A RSS feed, to grok all of it on grokit.
_ KiyoC__ v0.1.0 Released__I_ve started a new project_ a C__ 2D game engine.__I_ve reached a small milestone where you can use the Tiled level editor to place things around_ and can play through a complete level. The game compiles to Windows_ Linux and Web _HTML_WASM_. Here is what that demo level looks like.____first level__._2023-07-18_demo-level-v0p1p0.export.gif___You can play this level…
_ Paper Reading Notes_ Spark_ Cluster Computing With Working Sets____ Overview__This paper introduces Spark as a framework to run large-scale_ data-intensive workloads on commodity hardware. It is especially useful for workflows that are currently difficult to implement or expensive to run on Hadoop MapReduce _ref_H_MAPREDUCE_.__MapReduce _ref_MapReduce_ is not well suited for iterative jobs and…
_ Apache Hadoop Explained_ Kafka_ ZooKeeper_ HDFS and Cassandra.__Apache Hadoop is a suite of open-source components which serve as the building blocks of large distributed systems.__An obvious question to ask is _why Hadoop___ why not just slap a load-balancer over a few NGINX frontends and a few beefy MySQL servers_ The simplest answer is _gradual scaling__ Hadoop components are designed to…
__ CSharp C__ LinkedHashMap _ LRU Cache__dext.insertCode__LinkedHashMap.cs_____ CSharp C__ SortedMultiset__CSharp does not have a SortedMultiSet_T_ out of the box. _This _should_ work_ but it_s not extensively battle-tested and could have edge cases.__dext.insertCode__SortedMultiSet.cs____If you do not care __at all__ about performance _you just want to have something that will respect the…
_ Barbara Oakley_ Learning How to Learn__ As of now_ mostly notes from this video____iframe width__560_ height__315_ src__https___www.youtube.com_embed_vd2dtkMINIw_ frameborder__0_ allowfullscreen___iframe___Barbara will teach a class on that topic on coursera _https___www.coursera.org_learn_learning-how-to-learn_ beginning in November.____ Two Modes of Thinking_ Focused and Diffused__They…
_ Web Snippet_ Stanford Health Psychologist Kelly McGonigal Talks About Meditation_ Stress and Willpower.__This is a write down of the content of _this video__https___www.youtube.com_watch_v_z8igbSGUMfc_.__ _iframe width__560_ height__315_ src__https___www.youtube.com_embed_z8igbSGUMfc_ frameborder__0_ allowfullscreen___iframe_____ How to Identify Which Research is Valid__- Sufficient research…
_ Paper Reading Notes_ Column-Stores vs. Row-Stores_ How Different Are They Really___Link to paper_ _ACM website for citations__http___dl.acm.org_citation.cfm_id_1376712__ _full pdf__http___db.csail.mit.edu_projects_cstore_abadi-sigmod08.pdf_.____ Overview__SQL databases are typically row-oriented. These row-stores _RS_ are well suited for applications such as _customer relationship management__…
__ YouTube Lecture Notes_ Multi-Clouds and Consensus__Those are my notes from watching the following video_ _Google I_O 2009 - Transactions Across Datacenters_.__URL_ _https___www.youtube.com_watch_v_srOgpXECblk__https___www.youtube.com_watch_v_srOgpXECblk___Those notes are not curated_ with lots of open questions. Take it for what it is.___ Different Kind of Consistencies____ None__You can just…
_ _Paper Reading Notes_ Consistent Hashing and Random Trees_ Distributed Caching Protocols for Relieving Hot Spots on the World Wide Web__This is the famous paper by David K. et al. which introduces two distributed computing concepts_ __distributed hashing__ and __random trees__.____Link to paper___ _ACM website for citations__http___dl.acm.org_citation.cfm_id_258660__ _full…
__ anim.js to Create Simple Interactive Canvas Elements__This is a simple demo on how to do animations using HTML5 canvas. You can just steal the bare-bone anim.sj which will take care to animate everything as long as you provide the following three JavaScript functions___ createWorldObjects_world__ drawLogic_world__ updateLogic_world___If you look in atom.js __you can check all the most up to…
__ Epidemic Algorithms for Replicated Database Maintenance__The paper presents a way to efficiently maintain consistency for data replicated across many sites. It is the earliest known _gossip_ algorithm paper.__The problem to solve is_ given a system with N nodes_ how do you make a change at a single node propagate to all other nodes___An obvious answer is to simply broadcast from the changed…
__ Notation for Software Engineering and CS__CS and Math have a rich and well defined syntax to express the difference between different primitives _e.g_ literal_ set_ list_ ..._. However_ since ideas and documentation often needs to be done in plain-text_ there is no official__This article attempts to achieve the following goals___1. All-in one place definition and explanation of the notation for…
__ Paper Reading Notes_ Scaling Memcache At Facebook__Facebook uses memcache as a key-value cache in between frontend instances and MySQL databases. It is optimized for read-heavy scenarios where direct SQL databases use would be prohibitive. Memcache in itself _the original open-source project_ is an in-memory_ single computer_ key-value cache_ this paper explains how Facebook scaled this out to…
__ Paper Reading Notes_ Dynamo_ Amazon_s Highly Available Key-value Store__Dynamo is a key-value NoSQL database service that is designed for high availability and elastic scalability at the cost of lenient consistency. It offers an alternative to relational databases who are constrained by their requirement to support ACID properties which do not scale well horizontally.__The paper goes over a…
__ Fractals __I wrote a small Javascript runner in the browser where you can play with the formula. You can save your fractal as a URL and share with friends. Of course_ I provided a Mandelbrot set as the default fractal.___Click here to get started__http___www.grokit.ca_s_fractals__.____http___www.grokit.ca_spc_fractals___._Fractals_Example00.png___As always_ this is all open-source including the…
__ DNS in a Nutshell__The DNS _Domain Name System_ is used to translate a domain name _e.g_ www.grokit.ca_ into an IP address _e.g_ 74.125.20.121_. This is a necessary since data is routed on the Internet using IP addresses_ not domain names.__Even though you type a human-readable domain name in your browser_ it cannot be directly used to convey data on the Internet _IP addresses are used for that…
__ Speed Of Computing__Goal_ accumulate all reference material to answers questions such as_ _You are running a web service that does X_ how many servers do you need__.____ Example Question__You run a web service where 1000 users upload a 700 kB picture every second _assume that nothing else happen on this system_. How many frontend and backend machines do you need______ Tentative Answer__The…
__ Https Share__This script allows you to securely share files over HTTPS. _You can get the _full source on GitHub__https___github.com_nothing1212_https_share__.__You simply start the script using the following___ python3 https_share.py -a magic-access-token_fj9efd3c -p 4443__Now_ you need the magic token in order to access the files. If you access the https URL without setting the magic token…
__ Computationally Feasible__Given problem x_ _can you compute the answer__ Is it feasible to brute-force the answer___This is easy to answer experimentally. If I define computable as something that I can run on my laptop in under 1 minutes with a slow language _Python____ --------------------_ Loop 2_24 in 1.30s_ Loop 2_25 in 2.60s_ Loop 2_26 in 5.21s_ Loop 2_27 in 10.54s_ Loop 2_28 in 20.83s_…
_ TCP _ HTTP Listening On Ports_ How Can the Server Handle Multiple Connections on the Same Port__So_ what happens when a server listen for incoming connections on a TCP port_ For example_ let_s say you have a web-server on port 80. Let_s assume that your computer has the public IP address of 24.14.181.229 and the person that tries to connect to you has IP address 10.1.2.3. This person can connect…
_ Should You Drink Coffee_ The Academic Answer__Coffee is a drug I enjoy consuming_ and I want to know what science has to say on its effect of my health. __For example_ The Atlantic recently published __The Case for Drinking as Much Coffee as You Like__http___www.theatlantic.com_health_archive_2012_11_the-case-for-drinking-as-much-coffee-as-you-like_265693____ an article that presents coffee as a…
__ HTTPS And Certificates Tools__This is not really an article but a dump of different tools and commands that are useful when dealing with HTTPS and certificates.___ OpenSSL Commands____ Generate Certificate____openssl genrsa 2048 _ private_key.pem___openssl req -x509 -new -key private_key.pem -out public_cert.pem___openssl pkcs12 -export -in public_cert.pem -inkey private_key.pem -out…
__ C__ Linker Errors Debugging__C__ compilers generally do not produce very helpful error messages _it is part of the training of a C__ code to learn to _interpret_ the error messages -- one needs to understand that the error message is a _symptom_ that can lead to the error and rarely the error itself_ except in the most trivial cases_. C__ linkers are worse.__I had the really funny error today…
__ Implementation of the Distance Transform on OpenCL _CUDA_ GPU___I am currently working in biomedical engineering_ and it is fairly common to have to use the distance transform. The distance transform _DT_ is very CPU intensive and very easily parallelizable_ so I decided to take at shot at implementing it on GPU _since it is the trendy thing to do these days_.__The OpenCL file for the DT in…
__ Common Problems With CMake and Associated Solutions____ Unknown extension _.c_ for file__Sometimes CMake will refuse to compile files that one would think it would automatically know what to do with _e.g. C files____ CMake Error at cmake-2.8_Modules_CheckSymbolExists.cmake_63 _TRY_COMPILE___ Unknown extension _.c_ for file__…
__ Groks Science Show 2011-01-19_ Behavioral Happiness__Interview with Shawn Author _author of _The Happiness Advantage__. _Link to podcast page__http___grokscience.wordpress.com_2011_01_19_behavioral-happiness__. He is a researcher on positive psychology_ talking about work he did at Harvard and various blue chip U.S corporation _Adobe_ Morgan Stanley_ Google_.__The main point he is trying to…
__ Get Full Access Right to A Folder Using Cygwin Under Windows 7__It can be pretty hard to get full access rights to a directory and all its contents recursively when using cygwin under windows 7. In theory a simple _chmod 777 -R _c__path_to_target_folder_ should do the trick_ but it just isn_t so. Here is the most _bulletproof_ way I found to make sure I get proper ownership of a folder___…
____ Preface__This page is my reading notes that I took while reading the book. It is in a chapter-by-chapter reading notes format that attempts to capture the information outlined in the book in a concise format. However_ since I write the reviews out of memory_ there will be discrepancies with the book.____GTD_Pic__._GTD_BookOnDeskWithPapers.jpg____ Getting Things Done_ Chapter-by-Chapter…
QtNetworkMonitor___________________A free_ open source_ portable network monitor.__This is the home page for the Qt Network Monitor project. It is built in C__ and uses the underlying library libpcap _ WinPcap to gather information about the network traffic. The GUI is built in QT and faily independent from the implementation of the device listener. You need to install WinPcap _download here_…
__ Weight Watch_ Monitor Your Weight Efficiently____ News_ 2011-01-03_ New Version _1.3___The old version used either _the excellent_ matplotlib. Unfortunately_ it does not work with python 3. So I ported the graphics generation to _google chart API__http___code.google.com_apis_chart__. The drawback is that you need an internet connexion in order to generate the graphics and that I am now…
__ Krowten Emagyp__This is a small game that I developed along with 2 other students as a class project_ back in my college days. It is a small Mario-clone platformer game engine demo with interesting physics and that supports online multiplayer. It is full of bugs_ the code is awful _our first contact with the Python programming language_ but the end result is quite fun. Built with Python _…
__ Memories of Very Old Projects _1995-1998 Perhaps__ _ _I was digging through old archives and I found some old projects coded in Visual Basic. I had zero training or understanding of how coding worked_ but by playing around with it was able to brute-force my way to something that worked _I remember thinking _it would be great if I could reuse the same chunks of code around_ -- I would later…
__ Crypto Crumbs__dext.insertCode__crumbs.data___dext.insertCode__signatures_00.data____...