# Exploring Variability of Visual Accessibility Options in Operating Systems
## 7 Related Work
### OS Visual Accessibility Comparisons  
Earlier studies compared the main OS (Table 11), or analyzed the standards [6] and their implementation [4]. Papers [4;6] are not recent, and indicated the needs for guidelines [4] or for standard dissemination [6]. Going from accessibility standards and recommendations to concrete software implementation is a recurring problem, as was again highlighted in [11], and is still to be addressed, as shown in the recent survey on software accessibility in [5].  
For most of the papers about OS, the context is education [12; 13; 14] as in software in general [5]. In [13; 14; 15], the authors discuss different disabilities: visual, hearing and motor disabilities in [13; 14; 15]; cognitive disability in [15]. Some papers study to what extent the OS comply to these standards, in order to help administrations to choose a non-discriminatory system. e.g., in [42], it is shown that Ubuntu 6.10 provides more accessibility features than Windows XP Service Pack 2. In [12], authors determine the most common features in three OS (Linux, MacOS and Windows). E.g., they show that features _Display Customization_ and _Basic Screen Magnification Software_ belong to all systems. Ref. [15] analyzes the latest OS versions of Apple, Microsoft and Google and concludes that the same high-level vision accessibility features are implemented in these platforms. In [13; 15], the versions of the systems involved in the analysis are not explicitly specified. Their findings, restricted to the accessibility options we are studying in this paper, are respectively presented in Tables 12-14. These tables show that these studies are very concentrated on a few aspects, a restricted set of systems and high-level descriptions.  
Compared to these approaches that focus on a particular problematic and coarse-grained features, we give a general framework for a more systematic analysis and comparison. Existing comparative tables cannot be used to make precise comparisons or help users or manufacturers. In our work, all visual options (fine-grained features) are considered. We also identified the problem of defining a unifying ontology and the mappings between OS and the ontology. Some logical relationships are systematically extracted. In addition, the concept lattices provide a space for accessibility exploration, at the level of a single mechanism or considering the whole set of mechanisms as well.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Previous Work** & **Operating Systems** \\ \hline
[12] & Linux, MacOS, Windows \\ \hline
[13] & iOS, Mac, Windows \\ \hline
[14] & MacOS 7-9, MacOS X, Windows 95-2000, Windows XP \\ \hline
[42] & Linux Ubuntu 6.10, Windows XP Service Pack 2 \\ \hline
[15] & Windows, Android, Apple Operating System \\ \hline \hline \end{tabular}
\end{table}
Table 11: List of operating systems analyzed in the literature.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Features**} & \multicolumn{4}{c}{**Operating Systems**} \\ \cline{2-5}  & **Mac OS 7-9** & **Mac OS X** & **Windows 95-2000** & **Windows XP** \\ \hline Magnification & CloseView & Zoom & Magnifier & Magnifier \\ \hline Contrast & Yes & Yes & Yes & Yes \\ \hline Display & Yes & Yes & Yes & Yes \\ \hline \hline \end{tabular}
\end{table}
Table 12: OS and their features from [14].