Light pen


Light pen

A small, photosensitive device connected to a computer and moved by hand over an output display in order to manipulate information in the computer.

Light pens have the advantage of 'drawing' directly onto the screen, but this can become uncomfortable, and they are not as accurate as digitising tablets.

An input device that utilizes a light-sensitive detector to select objects on a display screen. A light pen is similar to a mouse, except that with a light pen you can move the pointer and select objects on the display screen by directly pointing to the objects with the pen.

A light-sensitive stylus wired to a video terminal used to draw pictures or select menu options. The user brings the pen to the desired point on screen and presses the pen button to make contact. Contrary to what it looks like, the pen does not shine light onto the screen; rather, the screen beams into the pen. Screen pixels are constantly being refreshed. When the user presses the button, the pen senses light, and the pixel being illuminated at that instant identifies the screen location.

An early pointing device which the user pointed at a raster -scanned display screen. A photocell in the pen detected the flying spot of the raster scan. The position of the spot at that instant, obtained from the scanning electronics, was made available to software as (x, y) co-ordinates.

File extensions

File extensions
You may have noticed that file names are usually followed by a period and three letters. This three letter sequence is known as the ‘file extension’ and is a way for the computer to recognize what type of file formatting you are opening.

Some of the more common file extensions are as follows:
Microsoft Word  —.doc
Microsoft Excel  —.xls
Microsoft PowerPoint  —.ppt
Images .gif or  —.jpg
Video .mov or  —.mpg
Sound or Audio  —.mp3 or .wav
7z — 7-Zip compressed file
ISO — The generic file format for most optical media, including CD-ROM, DVD-ROM, Blu-ray Disc, HD DVD and UMD.

Desktop publishing extensions
AI — Adobe Illustrator
AVE / ZAVE — Aquafadas
CDR — CorelDRAW
CHP / pub / STY / CAP / CIF / VGR / FRM — Ventura Publisher — Xerox (DOS / GEM)
CPT — Corel Photo-Paint
DTP — Greenstreet Publisher, GST PressWorks
GDRAW — Google Drive Drawing
ILDOC — Broadvision Quicksilver document
INDD — Adobe InDesign
PSD — Adobe Photoshop
MCF — FotoInsight Designer
PDF — Adobe Acrobat or Adobe Reader
PMD — Adobe PageMaker
PPP — Serif PagePlus
PUB — Microsoft Publisher
QXD — QuarkXPress
FM — Adobe FrameMaker
SLA / SCD — Scribus
WLMP — Windows Live Movie Maker project file

Font extensions

ABF — Adobe Binary Screen Font
AFM — Adobe Font Metrics
BDF — Bitmap Distribution Format
BMF — ByteMap Font Format
FNT — Bitmapped Font — Graphics Environment Manager (GEM)
FON — Bitmapped Font — Microsoft Windows
MGF — MicroGrafx Font
OTF — OpenType Font
PCF — Portable Compiled Format
PostScript Font — Type 1, Type 2
PFA — Printer Font ASCII
PFB — Printer Font Binary — Adobe
PFM — Printer Font Metrics — Adobe
AFM — Adobe Font Metrics
FOND — Font Description resource — Mac OS
SFD — FontForge spline font database Font
SNF — Server Normal Format
TDF — TheDraw Font
TFM — TeX font metric
TTF (.ttf, .ttc) — TrueType Font
WOFF — Web Open Font Format

Click versus right click

Click versus right click

When you look at your mouse, you should instantly notice that there are two (or sometimes three) different buttons which can be clicked. For most situations the user will use the left button. For this reason when people refer to ‘click’ they are referring to left click. In contrast, clicking on the right button is always referred to as ‘right click’. In this job aid we will always refer to left click as ‘click’, and right click as ‘right click’.

The standard mouse has two buttons, plus a scroll wheel in the middle which sometimes is a button. But most mice do just two things: right- and left-click. Left-click is often referred to as “normal-click” or “regular-click.” Most tasks on a computer can be accomplished solely through using the left mouse button. Pressing the left mouse button seems to simulate the mouse cursor being pressed down on the screen: you can drag items or select text or open files.

A double-click is a special type of left-mouse-button click which is getting used less and less. A double-click is usually used for opening files on your computer, where a single-click is used for navigating webpages. Because so much computer is online, the double-click is declining in use.

The right mouse button is often ignored for weeks or months at a time, and it’s less understood than its brother. However, the right mouse button is one of the most valuable tools on the computer. It’s not strictly defined as having a function which makes it hard to describe, but the basic purpose of the right mouse button is this: to give you information *about* what you’re clicking on. If the left mouse button directly interacts with an object, the right mouse button often allows you to indrectly interact. Right-clicking a file gives you a list of things to do with the file, or the option to see its properties. Right-clicking your desktop background allows you to modify the desktop. Right-clicking a link allows you to do other things with that link besides visit it

File storage in a Windows environment

File storage in a Windows environment

File storage in a Windows environment is simple and straightforward. The best way to access file storage is to use Windows Explorer, a software application that comes with Microsoft Windows.

The Windows Explorer environment allows for quick access to all the computer’s files. This includes all drives including: floppy disk drive, hard drive (on the CPU) and CD-ROM drives.

The environment is also hierarchical in that folders may be created within folders. Files, on the other hand, are saved within this hierarchy of folders.

Did you know that storing files directly on your desktop can harm your productivity? I used to be one of “those” people who downloaded files straight to the desktop. If you can identify with that, then I have good news for you: you can do better. Desktop storage is simple, sure, but it comes with hidden drawbacks you may not know about.

Kick the bad habit with these alternative file storage methods. They may not be as convenient but I promise that you’ll learn to love them in the long run.

The urge to save files to the desktop is understandable. It provides immediate access with a single click, which means that it’s tempting to turn the desktop into a de facto headquarters for storage. But unless you are strict with maintenance, you’ll eventually succumb to these issues:

No file protection. As noted by PC World, certain directories are not affected by System Restore, the most recognizable location being My Documents. Files on the desktop are affected by System Restore, which can result in unexpected file disappearances.

No file backups. Many file backup programs ignore desktop files by default. Most programs worth their salt will allow you to change the settings and include the desktop if necessary, but all it takes is one forgetful moment to accidentally lose an important desktop file.

Clutter, clutter, clutter. The story is always the same. You begin your desktop collection with a few documents. Over time, the collection grows to include images, music, programs, zip files, and more documents. Suddenly, finding the right document takes more time than actually opening it.

Separate Drive Partitions
One bit of computer wisdom that you should learn is this: “Never save data on the same partition as your operating system.” In Windows, the location of the desktop on the filesystem does reside on the same partition as the operating system itself.

Why is this important advice? Because you want to avoid putting all of your eggs in the same basket.

Let’s say that you happen to contract a mild virus or malware that attacks your operating system. It might wipe all files related to the operating system itself OR it may affect the entire partition that holds the operating system. By losing the operating system, you lose all of your saved data as well.

But if you installed Windows to the C: partition and stored all of your files on the D: partition, your files on D: would be safe even if C: were wiped clean. The only way D: would be affected is if the physical hard drive itself was wiped or damaged.

One additional benefit of having separate partitions is that you can reinstall Windows without losing your saved data. Tina has written on the subject of resizing Windows partitions, so check it out if you want to take advantage of this feature.

RAM, ROM

RAM, ROM what are they and how do they affect my computer?
RAM, or Random Access Memory, refers to the amount of ‘working memory’ that your computer as. More specifically, RAM is the feature of a computer that allows programs to run. The more RAM that a computer has, the faster programs will run. Having more RAM also allows the user to run more programs concurrently. For this reason newer computers, with more RAM, are able to process more programs at the same time. In order to keep your computer working as fast as possible, limit the number of programs which are open at any one time. Present computers usually have 64 or 128 MB of RAM.

ROM, or Read Only Memory, refers to the storage space that a computer can hold. Just like a glass which can contain only so much water, a computer can only hold so many programs and files. For this reason ROM has been likened to ‘long-term memory’.

Introduction computer basics for PC

Introduction computer basics for PC
Using a computer is not such a daunting task, especially when you are more familiar with some of its basic operations. This job aid will help the computer novice glide smoothly through some basic operations useful in a PC Windows environment.


Parts of a computer
Before we begin looking at some basic functions of a PC, it would be useful to review a basic computer system and its components.
Monitor: This is what we call the screen. It is formally called a cathode-ray tube.
Keyboard: This is the instrument we use in order to type text into the computer.
Mouse: This attachment rolls on a small circular ball and has buttons which can be clicked. This part of the system allows the user to work more easily with a computer interface. As the user moves the mouse around on its pad, a screen cursor moves correspondingly on screen. Some later models of the mouse no longer use a ball but use optical light technology.
LCD: This is an acronym for Liquid Crystal Display Projector. This device permits users to project what appears on their computer screen to a larger classroom/ conference room screen.
CPU: This is an acronym for the Central Processing Unit. It is the ‘nuts and bolts’ of the computer and is where the computer’s memory and storage space exists.
Modem: This is a component that resides inside your CPU. It allows the user to connect with the Internet and the World Wide Web (WWW).
Desktop: This comprises of what is plainly visible on the user’s computer screen or monitor.
Peripherals: Peripherals refer to technology that can be attached to the main computer station, such as printers, scanners or digital cameras.
Printer: This peripheral is a device that permits users to print files (i.e., documents, pictures, etc..) to paper.
Scanner: This peripheral device permits the user to digitally upload images or text which already exist non-electronically. These digital uploads can then be converted into computer files which can be
manipulated.
Digital Camera: Digital Cameras can now be connected to computer stations. This is may be done so that the video can be uploaded to the computer which can then be edited.

About Designing


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About Designing

Design is the creation of a plan or convention for the construction of an object, system or measurable human interaction (as in architectural blueprints, engineering drawings, business processes, circuit diagrams, and sewing patterns). Design has different connotations in different fields (see design disciplines below). In some cases, the direct construction of an object (as in pottery, engineering, management, coding, and graphic design) is also considered to be design.