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Software: explore STEM content (page 10 of 25) · openstem

All fields Software Mathematics Physics Chemistry Biology Engineering Astronomy Environmental Other Software Software groups

Explore STEM Content

Search the community's STEM library — free to study, yours to make your own.

Software

Programming, algorithms and systems on openstem — flashcards, notes, quizzes, sketches and flowcharts shared by the community. Study free, or clone anything into your library.

Content Groups1

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Note~86 words · 1 min

Mount, Update, and Unmount An effect always runs after the browser paints, never blocking the render. Its cleanup function runs before the effect fires again (when a dependency changed) and once more on unmount. `useLayoutEffect` follows th

Software

Software · L2 · React: Effect Lifecycle

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Software · L2 · React: Effect Lifecycle

Flowchart12 objects

Software

Software · L1 · Debugging: Find the Mistake

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Software · L1 · Debugging: Find the Mistake

Flashcards10 cards

What does this command do?1 / 10

It initializes a new, empty Git repository in the current directory by creating a hidden .git folder that stores all version history and metadata.

Software

Setup & Configuration

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Setup & Configuration

Flowchart11 objects

Software

Software · L1 · Operating Systems: The Process Lifecycle · flowchart

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Software · L1 · Operating Systems: The Process Lifecycle · flowchart

Flashcards10 cards

What are the three provider scopes, and what does each cost at runtime?1 / 10

`Scope.DEFAULT` (singleton) instantiates once and is shared. `Scope.REQUEST` creates a fresh instance per incoming request, so the whole injection chain above it also becomes request-scoped — adding per-request allocation and a `ContextId` lookup. `Scope.TRANSIENT` gives each consumer its own dedicated instance. Request/transient scope sacrifice the singleton fast path, so reserve them for genuinely per-request or per-consumer state.

Software

DI Container, Modules & Execution Context

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DI Container, Modules & Execution Context

Quiz5 questions

You need O(1) average lookups by key and don't care about ordering. What's the best fit?

AHash tableBBalanced BSTCSingly linked listDUnsorted array

Software

Software · L1 · Data Structures & Algos: Picking the Right Approach

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Software · L1 · Data Structures & Algos: Picking the Right Approach

Flashcards10 cards

What is AWS Lambda?1 / 10

Lambda is a serverless compute service that runs your function code in response to events without you provisioning or managing servers, billing per request and execution duration.

Software

Serverless & Lambda

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Serverless & Lambda

Collection4 items

01Processes & Threads

02OS Fundamentals

03Software · L1 · Operating Systems: The Process Lifecycle

+1 more

Software

Software · L1 · Operating Systems

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Software · L1 · Operating Systems

Flashcards8 cards

What is the difference between BFS and DFS?1 / 8

BFS explores level by level (queue) — optimal for shortest paths in unweighted graphs. DFS goes deep first (stack/recursion) — useful for topological sort, cycle detection, and connected components.

Software

Graphs & Traversals

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Graphs & Traversals

Collection2 items

01Schema Design & Modeling

02Replication & Transactions

Software

Software · L3 · MongoDB

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Software · L3 · MongoDB

Note~97 words · 1 min

Init, Plan, Apply, Destroy Terraform's day-to-day workflow is short and repeatable: prepare the working directory, preview the change, then decide whether to make it real. Only apply and destroy ever touch real resources — plan is always sa

Software

Software · L1 · Terraform: The Core Workflow

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Software · L1 · Terraform: The Core Workflow

Quiz5 questions

What does `on FormatException catch (e)` do differently from a plain `catch (e)`?

AIt only catches FormatException (and subtypes), letting other errors propagateBIt catches every possible error typeCIt silently ignores the error without running any codeDIt only works inside async functions

Software

Software · L2 · Dart: Error Handling & Testing

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Software · L2 · Dart: Error Handling & Testing

Quiz5 questions

You need to limit concurrent access to a pool of exactly 5 database connections. Which primitive fits?

ASemaphore (count = 5)BMutexCSpin lockDThread-local storage

Software

Software · L2 · Concurrency: Choosing a Synchronization Primitive

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Software · L2 · Concurrency: Choosing a Synchronization Primitive

Flashcards10 cards

What does this query return?1 / 10

Each department and its employee count, but only departments with more than 5 employees. WHERE filters rows before grouping; HAVING filters the groups after aggregation.

Software

Aggregation & Grouping

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Aggregation & Grouping

Flashcards10 cards

What are generics in TypeScript?1 / 10

Generics let you write reusable code that works with multiple types while preserving type safety. `function identity<T>(x: T): T` returns the same type it receives — T is inferred at the call site.

Software

Generics & Utility Types

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Generics & Utility Types

Quiz5 questions

What is pubspec.yaml?

AThe project manifest declaring its name, SDK constraint, and dependenciesBA compiled binary produced by dart buildCA file that stores runtime log outputDThe entry-point Dart source file

Software

Software · L1 · Dart: Packages & Tooling

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Software · L1 · Dart: Packages & Tooling

Collection4 items

01Language Basics

02Control Flow & Functions

03Software · L1 · Dart: Packages & Tooling

+1 more

Software

Software · L1 · Dart

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Software · L1 · Dart

Flashcards10 cards

What is the event loop?1 / 10

The event loop runs the call stack until empty, then drains ALL microtasks (Promises, queueMicrotask), then picks ONE macrotask (setTimeout, setInterval, I/O), then repeats. Microtasks always run before the next macrotask.

Software

Async & Promises

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Async & Promises

Collection3 items

01Isolates & Concurrency

02Streams & Async Generators

03VM, AOT/JIT & Performance

Software

Software · L3 · Dart

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Software · L3 · Dart

Note~167 words · 1 min

From main() to a Running App Calling `SpringApplication.run(App.class, args)` bootstraps the whole application: it creates the ApplicationContext, loads and registers beans, applies autoconfiguration, and (for a web app) starts the embedded

Software

Software · L1 · Spring Boot: Application Lifecycle & Logging

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Software · L1 · Spring Boot: Application Lifecycle & Logging

Quiz5 questions

Which algorithm is provably optimal for minimizing average wait time, given known burst lengths?

AShortest Job FirstBRound RobinCPriority SchedulingDFirst-Come First-Served

Software

Software · L2 · Operating Systems: Choosing a CPU Scheduling Algorithm

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Software · L2 · Operating Systems: Choosing a CPU Scheduling Algorithm

Flashcards10 cards

Walk through the singleton bean creation lifecycle in order.1 / 10

Instantiate (constructor) → populate properties (dependency injection) → call *Aware interfaces (BeanNameAware, BeanFactoryAware, ApplicationContextAware) → BeanPostProcessor.postProcessBeforeInitialization → init callbacks (@PostConstruct, then InitializingBean.afterPropertiesSet, then a custom init-method) → BeanPostProcessor.postProcessAfterInitialization → bean is ready. On shutdown: @PreDestroy, then DisposableBean.destroy, then a custom destroy-method.

Software

IoC Container, Bean Lifecycle & AOP

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IoC Container, Bean Lifecycle & AOP

Collection4 items

01Distributed Systems Engineering

02Software · L4 · Distributed Systems Engineering

03Software · L4 · Quorum Write/Read and Leader Fencing

+1 more

Software

Software · L4 · Distributed Systems Engineering

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Software · L4 · Distributed Systems Engineering

Flowchart30 objects

Software

Software · L4 · Quorum Write/Read and Leader Fencing

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Software · L4 · Quorum Write/Read and Leader Fencing

Flashcards9 cards

What are G, M, and P in the Go scheduler?1 / 9

G is a goroutine, M is an OS thread (machine), and P is a logical processor holding a run queue and the resources needed to execute Go code. A G runs on an M only while that M holds a P.

Software

Runtime & Scheduler

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Runtime & Scheduler

Collection4 items

01Site Reliability Engineering

02Software · L4 · Site Reliability Engineering practice

03Software · L4 · Incident lifecycle

+1 more

Software

Software · L4 · Site Reliability Engineering

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Software · L4 · Site Reliability Engineering

Note~688 words · 3 min

Two Axes of Parallelism Training a large model at scale requires distributing computation across many accelerators, and there are two orthogonal ways to do it. Data parallelism replicates the entire model on every worker i and partitions a

Software

Software · L5 · Systems for Distributed Machine Learning

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Software · L5 · Systems for Distributed Machine Learning

Flashcards10 cards

What is the difference between composition and inheritance in module design?1 / 10

Terraform has no inheritance — a root module composes child modules by passing outputs of one as inputs to another. Favor small, single-purpose modules wired together over deep nesting, which makes the data flow explicit and keeps blast radius and reuse bounded.

Software

Module Design, Providers & Scale

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Module Design, Providers & Scale

Collection4 items

01Event Streaming & Kafka

02Software · L4 · Event Streaming & Kafka

03Software · L4 · Consumer Group Partition Assignment and Rebalance

+1 more

Software

Software · L4 · Event Streaming & Kafka

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Software · L4 · Event Streaming & Kafka

Flashcards10 cards

What is Test-Driven Development (TDD)?1 / 10

Write a failing test first (Red), write the minimal code to pass it (Green), then improve the design (Refactor) — repeat. It drives design from requirements and creates a safety net for refactoring.

Software

Practices

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Practices

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