Embedded Linux & Drivers interview questions

1. A.second-stage bootloader that initialises DRAM and storage, loads the kernel image and hardware description and passes bootargs, with a scriptable command shell and environment
2. B.real-time patch set, mainlined in kernel 6.12, that makes most kernel code preemptible with threaded interrupts and priority-inheriting locks, cutting worst-case latency to tens of microseconds
3. C.hardware description compiled from .dts into a .dtb blob that the kernel parses at boot to bind drivers to peripherals through compatible strings, replacing hard-coded board files
4. D.driver registering a major and minor number with file_operations for open, read, write and ioctl so user space reaches the hardware through a /dev node

Answer + AI explanation with Pro

1. A.Device tree
2. B.Kernel module
3. C.Yocto Project
4. D.PREEMPT_RT

Answer + AI explanation with Pro

1. A.Device tree — driver registering a major and minor number with file_operations for open, read, write and ioctl so user space reaches the hardware through a /dev node
2. B.Device tree — layered build system using BitBake recipes and metadata layers to produce a reproducible custom Linux image, SDK and package feed for a board
3. C.Device tree — hardware description compiled from .dts into a .dtb blob that the kernel parses at boot to bind drivers to peripherals through compatible strings, replacing hard-coded board files
4. D.Device tree — building on an x86 host for an ARM target with a toolchain prefixed such as aarch64-linux-gnu-, using a sysroot holding the target's headers and libraries

Answer + AI explanation with Pro

1. A.second-stage bootloader that initialises DRAM and storage, loads the kernel image and hardware description and passes bootargs, with a scriptable command shell and environment
2. B.virtual filesystem under /sys exposing kernel objects and driver attributes as files, letting user space read or set values such as GPIO direction or LED brightness
3. C.loadable .ko object with module_init and module_exit entry points, inserted with insmod or modprobe, running in kernel space with no memory protection from the rest of the kernel
4. D.driver registering a major and minor number with file_operations for open, read, write and ioctl so user space reaches the hardware through a /dev node

Answer + AI explanation with Pro

1. A.PREEMPT_RT
2. B.Platform driver model
3. C.Yocto Project
4. D.U-Boot

Answer + AI explanation with Pro

1. A.U-Boot — second-stage bootloader that initialises DRAM and storage, loads the kernel image and hardware description and passes bootargs, with a scriptable command shell and environment
2. B.U-Boot — platform devices matched to drivers by compatible string through probe and remove callbacks, with devm_ managed resources releasing memory and IRQs automatically on removal
3. C.U-Boot — hardware description compiled from .dts into a .dtb blob that the kernel parses at boot to bind drivers to peripherals through compatible strings, replacing hard-coded board files
4. D.U-Boot — loadable .ko object with module_init and module_exit entry points, inserted with insmod or modprobe, running in kernel space with no memory protection from the rest of the kernel

Answer + AI explanation with Pro

1. A.second-stage bootloader that initialises DRAM and storage, loads the kernel image and hardware description and passes bootargs, with a scriptable command shell and environment
2. B.hardware description compiled from .dts into a .dtb blob that the kernel parses at boot to bind drivers to peripherals through compatible strings, replacing hard-coded board files
3. C.building on an x86 host for an ARM target with a toolchain prefixed such as aarch64-linux-gnu-, using a sysroot holding the target's headers and libraries
4. D.driver registering a major and minor number with file_operations for open, read, write and ioctl so user space reaches the hardware through a /dev node

Answer + AI explanation with Pro

1. A.Yocto Project
2. B.Cross-compilation
3. C.Kernel module
4. D.Character device driver

Answer + AI explanation with Pro

1. A.Cross-compilation — driver registering a major and minor number with file_operations for open, read, write and ioctl so user space reaches the hardware through a /dev node
2. B.Cross-compilation — virtual filesystem under /sys exposing kernel objects and driver attributes as files, letting user space read or set values such as GPIO direction or LED brightness
3. C.Cross-compilation — building on an x86 host for an ARM target with a toolchain prefixed such as aarch64-linux-gnu-, using a sysroot holding the target's headers and libraries
4. D.Cross-compilation — layered build system using BitBake recipes and metadata layers to produce a reproducible custom Linux image, SDK and package feed for a board

Answer + AI explanation with Pro

1. A.driver registering a major and minor number with file_operations for open, read, write and ioctl so user space reaches the hardware through a /dev node
2. B.hardware description compiled from .dts into a .dtb blob that the kernel parses at boot to bind drivers to peripherals through compatible strings, replacing hard-coded board files
3. C.building on an x86 host for an ARM target with a toolchain prefixed such as aarch64-linux-gnu-, using a sysroot holding the target's headers and libraries
4. D.layered build system using BitBake recipes and metadata layers to produce a reproducible custom Linux image, SDK and package feed for a board

Answer + AI explanation with Pro

1. A.Yocto Project
2. B.Character device driver
3. C.sysfs
4. D.PREEMPT_RT

Answer + AI explanation with Pro

1. A.Yocto Project — layered build system using BitBake recipes and metadata layers to produce a reproducible custom Linux image, SDK and package feed for a board
2. B.Yocto Project — hardware description compiled from .dts into a .dtb blob that the kernel parses at boot to bind drivers to peripherals through compatible strings, replacing hard-coded board files
3. C.Yocto Project — building on an x86 host for an ARM target with a toolchain prefixed such as aarch64-linux-gnu-, using a sysroot holding the target's headers and libraries
4. D.Yocto Project — real-time patch set, mainlined in kernel 6.12, that makes most kernel code preemptible with threaded interrupts and priority-inheriting locks, cutting worst-case latency to tens of microseconds

Answer + AI explanation with Pro

1. A.hardware description compiled from .dts into a .dtb blob that the kernel parses at boot to bind drivers to peripherals through compatible strings, replacing hard-coded board files
2. B.real-time patch set, mainlined in kernel 6.12, that makes most kernel code preemptible with threaded interrupts and priority-inheriting locks, cutting worst-case latency to tens of microseconds
3. C.loadable .ko object with module_init and module_exit entry points, inserted with insmod or modprobe, running in kernel space with no memory protection from the rest of the kernel
4. D.building on an x86 host for an ARM target with a toolchain prefixed such as aarch64-linux-gnu-, using a sysroot holding the target's headers and libraries

Answer + AI explanation with Pro

1. A.Kernel module
2. B.Device tree
3. C.Cross-compilation
4. D.PREEMPT_RT

Answer + AI explanation with Pro

1. A.Kernel module — virtual filesystem under /sys exposing kernel objects and driver attributes as files, letting user space read or set values such as GPIO direction or LED brightness
2. B.Kernel module — hardware description compiled from .dts into a .dtb blob that the kernel parses at boot to bind drivers to peripherals through compatible strings, replacing hard-coded board files
3. C.Kernel module — driver registering a major and minor number with file_operations for open, read, write and ioctl so user space reaches the hardware through a /dev node
4. D.Kernel module — loadable .ko object with module_init and module_exit entry points, inserted with insmod or modprobe, running in kernel space with no memory protection from the rest of the kernel

Answer + AI explanation with Pro

1. A.building on an x86 host for an ARM target with a toolchain prefixed such as aarch64-linux-gnu-, using a sysroot holding the target's headers and libraries
2. B.driver registering a major and minor number with file_operations for open, read, write and ioctl so user space reaches the hardware through a /dev node
3. C.hardware description compiled from .dts into a .dtb blob that the kernel parses at boot to bind drivers to peripherals through compatible strings, replacing hard-coded board files
4. D.layered build system using BitBake recipes and metadata layers to produce a reproducible custom Linux image, SDK and package feed for a board

Answer + AI explanation with Pro

1. A.U-Boot
2. B.Character device driver
3. C.Platform driver model
4. D.Cross-compilation

Answer + AI explanation with Pro

1. A.Character device driver — driver registering a major and minor number with file_operations for open, read, write and ioctl so user space reaches the hardware through a /dev node
2. B.Character device driver — hardware description compiled from .dts into a .dtb blob that the kernel parses at boot to bind drivers to peripherals through compatible strings, replacing hard-coded board files
3. C.Character device driver — loadable .ko object with module_init and module_exit entry points, inserted with insmod or modprobe, running in kernel space with no memory protection from the rest of the kernel
4. D.Character device driver — real-time patch set, mainlined in kernel 6.12, that makes most kernel code preemptible with threaded interrupts and priority-inheriting locks, cutting worst-case latency to tens of microseconds

Answer + AI explanation with Pro

1. A.driver registering a major and minor number with file_operations for open, read, write and ioctl so user space reaches the hardware through a /dev node
2. B.virtual filesystem under /sys exposing kernel objects and driver attributes as files, letting user space read or set values such as GPIO direction or LED brightness
3. C.building on an x86 host for an ARM target with a toolchain prefixed such as aarch64-linux-gnu-, using a sysroot holding the target's headers and libraries
4. D.real-time patch set, mainlined in kernel 6.12, that makes most kernel code preemptible with threaded interrupts and priority-inheriting locks, cutting worst-case latency to tens of microseconds

Answer + AI explanation with Pro

1. A.Platform driver model
2. B.U-Boot
3. C.Kernel module
4. D.sysfs

Answer + AI explanation with Pro

1. A.sysfs — second-stage bootloader that initialises DRAM and storage, loads the kernel image and hardware description and passes bootargs, with a scriptable command shell and environment
2. B.sysfs — layered build system using BitBake recipes and metadata layers to produce a reproducible custom Linux image, SDK and package feed for a board
3. C.sysfs — virtual filesystem under /sys exposing kernel objects and driver attributes as files, letting user space read or set values such as GPIO direction or LED brightness
4. D.sysfs — loadable .ko object with module_init and module_exit entry points, inserted with insmod or modprobe, running in kernel space with no memory protection from the rest of the kernel

Answer + AI explanation with Pro

1. A.layered build system using BitBake recipes and metadata layers to produce a reproducible custom Linux image, SDK and package feed for a board
2. B.real-time patch set, mainlined in kernel 6.12, that makes most kernel code preemptible with threaded interrupts and priority-inheriting locks, cutting worst-case latency to tens of microseconds
3. C.second-stage bootloader that initialises DRAM and storage, loads the kernel image and hardware description and passes bootargs, with a scriptable command shell and environment
4. D.virtual filesystem under /sys exposing kernel objects and driver attributes as files, letting user space read or set values such as GPIO direction or LED brightness

Answer + AI explanation with Pro

1. A.Device tree
2. B.PREEMPT_RT
3. C.sysfs
4. D.Yocto Project

Answer + AI explanation with Pro

1. A.PREEMPT_RT — real-time patch set, mainlined in kernel 6.12, that makes most kernel code preemptible with threaded interrupts and priority-inheriting locks, cutting worst-case latency to tens of microseconds
2. B.PREEMPT_RT — platform devices matched to drivers by compatible string through probe and remove callbacks, with devm_ managed resources releasing memory and IRQs automatically on removal
3. C.PREEMPT_RT — hardware description compiled from .dts into a .dtb blob that the kernel parses at boot to bind drivers to peripherals through compatible strings, replacing hard-coded board files
4. D.PREEMPT_RT — loadable .ko object with module_init and module_exit entry points, inserted with insmod or modprobe, running in kernel space with no memory protection from the rest of the kernel

Answer + AI explanation with Pro

1. A.virtual filesystem under /sys exposing kernel objects and driver attributes as files, letting user space read or set values such as GPIO direction or LED brightness
2. B.driver registering a major and minor number with file_operations for open, read, write and ioctl so user space reaches the hardware through a /dev node
3. C.real-time patch set, mainlined in kernel 6.12, that makes most kernel code preemptible with threaded interrupts and priority-inheriting locks, cutting worst-case latency to tens of microseconds
4. D.platform devices matched to drivers by compatible string through probe and remove callbacks, with devm_ managed resources releasing memory and IRQs automatically on removal

Answer + AI explanation with Pro

1. A.Cross-compilation
2. B.Platform driver model
3. C.sysfs
4. D.U-Boot

Answer + AI explanation with Pro

1. A.Platform driver model — platform devices matched to drivers by compatible string through probe and remove callbacks, with devm_ managed resources releasing memory and IRQs automatically on removal
2. B.Platform driver model — layered build system using BitBake recipes and metadata layers to produce a reproducible custom Linux image, SDK and package feed for a board
3. C.Platform driver model — loadable .ko object with module_init and module_exit entry points, inserted with insmod or modprobe, running in kernel space with no memory protection from the rest of the kernel
4. D.Platform driver model — virtual filesystem under /sys exposing kernel objects and driver attributes as files, letting user space read or set values such as GPIO direction or LED brightness

Answer + AI explanation with Pro