Complete archive

Archive

3,240 articles, newest first · page 21 of 54. For subject-based browsing use topics; for keyword lookup try search. Dates shown are assigned archive dates that order the library; they are not historical publication records.

2025
Nov 19, 2025 User-Level Threads and the M:N Scheduling Problem How a runtime multiplexes many logical threads over few kernel threads, why a blocking system call breaks it, and what stack growth costs. operating systems · advanced
Nov 18, 2025 Counting Round Trips in Connection Setup How handshakes, name resolution, and security negotiation add serial round trips before the first byte of payload, and which of them can be overlapped. networking · intermediate
Nov 18, 2025 Distinguishing Strings and the Myhill-Nerode Theorem How the set of right contexts partitions a language into classes, why that partition is exactly the minimal DFA, and how to use it as an upper bound in proofs. computation theory · intermediate
Nov 18, 2025 Drift Detection Without Reading Every Host: Sampling, Fingerprints, and Reconciliation How to find hosts whose state no longer matches their declaration, what a fingerprint over a state subtree can and cannot prove, and how detection frequency trades against read cost. devops · advanced
Nov 18, 2025 Selectivity Estimation from Histograms and Most-Common-Value Lists How a single-column statistic turns a predicate into a row count, why equidepth buckets are chosen over equiwidth, and where the estimate fails for correlated columns. databases · foundational
Nov 17, 2025 Backfilling a Table While Its Stream Keeps Running A historical re-read competes with the live feed for the same keys, so the merge rule and the rate limit matter more than the query itself. data engineering · intermediate
Nov 17, 2025 How an Accessibility Rule Engine Decides The parse, match, evaluate, and report stages inside a checker like axe-core, how rule results are graded, and why the same page yields different reports from different tools. accessibility · foundational
Nov 17, 2025 Longest Increasing Subsequence and the Tails Array Invariant The O(n log n) patience-sorting method keeps one number per length instead of a full two-dimensional table, and the invariant explaining why is a dominance argument. algorithms · intermediate
Nov 17, 2025 Model-Based Congestion Control: Delivery Rate, Minimum RTT, and Pacing Estimating the bottleneck rate and the propagation delay separately lets a sender set its window from the product of the two instead of probing for loss. The estimators are the whole design. networking · advanced
Nov 17, 2025 Relicensing a Mature Project: Consent, Forks, and Downstream Effects Changing a project license is a copyright transaction with every rightsholder in the tree, not a policy announcement; the routes that avoid consent, the audit that establishes who must be asked, and what a change cannot reach. computing history · advanced
Nov 17, 2025 Tombstones, Merges, and the Cost of Keeping a Vector Index Current Why deleting from a proximity graph is harder than inserting, how segment-and-merge maintenance bounds the damage, and when a rebuild is cheaper than incremental repair. information retrieval · advanced
Nov 16, 2025 Maximal Munch and the Boundary Between Tokens How a lexer decides where one token ends, why the longest-match rule is separate from the grammar, and which token sequences it produces that the source text does not appear to contain. compilers · foundational
Nov 15, 2025 ARP and the Neighbour Cache Lifecycle How an IPv4 address becomes a MAC address, why the cache entry has states rather than an expiry, and what happens to queued packets during resolution. networking · intermediate
Nov 15, 2025 procfs and the Limits of Representing Kernel State as Files How a virtual filesystem synthesises readable text for process and kernel state, why the files violate ordinary file assumptions, and where the interface gives inconsistent answers. computing history · advanced
Nov 14, 2025 Durability Barriers, Flushes, and What fsync Actually Waits For The storage-stack path a flush traverses, why a drive cache that ignores it voids every journal guarantee, and what a directory fsync must order. filesystems · advanced
Nov 14, 2025 Happens-Before and the Scalar Logical Clock How Lamport replaced physical time with a partial order defined by message passing, why one integer per process suffices for that order, and what the integer provably cannot tell you. distributed systems · foundational
Nov 14, 2025 Value Representation: Tagged Pointers and NaN Boxing How a dynamically typed runtime distinguishes integers, heap objects, and doubles inside one machine word, and what each encoding costs in branches, memory, and portability. programming languages · intermediate
Nov 13, 2025 Billing Units and Why a Cloud Bill Is an Estimate How usage records become invoice lines: instance-hours, the GB-month integral, minimum billing increments, and the order in which discounts are applied. cloud infrastructure · foundational
Nov 13, 2025 Wake Locks, Reference Counting, and the Cost of a Held CPU Why a wake lock is a counted system resource rather than a flag, what a partial lock actually keeps powered, and how an unbalanced acquire turns into a battery complaint. mobile computing · advanced
Nov 12, 2025 Bulk Copy and Change Stream: Making an Online Copy Consistent Why a snapshot must be pinned to a stream position before the copy begins, how the catch-up phase terminates, and where replication lag turns into an unbounded delay. cloud infrastructure · foundational
Nov 12, 2025 Momentum Encoders and Stop-Gradients Why contrastive and self-distillation methods train one branch with gradients and update the other by exponential moving average, and what the asymmetry buys in stability and target quality. deep learning · intermediate
Nov 11, 2025 Carry Propagation in the Difference Engine No. 2 How a figure wheel registers that a carry is owed without performing it, how the latched warnings are serviced by staggered carry arms, and what the two-phase cycle costs in timing. computing history · foundational
Nov 11, 2025 How Key-Value Cache Bytes Set the Batch Ceiling The byte arithmetic that decides how many sequences fit beside the weights, why the ceiling moves with context length, and what remains after it is reached. inference systems · foundational
Nov 11, 2025 Successive-Approximation ADCs: Sample-and-Hold Settling and Conversion Timing What limits the sample rate of a SAR converter, why the sampling switch needs a settling budget, and how source impedance turns a datasheet accuracy figure into a smaller one. embedded systems · intermediate
Nov 10, 2025 Fixture Scoping and the Lifetime of Shared Test State How setup and teardown become a dependency graph with scoped lifetimes, why a session-scoped object couples tests that never mention each other, and how teardown failures are attributed. developer tools · foundational
Nov 10, 2025 Grace Periods and Reclaiming State After a Server Restart A server that keeps open state loses it on reboot, while its clients still believe they hold locks and delegations. The grace period is the interval in which only reclaims are accepted, and its length is a bet on how fast clients notice. filesystems · advanced
Nov 10, 2025 Queue Time, Service Time, and What a Timeout Measures A client-side timeout covers every wait in the path, including queues the client never sees, and that decomposition explains why a server can look fast while its callers time out. backend systems · foundational
Nov 10, 2025 Relocation Arithmetic: Patching Machine Code at Link Time The formulas behind absolute, PC-relative, and GOT-relative relocations, the range limits that make them fail, and why the addend must be stored separately on some architectures. compilers · foundational
Nov 10, 2025 The Post Correspondence Problem as a Reduction Source How a set of domino pairs encodes a computation through matched strings, why no algorithm can decide whether a match exists, and why this formulation is the convenient origin for other undecidability proofs. computation theory · advanced
Nov 10, 2025 Write-Ahead Logging and the Commit Record How a log turns many scattered writes into one ordered append, what makes a commit record valid, and why replay must be idempotent to survive a crash during recovery. memory systems · intermediate
Nov 7, 2025 Sizing Regional Capacity for the Loss of a Region Why N+1 regional capacity is larger than the arithmetic suggests, how queueing turns the last few percent of utilization into latency, and where failover load comes from. cloud infrastructure · advanced
Nov 7, 2025 The Durable Outbox: Committing Locally Before the Network Agrees How an app records an intended write on disk, drains it in order, and survives process death, so that a user action is never lost to a failed request. mobile computing · intermediate
Nov 6, 2025 Choosing a Workload Whose Profile Describes Real Traffic A profile is a property of the run as much as of the program; input distribution, cache state, concurrency, and clock behaviour all decide whether the result transfers. performance engineering · advanced
Nov 6, 2025 Clock Domain Crossing: Synchronizers, Handshakes, and Asynchronous FIFOs Why a signal crossing between unrelated clocks cannot be checked by static timing, and the three structures that carry data across a boundary safely. hardware engineering · advanced
Nov 6, 2025 MFM Encoding and the Fixed Geometry of a Floppy Sector Why magnetic media store clock bits alongside data, how a sector is framed by address marks and gaps, and how FAT12 packs a cluster chain into twelve-bit entries. computing history · intermediate
Nov 6, 2025 Monotone Circuits and the Approximation Method Why negations make lower bounds hard, how Razborov and Alon-Boppana proved exponential monotone size for clique, and what the method cannot say about matching. computation theory · intermediate
Nov 6, 2025 Ownership Across the FFI Boundary and Who Frees What Two runtimes with two allocators meet at a foreign function call, and every pointer that crosses must have an unambiguous owner, layout, and deallocation routine. systems programming · advanced
Nov 6, 2025 Reserved Versus On-Demand Capacity: The Break-Even Utilization Comparing a discounted commitment against pay-per-use pricing when demand has a diurnal shape, including the utilization at which the commitment stops saving money. inference systems · intermediate
Nov 6, 2025 Safety and Idempotence in HTTP Method Semantics What each method promises about side effects, how caches and retrying intermediaries use those promises, and where real endpoints quietly break them. backend systems · foundational
Nov 5, 2025 Front Coding the Term Dictionary How sharing prefixes between adjacent sorted terms compresses the dictionary, what block size has to do with random access, and where the savings actually come from. information retrieval · intermediate
Nov 5, 2025 Inside the VMCS: What Hardware Virtualization Actually Saves and Restores The control structure that replaced ring deprivileging, which fields decide whether a guest instruction exits, and why the exit path costs more than the instruction it intercepts. virtualization · intermediate
Nov 5, 2025 SPDX License Expressions and Machine-Readable Provenance How a single identifier grammar replaced prose license statements, what the operators and version suffixes encode, and why the declared license of a package and the licenses of its files routinely disagree. computing history · intermediate
Nov 4, 2025 Class Imbalance, Class Priors, and Cost-Sensitive Thresholds Why resampling and thresholding both leave the fitted probabilities unchanged or wrong, how a prior shift translates into an intercept adjustment, and where the expected-cost optimum sits. machine learning · intermediate
Nov 4, 2025 Fencing Tokens and the Arithmetic of Lease Expiry Why a promoted primary must wait out the old primary lease before accepting writes, how fencing tokens stop a stalled writer, and where the wait comes from. cloud infrastructure · advanced
Nov 4, 2025 Incremental Static Analysis: Dirty Sets and Cache Invalidation What can be reused when one file changes, how cache keys must cover dependencies and configuration, and why under-approximated invalidation produces confident wrong answers. developer tools · advanced
Nov 4, 2025 Selecting a Decision Threshold from the Confusion Matrix Why a classifier produces a score rather than a label, how the threshold trades false positives against false negatives, and what determines where it belongs. machine learning · foundational
Nov 4, 2025 Walking a Multi-Level Page Table How four levels of tables turn a 36-bit page number into a frame, what each level costs in memory and cache misses, and why the walk is not free even when it succeeds. memory systems · foundational
Nov 3, 2025 Link MTU, Jumbo Frames, and Where the Path Breaks Why 1500 bytes became the standard payload, what changes when both ends agree on more, and how MTU mismatches appear as silent large-packet loss. networking · advanced
Nov 3, 2025 RTT Fairness: Why Shorter Paths Win and How Algorithms Compensate Two flows on the same bottleneck with different round trips do not get equal shares, and the bias is a direct consequence of the control law. The fixes trade that bias against stability. networking · advanced
Nov 2, 2025 Geometric Growth, Copy Cost, and Peak Footprint Why dynamic arrays grow by a constant factor, where the amortised argument breaks down, and how the transient copy raises a program peak memory. performance engineering · intermediate
Nov 2, 2025 The Natural Proofs Barrier and Why Circuit Lower Bounds Stall What makes a lower-bound argument natural, why such arguments cannot separate P from NP unless factoring is easy, and which techniques escape the barrier. computation theory · advanced
Nov 1, 2025 Averaging Ratios and the Geometric Mean in Composite Scores Why the arithmetic mean of normalised ratios depends on the reference machine, when the geometric mean is the right summary, and where the harmonic mean is forced by the arithmetic of rates. performance engineering · advanced
October
Oct 31, 2025 Enrichment Order and Redaction in Flight Why the sequence of attribute processors changes the output, how a redaction rule can be undone by a later lookup, and where enrichment belongs in a pipeline. observability · intermediate
Oct 31, 2025 The ST 2084 Perceptual Quantizer: How an Absolute Luminance Curve Encodes 10,000 nits Why PQ is defined in absolute nits instead of relative intensity, the Barten-model design behind its 10,000-nit ceiling, and what 12-bit code values buy. computer graphics · advanced
Oct 30, 2025 Combinational Hazards and Why Consensus Terms Eliminate Glitches How unequal path delays produce output pulses in a logically correct circuit, how static and dynamic hazards differ, and when adding redundant logic is the fix. hardware engineering · intermediate
Oct 30, 2025 Floyd-Warshall, Johnson Reweighting, and the All-Pairs Choice Two all-pairs methods with opposite preconditions: one tolerates negative edges through a triple loop, the other restores nonnegativity by changing the weights and then runs Dijkstra from every vertex. algorithms · intermediate
Oct 30, 2025 Inlining Decisions and the Cost Model Behind Them Inlining is chosen by a profitability estimate over caller and callee size, call frequency, and constant-argument opportunities, and every model trades code size against a set of downstream optimizations. compilers · intermediate
Oct 30, 2025 Leakage Power and the Electrothermal Feedback Loop Why subthreshold and gate leakage rise exponentially with temperature, how that turns the power budget into a positive feedback loop, and where the loop stabilises or runs away. hardware engineering · advanced
Oct 30, 2025 Why VPC Peering Is Not Transitive and What a Transit Gateway Adds How a peering connection is a pairwise route exchange rather than a shared fabric, why a hub VPC cannot relay between its peers, and what a transit gateway changes about the routing model. cloud infrastructure · advanced
Oct 29, 2025 Distributing Tests Across Workers Without Losing Determinism Why the tail of a suite dominates the makespan, how the unit of distribution constrains fixture sharing, and which sources of non-determinism only appear once tests run concurrently. developer tools · intermediate

2025

October