Erlang Questions and Answers for Viva

Answer-1: Processes in Erlang are lightweight and run in isolation, making concurrency efficient.

Answer-2: OTP (Open Telecom Platform) provides libraries and design principles for building robust applications.

Answer-3: Concurrency in Erlang is achieved through lightweight processes and message passing.

Answer-4: A tuple is a fixed-size collection of values enclosed in curly braces, e.g., {1, 2, 3}.

Answer-5: Lists are sequences of elements enclosed in square brackets, e.g., [1, 2, 3].

Answer-6: Pattern matching is used to match and destructure data structures directly in code.

Answer-7: Hot code swapping allows updating code in a running system without downtime.

Answer-8: Fault tolerance is achieved through process isolation, supervision trees, and OTP principles.

Answer-9: A supervision tree is a hierarchical structure for monitoring and restarting processes.

Answer-10: An atom is a constant whose name is its value, often used to represent states or commands.

Answer-11: Strings are represented as lists of integers where each integer corresponds to a character's ASCII value.

Answer-12: Guards are additional conditions in pattern matching that refine matching criteria.

Answer-13: A record is a data structure for grouping related fields, defined using -record.

Answer-14: Erlang uses garbage collection, with each process having its own isolated memory space.

Answer-15: spawn creates a new process to execute a given function concurrently.

Answer-16: send sends messages to processes, while receive retrieves messages from a process's mailbox.

Answer-17: gen_server is a generic OTP behavior module for implementing server processes.

Answer-18: The module attribute defines the name of the module, e.g., -module(module_name)..

Answer-19: List comprehensions are concise ways to generate lists by filtering and transforming elements.

Answer-20: Errors are handled using try...catch, throw, and OTP supervision strategies.

Answer-21: Ports enable communication between Erlang processes and external programs.

Answer-22: The receive block is used to handle incoming messages in a process's mailbox.

Answer-23: Data in Erlang is immutable, meaning once created, it cannot be changed.

Answer-24: Recursion is the primary way to implement loops in Erlang, as it lacks traditional loop constructs.

Answer-25: mnesia is a distributed database management system integrated into Erlang.

Answer-26: Functions are defined with function_name(Arguments) -> Body.

Answer-27: gen_fsm is an OTP behavior module for implementing finite state machines.

Answer-28: Macros are compile-time constants or code snippets defined using -define.

Answer-29: fun creates an anonymous function, while function refers to named functions.

Answer-30: Erlang provides tools like observer, dbg, and trace for debugging applications.

Answer-31: process_flag is used to change process-specific flags like trapping exits.

Answer-32: Modules are compiled using the c(ModuleName). command in the Erlang shell.

Answer-33: exit terminates a process, while throw is used for non-fatal exceptions.

Answer-34: ETS (Erlang Term Storage) tables are in-memory storage for large data sets.

Answer-35: Variables in Erlang start with an uppercase letter and are immutable after assignment.

Answer-36: link creates a bi-directional link between two processes for fault detection.

Answer-37: Use the erl command to start the shell and execute the application module.

Answer-38: A pid is a unique identifier for a process in Erlang.

Answer-39: Synchronous communication waits for a response, while asynchronous communication does not.

Answer-40: gen_event is an OTP behavior module for implementing event handling and dispatching.

Answer-41: Dependencies are managed using tools like rebar3.

Answer-42: Processes in Erlang can be normal processes, system processes, or supervisors.

Answer-43: The timer module provides functions for time-related operations like delays and intervals.

Answer-44: dialyzer is a static analysis tool for finding type errors and code inconsistencies.

Answer-45: The rpc module provides remote procedure call functionalities for distributed systems.

Answer-46: Scalability in Erlang is achieved through lightweight processes, message passing, and fault-tolerant design.

Answer-47: Erlang is a functional programming language used for building scalable and fault-tolerant systems.

Answer-48: Erlang was created by Ericsson in the 1980s for use in telecommunications systems.

Answer-49: Erlang excels at handling concurrent, distributed, and fault-tolerant applications.

Answer-50: BEAM is Erlang's virtual machine that executes compiled bytecode.