LEARNING OBJECTIVES
What you will be able to do
- distinguish system and application software
- explain operating systems, utilities and language translators
- describe internet and web technologies
- analyse cyber threats and layered protections
AT A GLANCE
INTRODUCTION · THE BIG IDEA
Explain system software, translators, web technologies and cyber-security controls.
Software turns general-purpose hardware into useful systems. Operating systems manage resources, translators turn source code into executable form, and applications solve user tasks.
The internet is the network infrastructure; the World Wide Web is one service using it. Every connected service also creates security risks that require technical and human controls.
SECTION 01
Operating systems and utilities
Operating systems manage memory, processors, files, devices, users, security, interrupts and multitasking. They may provide graphical or command-line interfaces.
Utility software performs maintenance or protection such as anti-malware scanning, backup, compression, encryption, disk tools and file management. Application software performs user tasks such as word processing, modelling or media editing.
| Category | Purpose | Example |
|---|---|---|
| Operating system | manage system resources | memory and file management |
| Utility | maintain or protect | backup or anti-malware |
| Application | perform user task | spreadsheet or editor |
SECTION 02
Translators and development tools
An assembler translates assembly language. A compiler translates a whole high-level program before execution and can produce an executable; an interpreter translates and executes statement by statement.
Compilers usually give faster final execution and protect source distribution, while interpreters support immediate testing but require translation each run. An integrated development environment can provide an editor, syntax highlighting, auto-completion, error diagnostics, breakpoints, stepping and variable inspection.
Choosing a translator for distribution
- A developer will sell a finished desktop application without its source code.
- Users need fast repeated execution and should not require the source language translator.
- A compiler can translate the whole program and create distributable executable code.
Answer: A compiler is more suitable than an interpreter for this scenario.
SECTION 03
Internet and web technologies
The internet is a global network of networks. A URL identifies a resource; DNS translates a domain name to an IP address; a browser requests resources from a web server using protocols such as HTTP or secure HTTPS.
HTML structures web content and CSS controls presentation. Cookies store small pieces of browser data for sessions or preferences and raise privacy considerations. Digital currencies use electronic records; blockchain can provide a distributed, tamper-evident ledger but does not make every application anonymous or risk-free.
SECTION 04
Cyber threats and protection
Threats include brute-force access, interception, distributed denial of service, hacking, malware, pharming, phishing and social engineering. Malware includes viruses, worms, Trojan horses, spyware, ransomware and adware with different spread and effects.
Controls include strong unique passwords, multi-factor authentication, access levels, firewalls, anti-malware, updates, encryption, secure protocols, backups, user training and penetration testing. Biometric authentication compares measured characteristics and can produce false acceptances or rejections.
Layered security is stronger because one control rarely prevents every threat. Backups support recovery from ransomware but must be isolated and tested.
| Threat | Useful control |
|---|---|
| Phishing | user verification and filtering |
| Brute force | rate limits, strong passwords and MFA |
| Malware | updates, anti-malware and least privilege |
| Data interception | encryption and secure protocols |
QUICK CHAPTER SUMMARY
The ideas to carry forward
- System software manages and protects the computer.
- Translator choice affects development and execution.
- DNS, URLs, protocols, servers and browsers work together on the web.
- Cyber security requires matched, layered controls.
QUICK REVISION CHECKLIST
Can you do each of these without your notes?
- distinguish system and application software
- explain operating systems, utilities and language translators
- describe internet and web technologies
- analyse cyber threats and layered protections