en:docs:boot:freeldr:history

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en:docs:boot:freeldr:history [2014/05/21 21:12]
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en:docs:boot:freeldr:history [2019/01/13 20:15] (current)
valerius
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 But then it was realized, that the 16-bit internals make more difficult implementing the loader extensions and access the whole machine physical memory. The 64k limitation makes it hard to use more than 64k in loader executable. We were planned to use MSDOS style executables first. As our [[wp>​bootloader|bootloader]] was written in C with small amount of assembly code, the 64k could be reached soon. Then we decided to switch to FLAT 32-bits memory model and protected mode, and take [[http://​www.gnu.org/​software/​grub/​|GRUB]] scheme as a sample. But then it was realized, that the 16-bit internals make more difficult implementing the loader extensions and access the whole machine physical memory. The 64k limitation makes it hard to use more than 64k in loader executable. We were planned to use MSDOS style executables first. As our [[wp>​bootloader|bootloader]] was written in C with small amount of assembly code, the 64k could be reached soon. Then we decided to switch to FLAT 32-bits memory model and protected mode, and take [[http://​www.gnu.org/​software/​grub/​|GRUB]] scheme as a sample.
  
-Then, in the beginning of 2007, the new 32-bit protected mode loader was started, almost from scratch. We were still reusing [[http://​www.gnu.org/​software/​grub/​|GRUB]] routines for base [[http://​www.gnu.org/​software/​grub/​grub-2.en.html#​multiboot|multiboot]] support. The [[http://​www.gnu.org/​software/​grub/​|GRUB]] filesystem support code was recomposed to be loaded as separate loader plug-in modules. ([[http://​www.gnu.org/​software/​grub/​|GRUB]] has all FS support code compiled-in. We decided to move it to a separate "​blackboxes"​). Also, we proposed to introduce the new kinds of blackboxes to support different transparent decompression algorithms (http://​www.gnu.org/​software/​grub|GRUB]] had ungzipping on-the fly support, which was compiled-in too), terminal access, executable formats support etc.+Then, in the beginning of 2007, the new 32-bit protected mode loader was started, almost from scratch. We were still reusing [[http://​www.gnu.org/​software/​grub/​|GRUB]] routines for base [[http://​www.gnu.org/​software/​grub/​grub-2.en.html#​multiboot|multiboot]] support. The [[http://​www.gnu.org/​software/​grub/​|GRUB]] filesystem support code was recomposed to be loaded as separate loader plug-in modules. ([[http://​www.gnu.org/​software/​grub/​|GRUB]] has all FS support code compiled-in. We decided to move it to a separate "​blackboxes"​). Also, we proposed to introduce the new kinds of blackboxes to support different transparent decompression algorithms ([[http://​www.gnu.org/​software/​grub|GRUB]] had ungzipping on-the fly support, which was compiled-in too), terminal access, executable formats support etc.
  
 [[en:​docs:​boot:​freeldr:​history]] [[en:​docs:​boot:​freeldr:​history]]

en/docs/boot/freeldr/history.txt · Last modified: 2019/01/13 20:15 by valerius