(a) i() What is firewall? (ii) List two methods used in protecting the computer system. (b) Explain the following stages of the System Development Life Cycl...

Answer Details

(a)(i) What is a firewall?

A firewall is a hardware device, software program, or a combination of both that monitors and controls the flow of data (network traffic) between a computer or private network and an external network such as the Internet. It works by examining incoming and outgoing packets against a set of security rules, allowing safe traffic to pass while blocking unauthorised or malicious traffic. In this way it acts as a protective barrier that prevents intruders and harmful data from reaching the protected system.

(a)(ii) Two methods used in protecting the computer system:

• Installing and updating anti-virus software to detect, quarantine and remove malicious programs.
• Using passwords and user authentication (strong passwords, PINs or biometrics) to restrict access to authorised users only.

Other acceptable methods: using a firewall, regular data backup, encryption of data, keeping the operating system patched/updated, physically securing the hardware.

(b) Stages of the System Development Life Cycle (SDLC):

(i) Feasibility study: This is the early investigation stage that examines whether the proposed system is worth developing. The analyst studies the existing system and assesses the project in terms of technical feasibility (can it be built with available technology?), economic feasibility (do the benefits justify the cost?), and operational feasibility (will users accept and use it?). The result is a feasibility report that recommends whether the project should proceed.

(ii) Design: At this stage the requirements gathered in earlier phases are translated into a detailed plan for the new system. The designer specifies the inputs, outputs, processes, user interfaces (screens and reports), file and database structures, and the hardware and software needed. Both the logical design (what the system will do) and the physical design (how it will be built) are produced as a blueprint for the programmers.

(iii) Maintenance: This is the ongoing stage after the system has been installed and is in use. It involves correcting errors (bugs) discovered during operation, adapting the system to changes in the environment or organisation, and improving or upgrading it to meet new requirements. Maintenance keeps the system accurate, reliable and useful throughout its working life.