Sample Critique Essay

1353 Words May 24th, 2013 6 Pages
No Name
WRTG 393

Part I: Technical Description
Jailbreaking an Iphone

An Apple iPhone is a popular multimedia, internet based smartphone sold and marketed by Apple, Inc. An iPhone can function as a video camera (video recording was not a standard feature until the iPhone 3GS was released), a camera phone, a portable media player, and an Internet client with email and web browsing capabilities, can send texts and receive visual voicemail, and has both Wi-Fi and 3G connectivity. The user interface is built around the device's multi-touch screen, including a virtual keyboard rather than a physical one. Third-party as well as Apple applications software is run on the iPhone to increase the functionality. These
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Aside from third-party applications, one of the most common reasons for jailbreaking an iPhone is to unlock it. Unlocking an iPhone breaks the lock on the SIM card and allows the phone to work with all carriers, not just the official, Apple-approved carrier. When an iPhone boots up, it walks through a chain of command, which is a series of signature checks among software components always done in a specific order. It begins with boot ROM which controls the booting, moves on to loading low-level bootloader software which controls general data storage and transfer between computers and digital devices, then iBoot, then the operating system kernel, and finally the operating system kernel loads all the user applications. As the chain of command is executed when you turn on your iphone, checks are being done for any unauthorized software. When you jailbreak an iPhone you're modifying, or patching, the iBoot and operating system kernel in this process, rendering them unable to do the digital signature checks that evaluate and distinguish authorized or unauthorized software. Jailbreaking an iPhone differs from iPhone to iPhone, it depends on what version of firmware the phone is running and if your computer is Windows or Mac. To do it you need an iPhone, a computer with the latest version of iTunes installed, a downloaded

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