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Software: explore STEM content (page 11 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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Flashcards10 cards

When should you embed related data versus reference it?1 / 10

Embed when data is accessed together and bounded in size; reference when data is large, shared, or grows unbounded.

Software

Schema Design & Modeling

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Schema Design & Modeling

Collection4 items

01Observability: Metrics, Logs, and Traces

02Software · L4 · Observability: Metrics, Logs, and Traces

03Software · L4 · From Alert to Root Cause Across the Three Pillars

+1 more

Software

Software · L4 · Observability: Metrics, Logs, and Traces

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Software · L4 · Observability: Metrics, Logs, and Traces

Collection4 items

01Core Concepts

02Setup & Configuration

03Software · L1 · Git & Dev Workflow: The Feature Branch Workflow

+1 more

Software

Software · L1 · Git & Dev Workflow

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Software · L1 · Git & Dev Workflow

Collection4 items

01Core Services

02Cloud Fundamentals

03Software · L1 · Google Cloud: Storage & Database Options

+1 more

Software

Software · L1 · Google Cloud

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Software · L1 · Google Cloud

Flowchart14 objects

Software

Software · L1 · Git & Dev Workflow: The Feature Branch Workflow · flowchart

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Software · L1 · Git & Dev Workflow: The Feature Branch Workflow · flowchart

Note~92 words · 1 min

Where the Accessible Name Comes From An interactive element's 'accessible name' — what a screen reader actually reads aloud — is computed by checking several sources in a strict priority order, stopping at the first match. An element marked

Software

Software · L2 · HTML & CSS: Computing an Element's Accessible Name

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Software · L2 · HTML & CSS: Computing an Element's Accessible Name

Flashcards10 cards

State the full cascade ordering the browser uses to pick a value.1 / 10

In decreasing priority: (1) origin + importance — normal user-agent, normal user, normal author, then animations, then author `!important`, user `!important`, UA `!important` (importance reverses the origin order); (2) cascade layers, where later `@layer` wins, and unlayered author styles beat layered ones; (3) specificity; (4) source order. Each tier is a tiebreaker only when the prior tiers are equal.

Software

CSS Cascade, Layout Internals & Architecture

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CSS Cascade, Layout Internals & Architecture

Note~111 words · 1 min

The Build-to-Release Chain GCP separates CI/CD into focused services: Cloud Build compiles and tests, Artifact Registry stores the resulting images/packages, and Cloud Deploy manages progressive rollout to your runtime of choice. What Happe

Software

Software · L2 · Google Cloud: CI/CD & Deployment

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Software · L2 · Google Cloud: CI/CD & Deployment

Flashcards10 cards

What is the Singleton pattern and what is its main drawback?1 / 10

Ensures a class has only one instance with a global access point. Useful for shared resources (config, logging) but is often an anti-pattern: it introduces global state, hides dependencies, and makes unit testing harder (hard to mock/reset).

Software

Creational Patterns

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Creational Patterns

Note~82 words · 1 min

What Is a Pattern? A pattern is something that repeats in the same way. You can find patterns everywhere! Computers use patterns too. When a program does the same thing over and over, it follows a pattern. Spotting patterns helps you solve

Software

Software · L1 · Patterns: Spotting What Repeats

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Software · L1 · Patterns: Spotting What Repeats

Flashcards10 cards

Walk the critical rendering path from bytes to pixels.1 / 10

Parse HTML into the DOM and CSS into the CSSOM; combine them into the render tree (only visible nodes, with computed styles); run layout to assign each box a geometry; paint draw-order display lists into layers; then composite those layers (often on the GPU) into the final frame. DOM and CSSOM build in parallel, but the render tree needs both.

Software

Browser Rendering & Performance

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Browser Rendering & Performance

Quiz2 questions

Can a computer think for itself without any instructions?

AYes, computers are very smart on their ownBNo, computers only do what people tell themCOnly if they are switched onDOnly if they are connected to the internet

Software

Software · L1 · Computers and What They Do

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Software · L1 · Computers and What They Do

Flashcards9 cards

What is the fundamental trade-off between symmetric and asymmetric encryption?1 / 9

Symmetric ciphers (AES) are orders of magnitude faster and use one shared key, but distributing that key securely is hard. Asymmetric ciphers (RSA, ECC) solve key distribution with public/private key pairs but are far more computationally expensive. Real protocols (TLS) use asymmetric crypto only to exchange a symmetric session key, then switch to symmetric encryption for bulk data — a hybrid scheme.

Software

Applied Cryptography for Engineers

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Applied Cryptography for Engineers

Flashcards10 cards

What port does HTTPS use by default?1 / 10

HTTPS uses TCP port 443 by default, versus port 80 for plain HTTP.

Software

TLS & HTTPS

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TLS & HTTPS

Note~162 words · 1 min

Why Simple Code Breaks Under Concurrency Code like `counter++` looks like one step but is really read, add one, write — three separate steps. If two threads interleave those steps, one thread's update can silently vanish. This is the root c

Software

Software · L1 · Concurrency: Protecting Shared State

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Software · L1 · Concurrency: Protecting Shared State

Collection4 items

01Test Types

02Practices

03Software · L1 · Testing: The Red-Green-Refactor Cycle

+1 more

Software

Software · L1 · Testing

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Software · L1 · Testing

Flowchart6 objects

Software

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

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

Collection5 items

01Modules & Variables

02State Management

03Providers & Resources

+2 more

Software

Software · L2 · Terraform

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Software · L2 · Terraform

Flashcards10 cards

Is Node.js single-threaded?1 / 10

JavaScript execution in Node is single-threaded (one event loop), but I/O is handled asynchronously by libuv's thread pool and the OS. CPU-bound work blocks the loop; offload it to Worker Threads or child processes.

Software

Core & Event Loop

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Core & Event Loop

Flashcards8 cards

What happens inside the kernel during a context switch between two threads?1 / 8

The scheduler saves the outgoing thread's registers (including SP and PC) into its kernel thread struct (task_struct on Linux), selects the next thread, restores its register file, switches the memory context (CR3 on x86, TLB flush if different process), then returns to the new thread's execution point.

Software

Kernel Internals

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Kernel Internals

Flashcards9 cards

What is the difference between a process and a thread?1 / 9

A process is an independent program with its own memory space, file handles, and resources. Threads within a process share the same memory and resources but have their own stack, registers, and program counter. Processes are isolated; threads are lightweight peers within a process.

Software

Threads & Processes

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Threads & Processes

Note~131 words · 1 min

Cache Strategies at a Glance Every caching strategy is really a decision about when the cache and the database are allowed to disagree, and for how long. Which Strategy Fits? The deciding factors are usually how tolerant the application is

Software

Software · L2 · System Design: Choosing a Cache Strategy

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Software · L2 · System Design: Choosing a Cache Strategy

Flashcards10 cards

What are xmin and xmax on a PostgreSQL heap tuple?1 / 10

Every heap row has system columns: `xmin` is the transaction ID that inserted it; `xmax` is the XID that deleted/updated it (0 = still live). MVCC uses these to determine which rows are visible to a snapshot.

Software

Internals & MVCC

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Internals & MVCC

Flashcards10 cards

What runs in Next.js middleware, and why does its placement matter?1 / 10

Middleware executes before the matched route resolves, on every request that passes its `matcher`, letting you rewrite, redirect, or set headers/cookies (e.g. auth gating, locale routing). Because it runs on the critical path for matched requests, the work must be cheap — heavy logic or per-request data fetches there add latency to everything behind it.

Software

Routing, Middleware & Edge Runtime

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Routing, Middleware & Edge Runtime

Collection4 items

01Applied Cryptography for Engineers

02Software · L4 · Applied Cryptography for Engineers

03Software · L4 · TLS 1.3 handshake

+1 more

Software

Software · L4 · Applied Cryptography

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Software · L4 · Applied Cryptography

Collection2 items

01Concurrency Models

02Atomics & Memory Model

Software

Software · L3 · Concurrency

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Software · L3 · Concurrency

Collection4 items

01Types & Inference

02Everyday Types

03Software · L1 · TypeScript: Handling Optional and Nullish Values

+1 more

Software

Software · L1 · TypeScript

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Software · L1 · TypeScript

Quiz10 questions

Average-case lookup time in a hash map?

AO(1)BO(log n)CO(n)DO(n log n)

Software

Software · L4 · Time complexity — 10 Q

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Software · L4 · Time complexity — 10 Q

Note~887 words · 4 min

Why Formal Semantics? A programming language's syntax says what programs look like; its semantics says what they mean — precisely and unambiguously enough to prove theorems about programs (does this optimisation preserve behaviour? does thi

Software

Software · L5 · Programming Language Semantics

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Software · L5 · Programming Language Semantics

Flashcards10 cards

What is the difference between TCP and UDP?1 / 10

TCP is connection-oriented and reliable — ordered, error-checked, retransmitted (web, email, file transfer). UDP is connectionless and unreliable but fast and low-overhead — no ordering or delivery guarantees (video streaming, gaming, DNS).

Software

TCP/IP & DNS

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TCP/IP & DNS

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