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In most of today's operating system architectures, device drivers are tightly coupled with other kernel components. In such systems, a fault caused by a malicious or faulty device driver often leads to complete system failure, thereby reducing the overall reliability of the system. Even though a majority of the operating systems provide protection mechanisms at the user level, they do not provide the same level of protection for kernel components. Using virtualization, device drivers can be executed in separate, isolated virtual machines, called driver domains. Such domains provide the same level of isolation to device drivers as operating systems provide to user level applications. Domain-based isolation has the advantage that it is compatible with existing drivers and transparent to the kernel. However, domain-based isolation incurs significant performance overhead due to the necessary interdomain communication. This thesis investigates techniques for reducing this overhead. The key idea is to replace the interrupt-based notification between domains with a spinning-based approach, thus trading CPU capacity for increased throughput. We implemented a prototype, called the Isolated Device Driver system (IDDR), which includes front-end and back-end drivers and a communication module. We evaluated the impact of our optimizations for a variety of block devices. Our results show that our solution matches or outperforms Xen's isolated driver domain in most scenarios we considered. / Master of Science

Thesis (Ph. D.)--University of Cincinnati, 2005. / Includes bibliographical references (p.100-116). Also available online via the OhioLINK website (http://www.ohiolink.edu/).

Typescript. Includes bibliographical references (leaves xliii-xlv).

New peripheral devices are being developed at an ever increasing rate. Before such accessories can be used in the UNIX environment (UNIX is a trademark of Bell Laboratories), they must be able to communicate with the operating system. This involves writing a device driver for each device. In order to do this, very detailed knowledge is required of both the device to be integrated and the version of UNIX to which it will be attached. The process is long, detailed and prone to subtle problems and errors. This paper presents a menu-driven utility designed to simplify and accelerate the design and implementation of UNIX device drivers by freeing developers from many of the implementation specific low-level details.

Although some descriptions of stereotypes about drivers are documented in the literature, the specific behaviours representing these stereotypes have not been previously explored. In addition to identifying specific behaviours associated with stereotypes about female drivers, this thesis looks at the way that these stereotypes may be affected by the age of the stereotyped driver. Furthermore, a debate exists in the field of social psychology about whether the awareness of these stereotypes affects the performance of drivers from the stereotyped groups through the phenomenon known as stereotype threat. This thesis explores these topics through a series of three studies. In the first study, participants watched videos illustrating a variety of driving behaviours and indicated whether the driver was more likely to be male or female. In the second study, participants were told to imagine male and female drivers of different ages approaching a car, and the participants were asked to indicate which driver was more likely to take the wheel of the car and whether that driver was the safer of the two. In the third study, which consisted of two experiments, female participants were invited to complete several driving scenarios in a driving simulator. The first of the two experiments had two conditions: stereotype threat and neutral; the second experiment had an enhanced stereotype threat and a counterstereotype condition. The findings of the first study elucidated the specific behaviours that are stereotypically associated with male and female drivers. The second study showed that in many ways, driving is still considered to be a man’s prerogative, since men were frequently rated as more likely to drive and safer drivers than women. The results of the third study showed that the effects of these stereotypes on drivers can be difficult to detect using the stereotype threat paradigm in a driving simulator environment. Although stereotypes about male and female drivers from different age groups are still prevalent, their effects on the behaviour of the drivers from the stereotyped groups may be elusive and hard to reproduce in a simulated driving context.

This thesis is a sociological investigation into Aberdeen’s ‘boy racer’ culture and the reaction it has provoked amongst various outside groups.  Ethnographic research was conducted which included participant observation and semi-structured interviews with members of the subculture.  The attitudes of outside groups were explored though semi-structured interviews with police officers, journalists, residents and politicians; and content analysis of media articles, council reports and statistics.  The first strand of the research involves an exploration of the internal dynamics of the ‘boy racer’ culture.  Here, I explore the rituals engaged in by members of the culture which include car modification, subcultural media and events, their appropriation of public space and the quest for celebrity status.  The thesis also addresses the role of gender within a male-dominated culture.  Conflict within the subculture is also explored using the notion of respectability.  Participants viewed themselves as respectable members of the culture in contrast to the ‘rough racers’.  This respectability related to the pride they took in their cars and driving skills, and their adherence to societal laws and subcultural norms.  In the second strand of the thesis I argue that the reaction to Aberdeen’s ‘boy racer’ culture is evidence of a local moral panic.  The threat posed by the drivers’ presence at Aberdeen’s seafront was exaggerated and distorted by members of the outside groups, including in particular, the local media.  Moreover, the moral panic concerning deviant driving practices by youths was institutionalized through the use of powers under the Antisocial Behaviour etc.(Scotland) Act 2004.  Members of the culture in Aberdeen attempted to distance themselves from the ‘boy racer’ label and instead viewed themselves as car modifiers or enthusiasts.  Ironically, the space used to express their opinions – their own forms of subcultural media, also became the focus of the moral panic.

The purpose of this thesis is to focus on some of the different decisions taken by taxi drivers. The three main areas considered are when a taxi driver chooses to work, where they choose to work and having chosen when and where, the strategy employed by the taxi driver. The chapter examining the decision on when a taxi driver chooses to work considers whether drivers are consistent with the neoclassical model of labour supply. Existing literature on taxi drivers has suggested taxi drivers behave in different ways. This thesis finds that taxi drivers respond to earning opportunities and are more likely to work when the earning opportunities are better than usual. The decision on where a taxi driver chooses to look for fares uses an experimental approach, putting subjects in the position of drivers choosing locations in a square grid. The location choice is a two dimensional extension of Hotelling’s model. In this particular experiment, Nash equilibrium is not obtained through minimum nor maximum differentiation and the learning of subjects and subsequent performance improvement is slow. Simulation through agent-based computational economics is used to investigate the different strategies taxi drivers can use. The simulations show that drivers can increase their own earnings and reduce the waiting time of potential customers by adopting a strategy which makes use of all the available information. The simulations also show that the effectiveness of a strategy is dependent on the choices of other drivers. This thesis suggests a different approach to the analysis of the labour supply decisions of taxi drivers and makes some recommendations regarding regulation of taxi services. The experimental and simulation chapters contribute to the literature through making use of these approaches in the context of looking at taxi drivers. The experiment and simulation could also be extended into other areas.