Development Intermediate

LLM

Large Language Model - Large-scale language models that can understand and generate human-like text, such as GPT-4, Claude, and Gemini.

Pronunciation

/ɛl ɛl ɛm/
"ell-ell-emm"
Listen on: Forvo

What it is

LLM (Large Language Model) is a type of artificial intelligence model trained on massive amounts of text to:

  1. Understand natural language - Comprehend questions, instructions, and context
  2. Generate coherent text - Responses, code, documentation
  3. Reason - Follow logic, solve problems step by step
  4. Translate and summarize - Between languages and formats

LLMs are the “brain” behind ChatGPT, Claude, Gemini, and Copilot.

Pronunciation

IPA: /ɛl ɛl ɛm/

Sounds like: “ell-ell-emm” - pronouncing each letter separately

Also called:

  • “Large Language Model” in full
  • “Foundation model” (broader term)

How it works

┌─────────────────────────────────────────────────────────────┐
│                    LLM ARCHITECTURE                          │
├─────────────────────────────────────────────────────────────┤
│                                                              │
│   TRAINING (once)                                           │
│   ┌──────────────────────────────────────────────────────┐  │
│   │  Internet, books, code, conversations                │  │
│   │  → Trillions of text tokens                          │  │
│   │  → Weeks/months on thousands of GPUs                 │  │
│   └──────────────────────────────────────────────────────┘  │
│                           │                                  │
│                           ▼                                  │
│   TRAINED MODEL                                             │
│   ┌──────────────────────────────────────────────────────┐  │
│   │  Parameters: 7B → 70B → 175B → 1T+                   │  │
│   │  Knowledge "frozen" in weights                       │  │
│   └──────────────────────────────────────────────────────┘  │
│                           │                                  │
│                           ▼                                  │
│   INFERENCE (each use)                                      │
│   ┌──────────────────────────────────────────────────────┐  │
│   │  User: "Explain what Kubernetes is"                  │  │
│   │  LLM: Predicts next token → next → ...               │  │
│   │  Response: "Kubernetes is a platform..."             │  │
│   └──────────────────────────────────────────────────────┘  │
│                                                              │
└─────────────────────────────────────────────────────────────┘

Major LLMs (2026)

ModelCompanyParametersStrength
GPT-5OpenAI~1T+General reasoning
Claude 3.5/4Anthropic~200BCode, safety
Gemini 2Google~1T+Multimodal, search
Llama 3Meta8B-405BOpen source
MistralMistral AI7B-22BEfficiency, EU

LLM vs SLM

AspectLLM (Large)SLM (Small)
Parameters70B - 1T+1B - 13B
HardwarePowerful GPUs, cloudLaptop, phone
CostHigh ($0.01-0.10/1K tokens)Low or free locally
CapabilityComplex tasksSpecific tasks
ExamplesGPT-4, ClaudePhi-3, Llama 7B

Practical Example: LLM in Development

Before (without LLM)

Developer: Search Stack Overflow
           Read documentation
           Copy/adapt code
           Debug manually
Time: 2-4 hours for simple feature

Now (with LLM)

Developer: "Implement JWT authentication in Express"

LLM: Generates complete code + tests + documentation
     Explains each part
     Suggests security improvements

Time: 15-30 minutes with review

Limitations

What LLMs can NOT do well

LimitationDescription
HallucinationsMake up information that sounds real
Limited knowledgeTraining cutoff date
Complex mathErrors in long calculations
Private dataCannot access your database
Real-timeDo not know current time

Mitigations

┌────────────────────────────────────────┐
│   HOW TO IMPROVE LLMs                   │
├────────────────────────────────────────┤
│                                         │
│   + RAG (Retrieval)                    │
│     → Access to current documents      │
│                                         │
│   + Tools/Function Calling             │
│     → Execute code, APIs               │
│                                         │
│   + Fine-tuning                        │
│     → Specialize in your domain        │
│                                         │
│   + Agents                             │
│     → Plan and execute tasks           │
│                                         │
└────────────────────────────────────────┘
  • [[Agentic AI]] - LLMs that can act autonomously
  • [[SLM]] - Small models for local devices
  • [[MCP]] - Protocol to connect LLMs to tools
  • [[Prompt Injection]] - Security attacks against LLMs

Remember: LLMs are powerful tools but not perfect. Always verify critical information and use your professional judgment.