DCNSA Level I

Introduction to Computing Systems flashcards

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What is the difference between data and information?

Data: raw, unprocessed facts and figures with no context of their own, such as the number 37 or the word 'Nakuru'. Information: data processed, organised or given context so that it is meaningful, such as '37 students registered from Nakuru this term'. A useful test: if you can act on it, it is information; if you first have to sort, count, compare or label it, it is still data.

How does RAM differ from secondary storage such as an SSD or a hard disk?

RAM is primary storage: fast and volatile, holding whatever is running right now and losing it at power-off. Secondary storage is permanent: a hard disk drive (spinning platters), a solid-state drive (flash chips, no moving parts, far faster) and removable flash drives and memory cards.

How does a compiler differ from an interpreter?

Compiler: translates the whole high-level program into machine code once, reports all errors before anything runs, and produces a fast executable that runs without the source. Interpreter: translates and executes one statement at a time on every run, reports an error at the line where it occurs, and runs more slowly.

How do you convert a decimal number to binary?

Divide by 2 repeatedly, recording the remainder each time, until the quotient reaches zero. The remainders read from last to first are the answer. Example: 173 gives remainders 1, 0, 1, 1, 0, 1, 0, 1, so 173 = 10101101. Check by place value: 128 + 32 + 8 + 4 + 1 = 173.

What does each of a hub, a switch and a router forward on, and what does it join?

Hub: electrical signals, sent to every port; joins devices on one LAN. Switch: MAC addresses, sent only to the port with the destination; joins devices on one LAN. Router: IP addresses, sent to the next network on the path; joins different networks.

Are the internet and the world wide web the same thing?

No. The internet is the global network of interconnected networks that carries the data, speaking the TCP/IP family of protocols. The world wide web is one service that runs on it: linked pages addressed by URLs and transferred by HTTP and HTTPS, alongside other services such as email, file transfer and video calls.

What are the three properties of the CIA triad?

Confidentiality: only authorised people can read data. Integrity: data is not altered without authorisation. Availability: systems and data are there when needed.

What are the stages of the booting process, from power-on to ready for use?

1. Power-on: the power supply delivers stable voltages and the processor starts executing firmware. 2. POST: the firmware checks the processor, memory, keyboard, display adapter and storage controllers. 3. The firmware (BIOS or UEFI) finds a bootable device in the boot order. 4. The bootloader is loaded and hands control to the operating system kernel. 5. The kernel loads drivers, starts services and presents the login screen. 6. After login, the user's profile and startup programs load.

Why should daily work be done from a standard account rather than an administrator account?

Least privilege. Malware that runs under an administrator account can install itself system-wide; under a standard account it is confined to that user's profile. A standard user can run programs and manage their own files only, so give standard rights by default, even to the technician.

What is the difference between an exploit and a breach?

Exploit: the method. Code or a technique that takes advantage of a specific vulnerability to compromise a system. Breach: the outcome. Unauthorised access to data or systems actually occurring. An exploit can be attempted and blocked without a breach, and a breach can happen with no exploit at all, through a shared password.

What is a computer, and what cycle does every computer follow?