Systems Computing Skill

Skill Metadata

skill_config:
  version: "1.0.0"
  category: systems
  prerequisites: [cs-foundations]
  estimated_time: "10-12 weeks"
  difficulty: intermediate-advanced

  parameter_validation:
    domain:
      type: string
      enum: [cpu, memory, os, network, database, distributed]
      required: true
    scale:
      type: string
      enum: [single, cluster, global]
      default: single

  retry_config:
    max_attempts: 3
    backoff_strategy: exponential
    initial_delay_ms: 500

  observability:
    log_level: INFO
    metrics: [domain_usage, design_pattern_frequency]

Quick Start

Master how modern computers actually work, from circuits to distributed systems.

Digital Logic & CPU

CPU Concepts

Instruction execution cycle
Registers and cache hierarchy
Pipelining
Branch prediction

Cache Memory

L1, L2, L3 hierarchy
Temporal and spatial locality
Cache lines and blocks

Operating Systems

Process Management

Process states and context switching
Scheduling algorithms: FCFS, SJF, round-robin

Memory Management

Virtual memory and paging
Page tables and TLB
Page replacement: LRU, optimal

Concurrency

Race conditions and critical sections
Mutual exclusion: locks, semaphores
Deadlock: conditions, detection, recovery

Networking

OSI Model

Layer 1: Physical (signals, cables)
Layer 2: Data Link (MAC, switching)
Layer 3: Network (IP, routing)
Layer 4: Transport (TCP, UDP)

Protocols

HTTP/HTTPS: Web
TCP: Reliable connection
UDP: Fast connectionless
DNS: Name resolution

Distributed Systems

CAP Theorem

Consistency: all nodes same data
Availability: responds to requests
Partition tolerance: survives splits
Can guarantee only 2 of 3

Consensus Algorithms

Paxos: proven consensus
Raft: simpler consensus

Troubleshooting

| Issue | Root Cause | Resolution | |-------|------------|------------| | High latency | Slow DB queries | Add indexes, cache | | Memory exhaustion | Memory leak | Profile, fix leaks | | Connection exhaustion | Pool too small | Increase pool size | | Cascading failure | No circuit breaker | Add circuit breakers |

Key Concepts

Latency: Time to complete one task
Throughput: Tasks completed per unit time
Scalability: Performance with increasing load
Fault tolerance: Reliability despite failures

Interview Questions

How do caches work?
Explain virtual memory
What is thrashing?
Difference between TCP and UDP?
How do transactions work?
Design a system that scales to millions of users