Hardware vs. Software basics.

Normal apps run in user space and kernel space handles system control. For exams identify them by permission level.

In memory mapped input output hardware devices can be accessed through addresses. For exams treat it as a link between hardware and system software.

An input output port can be a hardware communication point and driver uses it. For exams separate physical contact and instructions.

Sometimes different software layers work together for one device. For exams do not always treat driver as only one file.

A computer bus driver helps devices connected to a hardware bus work with the system. For exams do not confuse bus with a vehicle.

A device tree can help provide hardware details to software. For exams connect it with hardware description.

It helps the system handle power states and hardware configuration. For exams connect it with cooperation of operating system and firmware.

Power state tells whether a device is active low power or off. For exams connect it with energy management.

High heat can damage hardware so speed may reduce. For exams remember the relation between temperature and performance.

A watchdog timer can be useful in embedded and system safety. For exams connect it with hardware and software monitoring.

A real time system gives high importance to timely response. For exams connect it with industry and embedded systems.

Hard real time has very strict timing deadlines. For exams remember the importance of time in control systems.

Scheduler affects process order and CPU use. For exams connect it with operating system resource management.

Direct answer: Option A is correct. Starvation is an operating-system scheduling problem in which a process waits for a very long time because other processes repeatedly receive the needed resource or priority. Step by step: a process needs CPU time, memory, a file, or another shared resource; the scheduler chooses which waiting process gets it; if one process is continually ignored, it remains ready or waiting; this indefinite delay is called starvation. Option A correctly describes a process not getting resources for a long time. Option B is wrong because a printer cannot literally need food, and this has no connection with process scheduling. Option C is wrong because dust on a monitor is a physical maintenance issue, not unfair resource allocation. Option D is wrong because mouse weight has no relation to operating-system scheduling. A fair scheduler may use ageing, gradually increasing the priority of a waiting process, to reduce starvation. Memory cue: starvation means a process is hungry for a resource for too long.

A device may do limited work at a time so requests can be queued. For exams connect queue with input output management.

Controller can physically manage a device and driver communicates with system. For exams check role and form.

Emulation can provide behavior like another hardware through software. For exams separate imitation and real device.

A paravirtual driver can provide better hardware like service in a virtual environment. For exams connect it with virtualization.

A snapshot can save the disk and state of a virtual machine. For exams distinguish it from a normal screenshot.

A disk image file is data that can contain a storage like structure. For exams keep file and physical disk separate.

A disk image file can be used by the system like a virtual drive. For exams understand the idea of virtual storage.

SMART data helps understand the condition of a drive. For exams connect it with storage hardware monitoring.

Software can read indicators from drive hardware and give warning. For exams separate sensor data and reporting.

Direct answer: Option A is correct. ECC means Error-Correcting Code. ECC memory stores extra checking information along with ordinary data. Step by step: data is written into memory; additional bits are calculated and stored; when the data is read, the memory controller checks the data against those bits; some errors, commonly single-bit errors, can be corrected, while other errors can at least be detected. Thus ECC improves reliability and helps prevent silent corruption. Option A is correct because detecting or correcting memory errors is the purpose of ECC. Option B is wrong because display brightness is controlled by a monitor or graphics settings, not ECC memory. Option C is wrong because ECC cannot change a printer into a scanner; those are different devices and functions. Option D is wrong because washing a mouse pad is cleaning, not memory error control. ECC is useful where reliability matters, such as servers. Memory cue: ECC means extra checking bits for safer memory data.

Parity bit is related to a simple technique of detecting data errors. For exams connect it with data reliability.