A computer is a complex device but having a basic idea of the building blocks can help understand enough to make sensible choices of devices.
A mobile phone, tablet/iPad, laptop or desktop computer are all computers and have some of the building blocks described here.
The image below is a simplified diagram of the major elements of any computer.
It does NOT show the electrical connections between each part.
Not every computer has all of the parts shown, but the table below the picture gives some ideas of what might be in your device.
The parts and their functions are described below:
Component | Function | Desk Computer | Laptop | Tablet | Mobile Phone |
Processor | Computing instructions from apps & user | Yes | Yes | Yes | Yes |
RAM Memory | Storing instructions and results | Yes | Yes | Yes | Yes |
Storage | Storing apps & data | Yes | Yes | Yes | Yes |
Power Pack | Provides power to all parts | Yes | Yes | Yes | Yes |
Screen | Displays information to user | Yes | Yes | Yes | Yes |
Keyboard/mouse or Touch Screen | Input by user to control or add data | Keyboard | Keyboard/screen | Touch Screen | Touch Screen |
Internet by cable | Cable based connection to the internet (NBN) | Yes | Yes | Yes | Yes |
WiFi | Wireless connection to internet or other device | Some | Yes | Yes | Yes |
Mobile SIM | Connection to mobile network | No | Some | Some | Yes |
Bluetooth | Local wireless connection to accessories like headphones | Some | Some | Yes | Yes |
USB | Connections for printers, portable drive, scanner, USB stick | Yes | Yes | Yes | Yes |
Sound | Audio output to speakers or headphones | Yes | Yes | Yes | Yes |
The most important parts to consider are:
Size of the Working Memory
Measured in Gigabytes, 4-32 GB in computers, 2-4GB in mobile devices.
- Where working memory is concerned, more is better.
- On a desktop or laptop computer this memory is usually referred to as RAM (random access memory)
- On mobile devices it is not mentioned much
Size of the Long Term Storage
Measured in Gigabytes, 128 - 2000 GB in computers, 16 - 128GB in mobile devices.
- Up to a point, more is better but also consider budget impacts
- Long Term Storage can be a 'hard drive' or 'flash memory' (no mechanical parts)
- Hard drives are usually slower but larger and used on desktop computers.
- Flash memory is usually faster, more expensive; used on tablets and mobile phones.
- Desktop and laptop computers can use Solid State Drives (SSD) for greater speed at slightly higher cost over a hard drive. (SSD is a type of flash memory)
Power of the Processing unit
Newer is generally faster, but the newest and fastest are also the most costly.
Often a middle of the range processor is adequate in performance for most tasks and is cost-effective.
Mobile SIM
The connection to the mobile phone network or cellular network is made using a SIM card
- This is essential in a mobile phone for calls and data via the internet
- Optional at higher cost in tablets for internet connection but NOT phone calls
- Some laptops include this as an option for internet data only (no phone calls) or can use a plug-in internet connection (USB Modem)
Images and Video
A desktop computer can plug in a 'web' camera
Laptop computers usually have a camera built in above the screen
Tablets and mobile phones usually have a camera at the back and another at the front (for 'selfies')
Any of these cameras can take still and video images.
For a short course on how a computer works click here for tutorial.