bootstrap loader การใช้

• The regular loader read a more compact format tape than the bootstrap loader.
• This allows a program to be loaded without the need for a ROM-based bootstrap loader.
• The default bootstrap loader is GNU GRUB version 2, though the package name is simply grub, while version 1 was renamed to grub-legacy.
• The CPU additionally contained instructions, operator communication, bootstrap loaders, and hardware test programs, that were implemented in a 1K read-only memory.
• A "'RAM image "'is a sequence of machine code instructions and associated data kept permanently in the non-volatile bootstrap loader.
• Since the early minicomputers used magnetic core memory, which did not lose its information when power was off, these bootstrap loaders would remain in place unless they were erased.
• It would often take upwards of five minutes to load the tiny program into memory, and a single error while flipping the switches meant that the bootstrap loader would crash the machine.
• In order to do anything useful, the user had to enter a small program known as the " bootstrap loader " into the machine using these switches, a process known as booting.
• A user would normally use the " ( L ) oad " command to load a bootstrap loader ( i . e ., for CP / M ) from a floppy or the fixed disk.
• When a Windows system boots, the bootstrap loader ( the same that loads the kernel and other boot files, such as boot drivers, from the boot partition ) loads the SYSTEM file into memory.
• To program the machine after switching it on the bootstrap loader program had to be entered, without error, in binary, then a paper tape containing a BASIC interpreter loaded from a paper-tape reader.
• But DISKZ started its sector addressing with the first available unused sector, while the others started with sector zero of the disk, making it easy for a Fortran programmer dabbling in assembler to inadvertently overwrite the bootstrap loader.
• When Intel designed the 286, it was not designed to be able to multitask real-mode applications; real mode was intended to be a simple way for a bootstrap loader to prepare the system and then switch to protected mode.
• The term " boot " comes from the idea of lifting oneself by one's own bootstraps : the computer contains a tiny program ( bootstrap loader ) which will load and run a program found on a boot device.
• In the case of a computer, the POST routines are part of a device's "'pre-boot sequence "'and only once they complete successfully is the bootstrap loader code invoked to load an operating system.
• The first 8 byte data area contains a PSW which, when fetched at the conclusion of the IPL, causes the CPU to branch to the bootstrap loader ( called " IPL Text " ) at the main storage address where it was just loaded.
• Typically the RAM image is loaded into RAM when the system is switched on, and it contains a second-level bootstrap loader and basic hardware drivers, enabling the unit to function as desired, or else more sophisticated software to be loaded into the system.
• In conjunction with LOADER, Multiuser DOS and REAL / 32 boot sectors use this to locate the boot sector of the active partition ( or another bootstrap loader like IBMBIO . LDR at a fixed position on disk ) if the boot file ( LOADER . SYS ) could not be found.
• The VBR is loaded at memory location 0000h : 7C00h and with the following CPU registers set up when the prior bootstrap loader ( that is, typically the BIOS or MBR, but possibly another boot loader ) passes execution to it by jumping to 0000h : 7C00h in the CPU's real mode.
• These techniques could generally be easily circumvented since the code to read the bad sectors was usually in the bootstrap loader on the disk itself, so by reverse engineering and rewriting the bootstrap loader, it would not look for the bad sectors, and the comparison for a known bit pattern would have to be encoded there, too.