Consensus

Communication Protocols in Distributed Systems Distributed systems rely on multiple machines that must coordinate. The choice of communication protocol affects how quickly data moves, what can fail gracefully, and how easy it is to evolve the system. A simple decision here saves many problems later. Types of communication patterns Request-response: a client asks a service and waits for a reply. Publish-subscribe: events or messages are delivered to many subscribers. Message queues: work items flow through a broker with buffering and retries. Streaming: long-running data flow, useful for logs or real-time feeds. These patterns can be combined. For example, a backend may use gRPC for fast request-response and a message broker to handle background tasks. ...

Blockchain Beyond Crypto: Use Cases and Architectures Blockchain is often tied to crypto, but its real strength is a shared ledger that many parties can trust without a middleman. It records facts once and keeps them secure through cryptography and consensus. This makes it useful for supply chains, contracts, identity, and data sharing. Clear goals help teams pick the right tools and partners. In business, a well designed blockchain system focuses on four ideas: a reliable record, clear governance, scalable performance, and privacy where needed. These ideas guide how you pick technology and who participates. Start with the problem you want to solve, then map who should access what data and when. ...

Blockchain Beyond Bitcoin: Use Cases and Architecture Blockchain is often linked to Bitcoin, but its value extends far beyond digital money. Today, businesses and public bodies use blockchains to boost trust, traceability, and automation across many sectors. A blockchain combines a shared ledger, cryptography, and smart rules that run on a network of computers. This mix can reduce fraud, cut delays, and open new ways to work together. Architecture helps explain how it all fits. A typical blockchain stack has several layers. The data layer records transactions as blocks. The network layer connects participants. The consensus layer agrees on the order of events. The smart contract layer stores and runs business rules. The application layer serves user apps. Access can be open to the world or limited to trusted partners. To keep data private and fast, many designs use off-chain storage and selective data sharing, with only essential proofs on-chain. ...

Distributed Databases: Consistency, Latency, and Availability Distributed databases store data across multiple machines and locations. This design helps scale, stay resilient, and serve users quickly. But it also creates a classic trade-off among consistency, latency, and availability, a trio often summarized by the CAP idea. In practice, teams pick a balance based on user needs and failure scenarios. Consistency models guide how up-to-date data must be. Strong consistency makes every read show the latest write. It is easier to reason about, but it can add latency if writes must reach a majority of replicas. Eventual consistency allows faster reads and writes and can survive partitions, but reads may see older data for a while. Causal consistency is a middle ground: operations that depend on each other stay ordered, while unrelated actions may be stale. ...

Blockchain Beyond Bitcoin: Use Cases and Architecture Blockchain technology is often tied to Bitcoin, but its value comes from a broader idea: a shared, tamper‑evident ledger that multiple parties can trust. In practice, this means faster settlement, clearer records, and new ways to automate trust without a central authority. By combining cryptography, distributed consensus, and smart contracts, organizations can build systems that are open where appropriate and private where needed. ...

Intro to Blockchain and Smart Contracts Blockchain is a shared digital ledger that records transactions across many computers. This design keeps data transparent and resistant to tampering. Each block contains a list of transactions and a link to the previous block, forming a chain. Because many people hold copies of the ledger, changing records requires broad agreement from the network. This is why trust can be built without a central authority. ...