Re: [Freedos-user] DOs, or open source boot loaders?

[tom e. <te...@dr...>]

Unfortunately I misspoke ithis - a bit.

>> Boot sequence of legacy BIOS with MBR formated storage media (eg. hard
>> drive with formated MBR partition structures); 1) BIOS looks for MBR
>> activate partition, 2) BIOS then looks for executable boot code, for
>> example DOS IO.SYS/MSDOS.SYS, FreeDOS FDCONFIG.SYS/CONFIG.SYS, are then
>> loaded into memory and executed.

> Unfortunately this is complete nonsense.

> 1) BIOS reads the first sector (512 Byte) on the disk and executes it.
THIS *is* the MBR aka Master Boot Record.

> 2) This code scans the partitiontable (part of the 512 Byte) for an active
> partition, then reads *this* sector and executes it. the MBR.
This is often called the the PBR or Partition Boot Record.

> 3) This sector - which is probably different for FAT12, FAT16, FAT32, EXTFS filesystems
>   and OS. E.g. FreeDOS searches for "KERNEL.SYS", MSDOS searches for IO.SYS, loads it
>   and executes it.

> 4) KERNEL.SYS is then responsible to locate FDCONFIG.SYS and FDAUTO.BAT, COMMAND.COM.

>  
Tom