to have an Intel i9 processor while the cheaper models will have Celeron or Athlon processors. If you want now what the latest models are, go to these two companies websites.

How Quick is a Processor? There are lots of factors which determine how fast a processor performs, but the figure 5.00 GHz is an indication of speed. 5 GHz (Gigahertz) means that the processor clock pulses 5,000,000,000 per second. A program instruction may take 1, 2 or more pulses to execute.

Memory This is a memory chip. Modern computers usually have between 4GB and 32GB.

Memory When a computer program is running it is placed in the computers Memory (RAM Random Access Memory) together with any data it needs, while it waits to have the instructions executed. Most modern computers have 4, 8, 16 or 32 GB – 1GB =1,000,000,000 characters. Each instruction is taken from the memory to the processor to be executed. This is called the Fetch-Decode-Execute cycle. The size and the number of programs being run determines how much memory is used. As a rough rule the more memory a computer has the more efficient it will run. Data Bus Processor Memory Address Bus

Hard Disk Most hard disks or hard drives in modern computers are between 1Tb or 2Tb. 1 terabyte = 1099511627776.00 characters 1 terabyte ≈ 1,000,000 Mb So your hard disk would hold 2,00,000 music tracks or photographs.

Hard Drive This is where the programs and data files are held when they are not being used and when the computer is switched off. A hard drive consists of platters that are coated with magnetic material. The data is stored in tracks and sectors. The data and programs are read or written using read / write heads. There is a index on the disk recording where the files are stored on the disk. This technology is relatively old, but they are still used because they are cheap reliable and can hold a vast amount of data.

Solid State Device Solid State Device is an electronic device in which electricity flows through solid semiconductor crystals and is used to store data. A SSD inside a computer, mobile phone or tablet is similar to the electronics in a “memory stick”. A SSD is able to hold data even when the device is turned off. These devices are now being used in computers because they function at a faster speed than a traditional hard disk. SSDs do not contain moving parts. Currently SSDs have lower capacities than a hard disk.

Other Items Other components of a computer include: CD Drives Graphic Cards Screen Keyboard & Mouse