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Questions tagged [mbr]

Master Boot Record: the first sector on disk, containing partition info

A Master Boot Record (MBR) is a special type of boot sector at the very beginning of partitioned computer mass storage devices. The MBR holds the information on how the logical partitions, containing file systems, are organized on that medium.

It identifies how and where an operating system is located, so that it can be bootstrapped.

Wikipedia with full partition table info

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Why doesn't BIOS load the Linux Kernel directly - why the MBR and all that trouble?

I've recently learned about the boot process for Linux. I can't help but wonder why we go through the trouble of acccessing the MBR after BIOS so that instructions there can, in turn, load the kernel into RAM. Why the middle man - why doesn't BIOS…
PinkElephantsOnParade
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winapi c - read/write mbr of system drive

Does anyone have any example code that shows how to identify the system boot harddisk, and read/write the mbr from the harddisk in windows xp and vista? I know createfile can be used. But I do not know how to properly identify which device is the…
kiasecto
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dos boot before win7 boot

I've got a question for dos & win7 boot process. Is it possible that dos boot and execute some dos-app before win7 boot without reboot? I mean boot process like win95 or win3.1. I'll explain more detail. dos boot -> execute some dos app ->…
Ruony
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Can I use ffmpeg to create multi-bitrate (MBR) MPEG-4 videos?

I am currently in a webcam streaming server project that requires the function of dynamically adjusting the stream's bitrate according to the client's settings (screen sizes, processing power...) or the network bandwidth. The encoder is ffmpeg,…
hoangbv15
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Image is not of type ARM barebox image but of type MBR sector, update failed

I have phyBOARD-MIRA i.MX6 development board from PHYTEC. It comes with preinstalled barebox bootloader on NAND Flash, and one can build embedded Linux distribution (more or less) easily using Yocto and documentation of PHYTEC. I have built new…
Ricky12
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Trying to run a simple bootloader in qemu

I am trying to run a simple bootloader with a dummy kernel in qemu, the bootloader seems to work fine, I get no errors running qemu or commands compiling it, just a warning from qemu that probing guessed raw. My boot loader is : [org 0x7c00] [bits…
kwphil
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How to write message to MBR without affecting MBR initialization functionality in C#?

I was studying the MBR (Master Boot Record) of Windows, and I found that it can be modified and show a message, I was looking more about it on GitHub, and I found SyfuMBR and Fuc.MBR, only they are not very relevant to me because they just destroy…
Junior Plays
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How do i Implement a variant of connect that takes and offset and a length and returns a single partition?

Currently working on a mirage block partition issue. "The current connect interface has the nice property that it is difficult to create overlapping partitions. However, in the context of Mirage the Functoria API doesn't have a concept of pairs. It…
rotensepro
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In mbr start.S, does the way the Ax register is set affect subsequent mbr interpretation

As we know, the first step in mbr is to set the segment register to 0. But there can be two methods to set the segment register, first we can use "xorw %ax, %ax" to set AX to 0, and second we can use "movw %cs, %ax" to set AX, then we will use the…
ruoqiu
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How to read year info from MBR

I want to fetch the year information from the MBR. Here is my approach for this problem. For any program, whenever we use 'version' flag we get the year information also. I gues it is the release year of that tool. For example, ls --version ls (GNU…
atulya
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Set virtual address of section to custom byte

I'm trying to put a small boot loader into the mbr of an exfat drive, but I'm having trouble getting ld to set the virtual address correctly. according to the ExFat Specification, I need to put the bootloader at byte 0x78 (120). So I set the…
an inconspicuous semicolon
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Assembly and C project loop

I am trying to get my C program to run on a computer with no operating system. I have a version of an MBR that just prints a (!), but when i try to add code to run my C program, as shown here the machine just reboots infinitely. I only just got the…
Evan McAfee
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I am trying to print a string that contains the ascii letters signatures of the master boot record

But it just prints an empty string, unless I set the address to something like 0x00 or 0x20, then it prints some ascii characters . Also I am new to assembly and x86 segmentation so I barely know if I am doing things right . INT 10H 1300H: Display…
Todor Yanev
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Does the first sector (MBR) of a flash drive get executed on insertion into a computer

Do the first 512 bytes get executed whenever I insert the flash drive into any computer? If yes (which should be the case), then I suppose if I extract and disassemble the MBR and put in a reference that points to a memory location of a stored…
Rushil Paul
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How can I copy an existent BPB and put it in my bootloader code

I am currently working on a simple operating system (GitHub: https://github.com/Nutty000/PlanetOS) I would like to make the os work on real hardware, but I am having trouble doing it because of the file system... I want my OS to be based on the…
Nutty
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