{"id":117,"date":"2020-03-05T12:26:57","date_gmt":"2020-03-05T12:26:57","guid":{"rendered":"https:\/\/arms10.org\/android\/?p=117"},"modified":"2020-03-05T12:26:59","modified_gmt":"2020-03-05T12:26:59","slug":"implementation-of-android-based-set-top-box","status":"publish","type":"post","link":"https:\/\/arms10.org\/android\/implementation-of-android-based-set-top-box\/","title":{"rendered":"Implementation of Android based set-top box"},"content":{"rendered":"\n

Implementation of Android based set-top box <\/a><\/h2>\n\n\n\n

This paper gives an overview of extending Android system with the Disaster Recovery Agent (DRA). The focus of this paper is on switching from bad, critical system state to working, default system state. Adding this feature involves changing existing bootloader and recovery of Android. <\/p>\n\n\n\n

Android comes with default, stock recovery console which is very limited. Its main purpose is to perform system updates and wipes user data. Source code of Android is open and has the recovery source code available, so there is a possibility of making custom recoveries. These custom recoveries offer more tools than stock recoveries. Backup and restore, selective deletion of data, mounting various partitions and much more is available using these recoveries. However, there is no recovery which offers automatic system restore when system is corrupted. Our DTV (Digital television) set-box solution runs on Android OS[1], and we need fully automated system update and system recovery. In order to achieve that we have customized stock recovery and developed Disaster Recovery Agent (DRA). In our Android system, Disaster Recovery Agent refers to the dedicated, bootable partition that has DRA console installed. This partition will boot in case of unstable or corrupted system state, and DRA console will be started. Whole DRA system is fully automated, and no user interaction is needed. CodeShoppy<\/a><\/p>\n\n\n\n

DRAFROMBOOTLOADERANDBOOTLOADERCHANGES Starting the Disaster Recovery Agent, or more precisely checking if there is a need to start Disaster Recovery Agent has to be performed during the Android startup sequence. During the Android startup sequence it is easy to find out if there is a bad behavior of important elements of Android OS which can cause Android OS failure. Two processes of Android startup sequence initializes and start these important elements of Android OS. The first process is a system program that loads and starts the operating system \u2013 Bootloader, while the secondprocess is a program that performs initialization and run elements of the Android OS \u2013 init program. Bootloader is code that is executed before any Operating System starts to run. Bootloader sets the instructions to boot an operating system. Every Android device has a bootloader that instructs the operating system kernel [2] to boot normally. There are five steps in bootloader workflow: 1)Configure pinmux for UART and NAND 2)Load and verify System Manager, kick off System Manager 3)Load and verify Linux 4)Send message to System Manager to indicate Linux boots up 5)Start Linux Kernel First critical point of this workflow is \u201cLoad and verify Linux\u201d step. In this step boot and kernel image should be loaded. If some error occurs here, system will not be able to boot. In order to avoid system boot failure, we have added error checking subsystem here which will initiate proper actions if an error occurs. At starting point, bootloader is in normal boot mode and tries to load and verify boot and kernel image. If bootloader fails it will set flags for DRA boot mode, and notify system manager about failure, and the boot mode change. Then DRA will be loaded in step \u201cLoad and verify Linux\u201d. <\/p>\n\n\n\n

DRA FROM SYSTEM INITIALIZATION AND INIT PROGRAM CHANGES One key component of the Android bootup sequence is the program \u201cinit\u201d. This is program which initialize elements of Android system. The Android \u201cinit\u201d program processes two files and executes all the commands it finds in them. The first file is the \u201cinit.rc\u201d and the second one is the \u201cinit.{nameofmachine}.rc\u201d, where \u201cnameofmachine\u201d is the code word for the hardware that Android OS is running on. The file \u201cinit.rc\u201d is used for general initialization, and \u201cinit.{nameofmachine}.rc\u201d is used for machine-specific initializations. If some crucial part of initialization fails to execute, the system will not boot and probably get caught in a \u201cboot loop\u201d. \u201cBoot loop\u201d is an endless rebooting process caused by the boot failure.The \u201cBoot loop\u201d failure is avoided with the boot failure counter and Disaster Recovery Agent. If a system fails to boot for a specific number of times, it is rebooted with DRA parameters for boot. Changes made in the \u201cinit\u201d program are related to a signal handler [3] of the \u201cinit\u201d program. Signal handler of the \u201cinit\u201d program is realized to wait for the SIGCHLD signal. The SIGCHLD signal is sent to the parent of a child process when it exits, is interrupted, or resumes after being interrupted. The \u201cinit\u201d program represents parent process, while all programs and elements which \u201cinit\u201d program initializes and starts represent child processes. If a SIGCHLD signal for some program from initialization process is caught, a crash counter is increased. If this crash counter reaches a specific value, a reboot command with DRA specific parameters will be executed. <\/p>\n\n\n\n

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https:\/\/codeshoppy.com\/php-projects-titles-topics.html<\/a><\/pre>\n","protected":false},"excerpt":{"rendered":"
Implementation of Android based set-top box This paper gives an overview of extending Android system with the Disaster Recovery Agent (DRA). The focus of this paper is on switching from bad, critical system state to working, default system state. Adding this feature involves changing existing bootloader and recovery of Android. Android comes with default, stock… Continue reading Implementation of Android based set-top box<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_joinchat":[]},"categories":[306],"tags":[],"yoast_head":"\nAndroid App Ideas - Implementation of Android based set-top box - Arms10 - Android<\/title>\n<meta name=\"description\" content=\"Android App Ideas - Implementation of Android based set-top box - Download abstract and Buy source code sonline for android PHP Project ideas 2020 - Arms10 - Android\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/arms10.org\/android\/implementation-of-android-based-set-top-box\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Android App Ideas - 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