Qualcomm SDE Interview Questions and Answers

Program with 2 threads printing even and odd numbers in sequence. How to make it SMP safe?

• Use mutex locks to ensure only one thread accesses the shared resource (the number to be printed) at a time

• Use condition variables to signal when it's safe for the other thread to access the shared resource

• Use atomic variables to ensure that the shared resource is accessed atomically

• Use thread-safe data structures to store the shared resource

• Use thread-local storage to avoid contention b...read more

Endianess refers to the order in which bytes are stored in memory. Little endian stores the least significant byte first.

• Check the byte order of a multi-byte integer value

• Use a test value with known byte order to determine the system's endianess

• Check the system's documentation or specifications

• Use a code snippet to determine the endianess

Inter-process communication mechanisms like pipes, sockets, message queues, shared memory can be used to call a function from one user process to another.

• Use pipes to establish a unidirectional communication channel between two processes.

• Use sockets to establish a bidirectional communication channel between two processes.

• Use message queues to send messages between processes.

• Use shared memory to share data between processes.

• Remote Procedure Call (RPC) can also be used to call ...read more

Function pointers can be shared across processes using inter-process communication mechanisms like shared memory, pipes, sockets, etc.

• Function pointers can be stored in shared memory regions that are accessible by multiple processes.

• Processes can communicate with each other using pipes or sockets and pass function pointers as arguments.

• Remote Procedure Call (RPC) mechanisms can also be used to share function pointers across processes.

• Message Passing Interface (MPI) is another...read more

4 IPCs used in user level process in Linux

• Message Queues - allows processes to exchange data through messages

• Shared Memory - allows processes to share a portion of memory

• Semaphores - used for synchronization between processes

• Pipes - allows communication between two related processes

Binder is a mechanism for inter-process communication in Android.

• Binder allows different processes to communicate with each other.

• It is used for implementing Android's IPC (Inter-Process Communication) system.

• Binder uses a client-server model where the client sends requests to the server and the server responds with the requested data.

• It is used for sharing data between different components of an Android application.

• Binder is implemented using kernel-level drivers and user-le...read more

Device tree is a data structure used to describe hardware components in a system and their interconnections.

• Device tree is used in embedded systems to provide a standardized way of describing hardware components.

• It is written in a language called Device Tree Source (DTS) and compiled into a binary format called Device Tree Blob (DTB).

• The device tree is loaded by the bootloader and used by the kernel to configure the hardware.

• It allows for easy configuration of hardware compon...read more