Computers Miscellany

A miscellany of items pertaining to computers.

Mediums

• types, extensions, and apps.
• audio, video, picture formats.
• asx is wm playlist?
• foobar2000
  • Playlists: .fpl .m3u8 .m3u .pls
  • Uncompressed formats: wav aiff aif iff svx snd au voc
  • cue
  • ogg
  • musepack: .mpc .mp+ .mpp
  • mpeg-1 audio: .mp3 .mp2
  • mpeg-4 audio: mp4 m4a aac
  • flac: .flac .fla
  • monkey's audio: .ape .mac
  • wavepack: .wv
  • speex: .spx
  • modules: .xm .it .s3m .mod .mtm .umx
  • compressed modules: .mdz .s3z .itz .xmz .mo3
  • audio cd: .cda, audio cd

Major Models

• Create, Read, Update, Delete (CRUD). The four basic functions of persistent storage.
  • Corresponds roughly to the standard SQL statements: Insert, Select, Update, Delete (ISUD).
  • Using 3-letter words: Add, Get, Set, Cut (AGSC). I also like "Not" for toggling membership in a collection.
  • Corresponds to some HTTP request methods (verbs): POST, GET (List collection, Retrieve item), PUT (replace, update, and sometimes create), DELETE (PGPD).
• Confidentiality, Integrity, Availability (CIA). Some folks make think it should be Confidentiality, Integrity, Availability, Accountability (CIAA). CIAA is the foundation of information security.
• Atomicity, Consistency, Isolation, Durability (ACID). ACID are properties that help ensure that database transactions are processed reliably. Relational databases (EG MySQL, MS SQL, PostgreSQL) are very good at ACID, while non-relational databases (aka NoSQL DBs. EG: BigTable by Google, Dynamo by Amazon, Cassandra by Apache) often sacrifice some ACID (especially consistency) for speed and volume.
• Extract, Transform, and Load (ETL). Data is typically Extracted from some source, then Transformed (cleaned; scrubbed) into something more useable, and then Loaded into its destination environment.
• Representational state transfer (REST). In the client-server model the resources at either the client or the server are said to have or make representations of resources. The resources may be in different states (EG: Processing, Waiting, Sleeping). The state of representations are transferred around so things happen as needed.
• Client Server. Clients make requests to servers; Servers process requests and make appropriate responses to the client.
• The usual 3-tier scenario:
  • Presentation tier: user interface. EG: Client-side Javascript.
  • Application tier: business logic. EG: If the X value changes, then set Y value.
  • Database tier: persistence. EG: CRUD the database.
  In a 2-tier scenario (usually client-server) the application tier is generally absorbed into one of the other tiers. In a 4-tier scenario there might be an integration/middle tier; EG: Instead of getting data directly from the database, call the generateProductTree() method to generate data in a particular format.
• Model-View-Controller (MVC). A software architecture that has the Model (data; relational rules) connected to the View (presentation; widgets) via the Controller (process user events from View; interact with Model).
• Open System Interconnection Reference Model (OSI Reference Model or OSI Model). The OSI Model is an abstract description of computer communications, especially across networks. The OSI Model divides responsibilities into seven ordered layers: Application, Presentation/Syntax, Session, Transport, Network, Data Link, and Physical. Each layer can interact indirectly with a layer immediately next to it but a layer on one host also interacts with a peer layer on another host. Only the physical layer can communicate directly between computers. See also my article on OSI.

Directory Trees

• Each directory object has an object list associated with it.
  • Selecting the icon or name of a file object shows its file content in the RHS pane.
  • Clicking the +/- icon of a directory object expands/collapses its object list in the LHS pane.
  • Selecting the regular icon of a directory object shows its object list in the RHS pane.
  • Selecting the name of a directory object shows its object list in the RHS pane. Note in some newer trees this also expands/collapses its object list in the LHS pane.
• Each directory object has an object list associated with it, as well as a file page.
  • Selecting the icon or name of a file object shows its file content in the RHS pane.
  • Clicking the +/- icon of a directory object expands/collapses its object list in the LHS pane.
  • Selecting the regular icon of a directory object shows its file content in the RHS pane. Note in some newer trees this also expands/collapses its object list in the LHS pane.
  • Selecting the name of a directory object shows its file content in the RHS pane. Note in some newer trees this also expands/collapses its object list in the LHS pane.

Programming

• Threading
  • http://en.wikipedia.org/wiki/Thread_%28computer_science%29
  • http://en.wikipedia.org/wiki/Threaded_code
• Class based (classes and instances/objects. EG: Java, C++) vs. Proto-type based (EG: JS).
• State. EG: stack, RPN, LIFO. EG: Sessions: ASP sessions vs cookies vs XML.
• When coding, put in your delimiters first then fill in. It will help you not forget the closing delimiter.
• Programming. General areas
  • Data Types, including choosing, including .net and xml data types
  • Error Checking
  • Functions
  • Time/Date
  • String
• Buy vs Build: Off-the-shelf/3rd party vs in-house development.
• App Verbs from IIS: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE

Top tips for new computer users

• Save often.
• Complete transactions. That is: Start a process and confirm its completion.
• Have anti-virus software.
• Close things that you aren't using now or very soon. Close applications, windows, tabs, etc.
• Do not have public computers save your user name and password.
• If there's a task you do often, there's a fair chance that there's a shortcut way to do it. See also my page on Microsoft Shortcuts. The most common shortcuts include:
  • Ctrl+C for Copy
  • Ctrl+X for Cut
  • Ctrl+V for Paste
  • Ctrl+Z for Undo
  • Ctrl+A for Select All
  • Ctrl+S for Save
  • Ctrl+F for Find. F3 is frequently "Find Again".
• Be wary of attachments. Only take simple things like images or text documents.
• More RAM.

Text Editors

Most computers should have an operating, a browser, and an office suite (although that can be done via the browser too). If you're a programmer, then you'll also want a more powerful text editor than the one that usually comes with the operating system. Programmer typically also use an Integrated Development Environment (IDEs) and a hex editor, but why go without a powerful text editor?

• The Editor War
  • vi and variants. Free gratis. Free libre. Cross-platform. See also vi commands.
  • emacs and variants. Free gratis. Free libre. Cross-platform.
• Notepad++ [notepad-plus-plus.org]. Free gratis. Free libre. Windows.
• TextMate [macromates.com]. Free gratis. Free libre. MacOS X.
• UltraEdit [ultraedit.com]. Not free gratis. Not free libre. Cross-platform.
• Eclipse [eclipse.org]. More an IDE than a text editor. Free gratis. Free libre. Cross-platform.

Off site links related to text editors.

• Wikipedia:
  • Text editor
  • Comparison of text editors
  • List of text editors
  • Editor war
• texteditors.info
• "Best Text Editors" [http://lifehacker.com/385929/best-text-editors]

Miscellany

• An often overlooked feature in browsers is the Find feature. It is especially good if you are looking for something specific on any given page.
• Most macro viruses can be avoided with the following steps. If you're opening an external Microsoft Office document, make sure you have the application's macro virus protection option turned on. This option is usually set by choosing the Tools menu, Options selection, and then General tab.
• More frequently than not, it is quicker to retype something, than it would be to copy and paste it.
• Watch out for viruses hidden with a ".shs" extension. The extension is hidden from view, even if not chosen to hide extensions of known file types.
• 5 steps of privacy policies: Notice. Choice. Access. Security. Enforcement.
• Since American Express cards start with the digit 3, Visa with 4, MasterCard with 5, and Discover with 6, those numbers are often used to identify or validate the numbers. Cash is usually identified with the number 1 and checks with the number 2.
• Ergonomics for working with a desktop computer:
  • Keep monitor away from windows or perpendicular to windows to reduce glare.
  • Line the top of the monitor screen with your eyes to reduce neck strain. This causes less stress on the neck muscles.
  • Keep your feet are flat on the floor or on a foot rest.
  • Your knees should be bent no more than 90 degrees.
  • There should be enough clearance under the workstation to move your legs around freely and without hindrance.
  • Your arms should be vertical at your sides. You should not have to hold your arms up at the shoulders. 
  • Your elbows should be at comfortable 90 degree angle.
• Some cross platform approximations

  Some Cross Platform Approximations
  PC	Mac
  Ctrl+z	Cmd+Opt+Esc or Cmd+.
  Opt+Ctrl+Del	Cmd+Ctrl+Power
  F2 at startup to modify BIOS settings	Shift+Power at startup to turn extensions off
  Print Screen	Cmd+Shift+3
  Alt+Ctrl+S	Cmd+Opt+Power rebuilds Desktop
  Zap PRAM	Cmd+Opt+p+r+Power

• Check out the real start up in the registry: Local Machine, Software, Microsoft, Windows, Current Version, Run.
• Operating Systems: histories and comparisons. Including BeOS, OS/2, FreeDOS, FreeBSD, and Mac.
• Distributed (data, transactions, and parallel processing) can form the basis of natural neural networks that mimic the brain. Most data is free form (short term memory), but some lock into place (long term memory).
• Domains
  • NT domain models, eg single, master, multiple mater, and complete trust.
  • 2000, 2003 domains
• Control copyright by making blank DVDs expensive to all but those who have rights to reproduce.
• RAM: SIMM, DIMM/SDRAM, RIMM/RDRAM

Page Modified: (Hand noted: 2007-10-04 21:23:10Z) (Auto noted: 2011-10-04 03:11:55Z)