Programming Languages & Core Development Topics
Programming languages, development fundamentals, coding concepts, and core data structures. Includes syntax, algorithms, memory management at a programming level, asynchronous patterns, and concurrency primitives. Also covers core data manipulation concepts like hashing, collections, error handling, and DOM manipulation for web development. Excludes tool-specific proficiency (see 'Tools, Frameworks & Implementation Proficiency').
Concurrency and Synchronization
Covers the principles and practical techniques for safely coordinating concurrent execution and access to shared resources. Topics include models of concurrency such as threads, processes, interrupt handlers, and tasks in a real time operating system; differences between preemptive and cooperative scheduling; shared data hazards including race conditions and read modify write hazards; critical sections and approaches to protect them including disabling interrupts in embedded contexts and scoped locks. Synchronization primitives and patterns are included: mutexes, binary semaphores, counting semaphores, condition variables, message queues, atomic operations and lock free primitives such as compare and swap. Memory ordering concerns and memory barrier usage on multi core systems are covered, along with priority inversion and priority inheritance. Also addressed are deadlock, livelock, and starvation concepts and avoidance strategies, granularity and performance trade offs of locking, and practical synchronization patterns. Preparation should include identifying and fixing races in code, designing correct concurrent interfaces, and debugging and testing techniques such as stress testing, instrumentation, deterministic replay, race detectors, static analysis, and code review strategies.
Debugging and Code Optimization
Practical debugging skills and techniques for improving code performance and complexity. Topics include tracing and reproducing bugs, stepping through execution, reasoning about time and space complexity, refactoring for performance, and applying algorithmic optimizations. Candidates should be able to demonstrate logical debugging approaches and make safe, measurable performance improvements to working code.
Systems Programming & Low-Level Concepts
Systems programming concepts including memory management, pointers, memory layout, CPU architecture considerations, concurrency primitives, OS interactions, and performance optimization in low-level languages (C, C++). Covers how languages expose low-level resources, toolchains, and platform-specific behaviors; excludes high-level application development.
Shell Scripting Basics
Practical ability to write and maintain simple shell scripts using Bash and other Unix shells to automate routine system and DevOps tasks. Core skills include variable assignment and substitution, control flow with conditionals such as if and else, looping constructs such as for and while, defining and invoking functions, basic error handling and exit code checks, and logging for observability. Candidates should also be comfortable with basic file and directory operations, invoking and composing commands, and text processing using tools such as grep, sed, and awk. Emphasis is placed on scripting best practices including input validation, defensive programming, clear code organization and readability, making scripts idempotent where appropriate, and handling common edge cases when automating system administration or deployment workflows.
Python for Infrastructure Automation
Use the Python programming language to build automation for infrastructure tasks. Relevant skills include file input and output, parsing and emitting JSON and YAML configuration files, invoking and managing subprocesses, error handling and retries, working with common HTTP and SSH libraries for automation, and processing and transforming infrastructure data structures. Candidates should be able to demonstrate writing reliable scripts and small programs for provisioning, configuration, orchestration, and integrating with automation tooling and APIs.
Error Handling and Defensive Programming
Covers designing and implementing defensive, fault tolerant code and system behaviors to prevent and mitigate production failures. Topics include input validation and sanitization, null and missing data handling, overflow and boundary protections, exception handling and propagation patterns, clear error reporting and structured logging for observability, graceful degradation and fallback strategies, retry and backoff policies and idempotency for safe retries. Also address concurrency and synchronization concerns, resource and memory management to avoid exhaustion, security related input checks, and how to document and escalate residual risks. Candidates should discuss pragmatic trade offs between robustness and complexity, show concrete defensive checks and assertions, and describe test strategies for error paths including unit tests and integration tests and how monitoring and operational responses tie into robustness.
Python Fundamentals for Infrastructure
Core Python programming skills and idioms needed to write reliable infrastructure scripts and small tools. Topics include data types and collections, variables and scope, functions and modular code organization, conditionals and loops, file input and output, string manipulation and formatting, basic use of the standard library for operating system interaction and process control, simple error handling and logging patterns, and working with structured data formats such as JavaScript object notation. Candidates should be able to write clear, readable scripts, explain common language features, and demonstrate how these fundamentals are applied to basic tasks in configuration management, system monitoring, and repetitive administration tasks.
Algorithm Implementation and Data Structures
Focuses on implementing algorithms correctly and efficiently, and choosing the right data structure for the problem. Candidates should analyze time and space complexity (Big-O), select data structures that balance correctness, memory footprint, and access patterns (arrays, hash maps, trees, heaps, graphs), handle edge cases and precision/overflow pitfalls where relevant, apply techniques such as caching, indexing, batching, or parallelization to remove performance hotspots, and balance optimization against code readability, maintainability, and testability.
Concurrency and Multithreading
Principles and practical techniques for concurrent execution and safe access to shared state across threads or execution contexts. Covers synchronization primitives (locks, mutexes, semaphores, condition variables), atomic operations and memory ordering, avoiding deadlocks, race conditions, and livelocks, designing thread safe data structures, thread pools and work scheduling, and asynchronous or event driven execution models such as coroutines, futures and promises, and reactive streams. Also covers platform and language specific concurrency tools, for example java.util.concurrent and POSIX threads on backend systems, Grand Central Dispatch and OperationQueue on iOS, coroutines and structured concurrency on Android/Kotlin, and async/await models in other languages. Evaluations focus on reasoning about correctness under concurrent access, performance trade offs (throughput, latency, contention), and preventing blocking of latency sensitive execution paths (server request handlers, UI threads, game loops) to maintain responsiveness.