Computer Architecture

Match each computer component with the task it performs: (a) CPU, (b) RAM, (c) hard drive or SSD, (d) motherboard. Tasks: 1. stores files in the long term, even when the computer is turned off; 2. executes program instructions, acting as the 'brain' of the computer; 3. connects all the other components to each other; 4. temporarily stores the data being worked on at any given moment.

Explain in your own words the difference between RAM and storage (hard drive or SSD). Use an everyday simile to help you, for example using kitchen or study furniture.

True or false? Justify each answer with a sentence: (a) RAM saves your photos even if you turn off the computer; (b) the CPU executes program instructions; (c) the motherboard connects all the components together; (d) the hard drive loses all its contents every time the computer is switched off.

You close the document without saving and turn off the computer: the text you had written disappears. Explain what RAM has to do with this loss and what the 'save' button actually does to prevent it.

Look up the specifications of a real computer (the one at home, in your classroom, or from an online shop) and write down its CPU, RAM and storage. Explain in your own words what each of these three pieces of information means.

A computer has $16\ \text{GB}$ of RAM. Between the operating system ($4\ \text{GB}$), the browser ($3\ \text{GB}$) and a game ($6\ \text{GB}$), calculate how much RAM is left free using the subtraction $16 - (4 + 3 + 6)$ and explain what might happen if you then open a program that requires $5\ \text{GB}$.

A camera takes photos that take up $4\ \text{MB}$ each. The cell phone where they are saved has $128\ \text{GB}$ of free storage. Knowing that $1\ \text{GB}$ is equivalent to $1\,000\ \text{MB}$, calculate the maximum number of photos that fit and express the result as a division with units: $\frac{128\,000\ \text{MB}}{4\ \text{MB}}$. Then explain why, in practice, fewer photos fit than calculated.

The Technology department wants to record a school documentary using a camera that records video in 4K quality, generating approximately $375\ \text{MB}$ of data for each minute of recording. For this purpose, you have an empty $256\ \text{GB}$ memory card.

1. a) Knowing that $1\ \text{GB} = 1\,000\ \text{MB}$, calculate how many hours and minutes of continuous recording theoretically fit on that card (show the development of the calculation with the decimal comma).
2. b) If the complete shoot requires recording $12$ hours of footage in total, how many $256\ \text{GB}$ cards will you need at a minimum? Justify your answer taking into account unforeseen events and the space required for formatting the cards.

The diagram shows the main blocks of a computer, but one of the components connected to the CPU is covered with a question mark, as shown in the figure.

The hidden component temporarily stores the data that the CPU is working with at any given moment and is erased when the computer is turned off. Which component is it? Explain what would happen if the computer did not have it.

When you play with a controller, the button command goes to a component that calculates what should happen in the game and sends the result to the monitor. Which component is that? Explain what you would notice in the game if that component were very slow.

When you double-click a document, data travels between the computer components. Put these steps in order and explain what role RAM plays in the process: (a) the CPU processes the document data, (b) the document is copied from storage to RAM, (c) you double-click the file icon, (d) the document is displayed on the screen.

When you open a game, data travels between four computer components. The figure shows these components connected by arrows, but the order indicated by the numbers on the cards is incorrect, as shown in the diagram.

Write the correct order of the data's journey, from 1 to 4, and explain what happens in each of the four stages.

Which component would you think of first in each case? Give reasons for your answers: (a) you want to store many more films on the computer; (b) you want the computer to calculate and 'think' faster; (c) you want to work with many programs open at the same time without it slowing down.

A classroom computer runs very slowly when many browser tabs are opened at the same time, even though its CPU is powerful and the drive has free space. Which component do you think is reaching its limit? Explain why and what hardware upgrade would solve it.

In a shop you compare two computers: Computer A has a CPU of $3.2\ \text{GHz}$, $8\ \text{GB}$ of RAM and an SSD of $256\ \text{GB}$; Computer B has a CPU of $2.8\ \text{GHz}$, $16\ \text{GB}$ of RAM and a hard drive of $1\ \text{TB}$. Explain what each piece of data means and reason which computer is best suited to a student who edits video with several programs open at the same time.

A computer takes three minutes to switch on because its hard drive is an older type with moving parts (HDD). Explain why replacing it with an SSD speeds up startup and the opening of programs, even if the CPU and RAM remain exactly the same.

A cell phone displays 'storage almost full', and yet it has $8\ \text{GB}$ of free RAM. Explain why deleting apps and videos frees up storage but not RAM, and reason which type of memory is filled by photos and videos.

An old computer has $4\ \text{GB}$ of RAM and an HDD hard drive, and there is only enough money for one upgrade: expanding to $16\ \text{GB}$ of RAM or switching to an SSD. Reason which one you would choose so that the computer 'runs faster' in daily use (starting up, opening programs, switching between windows) and explain what each option would and would not improve.

Imagine that you work in the school's technical support service and you receive three computers with performance issues:

• Computer A: It takes nearly ten minutes to boot up and open any program, but once the application is open it runs completely smoothly.

• Computer B: When having multiple browser tabs open along with a word processor and background music, the computer periodically freezes and stutters when switching windows.

• Computer C: During the final export of a high-definition video project, the process suddenly stops indicating that it is not possible to save the resulting file.

For each case, diagnose in a reasoned manner which hardware component (secondary storage, RAM, or processor/graphics card) is causing the bottleneck and propose an appropriate technical upgrade.

The technology classroom needs a new computer suitable for programming, video editing and educational games. Decide how much importance you would give to each component (CPU, RAM, graphics card and storage), justify your decisions and indicate which component you would save money on if the budget were tight.

An online shop's server serves thousands of people at the same time, all requesting pages and placing orders. Compare that server with your home computer: reason which components would need to be upgraded (CPU, RAM, storage, network connection) and why a 'very powerful' desktop computer would not be enough.

In a store's advertising flyer, you read the following claim about a mobile phone:

"Unbeatable performance! Features $12\ \text{GB}$ of memory, twice as much as your current phone: it will run twice as fast and you will be able to store twice as many photos and games".

1. a) Critically analyse the claim and explain with reasoning the two fundamental technical errors made by the advertisement when using the word "memory" and relating it to "speed".
2. b) Write a corrected, technically honest version of the advertisement that maintains an appealing tone for the buyer without resorting to misleading claims.

Two students compare two computers that cost the same for the Technology workshop:

• Computer A: Old processor with $1$ core running at $3.8\ \text{GHz}$.

• Computer B: Modern processor with $4$ cores running at $2.4\ \text{GHz}$.

One of them argues: "Computer A is clearly superior and faster because $3.8\ \text{GHz}$ means many more clock cycles per second than $2.4\ \text{GHz}$".

1. a) Explain what exactly frequency measured in gigahertz ($\text{GHz}$) represents and what happens inside the processor during each cycle.
2. b) Technically rebut your classmate's claim: justify why computer B's processor can offer much higher overall performance than A's in real work situations.

The robotics club is building a computer with a budget of $\$12\,000$ and this parts list: CPU for $\$4\,200$, RAM for $\$1\,600$, SSD for $\$2\,200$, graphics card for $\$3\,000$ and motherboard with power supply unit and case for $\$2\,400$. Add up the total and check if it fits within the budget; if it does not, decide what change you would make (which part you would downgrade or upgrade) and defend your decision based on the club's needs.