A summary about usability
Usability has much to say, but I will split in several posts, starting with this, introducing the subject, telling a small history of usability, their creators and objectives.
To Hix and Hartson (apud Heemamm, 1997), usability is the combination of easy learning, high speed execution of tasks, low rate of errors, subjective satisfaction and retention of knowledge of the interface, ie the user even after a long time without interacting with the interface, still remembering how to use. For Bevan (apud Days, 2003) suggests "usability" as a technical term to refer a use of an interface. According to ISO 9241, "usability" is defined as efficiency and satisfaction with which users achieve their objects in a system.
When we talk about usability, we are referring to how well users can use the resources of a website or software. "User Friend" is a world known term to determine if an interface helps the user, even if this is a website, software or game. However, "user friend" is different from usability, it's not a definition based on scientific fundaments, if you say that an user interface is "user friend", it gives no substrate and metrics, it is a vague term, and generic. It's better to say that an user friend interface it's an adjetive.
Nielsen joined the term "usability" into five attributes capable of measurement on an interface, which follow:
- Ease to learn;
- Efficiency of use;
- Ease to memorize;
- Low rate of errors and
- Subjective satisfaction
With these attributes, it is possible to measure the degree of usability of an interface, and become a more specific term. Tell if an interface has a high or low usability now it is possible.
Note that the usability is one of the most important factors when we are talking about a software, website or game. Because the user must first understand the navigation of the interface, before finally reaching the contents, in this case is what we is wanting to sell. Winckler & Pimenta (2002) listed some classics troubles you can have on an interface, which are:
Navigation: When the users has troubles to finding the desired information or functionality. They don't know to return to a previous page (in case of a website) or find a feature of the software. The figure below illustrates a software with this problem:
This is a video convertion tool, this software contains problems of navigation. Note these buttons, options and fields to fill, it's a mass! You hardly remember the control positions and you'll need to read all the interface again every time you use. And if you're using for the first time, you'll need time to adapt.
Multimedia Resources: Excessive use of videos, pictures and colors in the composition of a website. The figure below shows a website with this problem, although not so serious. Among the problems of multimedia resources, we can mention the abuse of colors, images, text highlights, font sizes, etc.).
Technology: Browser incompatibility, operating systems and hardware (connection speed). Very common among software and games, however, there are some websites that are very limited between browsers as Microsoft Internet Explorer versus Mozilla FireFox. The figure below shows a website accessed via FireFox, requires Microsoft Internet Explorer. Certainly the website will have a loss of visits and potential consumers. Looking all the functionalities, there is nothing special to run only on IE.
In our next post we will begin to explore more about Usability and talk about the Usability Engineering. This was more an introduce the subject to heat our engines!
Xerox is not only to copy paper
In the previous post I talked about the tory of the GUI, and I gave you a small introdution about GUIs and the Sketchpad. But one of the big jumps in the graphical interfaces world has been given by Xerox when they builded the first desktop system called 8010 Star Information System in 1981. T was the first commercial system with GUI that joined various technologies and after some years we could call it by "Personal Computer". T system was awesome, displaying true bitmaps (instead of vectors like Sketchpad) in its interface. And it was the first interface that uses the concept of windows, icons, folders and menus.
The main philosophy for the construction of t interface is that should be intuitive for the end user, to be used in offices and businesses. And to do that, they used the concept of "What You See Is What You Get" (WYSIWYG).
And then, we can see a screen where there are icons and folders, each representing a kind of file (file types like images, texts, etc), where clicking on t icon, it opens a new window with content inside. Note that in the Xerox Star there are not advanced programs like image editors and word processors, but each type of document opens in its appropriate application, and nothing more.
The Xerox Star's interface follows the concept of objects, for example, in a text editor you have an object "page", the object "paragraph", "line", "word", etc and if you click on t object you invoke a range of options such as copy, paste, crop and remove. In other cases it becomes a new "options window" where you can set different properties for each kind of object.
One of innovations also includes the hight compatibility between applications, for example, if you create an graph object into a image editor, you can insert it into the text editor together your text. T ability to include different objects inside other applications was included on Microsoft Windows nine years after, in 1990, when they created the OLE (Object Linking and Embedding) based on Xerox Star concepts.
We can see the result of t incredible creation in the image below, where you can observe the different objects interacting with each other. Note the widgets, icons and windows:
The appearance of the GUI
Historically, in the 60s there was no graphical interface, so far, everything was based on punched cards, if not, perforated paper with algorithms and alphabets and the output was done by printers. There was no interaction with the user.
In 1962, Ivan Sutherland (was born in 1938, and he still alive until today) created in his PhD thesis at Massachusetts Institute of Technology (MIT) the thing we could say: "The first Graphic User Interface ever". Called Sketchpad, this software was the predecessor of the Computer-Aided Drafting (CAD) and opened the doors to the user interface world.
The Sketchpad according to Wikipedia, using a simple interface but intuitive given the user a new experience about "operate a computer". With the touch sensitive monitor of the light pen, the user can "click" in specific regions where they designed for the options. The clickable areas were recognized in touch screen, and the terminal determines whether the area in a XY axis performed some action. Additionally, the user could draw on the screen with a Light Pen (something like a mouse today).