Knowledge Base
Technical systems reference, architectures, and engineering notes.
Communicating Sequential Processes (CSP)
A formal language and mathematical theory of concurrency introduced by C.A.R. Hoare in 1978 where concurrent processes interact exclusively via message-passing channels.
Copy-on-Write (CoW) Filesystems
A storage design pattern where modified data blocks are written to newly allocated blocks rather than overwriting existing data in place.
Data Scrubbing & Self-Healing in ZFS
The mechanisms used by ZFS to detect silent data corruption (bit rot) via 256-bit block checksums and automatically repair errors from redundant copies.
Error Budgets in SRE
The quantifiable margin of allowable unreliability defined as 100% minus the SLO, used to balance developer release velocity against service stability.
Go Concurrency Model: Goroutines & Channels
Go's lightweight concurrency model based on Communicating Sequential Processes (CSP), featuring goroutines, typed channels, and multiplexed select statements.
Open Systems Interconnection (OSI) Model
A 7-layer conceptual framework developed by ISO to standardize telecommunication and computer network communication.
OSI Layer 1: Physical Layer
The foundational layer of the OSI model responsible for transmitting unstructured raw bitstreams over a physical transmission medium.
OSI Layer 2: Data Link Layer
The OSI layer responsible for node-to-node framing, physical MAC addressing, media access control, and hop-by-hop error detection.
OSI Layer 3: Network Layer
The OSI layer responsible for logical addressing (IP), path determination, packet forwarding, and inter-network routing.
OSI Layer 4: Transport Layer
The OSI layer responsible for end-to-end communication, segmentation, flow control, error checking, and port addressing.
OSI Layer 5: Session Layer
The OSI layer that establishes, manages, synchronizes, and terminates dialogues (sessions) between network applications.
OSI Layer 6: Presentation Layer
The OSI layer responsible for data translation, syntax negotiation, compression, and encryption/decryption.
OSI Layer 7: Application Layer
The topmost layer of the OSI model directly interacting with software applications to provide end-user network services.
RAID Levels & ZFS RAID-Z
Comparison of standard hardware/software RAID configurations (RAID 0, 1, 5, 6, 10) against ZFS RAID-Z (RAIDZ1, RAIDZ2, RAIDZ3).
Service Level Terminology: SLI, SLO, & SLA
The foundational triumvirate of SRE reliability metrics: Indicators (what you measure), Objectives (what you target), and Agreements (what you promise legally).
Site Reliability Engineering (SRE)
An engineering discipline pioneered by Google that applies software engineering practices to infrastructure operations and reliability.
TCP/IP Protocol Suite (Internet Model)
The practical 4-layer network model that forms the architectural foundation of the global Internet.
The Go Programming Language (Golang)
An open-source, statically typed, compiled programming language designed at Google by Robert Griesemer, Rob Pike, and Ken Thompson for simplicity, concurrency, and high performance.
Toil Identification & Reduction
The SRE practice of categorizing and engineering away manual, repetitive, tactical operational work to preserve at least 50% engineering time.
Transport Layer Security (TLS)
A cryptographic protocol designed to provide end-to-end communication security, privacy, and data integrity over computer networks.
ZFS (Zettabyte File System)
An advanced, enterprise-grade file system and logical volume manager featuring copy-on-write, pooled storage, end-to-end data integrity checksumming, and snapshots.
ZFS Snapshots, Clones, & Replication
Point-in-time read-only copies (snapshots), writable branches (clones), and stream-based dataset replication (zfs send/recv).
ZFS Storage Pools (zpool) & VDEVs
The storage aggregation layer in ZFS that combines physical drives into Virtual Devices (VDEVs) to provide shared, elastic capacity.