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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.

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Software: explore STEM content (page 6 of 25) · openstem

Quiz5 questions

Which command must run first in a new Terraform working directory?

Aterraform applyBterraform initCterraform destroyDterraform plan

Software

Software · L1 · Terraform: The Core Workflow

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Software · L1 · Terraform: The Core Workflow

Flashcards10 cards

What is a discriminated union and why is it useful?1 / 10

A union of object types each with a shared literal property that TypeScript uses to narrow: `type Shape = { kind: 'circle'; r: number } | { kind: 'rect'; w: number; h: number }`. The `kind` discriminant lets TypeScript know which branch you're in.

Software

Patterns & Best Practices

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Patterns & Best Practices

Flowchart17 objects

Software

Software · L2 · TypeScript: Picking the Right Utility Type · flowchart

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Software · L2 · TypeScript: Picking the Right Utility Type · flowchart

Collection2 items

01DI Container, Modules & Execution Context

02Interceptors, Guards, Pipes & Microservices

Software

Software · L4 · NestJS

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Software · L4 · NestJS

Note~149 words · 1 min

Why Isolation Levels Exist When multiple transactions run at once, the database has to decide how much of each other's in-progress work they can see. A stricter isolation level prevents more anomalies but forces more transactions to wait on

Software

Software · L2 · SQL: Isolation Levels & Locking

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Software · L2 · SQL: Isolation Levels & Locking

Note~678 words · 3 min

Site Reliability Engineering practice SRE treats operations as a software problem: reliability targets are explicit, the tradeoff between velocity and stability is quantified, and incident response is a practiced discipline rather than impr

Software

Software · L4 · Site Reliability Engineering practice

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Software · L4 · Site Reliability Engineering practice

Note~154 words · 1 min

pubspec.yaml: Your Project's Manifest Every Dart/Flutter project has a `pubspec.yaml` at its root declaring the project's name, its SDK constraint, and its dependencies (and dev_dependencies, used only during development, like test tooling)

Software

Software · L1 · Dart: Packages & Tooling

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Software · L1 · Dart: Packages & Tooling

Collection4 items

01Core Types

02Functions & Decorators

03Software · L1 · Python: Choosing the Right Collection

+1 more

Software

Software · L1 · Python

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Software · L1 · Python

Collection4 items

01Architecture

02Decorators & Routing

03Software · L1 · NestJS: Request Lifecycle

+1 more

Software

Software · L1 · NestJS

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Software · L1 · NestJS

Quiz5 questions

You need to check membership of thousands of items as fast as possible, and order doesn't matter. Which collection fits best?

AlistBtupleCsetDA plain string

Software

Software · L1 · Python: Choosing a Collection

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Software · L1 · Python: Choosing a Collection

Flashcards10 cards

Explain the difference between == and === in JavaScript.1 / 10

`===` is strict equality — compares value AND type with no coercion. `==` is loose equality — coerces operands to a common type first (`0 == ""` is true). Always prefer `===`.

Software

Fundamentals

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Fundamentals

Flashcards8 cards

Define a Hoare triple {P} C {Q} and state what it asserts about program C.1 / 8

{P} C {Q} asserts partial correctness: if the precondition P holds in the initial state and command C terminates, then the postcondition Q holds in the resulting state. It says nothing about whether C actually terminates — a program that loops forever from any state satisfying P vacuously satisfies {P} C {Q} for any Q.

Software

Software · L5 · Hoare Logic & Program Verification

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Software · L5 · Hoare Logic & Program Verification

Flowchart5 objects

Software

Software · L2 · Design Patterns: Which Structural Pattern? · flowchart

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Software · L2 · Design Patterns: Which Structural Pattern? · flowchart

Flashcards10 cards

What is the difference between Compute Engine and Cloud Run?1 / 10

Compute Engine provides managed VMs (IaaS) that you size and patch. Cloud Run runs stateless containers serverlessly, scaling to zero and billing per request.

Software

Compute & Networking

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Compute & Networking

Flashcards10 cards

What does AWS Organizations provide?1 / 10

Organizations centrally manages multiple AWS accounts, enabling consolidated billing, organizational units (OUs), and Service Control Policies for governance at scale.

Software

Multi-Account & Advanced Networking

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Multi-Account & Advanced Networking

Flashcards10 cards

How do you declare an immutable vs mutable variable?1 / 10

`let x = 5;` is immutable by default; `let mut x = 5;` is mutable. Rust makes immutability the default to favor safety and clearer intent.

Software

Rust Syntax & Basics

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Rust Syntax & Basics

Collection5 items

01Structural Patterns

02SOLID Principles

03Behavioral Patterns

+2 more

Software

Software · L2 · Design Patterns

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Software · L2 · Design Patterns

Collection3 items

01Software · L5 · Compiler Construction Theory

02Software · L5 · Compiler Construction Theory

03Software · L5 · Compiler Construction Theory

Software

Software · L5 · Compiler Construction Theory

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Software · L5 · Compiler Construction Theory

Flashcards10 cards

What is a MongoDB replica set?1 / 10

A group of mongod nodes maintaining the same data: one primary accepts writes and secondaries replicate the oplog for redundancy and failover.

Software

Replication & Transactions

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Replication & Transactions

Flowchart14 objects

Software

Software · L5 · Decidability Hierarchy

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Software · L5 · Decidability Hierarchy

Flashcards10 cards

What is the difference between a logical plan and a physical plan?1 / 10

A logical plan is an algebraic, set-based description of WHAT to compute — joins, filters, projections, and aggregations as relational operators, independent of implementation. The physical plan is the optimizer's chosen execution strategy: it binds each logical operator to a concrete algorithm (e.g. a join becomes a hash join, a scan becomes an index scan) and fixes join order, ordering it by estimated cost. EXPLAIN shows the physical plan.

Software

Query Optimization & Execution Plans

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Query Optimization & Execution Plans

Flashcards10 cards

What does a @Controller decorator define?1 / 10

A class whose methods handle incoming requests for a route prefix, mapping HTTP verbs to handler methods via decorators like `@Get` and `@Post`.

Software

Controllers, Pipes & Guards

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Controllers, Pipes & Guards

Collection2 items

01Transactions & MVCC

02Performance Tuning

Software

Software · L3 · PostgreSQL

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Software · L3 · PostgreSQL

Quiz8 questions

What is the main tradeoff of leaderless (quorum-based) replication compared to leader-based replication?

AIt removes the need for any conflict resolutionBIt favors write availability during partitions, at the cost of needing explicit conflict resolution when replicas divergeCIt guarantees linearizability automaticallyDIt eliminates the need for multiple replicas

Software

Software · L4 · Distributed Systems Engineering

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Software · L4 · Distributed Systems Engineering

Flashcards10 cards

What does a conditional type `T extends U ? X : Y` evaluate to?1 / 10

It picks X when T is assignable to U and Y otherwise; it becomes a powerful tool when combined with generics and inference.

Software

Advanced Types (Conditional & Template Literal)

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Advanced Types (Conditional & Template Literal)

Collection2 items

01Internals & MVCC

02Replication & Scaling

Software

Software · L4 · PostgreSQL

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Software · L4 · PostgreSQL

Flowchart13 objects

Software

Software · L1 · React: The Render Cycle · flowchart

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Software · L1 · React: The Render Cycle · flowchart

Note~329 words · 2 min

Amortised Analysis Amortised analysis assigns a cost to each operation in a sequence so that the total amortised cost bounds the total actual cost, even when individual operations are expensive. Example: Dynamic Array (Doubling) A dynamic a

Software