17 Hardware Flashcards

Question

Register

Answer 1

* A storage location/ memory location inside the CPU * It is used to hold an instruction, an address or other single item of data * are extremely fast to access * are usually only a relatively small number Some registers play specific role in the fetch-decode-execute cycle. * holding a memory address (like program counter) * an instruction (like current instruction) * a piece of data (like accumulator)

Answer 2

* a register in CPU * Accumulator holds results of calculations performed by the ALU. * All input and output from CPU pass through the accumulator.

Answer 3

* a register in CPU * holds the memory address of the next instruction to be fetched

Answer 4

* a register in CPU * holds the instruction currently being executed

Answer 5

3 types of bus * Address bus - carries memory addresses between CPU and memory to identify a memory location * Data bus - carries the value to be read from/ written to memory * Control bus - carries the signals that determine what to do

Answer 6

* **carries memory addresses** between CPU and memory to **identify a memory location** * to specify the memory location or device that the CPU wants to read from or write to. * When the CPU needs to read data from or write data to memory (RAM), it sends the memory address of the desired location over the address bus. * The address bus is also used for input/output (I/O) operations. The CPU sends the address of the device it wants to communicate with over the address bus.

Answer 7

* **carries the value/data** to be **read from/ written to memory** * When the CPU needs to read data from memory, write data to memory, or transfer data to/from peripheral devices, it uses the **data bus to send or receive the data**.

Answer 8

* carries the **signals that determine what to do** (eg. to read or write the data and whne to do so) * Control signals sent over the control bus control the timing of data transfers, indicate the type of operation being performed, and manage the flow of data and instructions.

Answer 9

* the number of wires that make up a bus * determines the range of binary numbers that can be communicated

Answer 10

* is a sequence of steps performed by a **CPU to process a single instruction**. * It's the fundamental operation cycle of every digital computer. * The main stages are: **Fetching the instruction** from the computer's **memory**, Decoding it to **determine what action is required**, and **Executing the action**. 1. Fetch: where the CPU 'fetches' an instruction from the primary memory (RAM). * CU places the memory address of the next intruction on the address bus. * CU sends a signal on the control bus requesting to read data from memory. * The memory receives the signal and looks up that memory location. * The data in the memory is copied on to the data bus. * Data bus goes back to CPU from memory. * The CPU copied this into a special register. 2. Decode: CU identifies what action is required. * The CU analyses the contents of the register and determines the operation to be executed. * Then, it sends signals to the other parts of the CPU telling them what to do (eg. add numbers, store data back into the memory) 3. Execute: The decoded instruction is completed/ carried out by the CPU. (The result of the execution may be stored in registers, written back to memory, or used to update the CPU's state)

Answer 11

* **Clock speed**: The faster the clock speed, the faster the rate of processing. * **Number of processor cores**: Multi-core processors have multiple processing units (cores) that can execute instructions simultaneously. (Parallel processing and Multitasking) * **Size of cache**: The use of caches allow CPU to check the fast cache for the data it needs without needing to wait for it to be fetched from slower main memory. With a larger cache there is a greator probability that the instruction or data item to be fetched is in the cache. So, RAM will not need to be accessed. Consequently, this will speed up processing.

Answer 12

* **The cores work together on the same program.** * Each core in a multicore CPU operates independently. * Different parts of a program can be executed concurrently on different CPU cores, effectively dividing the workload and reducing overall computation time. * Parallel processing allows for faster execution and improved performance.

Answer 13

* **The cores work on different programs at the same time.** * Multitasking in a multicore CPU involves the ability to run multiple tasks or processes concurrently on different CPU cores. * Multiple tasks can execute simultaneously without having to share CPU resources or compete for processing time unlike single-core processors. * Each core in the multicore CPU can independently handle its own set of tasks. * Multitasking in multicore CPUs improves system responsiveness and overall performance.

Answer 14

* Static Random Access Memory/ Static RAM * Memory that retains data bits in its memory as long as power is being supplied and does not have to be refreshed

Answer 15

* Any kind of permanent/ non-volatile storage to which the contents of ROM/RAM are copied * store data for **long-term retention**, even when the power is turned off. * **slower to access**, **cheaper** and has much **higher capacity**, compared to RAM. * Unlike ROM, secondary stoage can be read and written to * commonly used for storing operating systems, applications, user files, and other data that needs to be preserved even when the computer is turned off. * Typical capacities are now in the terabytes. =========================== ================================ ============================= ======================== * Magnetic storage (HDD and magnetic tape storage) * Optical storage (CD, DVD and Blu-Ray disk) * Solid-state storage/ Electrical secondary storage/ Flash memory (SSD, SD card and USB memory stick)

Answer 16

* Secondary storage that works by making parts of a substance behave like a magnet, with **north and south poles to represent binary 1s and 0s** * Hard disks and magnetic tape storage

Answer 17

* A magnetic hard disk is made up of a stack of metal discs called **platters** with a magnetic coating. * Magnetic platter = stores bits * The platter is divided into “**Disk Sectors**” like pie, and “**Tracks**”/ concentric rings. * “**Track Sector**” = the intersection of a track and disk sector * Actuator = Moves the read-write arms back and forth. * Read/Write arm = moves the RW head across the platter * RW head - a tiny magnet with a tiny electromagnet alongside to write bits =========================== =========================== ================================= ========================== ================================== Data is recorded on each platter along circular tracks, each split into sectors. When data is written to: 1. The data is converted into a series of binary digits (0s and 1s). 2. The **arm moves across** to be above the right track. 3. The **required sector comes around under the head**. 4. The magnetic head **applies a magnetic field to the surface of the spinning disk**, magnetizing tiny regions of the magnetic material. 5. **Each bit of data being written** is represented by a **tiny magnetic region on the disk's surface**. 6. These regions can be magnetized in one of two directions **(north or south poles)**, typically represented as **0s or 1s**. In short, arm to the right track and disk spin,so, right sector under the head >> RW head magnetize the surface of the disk/ magnetic material >> north and sounth represents 0s and 1s =========================== =========================== ================================= ========================== ================================== When data is read: 1. The **arm moves across** to be above the right track. 2. The **required sector comes around under the head**. 3. The magnetic head **detects the magnetic field changes on the surface of the spinning disk** as it passes over the tracks. 4. **These changes in magnetic field represent the binary data stored on the disk**. 5. The disk controller translates this into 1s and 0s. In short, disk spins, arm moves and when required sector under the head, arm above the right track >> RW head detects macnetic field on disk surface >> those represent binary data =========================== =========================== ================================= ========================== ================================== Data does not come from the disk immediately. **Seek time** = the time it takes for the actuator arm to **move the read/write heads from their current position to the location** of the data that needs to be read or written **Latency** = the time it takes for the desired sector of the disk to rotate under the read/write heads after the heads are positioned over the correct track

Answer 18

**Advantages** * **Non-Volatile** * **High Storage Capacity**: offer vast storage capacities suitable for large amounts of data storage. Capacities range from a few **gigabytes (GB) to multiple terabytes (TB)**. * **Cost-Effective**: have a **relatively low cost per gigabyte** and are cost-effective for archiving large volumes of data over long periods. * **Durable**: is **resistant to wear and tear**, as **no physical contact between the read/write head and the storage surface**. This resilience ensures a **longer lifecycle** for magnetic storage devices compared to some other storage types. * **Widely Compatible**: is widely adopted and compatible with various devices such as desktops, laptops, servers, and external enclosures =========================== =========================== ================================= ========================== ================================== **Disadvantages** * **Slower Access Speeds**: Compared to SSDs, HDDs have **slower access and data transfer speeds**. The mechanical nature of HDDs contributes to **longer access times** and **potential performance bottlenecks**. * **Sensitivity to Physical Damage**: The moving components such as the **read/write head and spinning platters** make them susceptible to **mechanical failure and physical damage**. Accidental drops and exposure to extreme temperatures can cause **data loss**. * **Size and Weight**: HDDs, are generally **bulkier and heavier** compared to SSDs. * **Power Consumption**: HDDs **consume more power** than SSDs due to the **energy required for spinning platters and moving the read/write head**. Then, it can contribute to **increased operating costs and a higher environmental impact over time**. * **Noise**: generate **noise and vibration during operation** due to their mechanical nature.

Answer 19

* Secondary storage that works using **differences in light reflection** from a material * CD (lowest capacity), DVD, Blu-Ray disk (largest capacity) * **read/ write data by shining a laser at the disk** and processing the reflection * Shinner/ more reflective parts of the disk represents the 1s or 0s.

Answer 20

* A single grooved **track spirals from the centre of the disc outward**. Recorded data is stored in groove. * The track is divided into sectors for data organization. * The player uses **two lasers**: **one to write** data and the **other to read data**. * Light sensor detects reflection differences. * When a laser beam is directed onto the disc's surface, it reflects differently off pits compared to lands. This difference in reflection is detected by the optical drive's sensor and interpreted as binary data. =========================== =========================== ================================= ========================== ================================== Data is written **along a single track** that moves out from the centre of the disk in a spiral. When writing: 1. A **laser beam burns/ heats** the recording material. 2. It creates pits and lands on the surface of the disk that represents binary data. 3. The process is **slow** because the heating and cooling of the surface takes time. In short, laser heats the disk surface >> pits and lands created >> that represents the data =========================== =========================== ================================= ========================== ================================== When data is read: 1. The **disk spins** in the drive to ensure all data can be read. 2. The tracking machanism moves the laser into the correct position over the disk. 3. The laser **shines on to the disk** and is reflected back on to a light sensor. 4. **Light sensor detects variations in reflection**. 5. Signals from the sensor are translated into **1s and 0s**. In short, disk spins and place laser over correct position >> laser scans the disk surface >> light sensor detects and sends signals >> translated into binary data

Answer 21

Advantages * high storage capacity * good performance * durability * longevity * resistance to environmental factors Disadvantages * slower access time * compatibility issues * reliance on mechanical components * physical size and portability limitations

Answer 22

* Secondary storage that works by **storing charges/ electrons** * Flash memory * USB memory stick, SD card * uses chips (**NAND flash**) made of special kind of **transistors that can trap electrons in a pool** * 0 = electron in a pool, 1 = empty pool * Billions of transistors fit on a chip. * are **small** and have **high capacity** * Faster access to data than HDD

Answer 23

* uses chips (**NAND flash**) made of special kind of **transistors that can trap electrons in a pool** to store data * 0 = electron in a pool, 1 = empty pool =========================== =========================== ================================= ========================== ================================== When data is read from the chip: 1. **Control signals identify which bit** is to read out and **apply a small voltage**. 2. If the electron pool is empty, the transistor turns on and a 1 is read out. 3. If electron pool is full. transistor doesn't turn on and a 0 is read out. 4. The control signals are changed to read other bits. In short, control signals identify bits to read and apply voltage to those bits >> **0 = electron in a pool, 1 = empty pool** =========================== =========================== ================================= ========================== ================================== When data is written to chip: 1. **Control signal identify which bit** is to be written and **apply a higher voltage.** 2. This **pulls or removes electron into the pools of transistors**, recording 1s and 0s. In short, control signals identify bits to write and apply a higer voltage to those bit. =========================== =========================== ================================= ========================== ================================== **Erasing data requires higher voltages** to remove electrons from the pools. Both **erasing and writing** cause the **transistor to break down slowly**. Flash drives can only be **rewritten around 1 million times** before eventually failing.

Answer 24

**Advantages** * Speed: **faster read and write speeds** compared to traditional hard drives. * Durability: Since there are **no moving parts**, less likely to suffer from mechanical failure or physical damage. Hence, **more reliable**, especially for mobile devices and industrial applications. * Energy Efficiency: **consumes less power** >> beneficial for battery-operated devices like laptops and smartphones, **reduced heat generation**, contributing to extended device lifetimes and decreased cooling requirements in data centres (good for environment) * generally **smaller and lighter** >> ideal for **portable** devices and slim laptops. * Noise and Vibration: operate **silently** and produce no vibrations * Data Access: The lack of moving parts enables faster and **more consistent data access times**, **reducing latency** and ensuring a smoother user experience in applications requiring high-speed data processing. ========================================= ===================== **Disadvantages** * Cost: typically **more expensive per gigabyte** * Write Endurance: The process of writing data involves the **gradual degradation** of the memory cells >> have a **limited number of write cycles** before performance begins to decline. * **Compatibility**: Some devices or systems may have limited compatibility >> could require **additional hardware or software updates** to enable the use of certain SSDs * Storage Capacity: traditional hard drives currently offer larger storage capacities at a lower cost

Answer 25

* **Secondary storage** that is accessed **via a network** and **isn't** in the **same physical place as machine's RAM and ROM**. * Files stored on the cloud can be accessed **anywhere via the Internet connection**.

Answer 26

Any process that **hides the true nature** of a computing resource, making it look different, usually to simply the way it is accessed