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Software: explore STEM content (page 20 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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Collection2 items

01HTTP/2, HTTP/3 & QUIC

02CDNs, Anycast & BGP

Software

Software · L4 · Networking & HTTP

@openstem

Software · L4 · Networking & HTTP

Flashcards9 cards

What is the prototype chain?1 / 9

Every JS object has an internal `[[Prototype]]` link. When you access a property, JS looks on the object, then up the chain until it reaches `null`. This is how inheritance works — all arrays inherit from `Array.prototype`, which inherits from `Object.prototype`.

Software

Prototypes & Classes

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Prototypes & Classes

Flashcards10 cards

What is the result of this collection-if expression?1 / 10

[1, 2, 3] — collection-if conditionally includes the element 3 because the condition is true. Collection-if/for build lists inline.

Software

Collections & Generics

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Collections & Generics

Flashcards10 cards

What does the $inc update operator do?1 / 10

It increments (or decrements with a negative value) a numeric field by the given amount, creating the field at that value if it doesn't exist.

Software

CRUD & Operators

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CRUD & Operators

Note~129 words · 1 min

What Matters Most? No scheduling algorithm is best on every axis — each one optimizes for a particular goal at the expense of another. Picking one starts with naming what the workload actually needs. A Decision Path In practice, most genera

Software

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

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

Collection2 items

01Browser Rendering & Performance

02CSS Cascade, Layout Internals & Architecture

Software

Software · L4 · HTML & CSS

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Software · L4 · HTML & CSS

Flashcards10 cards

What does a Spring Data JPA repository interface give you for free?1 / 10

Extending `JpaRepository` provides CRUD, pagination, and sorting plus derived query methods generated from method names — no implementation needed.

Software

Data Access & JPA

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Data Access & JPA

Flashcards10 cards

What is the main risk of a single monolithic Terraform state for a large org?1 / 10

Everything shares one lock and blast radius: plans get slow, a single apply can touch unrelated systems, and concurrent work is serialized. Split state by service/layer instead.

Software

Advanced State & Scaling

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Advanced State & Scaling

Quiz3 questions

What are the three conditions under which the FLP impossibility result applies?

ASynchrony, randomisation, and majority fault toleranceBAsynchrony, determinism, and tolerance of at least one crash faultCPartial synchrony, Byzantine faults, and n > 3f processesDAsynchrony, probabilistic algorithms, and message loss

Software

Software · L5 · Distributed Systems Theory

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Software · L5 · Distributed Systems Theory

Flowchart12 objects

Software

Software · L1 · Node.js: Event Loop Walkthrough · flowchart

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Software · L1 · Node.js: Event Loop Walkthrough · flowchart

Flashcards5 cards

What is a variable?1 / 5

A variable is like a labelled box. You give it a name and put a value inside. The program can look at or change that value whenever it needs to.

Software

Software · L2 · Variables: Labelled Boxes for Values

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Software · L2 · Variables: Labelled Boxes for Values

Collection4 items

01Documents & Queries

02CRUD & Operators

03Software · L1 · MongoDB: Schema Design — Embedding vs Referencing

+1 more

Software

Software · L1 · MongoDB

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Software · L1 · MongoDB

Flowchart9 objects

Software

Software · L2 · AWS: CI/CD Pipelines · flowchart

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Software · L2 · AWS: CI/CD Pipelines · flowchart

Flashcards10 cards

Are components in the Next.js App Router server or client by default?1 / 10

They are Server Components by default; you opt into client behavior by adding the "use client" directive at the top of the file.

Software

App Router & Server Components

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App Router & Server Components

Flashcards10 cards

How do V8 and libuv divide responsibilities in Node.js?1 / 10

V8 compiles and executes JavaScript (heap, GC, JIT). libuv provides the event loop, async I/O, the thread pool, timers, and OS abstraction for network/file ops. Node's bindings glue the two together.

Software

Internals & Architecture

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Internals & Architecture

Collection2 items

01Data & Analytics (BigQuery)

02Architecture & Scale

Software

Software · L3 · Google Cloud

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Software · L3 · Google Cloud

Flashcards10 cards

What is the difference between authentication and authorization?1 / 10

Authentication (authn) verifies WHO you are (login, credentials). Authorization (authz) determines WHAT you are allowed to do (permissions, roles). Authentication always comes first.

Software

Authentication & Authorization

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Authentication & Authorization

Flashcards8 cards

Which decorator maps a GET request to a controller method?1 / 8

`@Get()` — placed on a controller method, optionally with a path segment like `@Get(':id')`. Sibling decorators include @Post, @Put, @Patch, and @Delete.

Software

Decorators & Routing

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Decorators & Routing

Flowchart9 objects

Software

Software · L2 · Rust: Option, Result, or panic!? · flowchart

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Software · L2 · Rust: Option, Result, or panic!? · flowchart

Collection4 items

01Software · L5 · Distributed Machine Learning Systems

02Software · L5 · Systems for Distributed Machine Learning

03Software · L5 · Distributed Training Architectures

+1 more

Software

Software · L5 · Distributed Machine Learning Systems

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Software · L5 · Distributed Machine Learning Systems

Note~107 words · 1 min

Request In, Response Streamed Out A raw Node HTTP server has no built-in middleware concept, but the pattern is simple: an ordered list of functions, each given the chance to act or hand off control to the next one via `next()`. Because Inc

Software

Software · L2 · Node.js: HTTP Middleware Pipeline

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Software · L2 · Node.js: HTTP Middleware Pipeline

Flashcards10 cards

How is an object's SHA computed, and what is the loose-object on-disk format?1 / 10

The hash is taken over the header `<type> <size>\0` concatenated with the raw content — not over the compressed bytes. On disk a loose object is that same header+content zlib-deflated, stored at `.git/objects/ab/cdef…` (first two hex chars name the directory).

Software

Git Internals: Objects, Refs & Plumbing

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Git Internals: Objects, Refs & Plumbing

Flashcards10 cards

How do IAM allow policies combine down the organization → folder → project → resource hierarchy?1 / 10

Each node has its own allow policy, and a principal's effective access is the union of all bindings inherited from every ancestor plus the resource itself. Allow policies are purely additive — a child cannot revoke a role granted higher up; that requires an IAM deny policy or removing the binding at its source.

Software

IAM, Resource Hierarchy & Security

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IAM, Resource Hierarchy & Security

Collection2 items

01Container Internals & Images

02Observability & Monitoring

Software

Software · L3 · Docker & Kubernetes

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Software · L3 · Docker & Kubernetes

Flashcards8 cards

What is the key difference between a message queue and a pub/sub topic?1 / 8

A queue delivers each message to exactly one consumer among a competing group (work distribution). A pub/sub topic delivers a copy of each message to every subscriber (fan-out/broadcast). Many real systems (Kafka, SNS+SQS) combine both: a topic fans out to several queues, each queue load-balanced across its own consumer group.

Software

Message Queues & Event-Driven Communication

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Message Queues & Event-Driven Communication

Collection4 items

01Joins

02Aggregation & Grouping

03Software · L1 · SQL: Transactions & ACID

+1 more

Software

Software · L1 · SQL

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Software · L1 · SQL

Note~623 words · 3 min

Replication Topologies Replication exists to survive node failure and to spread read load, but the topology chosen shapes the whole system's failure behavior. Leader-based (single-master) replication funnels writes through one node and stre

Software

Software · L4 · Distributed Systems Engineering

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Software · L4 · Distributed Systems Engineering

Note~149 words · 1 min

Representing a Graph A graph is a set of vertices connected by edges. The two common representations trade memory for lookup speed differently, and the right choice depends on how dense the graph is and what operations dominate. BFS vs DFS

Software