Software engineering, system design, and development practicehttps://quietin.dev/https://quietin.dev/posts/investigating-a-slow-internet-connection/https://quietin.dev/posts/investigating-a-slow-internet-connection/A real-world troubleshooting narrative that narrows intermittent network slowness across proxies, DNS, routing, and Wi-Fi.Wed, 14 Aug 2019 00:00:00 GMThttps://quietin.dev/posts/linux-process-and-thread-concepts/https://quietin.dev/posts/linux-process-and-thread-concepts/A conceptual map of Linux processes, threading models, LWPs, kernel and user-space threads, coroutines, and fibers.Sat, 04 May 2019 00:00:00 GMThttps://quietin.dev/posts/distributed-systems-theory-and-practice/https://quietin.dev/posts/distributed-systems-theory-and-practice/A connected introduction to FLP, CAP, BASE, ACID, distributed transactions, and distributed locks through practical scenarios.Sat, 09 Mar 2019 00:00:00 GMThttps://quietin.dev/posts/immutablemap-does-not-allow-null/https://quietin.dev/posts/immutablemap-does-not-allow-null/An explanation of Guava ImmutableMap's null restrictions and the tradeoffs of alternative immutable map wrappers.Sat, 29 Sep 2018 00:00:00 GMThttps://quietin.dev/posts/io-memory-and-file-systems-part-2/https://quietin.dev/posts/io-memory-and-file-systems-part-2/A systems-level survey of tmpfs, large-file access, memory mapping, Java RandomAccessFile, and huge pages.Thu, 09 Aug 2018 00:00:00 GMThttps://quietin.dev/posts/io-memory-and-file-systems/https://quietin.dev/posts/io-memory-and-file-systems/Notes on the Linux I/O stack, raw devices, journaling, buffering, Direct I/O, and Concurrent I/O.Thu, 02 Aug 2018 00:00:00 GMThttps://quietin.dev/posts/understanding-hashcode-in-java/https://quietin.dev/posts/understanding-hashcode-in-java/Notes on Java hashCode, its relationship with equals, and how collections use hash values.Sat, 21 Apr 2018 00:00:00 GMThttps://quietin.dev/posts/java-syntax-and-runtime-error-notes/https://quietin.dev/posts/java-syntax-and-runtime-error-notes/A diagnostic guide to Java enum switch labels, constant-expression requirements, and comparator contract violations.Fri, 23 Feb 2018 00:00:00 GMThttps://quietin.dev/posts/intellij-idea-notes/https://quietin.dev/posts/intellij-idea-notes/An IntelliJ IDEA troubleshooting reference for indexing, Maven variables, Lombok, framework support, imports, and serialVersionUID.Thu, 16 Feb 2017 00:00:00 GMThttps://quietin.dev/posts/thoughts-on-writing-a-technical-blog/https://quietin.dev/posts/thoughts-on-writing-a-technical-blog/Personal reflections on originality, rigor, professionalism, and expressing uncertainty when publishing technical writing.Sun, 15 Jan 2017 00:00:00 GMThttps://quietin.dev/posts/forwarding-traffic-with-iptables/https://quietin.dev/posts/forwarding-traffic-with-iptables/A practical iptables setup for relaying TCP connections through an intermediate server with DNAT and SNAT rules.Sun, 25 Dec 2016 00:00:00 GMThttps://quietin.dev/posts/maven-notes/https://quietin.dev/posts/maven-notes/A Maven reference for coordinates, settings files, profile precedence, repository selection, and Aliyun mirror configuration.Mon, 17 Oct 2016 00:00:00 GMThttps://quietin.dev/posts/arraylist-and-hashmap-thread-safety/https://quietin.dev/posts/arraylist-and-hashmap-thread-safety/Reproducible Java examples that expose ArrayList and HashMap failures when multiple threads modify them concurrently.Tue, 06 Sep 2016 00:00:00 GMThttps://quietin.dev/posts/java-notes/https://quietin.dev/posts/java-notes/A Java language notebook covering static initialization, inner classes, enums, object construction, and related runtime behavior.Tue, 06 Sep 2016 00:00:00 GMThttps://quietin.dev/posts/interpreter-wide-objects-in-python/https://quietin.dev/posts/interpreter-wide-objects-in-python/Several patterns for sharing mutable state across Python modules, illustrated by Tornado options and the standard logging module.Fri, 29 Jul 2016 00:00:00 GMThttps://quietin.dev/posts/configuring-a-new-cloud-server/https://quietin.dev/posts/configuring-a-new-cloud-server/A baseline Ubuntu server-hardening checklist covering SSH changes, root-login restrictions, sudo access, and essential security settings.Sun, 10 Jul 2016 00:00:00 GMThttps://quietin.dev/posts/automatically-import-modules-when-ipython-starts/https://quietin.dev/posts/automatically-import-modules-when-ipython-starts/A simple IPython startup-script setup that makes frequently used modules available in every interactive session.Sun, 12 Jun 2016 00:00:00 GMThttps://quietin.dev/posts/mocking-tornado-asynchronous-code-and-writing-decorators/https://quietin.dev/posts/mocking-tornado-asynchronous-code-and-writing-decorators/Testing patterns for mocking Tornado HTTP futures and safely applying decorators to coroutine-based request handlers.Sun, 05 Jun 2016 00:00:00 GMThttps://quietin.dev/posts/daemons-orphans-zombies-and-waitpid/https://quietin.dev/posts/daemons-orphans-zombies-and-waitpid/An overview of Unix daemon, orphan, and zombie process lifecycles, plus child-process cleanup with wait and waitpid.Mon, 16 May 2016 00:00:00 GMThttps://quietin.dev/posts/network-and-system-commands-on-os-x/https://quietin.dev/posts/network-and-system-commands-on-os-x/A command reference for inspecting listening ports, network connections, and system calls on OS X with lsof, netstat, telnet, and dtruss.Thu, 10 Mar 2016 00:00:00 GMThttps://quietin.dev/posts/running-a-django-project-with-pypy/https://quietin.dev/posts/running-a-django-project-with-pypy/A migration account of running Django on PyPy, including dependency compatibility fixes and observed performance gains over CPython 2.7.Tue, 01 Mar 2016 00:00:00 GMThttps://quietin.dev/posts/notes-on-socket-programming/https://quietin.dev/posts/notes-on-socket-programming/Systems-level socket notes on EAGAIN, MTU and MSS, send and receive buffers, and the effects of Nagle's algorithm.Sun, 21 Feb 2016 00:00:00 GMThttps://quietin.dev/posts/python-tips-part-2/https://quietin.dev/posts/python-tips-part-2/A second collection of Python 2 techniques for strings, lists, mutable references, slicing, ellipses, and file operations.Thu, 21 Jan 2016 00:00:00 GMThttps://quietin.dev/posts/python-singletons-and-metaclasses/https://quietin.dev/posts/python-singletons-and-metaclasses/Notes on Python singleton implementations and how metaclasses control class creation.Sun, 10 Jan 2016 00:00:00 GMThttps://quietin.dev/posts/python-functions-and-classes/https://quietin.dev/posts/python-functions-and-classes/Experiments with Python functions and classes involving binding, equality, method lookup, callability, and name mangling.Thu, 07 Jan 2016 00:00:00 GMThttps://quietin.dev/posts/python-decorators-and-descriptors/https://quietin.dev/posts/python-decorators-and-descriptors/Implementation-focused notes on Python function and class decorators, descriptor protocols, and common usage patterns.Sun, 03 Jan 2016 00:00:00 GMThttps://quietin.dev/posts/notes-on-python-sockets/https://quietin.dev/posts/notes-on-python-sockets/Python socket notes covering connection identity, listen queues, SO_REUSEADDR, TCP framing, and related API behavior.Mon, 28 Dec 2015 00:00:00 GMThttps://quietin.dev/posts/automating-logins-with-expect/https://quietin.dev/posts/automating-logins-with-expect/An Expect script pattern that accepts command-line options or defaults to automate password-based interactive SSH logins.Sat, 26 Dec 2015 00:00:00 GMThttps://quietin.dev/posts/load-django-settings-for-the-current-git-branch/https://quietin.dev/posts/load-django-settings-for-the-current-git-branch/A GitPython-based approach for detecting the active branch and loading its matching Django settings automatically.Tue, 22 Dec 2015 00:00:00 GMThttps://quietin.dev/posts/logging-in-to-segmentfault-and-backing-up-articles-with-python-continued/https://quietin.dev/posts/logging-in-to-segmentfault-and-backing-up-articles-with-python-continued/A refined SegmentFault backup implementation that traces redirects and cookies to replace browser automation with requests.Session.Tue, 22 Dec 2015 00:00:00 GMThttps://quietin.dev/posts/handling-ctrl-c-with-python-multiprocessing-pool/https://quietin.dev/posts/handling-ctrl-c-with-python-multiprocessing-pool/Why Python 2 multiprocessing pools can ignore Ctrl+C, with working and non-working ways to stop worker processes.Sun, 20 Dec 2015 00:00:00 GMThttps://quietin.dev/posts/iterm2-configuration-and-feature-notes/https://quietin.dev/posts/iterm2-configuration-and-feature-notes/Configuration notes for iTerm2 word-wise navigation, text selection, autocomplete, clipboard history, and related shortcuts.Sat, 19 Dec 2015 00:00:00 GMThttps://quietin.dev/posts/logging-in-to-segmentfault-and-backing-up-articles-with-python/https://quietin.dev/posts/logging-in-to-segmentfault-and-backing-up-articles-with-python/An investigation of SegmentFault authentication followed by a Python article-backup tool using Selenium, PhantomJS, and Tornado.Fri, 18 Dec 2015 00:00:00 GMThttps://quietin.dev/posts/encoding-and-decoding-in-python-2/https://quietin.dev/posts/encoding-and-decoding-in-python-2/A Python 2 guide to source encodings, Unicode and UTF-8 conversion, encode and decode, and terminal behavior.Sun, 13 Dec 2015 00:00:00 GMThttps://quietin.dev/posts/linux-command-line-tips/https://quietin.dev/posts/linux-command-line-tips/A short Linux shell reference for locating commands, reloading Bash configuration, and writing here-documents.Thu, 10 Dec 2015 00:00:00 GMThttps://quietin.dev/posts/converting-recursion-to-iteration/https://quietin.dev/posts/converting-recursion-to-iteration/A step-by-step look at replacing recursion with accumulators or explicit stacks in several representative algorithms.Mon, 23 Nov 2015 00:00:00 GMThttps://quietin.dev/posts/handling-circular-foreign-keys-between-two-tables/https://quietin.dev/posts/handling-circular-foreign-keys-between-two-tables/Two database design and insertion strategies for tables whose primary keys also form circular foreign-key references.Thu, 19 Nov 2015 00:00:00 GMThttps://quietin.dev/posts/multiple-inheritance-in-python/https://quietin.dev/posts/multiple-inheritance-in-python/An exploration of Python multiple inheritance through MRO, C3 linearization, diamond hierarchies, and super calls.Thu, 19 Nov 2015 00:00:00 GMThttps://quietin.dev/posts/fix-gevent-installation-errors-on-os-x-10-11/https://quietin.dev/posts/fix-gevent-installation-errors-on-os-x-10-11/A fix for gevent installation failures on OS X 10.11 caused by the protected system Python and bundled six package.Sat, 14 Nov 2015 00:00:00 GMThttps://quietin.dev/posts/drawing-css-triangles-with-borders/https://quietin.dev/posts/drawing-css-triangles-with-borders/A visual walkthrough of using border geometry, color, and transparency to construct CSS triangles and flag shapes.Fri, 09 Oct 2015 00:00:00 GMThttps://quietin.dev/posts/comparing-tuples-in-python/https://quietin.dev/posts/comparing-tuples-in-python/An explanation of Python's lexicographic tuple comparison rules, including what happens when tuple lengths differ.Tue, 22 Sep 2015 00:00:00 GMThttps://quietin.dev/posts/understanding-is-in-python/https://quietin.dev/posts/understanding-is-in-python/A guide to Python object identity, the is operator, and the implementation details that can make immutable objects share identities.Tue, 22 Sep 2015 00:00:00 GMThttps://quietin.dev/posts/chmod-s-permission-bit/https://quietin.dev/posts/chmod-s-permission-bit/An explanation of the setuid and setgid permission bits, their numeric forms, and their effects on files and directories.Fri, 18 Sep 2015 00:00:00 GMThttps://quietin.dev/posts/using-a-chinese-pypi-mirror/https://quietin.dev/posts/using-a-chinese-pypi-mirror/Instructions for selecting and configuring a Chinese PyPI mirror in pip for temporary or persistent use.Thu, 10 Sep 2015 00:00:00 GMThttps://quietin.dev/posts/python-tips/https://quietin.dev/posts/python-tips/A set of practical Python examples covering default values, copying, date conversion, iterators, parity, and dictionaries.Tue, 08 Sep 2015 00:00:00 GMThttps://quietin.dev/posts/common-ubuntu-problems-and-operations/https://quietin.dev/posts/common-ubuntu-problems-and-operations/A troubleshooting notebook for Ubuntu issues involving NVIDIA drivers, missing GPG keys, and PPA management.Sun, 06 Sep 2015 00:00:00 GMThttps://quietin.dev/posts/installing-common-software-on-ubuntu/https://quietin.dev/posts/installing-common-software-on-ubuntu/Installation notes for GCC 5 and Fcitx on Ubuntu, including compiler symlinks and language-support configuration.Sat, 05 Sep 2015 00:00:00 GMThttps://quietin.dev/posts/implementing-common-algorithms/https://quietin.dev/posts/implementing-common-algorithms/Python implementations and study notes for common sorting, searching, linked-list, string, and combinatorial algorithms.Tue, 01 Sep 2015 00:00:00 GMThttps://quietin.dev/posts/basic-linux-commands-for-users-system-information-and-packages/https://quietin.dev/posts/basic-linux-commands-for-users-system-information-and-packages/A compact command reference for Linux users, permissions, system information, package management, and Vim.Wed, 12 Aug 2015 00:00:00 GMThttps://quietin.dev/posts/setting-up-an-android-development-environment/https://quietin.dev/posts/setting-up-an-android-development-environment/A setup walkthrough for Android Studio, SDK packages, VirtualBox, and Genymotion on Ubuntu 12.04.Sun, 09 Aug 2015 00:00:00 GMThttps://quietin.dev/posts/calculating-response-time-statistics-with-awk/https://quietin.dev/posts/calculating-response-time-statistics-with-awk/A one-pass shell and awk workflow for calculating minimum, maximum, and average response times across Nginx logs.Wed, 05 Aug 2015 00:00:00 GMThttps://quietin.dev/posts/join-two-files-line-by-line-with-awk/https://quietin.dev/posts/join-two-files-line-by-line-with-awk/An awk associative-array technique for matching the first field and joining corresponding records from two files.Wed, 05 Aug 2015 00:00:00 GMThttps://quietin.dev/posts/css-layout-references/https://quietin.dev/posts/css-layout-references/A CSS layout reference covering centering, line height, vertical alignment, border behavior, and proportional sizing.Thu, 23 Jul 2015 00:00:00 GMThttps://quietin.dev/posts/useful-javascript-patterns/https://quietin.dev/posts/useful-javascript-patterns/Reusable JavaScript snippets for random integers, page-exit warnings, and prototype- versus closure-based objects.Sat, 11 Jul 2015 00:00:00 GMThttps://quietin.dev/posts/javascript-tutorials-worth-revisiting/https://quietin.dev/posts/javascript-tutorials-worth-revisiting/A compact reading list for revisiting JavaScript internals, inheritance, prototypes, and advanced jQuery animation.Thu, 25 Jun 2015 00:00:00 GMThttps://quietin.dev/posts/css-notes-and-tips/https://quietin.dev/posts/css-notes-and-tips/Notes on floats, BFCs, table-cell layouts, vertical alignment, and hover borders in CSS.Tue, 23 Jun 2015 00:00:00 GMThttps://quietin.dev/posts/fix-missing-hdmi-audio-on-ubuntu/https://quietin.dev/posts/fix-missing-hdmi-audio-on-ubuntu/Steps for restoring Ubuntu audio by switching output from HDMI to the computer's analog sound device.Fri, 19 Jun 2015 00:00:00 GMThttps://quietin.dev/posts/classic-interview-problems/https://quietin.dev/posts/classic-interview-problems/Solutions to two classic interview exercises: transforming random-number ranges and applying Newton's method.Thu, 18 Jun 2015 00:00:00 GMThttps://quietin.dev/posts/mysql-notes-and-tips/https://quietin.dev/posts/mysql-notes-and-tips/A collection of MySQL commands for table sizes, queries, schema export, and data import/export.Wed, 03 Jun 2015 00:00:00 GMThttps://quietin.dev/posts/common-front-end-animation-and-interaction-patterns/https://quietin.dev/posts/common-front-end-animation-and-interaction-patterns/Practical patterns for image lazy loading, event debouncing and throttling, and delayed hover interactions.Sat, 16 May 2015 00:00:00 GMThttps://quietin.dev/posts/python-references-and-notes/https://quietin.dev/posts/python-references-and-notes/An evolving reading list of useful Python articles, language notes, and implementation examples.Mon, 11 May 2015 00:00:00 GMThttps://quietin.dev/posts/useful-linux-commands/https://quietin.dev/posts/useful-linux-commands/A collection of Linux commands for files, processes, text search, IPC, and remote work.Wed, 29 Apr 2015 00:00:00 GMThttps://quietin.dev/posts/getting-started-with-android-development/https://quietin.dev/posts/getting-started-with-android-development/A concise guide to configuring Genymotion or Intel HAXM emulators and launching Android apps from Android Studio.Mon, 27 Apr 2015 00:00:00 GMThttps://quietin.dev/posts/redis-startup-script/https://quietin.dev/posts/redis-startup-script/A ready-to-adapt SysV init script for starting, stopping, restarting, and checking a Redis server.Sat, 25 Apr 2015 00:00:00 GMThttps://quietin.dev/posts/slow-networking-after-an-ubuntu-kernel-upgrade/https://quietin.dev/posts/slow-networking-after-an-ubuntu-kernel-upgrade/A troubleshooting account of tracing severe network instability after an Ubuntu kernel upgrade to the r8169 driver.Fri, 24 Apr 2015 00:00:00 GMThttps://quietin.dev/posts/django-resources/https://quietin.dev/posts/django-resources/A curated, evolving index of Django resources covering requests, responses, templates, and comparisons with Rails.Mon, 20 Apr 2015 00:00:00 GMThttps://quietin.dev/posts/fast-ways-to-empty-a-file-on-linux/https://quietin.dev/posts/fast-ways-to-empty-a-file-on-linux/A quick reference to shell redirection and utilities that clear file contents without removing the file itself.Wed, 15 Apr 2015 00:00:00 GMT