This document summarizes a technical report about the Gazelle web browser, which is constructed as a multi-principal operating system (OS). Gazelle's Browser Kernel runs as a separate OS process and exclusively manages resource protection and sharing across web site principals (origins). This construction exposes new design challenges not addressed in previous works, such as protecting cross-origin script sources and cross-principal display/events. The report describes Gazelle's security model and architecture, focusing on its solutions to these new challenges. It also discusses an implementation prototype and preliminary evaluation.
This short document promotes creating presentations using Haiku Deck, a tool for making slideshows. It encourages the reader to get started making their own Haiku Deck presentation and sharing it on SlideShare. In just one sentence, it pitches the idea of using Haiku Deck to easily create engaging slideshow presentations.
Presentation at the INSPIRE Workshop "Concrete steps to implement INSPIRE: synergies between the public and the private sector" - Florence, 24th June 2013
www.LRLiderTime.blogspot.ru Skype marinair2011
Приглашаем к сотрудничеству!
Крупная Немецкая компания прямых продаж LR HEALTH&BEAUTY SYSTEMS проводит набор менеджеров для рекламы компании и ее продукции для красоты и здоровья в России, Украине и Казахстане. Обучение проводится для менеджеров компании бесплатно. Критерии отбора: обучаемость, коммуникабельность, порядочность, активная жизненная позиция. Начинать работать у нас возможно от 18 лет, образование значения не имеет, пол тоже. Сотрудники компании имеют возможность получить весь ассортимент товаров по закупочной цене. При выполнении условий компании по продажам продукции дальнейшее обучение в г.Москва, а также обучение за границей. Возможно сотрудничество с ИП и юридич.лицами. Телефон для связи 89136910033
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
The document discusses the results of a survey conducted with 300 pharmacy students over 3 years to understand student opinions on the teaching of Pharmacognosy. Key findings included:
- 88.78% of students felt changes were needed to the Pharmacognosy syllabus.
- 80.88% felt developing practical skills should be emphasized.
- 70.54% suggested adding industry-based content to the syllabus.
- Over 80% agreed the workload was improperly distributed across the 4-year program.
The study highlights the need for reforms like adding industry experience, field work, and projects to improve Pharmacognosy education.
Highlights of Features Coming Soon in HPCC Systems 6.0.0!
Come learn how the upcoming 6.0 release can help you solve Big Data problems faster and more efficient. Topics include:
· How using the new Virtual slave Thor makes using a smart/lookup join faster
· How to add and leave tracing in your code without affecting the graph
· How the HPCC Systems Visualisations Framework provides easy and fast access to visualisations from data included in a workunit or Roxie query
· Plus, hear how our success with GSoC (Google Summer of Code) in 2015 is preparing us for this year
This short document promotes creating presentations using Haiku Deck, a tool for making slideshows. It encourages the reader to get started making their own Haiku Deck presentation and sharing it on SlideShare. In just one sentence, it pitches the idea of using Haiku Deck to easily create engaging slideshow presentations.
Presentation at the INSPIRE Workshop "Concrete steps to implement INSPIRE: synergies between the public and the private sector" - Florence, 24th June 2013
www.LRLiderTime.blogspot.ru Skype marinair2011
Приглашаем к сотрудничеству!
Крупная Немецкая компания прямых продаж LR HEALTH&BEAUTY SYSTEMS проводит набор менеджеров для рекламы компании и ее продукции для красоты и здоровья в России, Украине и Казахстане. Обучение проводится для менеджеров компании бесплатно. Критерии отбора: обучаемость, коммуникабельность, порядочность, активная жизненная позиция. Начинать работать у нас возможно от 18 лет, образование значения не имеет, пол тоже. Сотрудники компании имеют возможность получить весь ассортимент товаров по закупочной цене. При выполнении условий компании по продажам продукции дальнейшее обучение в г.Москва, а также обучение за границей. Возможно сотрудничество с ИП и юридич.лицами. Телефон для связи 89136910033
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
The document discusses the results of a survey conducted with 300 pharmacy students over 3 years to understand student opinions on the teaching of Pharmacognosy. Key findings included:
- 88.78% of students felt changes were needed to the Pharmacognosy syllabus.
- 80.88% felt developing practical skills should be emphasized.
- 70.54% suggested adding industry-based content to the syllabus.
- Over 80% agreed the workload was improperly distributed across the 4-year program.
The study highlights the need for reforms like adding industry experience, field work, and projects to improve Pharmacognosy education.
Highlights of Features Coming Soon in HPCC Systems 6.0.0!
Come learn how the upcoming 6.0 release can help you solve Big Data problems faster and more efficient. Topics include:
· How using the new Virtual slave Thor makes using a smart/lookup join faster
· How to add and leave tracing in your code without affecting the graph
· How the HPCC Systems Visualisations Framework provides easy and fast access to visualisations from data included in a workunit or Roxie query
· Plus, hear how our success with GSoC (Google Summer of Code) in 2015 is preparing us for this year
El documento presenta dos protagonistas, Bovina y Taurus, que son prendas de ropa diseñadas para disfrutar de la naturaleza. Ambas prendas son blancas y negras, pesan 200 gramos, son transpirables y resistentes. Fueron diseñadas para la temporada de verano de 2008-2009 por Daniel Moreno Casas y Oscar Martinez Amelibia.
El documento es una cotización para un producto valorado, expedida el 23 de junio de 2013 por Alberto Carlos Huévos de la empresa. Incluye secciones para las partes involucradas, el producto a valorar, el precio, la fecha de expedición, una descripción del producto, el membrete de la empresa, la firma de quien expide la cotización y la fecha de vencimiento.
This short document is a series of 11 photos credited to "nidhug" and encourages the reader to get inspired and create their own Haiku Deck presentation on SlideShare. The photos are not described but seem to illustrate a nature or landscape theme.
The document analyzes home repair and improvement search trends from 2012. It finds that spending on exterior building products is forecast to increase in 2013, driven partly by Hurricane Sandy. Search volumes have declined for air conditioners, furnaces, appliances and windows since their peaks in 2006-2012. Doors and faucets have shown consistent search volumes. The analysis suggests opportunities for suppliers to introduce their brands directly to consumers.
This document provides tips for scientists on how to spread their discoveries to the general public through journalists and media outlets. It advises focusing on practical consequences and everyday life impacts to attract journalists' interest. It also suggests using catchy opening lines and focusing on the intended audience when reaching out to general news publications versus scientific magazines. The document emphasizes making the message social through groups like "Dibattito scienza" on Facebook and considering both the effectiveness and ethics of experiments involving animals.
Speech recognition systems translate spoken words to text. They have evolved from discrete dictation to continuous dictation and have gotten smarter with grammar rules. Accuracy can be measured to examine a recognizer's ability. Some systems require training to a specific speaker while others are speaker independent. Computers do speech recognition by digitizing the audio, analyzing it acoustically and linguistically, and interpreting it based on phonemes and a grammar. Speech recognition has applications in navigation, mobile phones, home automation, education, security, and wearable computers. Generators are programs that create other programs, such as password generators, code generators, and random number generators used for licensing keys or testing.
Presentation on platform thinking in maths education to South African maths teachers at the 2015 AMESA conference held on the 1st of July 2015 at the University of Limpopo.
70% of all SAP on Linux customers rely on SUSE Linux
Reduce your SAP infrastructure TCO by up to 80%
Intel's Enterprise Computing Platform is pulling ahead of UNIX
How to get your SAP landscapes to SUSE Linux on Intel: SAP Consulting by Texperts
7 summer solstice2012-a cognitive heuristic model of epidemicsAle Cignetti
The document proposes a cognitive heuristic model for modeling epidemics that accounts for psychological and cognitive effects. It discusses limitations of traditional models and the need to consider adaptive cognitive strategies of agents. A tri-partite cognitive agent model is introduced containing modules for unconscious processes, reasoning, and learning. Finally, a recipe is outlined for an epidemics model incorporating a weighted network environment, viral features, economic factors, bounded agent cognition, and multiple timescales.
Chromium's security architecture separates the browser into two modules that run in separate protection domains: a browser kernel module and a sandboxed rendering engine module. This architecture aims to mitigate high-severity attacks by restricting an attacker who exploits a vulnerability in the rendering engine to using the browser kernel interface, rather than allowing arbitrary access to the user's system. The paper evaluates this architecture and finds that it would mitigate approximately 70% of past browser vulnerabilities that allowed arbitrary code execution.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
The document discusses how browsers have evolved to take on more functions traditionally associated with operating systems. It notes that browsers now offer communication tools, productivity suites, and other applications. The document then covers the history of browsers, including the rivalry between Netscape and Internet Explorer in the 1990s-2000s. Finally, it argues that browsers will continue integrating more operating system features through APIs, plug-ins, and local storage options, moving closer to fulfilling the vision of the "browser as the new OS."
The Google File System is a scalable distributed file system designed to meet the rapidly growing data storage needs of Google. It provides fault tolerance on inexpensive commodity hardware and high aggregate performance to large numbers of clients. The key design drivers were the assumptions that components often fail, files are huge, writes are append-only, and concurrent appending is important. The system has a single master that manages metadata and assigns chunks to chunkservers, which store replicated file chunks. Clients communicate directly with chunkservers to read and write large, sequentially accessed files in chunks of 64MB.
The Google File System is a scalable distributed file system designed to meet the rapidly growing data storage needs of Google. It provides fault tolerance on inexpensive commodity hardware and high aggregate performance to large numbers of clients. The key design drivers were the assumptions that components often fail, files are huge, writes are append-only, and concurrent appending is important. The system has a single master that manages metadata and assigns chunks to chunkservers, which store replicated file chunks. Clients communicate directly with chunkservers to read and write large, sequentially accessed files in chunks of 64MB.
This document compares the IndexedDB and SQLite databases. It begins with an introduction that describes the competition between native and web applications and the need for local data storage in web applications. It then outlines the theoretical background of IndexedDB and SQLite, describing their key characteristics and features. The document presents the research questions regarding the performance and security of IndexedDB compared to SQLite.
The document discusses the emergence and growth of web-based operating systems (web OS). A web OS functions like a traditional desktop OS but runs within a web browser and stores data/applications on remote servers rather than locally. Several companies now offer commercial and open source web OS options. While the technology faces limitations, proponents believe web OSs could become more popular as users grow more comfortable with cloud-based computing and web applications.
Google Chrome is a free web browser developed by Google. It aims to be secure, fast, simple and stable. Some key features include tabbed browsing, synchronization of bookmarks and settings across devices, and regular security updates. Firefox is an open-source web browser developed by Mozilla. It has features like tabbed browsing, extensions, and private browsing. Internet Explorer is Microsoft's web browser, included with Windows. It introduced features like tabbed browsing and support for favicons over several versions.
El documento presenta dos protagonistas, Bovina y Taurus, que son prendas de ropa diseñadas para disfrutar de la naturaleza. Ambas prendas son blancas y negras, pesan 200 gramos, son transpirables y resistentes. Fueron diseñadas para la temporada de verano de 2008-2009 por Daniel Moreno Casas y Oscar Martinez Amelibia.
El documento es una cotización para un producto valorado, expedida el 23 de junio de 2013 por Alberto Carlos Huévos de la empresa. Incluye secciones para las partes involucradas, el producto a valorar, el precio, la fecha de expedición, una descripción del producto, el membrete de la empresa, la firma de quien expide la cotización y la fecha de vencimiento.
This short document is a series of 11 photos credited to "nidhug" and encourages the reader to get inspired and create their own Haiku Deck presentation on SlideShare. The photos are not described but seem to illustrate a nature or landscape theme.
The document analyzes home repair and improvement search trends from 2012. It finds that spending on exterior building products is forecast to increase in 2013, driven partly by Hurricane Sandy. Search volumes have declined for air conditioners, furnaces, appliances and windows since their peaks in 2006-2012. Doors and faucets have shown consistent search volumes. The analysis suggests opportunities for suppliers to introduce their brands directly to consumers.
This document provides tips for scientists on how to spread their discoveries to the general public through journalists and media outlets. It advises focusing on practical consequences and everyday life impacts to attract journalists' interest. It also suggests using catchy opening lines and focusing on the intended audience when reaching out to general news publications versus scientific magazines. The document emphasizes making the message social through groups like "Dibattito scienza" on Facebook and considering both the effectiveness and ethics of experiments involving animals.
Speech recognition systems translate spoken words to text. They have evolved from discrete dictation to continuous dictation and have gotten smarter with grammar rules. Accuracy can be measured to examine a recognizer's ability. Some systems require training to a specific speaker while others are speaker independent. Computers do speech recognition by digitizing the audio, analyzing it acoustically and linguistically, and interpreting it based on phonemes and a grammar. Speech recognition has applications in navigation, mobile phones, home automation, education, security, and wearable computers. Generators are programs that create other programs, such as password generators, code generators, and random number generators used for licensing keys or testing.
Presentation on platform thinking in maths education to South African maths teachers at the 2015 AMESA conference held on the 1st of July 2015 at the University of Limpopo.
70% of all SAP on Linux customers rely on SUSE Linux
Reduce your SAP infrastructure TCO by up to 80%
Intel's Enterprise Computing Platform is pulling ahead of UNIX
How to get your SAP landscapes to SUSE Linux on Intel: SAP Consulting by Texperts
7 summer solstice2012-a cognitive heuristic model of epidemicsAle Cignetti
The document proposes a cognitive heuristic model for modeling epidemics that accounts for psychological and cognitive effects. It discusses limitations of traditional models and the need to consider adaptive cognitive strategies of agents. A tri-partite cognitive agent model is introduced containing modules for unconscious processes, reasoning, and learning. Finally, a recipe is outlined for an epidemics model incorporating a weighted network environment, viral features, economic factors, bounded agent cognition, and multiple timescales.
Chromium's security architecture separates the browser into two modules that run in separate protection domains: a browser kernel module and a sandboxed rendering engine module. This architecture aims to mitigate high-severity attacks by restricting an attacker who exploits a vulnerability in the rendering engine to using the browser kernel interface, rather than allowing arbitrary access to the user's system. The paper evaluates this architecture and finds that it would mitigate approximately 70% of past browser vulnerabilities that allowed arbitrary code execution.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
The document discusses how browsers have evolved to take on more functions traditionally associated with operating systems. It notes that browsers now offer communication tools, productivity suites, and other applications. The document then covers the history of browsers, including the rivalry between Netscape and Internet Explorer in the 1990s-2000s. Finally, it argues that browsers will continue integrating more operating system features through APIs, plug-ins, and local storage options, moving closer to fulfilling the vision of the "browser as the new OS."
The Google File System is a scalable distributed file system designed to meet the rapidly growing data storage needs of Google. It provides fault tolerance on inexpensive commodity hardware and high aggregate performance to large numbers of clients. The key design drivers were the assumptions that components often fail, files are huge, writes are append-only, and concurrent appending is important. The system has a single master that manages metadata and assigns chunks to chunkservers, which store replicated file chunks. Clients communicate directly with chunkservers to read and write large, sequentially accessed files in chunks of 64MB.
The Google File System is a scalable distributed file system designed to meet the rapidly growing data storage needs of Google. It provides fault tolerance on inexpensive commodity hardware and high aggregate performance to large numbers of clients. The key design drivers were the assumptions that components often fail, files are huge, writes are append-only, and concurrent appending is important. The system has a single master that manages metadata and assigns chunks to chunkservers, which store replicated file chunks. Clients communicate directly with chunkservers to read and write large, sequentially accessed files in chunks of 64MB.
This document compares the IndexedDB and SQLite databases. It begins with an introduction that describes the competition between native and web applications and the need for local data storage in web applications. It then outlines the theoretical background of IndexedDB and SQLite, describing their key characteristics and features. The document presents the research questions regarding the performance and security of IndexedDB compared to SQLite.
The document discusses the emergence and growth of web-based operating systems (web OS). A web OS functions like a traditional desktop OS but runs within a web browser and stores data/applications on remote servers rather than locally. Several companies now offer commercial and open source web OS options. While the technology faces limitations, proponents believe web OSs could become more popular as users grow more comfortable with cloud-based computing and web applications.
Google Chrome is a free web browser developed by Google. It aims to be secure, fast, simple and stable. Some key features include tabbed browsing, synchronization of bookmarks and settings across devices, and regular security updates. Firefox is an open-source web browser developed by Mozilla. It has features like tabbed browsing, extensions, and private browsing. Internet Explorer is Microsoft's web browser, included with Windows. It introduced features like tabbed browsing and support for favicons over several versions.
Express JS and Django Web Frameworks AnalyzedTien Nguyen
Dive into the world of Express JS and Django as we compare these popular web frameworks. Uncover their strengths in REST API development, database integration, testing, deployments, security, scalability, and more.
https://www.frontendmag.com/insights/express-js-vs-django/
Web development refers to tasks associated with developing websites, including web design, content development, and client-side/server-side scripting. There are different types of web developers such as front-end developers who code the front-end using HTML, CSS, and JavaScript, and back-end developers who build the server-side logic using languages like PHP, Ruby, or Python. A web development stack typically includes a front-end framework, back-end programming language, database, and content management system. Popular stacks include LAMP (Linux, Apache, MySQL, PHP), LEMP (Linux, Nginx, MySQL, PHP), and MERN (MongoDB, Express, React, Node). Companies use different technologies
Top 6 Practices to Harden Docker Images to Enhance Security9 series
Dockers can be considered equivalent to containers. Different verses of tools and platforms of containers are being used to develop containers to work more profitably. However, there are so many principles for protecting applications based on the container by collaborating with other secured applications.
Development of Multiplatform CMS System with Zend FrameworkSinisa Vukovic
This paper presents the use of the Zend framework in the realization of a CMS system that can generate multiplatform web content in a responsive web design approach.Use of a framework can help developers tocreate better web applications, which are easier to maintain, faster to build, multifunctional and multiplatform based. The Zend framework provides an implementation of the MVC pattern.
BrowserShield is a system that uses vulnerability-driven filtering to protect web browsers from exploits. It rewrites HTML pages and embedded scripts to apply runtime checks based on known vulnerabilities. When a page loads, the BrowserShield JavaScript library translates the page into a safe equivalent. Any scripts are rewritten using techniques like callee rewriting to allow interposition. This mediates access to the document tree and enforces policies like detecting and blocking the HTML Elements Vulnerability. Evaluation shows it can prevent all exploits of vulnerabilities while maintaining reasonable performance.
AngularJS has been designed to build front-end of web applications easily.Take your time to learn the frameworks to understand how the pieces fit together.
Design Decisions For Understanding Software ArchitectureTiffany Graham
This document discusses the "browser wars" between Netscape and Microsoft in the 1990s. Netscape initially dominated the browser market with its Netscape Navigator. However, Microsoft was able to gain majority market share by bundling its Internet Explorer browser with Windows. As a result, Netscape struggled and was eventually acquired by America Online. The summary examines the key events in the browser war between the two companies over browser market control in 3 sentences or less.
This document summarizes best practices for web development based on a study by Larry Wilson. It discusses using responsive design, flexible frameworks, HTML5 semantics and forms, CSS3 rules and properties, web fonts, JavaScript optimization, and usability testing. The goal is to implement these standards to create accessible, optimized websites that work across devices. Key aspects covered include mobile-first design, progressive enhancement, minimizing file sizes and requests, and testing with users.
The Google File System is a scalable distributed file system designed to meet the rapidly growing data storage needs of Google. It provides fault tolerance on inexpensive commodity hardware and high aggregate performance to large numbers of clients. Key aspects of its design include handling frequent component failures as the norm, managing huge files up to multiple gigabytes in size containing many objects, optimizing for file appending and sequential reads of appended data, and co-designing the file system interface to increase flexibility for applications. The largest deployment to date includes over 1,000 storage nodes providing hundreds of terabytes of storage.
The Google File System is a scalable distributed file system designed to meet the rapidly growing data storage needs of Google. It provides fault tolerance on inexpensive commodity hardware and high aggregate performance to large numbers of clients. Key aspects of its design include handling frequent component failures as the norm, managing huge files up to multiple gigabytes in size containing many objects, optimizing for file appending and sequential reads of appended data, and co-designing the file system interface to increase flexibility for applications. The largest deployment to date includes over 1,000 storage nodes providing hundreds of terabytes of storage.
The document describes the Google File System (GFS), a scalable distributed file system designed and implemented by Google to meet its rapidly growing data storage needs. Key aspects of GFS include using inexpensive commodity hardware, supporting large files and high throughput appending, and providing fault tolerance through replication across multiple servers. GFS differs from previous distributed file systems in its focus on high volume appending over rewriting, use of large files, and relaxed consistency to improve performance for Google's specific workload characteristics.
This document summarizes a technical report about the Gazelle web browser, which is constructed as a multi-principal operating system (OS). Gazelle's Browser Kernel runs as a separate OS process and exclusively manages resource protection and sharing across web site principals (origins). This construction exposes new design challenges not addressed in previous works, such as protecting cross-origin script sources and cross-principal display/events. The report describes Gazelle's security model and architecture, focusing on resource protection, and compares it to other browsers such as Google Chrome. It also discusses Gazelle's implementation in a prototype and evaluations of its performance and compatibility with popular websites.
This document provides definitions and information about common file types including their file extensions and intended uses. It discusses bitmap (.bmp), EPS, GIF, JPEG, PSD, PNG, TIFF, Illustrator (.ai), and PDF file types. For each file type, it describes whether it contains raster or vector data, its color support, compression methods, and whether it is best suited for web, print, or other uses. The document is intended to help understand which file format to use for different applications and programs.
EFLA competition - file and page format.pdfsptlove
The document provides file formatting specifications for a single page submission. It requires the file to be a PDF, with a minimum 300 dpi resolution for images and the file itself. The file size should be less than 15 MB. Color settings should use CMYK and fonts must be 6 points or greater and embedded. The file name should include the submitter's first and last name. The page size is 230 x 155 mm with a 3 mm bleed and the suggested margins are 10 mm from each side. The submitter's name can be included in the top right corner if desired.
This document provides two ways to change the default program that opens a specific file type on Windows 7. The easiest way is to right click a file, select "Open with", and then choose the preferred program from the menu and select the option to always use that program. Alternatively, one can open the Default Programs menu from the Start button, select "Associate a file type or protocol with a program", choose the file type and preferred opening program, and click OK to configure the change.
To download files from Moodle:
1) Log into your course on Moodle using your credentials. Multiple file types like PDF, Word, and PowerPoint can be distributed.
2) Click the link for the file you want - PDFs may open in a new window or embedded in Moodle, while other files give you an option to open or save the file.
3) Opening PowerPoint or Word files depends on your browser - they may open directly or save first before opening with the correct application.
This document provides two ways to change the default program that opens a specific file type on Windows 7. The easiest way is to right click a file, select "Open with", and then choose the preferred program from the menu and select the option to always use that program. Alternatively, one can open the Default Programs menu from the Start button, select "Associate a file type or protocol with a program", choose the file type and preferred opening program, and click OK to configure the change.
This document provides a collection of Unix/Linux commands useful for system administration and advanced users. It covers topics such as system information, processes, file systems, networks, encryption, version control, software installation and more. Each section provides concise explanations of commands within that topic area. The reader is expected to have a working knowledge of Unix-like systems.
The document provides instructions for completing Form I-9, which is used to verify employment eligibility in the United States. The form has three sections. Section 1 is completed by the employee to provide identity and employment authorization information. Section 2 is completed by the employer to examine identity and work authorization documents within 3 days of hire. Section 3 is used to update and reverify employment authorization when needed. Employers must retain completed I-9 forms for 3 years after hire or 1 year after employment ends.
This document summarizes a technical report about the Gazelle web browser, which is constructed as a multi-principal operating system (OS). Gazelle's Browser Kernel runs as a separate OS process and exclusively manages resource protection and sharing across web site principals (origins). This construction exposes new design challenges not addressed in previous works, such as protecting cross-origin script sources and cross-principal display/events. The report describes Gazelle's security model and architecture, focusing on resource protection, and compares it to other browsers such as Google Chrome. It also discusses Gazelle's implementation in a prototype and evaluations of its performance and compatibility with popular websites.
This document provides definitions and information about common file types including their file extensions and intended uses. It discusses bitmap (.bmp), EPS, GIF, JPEG, Photoshop (.psd), PNG, TIFF, Illustrator (.ai), and PDF file types. For each file type, it describes whether it contains raster or vector data, its color support, compression methods, and whether it is best suited for web, print, or other uses. The document is intended as a resource to help understand which file format to use for different programs and purposes.
The document provides file formatting specifications for a single page submission, including:
- File type must be .pdf
- Images must be at least 300dpi resolution
- File size cannot exceed 15mb
- Colour mode should be CMYK
- Font size must be 6 points or greater and fonts embedded
- File name should be in the format of firstname_lastname.pdf
It also specifies the page size at 230x155mm with 3mm bleed, and suggests including name/institution in top right corner.
To download files from Moodle:
1) Log into your course on Moodle using your credentials. Multiple file types like PDF, Word, and PowerPoint can be distributed.
2) Click the link for the file you want - PDFs may open in a new window or embedded in Moodle, while other files give you an option to open or save the file.
3) Opening PowerPoint or Word files depends on your browser - they may open directly or save first before opening with the correct application.
This document provides two ways to change the default program that opens a specific file type on Windows 7. The easiest way is to right click a file, select "Open with", and then choose the preferred program from the menu and select the option to always use that program. Alternatively, one can open the Default Programs menu from the Start button, select "Associate a file type or protocol with a program", choose the file type and preferred opening program, and click OK to configure the change.
This document provides a collection of Unix/Linux commands for system administration tasks. It covers topics such as the system, processes, file system, network, encryption, version control, software installation and more. Each section provides concise explanations of relevant commands and many include page references for further details. Advanced knowledge of the operating system is assumed.
The document provides instructions for completing Form I-9, the Employment Eligibility Verification form used by employers to verify that individuals are authorized to work in the United States. The summary includes:
1) The form must be completed within 3 business days of starting work to verify the identity and employment authorization of all new employees.
2) Section 1 is completed by the employee to provide identity and employment eligibility information. Section 2 is completed by the employer to examine identity and work authorization documents.
3) Acceptable identity and work authorization documents are separated into List A, B, and C. Employers must accept any valid combination of documents from these lists.
4) Completed I-9 forms must be
This document provides definitions and information about common file types including their file extensions and intended uses. It discusses bitmap (.bmp), EPS, GIF, JPEG, Photoshop (.psd), PNG, TIFF, Illustrator (.ai), and PDF file types. For each file type, it describes whether it contains raster or vector data, its color support, compression methods, and whether it is best suited for web, print, or other uses. The document is intended as a resource to help understand which file format to use for different applications and programs.
The document provides file formatting specifications for a single page submission, including:
- File type must be .pdf
- Images must be at least 300dpi resolution
- File size cannot exceed 15mb
- Colour mode should be CMYK
- Font size must be 6 points or greater and fonts embedded
- File name should be in the format of firstname_lastname.pdf
It also specifies the page size of 230x155mm with 3mm bleed and suggests including optional contact information such as name or institution in the top right corner.
To download files from Moodle:
1) Log into your course on Moodle using your credentials. Multiple file types like PDF, Word, and PowerPoint can be distributed.
2) Click the link for the file you want - PDFs may open in a new window or embedded in Moodle, while other files give you an option to open or save the file.
3) Opening PowerPoint or Word files depends on your browser - they may open directly or save first before opening with the correct application.
This document provides two ways to change the default program that opens a specific file type on Windows 7. The easiest way is to right click a file, select "Open with", and then choose the preferred program from the menu and select the option to always use that program. Alternatively, one can open the Default Programs menu from the Start button, select "Associate a file type or protocol with a program", choose the file type and preferred opening program, and click OK to configure the change.
This document provides a collection of Unix/Linux commands for system administration tasks. It covers topics such as the system, processes, file system, network, encryption, version control, software installation and more. Each section provides concise explanations of relevant commands and many include page references for further details. Advanced knowledge of the operating system is expected.
1. The Multi-Principal OS Construction of the Gazelle Web Browser
Helen J. Wang, Chris Grier, Alexander Moshchuk, Samuel T. King, Piali Choudhury, Herman Venter
Microsoft Research, University of Illinois at Urbana-Champaign, University of Washington
{helenw, pialic, hermanv}@microsoft.com, {grier, kingst}@uiuc.edu, anm@cs.washington.edu
MSR Technical Report MSR-TR-2009-16
Abstract
Web browsers originated as applications that people used to view static web sites sequentially. As
web sites evolved into dynamic web applications composing content from various web sites, browsers
have become multi-principal operating environments with resources shared among mutually distrusting
web site principals. Nevertheless, no existing browsers, including new architectures like IE 8, Google
Chrome, and OP, have a multi-principal operating system construction that gives a browser-based OS the
exclusive control to manage the protection of all system resources among web site principals.
In this paper, we introduce Gazelle, a secure web browser constructed as a multi-principal OS.
Gazelle’s Browser Kernel is an operating system that exclusively manages resource protection and shar-
ing across web site principals. This construction exposes intricate design issues that no previous work
has identified, such as legacy protection of cross-origin script source, and cross-principal, cross-process
display and events protection. We elaborate on these issues and provide comprehensive solutions.
Our prototype implementation and evaluation experience indicates that it is realistic to turn an ex-
isting browser into a multi-principal OS that yields significantly stronger security and robustness with
acceptable performance. Our security policies pose some incompatibility, the cost of which requires
further investigation.
1 Introduction
Web browsers have evolved to be a multi-principal operating environment where a principal is a web
site [39]. Similarly to a multi-principal OS, recent proposals [11, 12, 22, 39, 42] and browsers like IE 8 [30]
and Firefox 3 [15] advocate and support abstractions for cross-principal communication (e.g., PostMessage)
and protection (for frames) to web programmers. Nevertheless, no existing browsers, including new archi-
tectures like IE 8 [23], Google Chrome [33], and OP [20], have a multi-principal OS construction that gives
a browser-based OS, typically called Browser Kernel, the exclusive control to manage the protection and
fair-sharing of all system resources among browser principals.
In this paper, we present a multi-principal OS construction of a secure web browser, called Gazelle.
Gazelle’s Browser Kernel exclusively provides cross-principal protection and fair sharing of all system re-
sources. In this paper, we focus on resource protection only.
Browser Kernel runs in a separate OS process, directly interacts with the underlying OS, and exposes a
set of system calls for browser principals. We draw the isolation boundary across the existing browser prin-
cipal1 defined by the same-origin policy (SOP) [35], namely, the triple of <protocol, domain-name, port>,
using sandboxed OS processes. The processes are sandboxed so that they cannot interact with the underly-
ing system and must use system calls provided by Browser Kernel. Principals’ processes can communicate
1
In this paper, we use “principal” and “origin” interchangeably.
1
2. with one another through Browser Kernel using inter-process communications. Unlike all existing browsers
except OP, our Browser Kernel offers the same protection to plugin content as to standard web content.
Such a multi-principal OS construction for a browser brings significant security and reliability benefits
to the overall browser system: the compromise or failure of a principal affects that principal alone, and not
other principals or Browser Kernel.
Although our architecture may seem to be a straightforward application of multi-principal OS construc-
tion to the browser setting, it exposes intricate problems that didn’t surface in previous work, including
dealing with legacy protection for cross-origin script source, display protection, and resource allocations in
the face of cross-principal web service composition common on today’s web. We detail our solutions to the
first two problems and leave resource allocation as future work.
In our browser design, we take the general stance that security (maintaining the multi-principal OS
principles by having Browser Kernel exclusively manage the resource protection and sharing) comes before
backward compatibility. We will not trade significant security risks for compatibility. Nevertheless, we will
also not settle on a design that breaks many parts of the web to secure just a few sites. We present design
rationales for such decisions throughout our design.
We have built an IE-based prototype that realizes Gazelle’s multi-principal OS architecture and at the
same time utilizes all the backward-compatible parsing, DOM management, and JavaScript interpretation
that already exist in IE. Our prototype experience indicates that it is feasible to turn an existing browser into
a multi-principal OS while leveraging its existing capabilities.
With our prototype, we successfully browsed 19 out of the 20 Alexa-reported [5], most popular sites that
we tested. The performance of the prototype is acceptable, and a significant portion of the overhead comes
from IE instrumentation, which can be eliminated in a production implementation. We gave a preliminary
evaluation on backward compatibility of the policy enforced by Gazelle for the 100 Alexa-reported, most
popular sites. By enforcing Gazelle’s security policy, we modify the behavior of eight out of 100 sites.
For the rest of the paper, we first give an in-depth comparison with related browser architectures in Sec-
tion 2. We then describe Gazelle’s security model contrasted with existing browsers’ policies in Section 3.
In Section 4, we present our architecture, its design rationale, and how we treat the subtle issue of legacy
protection for cross-origin script source. In Section 5, we elaborate on our problem statement and design for
cross-principal, cross-process display protection. We give a security analysis including a vulnerability study
in Section 6. We describe our implementation in Section 7. We measured the performance of our prototype
and studied Gazelle’s backward compatibility with popular sites. We detail our evaluation methodology and
results in Section 8. Finally, we conclude and address future work in Section 9.
2 Related Work
In this section, we discuss related browser architectures and compare them with Gazelle.
In concurrent work [33], Reis et al detailed the various process models supported by Google Chrome: 1)
monolithic process, 2) process-per-browsing-instance, 3) process-per-site-instance, and 4) process-per-site.
A browsing instance contains all interconnected (or inter-referenced) windows including tabs, frames and
subframes despite their origin. A site instance is a group of same-site pages within a browsing instance. A
site is defined as a set of origins, as defined by SOP, that share a registry-controlled domain name, that is,
attackerAd.socialnet.com, alice.profiles.socialnet.com, and socialnet.com share the same registry-controlled
domain name socialnet.com, and are considered to be the same site or principal by Google Chrome. Google
Chrome uses the process-per-site-instance model by default. Furthermore, Reis et al [33] gave the caveats
that Chrome’s current implementation does not support strict site isolation in model 3 and 4: embedded
principals, such as a nested iframe sourced at a different origin from the parent page, are placed in the
same process as the parent page.
2
3. Process models 1 and 2 of Google Chrome are insecure since they don’t provide memory or other re-
source protection across multiple principals in a monolithic process or browser instance. Model 4 doesn’t
provide failure containment across site instances [33]. Google Chrome’s process-per-site-instance model is
the closest to Gazelle’s two processes-per-principal-instance model, but with several crucial differences: 1)
Chrome’s principal is site (see above) while Gazelle’s principal is the same as the SOP principal. Chrome’s
decision is to allow a site to set document.domain to a postfix domain (ad.socialnet.com set to social-
net.com). We argue in Section 3 that this practice has significant security risks. 2) A parent page’s principal
and its embedded principals co-exist in the same process in Google Chrome, whereas Gazelle places them
into separate processes. Pursuing this design led us to new research challenges including cross-principal,
cross-process display protection (Section 5). 3) Plugin content from different principals or sites share a plu-
gin process in Google Chrome, but are placed into separate processes in Gazelle. 4) Chrome also relies on
its rendering processes to correctly control network requests to enforce the same-origin policy. These dif-
ferences indicate that in Chrome, cross-principal (or -site) protection takes place in its rendering processes
and its plugin process, in addition to its Browser Kernel. In contrast, Gazelle’s Browser Kernel functions as
an OS, managing cross-principal protection on all resources, including networking and display.
The OP web browser [20] uses processes to isolate browser components (i.e., HTML engine, JavaScript
interpreter, rendering engine) as well as pages of the same origin. OP allows any security model to be
specified with such a framework. However, this flexibility comes with cost — intimate interactions between
browser components, such as JavaScript interpreter and HTML engine, must use IPC and go through its
browser kernel. When targeting a specific security model, such as that of existing browsers or Gazelle, the
additional IPC cost does not add any benefits: isolating browser components within an instance of a web
page provides no additional security protection. Furthermore, besides plugins, basic browser components
are fate-shared in web page rendering; the failure of any one browser component results in most web pages
not functioning properly; therefore, process isolation across these components doesn’t provide any failure
containment benefits either. Lastly, OP’s browser kernel doesn’t provide all the cross-principal protection
needed as an OS: it delegates display protection to its processes.
IE 8 [23] uses OS processes to isolate tabs from one another. This granularity is insufficient since a user
may browse multiple mutually distrusting sites in a single tab and a web page may contain an iframe with
content from an untrusted site (e.g., ads).
Tahoma [10] uses virtual machines to completely isolate (its own definition of) web applications, disal-
lowing any communications between the VMs. A web application is specified in a manifest file provided to
the virtual machine manager and typically contains a suite of web sites of possibly different domains. Con-
sequently, Tahoma doesn’t provide protection to existing browser principals. In contrast, Gazelle’s Browser
Kernel protects browser principals first hand.
3 Security model
3.1 Background: security model in existing browsers
The access and protection model for various resources are inconsistent in today’s browsers. These incon-
sistencies present significant hurdles for web programmers to build robust web services. In this section, we
give a brief background on the relevant security policies in existing browsers. Michal Zalewski gives an
excellent and the most complete description of existing browsers’ security model to date [44].
Script. The same-origin policy (SOP) [35] is the central security policy on today’s browsers. SOP gov-
erns how scripts access the HTML document tree and remote store. SOP defines the origin to be the triple of
<protocol, domain-name, port>. Two documents from different origins cannot access each other’s HTML
documents using the Document Object Model (DOM), which is the platform and language neutral interface
that allows scripts to dynamically access and update the content, structure and style of a document [13]. A
3
4. script can access its document origin’s remote data store using the XMLHttpRequest object, which issues
an asynchronous HTTP request to the remote server [41]. (XMLHttpRequest is the cornerstone of the AJAX
programming.) SOP requires a script to issue an XMLHttpRequest to only its enclosing page’s origin. A
script executes as the principal of its enclosing page though its source code is not readable in a cross-origin
fashion.
For example, an <iframe> with source http://a.com cannot access any HTML DOM elements from
another <iframe> with source http://b.com and vice versa. a.com’s scripts (regardless of where the scripts
are hosted) can issue XMLHttpRequests to only a.com. Furthermore, http://a.com and https://a.com are
different origins because of the protocol difference.
Cookies. Cookies have a different security policy from that of script. For cookie access, the princi-
pal is defined to be the URL including the path, but without the protocol [18, 28]. For example, if the
page a.com/dir/1.html creates a cookie, then that cookie is accessible to a.com/dir/2.html and other pages
from that directory and its subdirectories, but is not accessible to a.com/ . Furthermore, https://a.com/ and
http://a.com/ share the cookie store unless a cookie is marked with a “secure” flag. Non-HTTPS sites may
still set secure cookies in some implementations, just not read them back [44]. The browser ensures that
a site can only set its own cookie and that a cookie is attached only to HTTP requests to that site. The
path-based security policy for cookies doesn’t play well with SOP for scripts: Scripts can gain access to all
cookies belonging to a domain despite path restrictions because scripts can access all resources in a domain
regardless of the paths.
Plugins. Current major browsers cannot enforce any security on plugins because plugins are allowed
to interact with the local operating system directly. The plugin content is subject to the security policies
implemented in the plugin software rather than the browser.
3.2 Gazelle’s security model
Unified SOP across all resources. Gazelle’s security model is centered around protecting principals from
one another by separating their respective resources into hardware-isolated protection domains. Any sharing
between two different principals must be explicit using cross-principal communication (or IPC) mediated
by Browser Kernel.
We use the same principal as SOP, namely, the triple of <protocol, domain − name, port>. While it
is tempting to have a more fine-grained principal, such as a path-based principal, we need to be concerned
with co-existing with current browsers [39] [25]: The protection boundary of a more fine-grained principal,
such as a path-based principal would break down in existing browsers. It is unlikely that web programmers
would write very different versions of the same service to accommodate different browsers; instead, they
would forego the more fine-grained principal and have a single code base.
The resources that need to be protected across principals [39] are memory such as the DOM objects
and script objects, persistent state such as cookies, display, and network communications. With a principal-
driven approach, we have a consistent security policy across all these resources. This is unlike current
browsers where the security policies vary for different resources. For example, cookie uses a different
principal than that of DOM objects (see the above section); descendant navigation policy [7] [8] also cross
the SOP principal boundary implicitly (more in Section 5.1). We support some backward compatibility
when there are no perceived security risks, such as certain cross-principal cookie accesses (more later),
through the explicit use of cross-principal communications.
We extend the same principal model to all content types except scripts and style sheets (Section 4): the
elements created by <object>, <embed>, <img>, and certain types of <input>2 are treated the same
as an <iframe>; if the included content is from a different origin, the content belongs to the principal
2
<input> can be used to include an image using a “src” attribute.
4
5. of that origin. This means that we enforce SOP on plugin content3 . This is consistent with the existing
movement in popular plugins like Adobe Flash Player [19]: Starting with Flash 7, Adobe Flash Player uses
the exact domain match (as in SOP) rather than the earlier “superdomain” match (where www.adobe.com
and store.adobe.com have the same origin) [2]; and starting with Flash 9, the default ActionScript behavior
only allows access to same-origin HTML content unlike the earlier default that allows full cross-origin
interactions [1].
Mixed HTTPS and HTTP Content. When an HTTPS site embeds HTTP content, browsers typically
warn users about the mixed content since the HTTPS site’s content can resist a network attacker, but the
embedded HTTP content could be compromised by a network attacker.
When an HTTPS site embeds other HTTP principals (through <iframe>, <object>, etc.), HTTPS
principals and HTTP principals will have different protection domains and won’t interfere with each other.
However, when an HTTPS site embeds a script or style sheet delivered with HTTP, existing browsers
would allow the script to run with the HTTPS site’s privileges (after the user ignores the mixed content
warning). This is dangerous because a network attacker can then compromise the HTTP-transmitted script
and attack the HTTPS principal despite its intent of preventing network attackers. Therefore, in our system,
we deny rendering HTTP-transmitted scripts or style sheets for an HTTPS principal.
Subdomain treatment. Existing browsers and SOP make exceptions for subdomains (e.g., news.google.-
com is a subdomain of google.com) [35]: a page can set the document.domain property to suffixes of
its domain and assumes that identity. This feature was one of the few methods for cross-origin frames to
communicate before the advent of postMessage [23]. Changing document.domain is a dangerous practice
and violates the Principle of Least Privilege: Once a subdomain sets its domain to a suffix, it has no control
over which other subdomains can access it. This is also observed by Zalewski [44]. Therefore, in Gazelle,
we don’t allow a subdomain to set document.domain.
Nevertheless, we do need to be concerned of backward compatibility when it comes to cookie access.
Today, a subdomain can access a suffix domain’s cookies, which is widely used for features, such as single
sign-on. We support this through the use of cross-principal communications.
4 Architecture
4.1 Basic Architecture
Figure 1 shows our basic architecture. Different principals are placed into separate protection domains so
that they are protected from one another. Just as in desktop applications where instances of an application
are run in separate processes for failure containment, we run instances of principals in separate protection
domains for the same purpose. For example, when the user browses the same URL from different tabs,
it corresponds to two instances of the same principal; when a.com embeds two b.com iframes, the b.com
iframes correspond to two instances of b.com; however, the frames that share the same origin as the host
page are in the same principal instance as the page. Our principal instance is similar to Google Chrome’s
site instance [33], but with two crucial differences: 1) Google Chrome considers the sites that share the same
registrar-controlled domain name to be from the same site, so ad.datacenter.com, user.datacenter.com, and
datacenter.com are considered to be the same site and belong to the same principal. In contrast, we consider
them as separate principals. 2) When a site, say a.com, embeds another principal’s content, say an iframe
with source b.com, Google Chrome puts them into the same site instance. In contrast, we put them into
separate principal instances.
3
OP [20] calls this plugin policy the provider domain policy.
5