|
本帖最后由 wuwuzz 于 2016-9-29 06:26 编辑
Sorry for my poor English.
A usb storage device(such as ufd) has different CHS parameter during boot becase different BIOSes have different algorithms.
(we don't think about the other BIOS usb support bug or ufd firmware bug situations)
So during USB Boot normally, a ufd will be boot successful under A BIOS, on the other hand it probably boot fail under B BIOS.
This situation is similar to a hard disk have different modes(Normal/Large/LBA,and so on) and will boot fail when not use corresponding mode
environment in intel 386 times.
UD make customization MBR and mini special file system(normally cost 8MB space),every sector includes boot code.
In order to boot sucessful no matter how BIOS set up ufd CHS.
=======================================================================
But,only my personal opinion,Now I think that UD is not the best way.
Because
1、BIOS/UEFI value UFD'S firmware parameter. MBR(etc) is not most important thing.
So ud's thinking is not always effective.(Stronger BIOSes can cover this)
2、UD use special MBR,is not the most simple、most original MBR -- DOS FAT MBR.
It will make some questions.
3、UD is devloped when we did not know BIOS sorce codes and BIOS how to boot USB.
Now it's better to be different .We can fit BIOS/UEFI accordingly.
Because there are leak of the BIOS/UEFI source code can be some references.
=======================================================================
How to use simple MBR (or complex MBR--although unnecessary )to get most boot compatibility?
We have to find UFD(chip/firmware) that can change firmware parameter be related to USB boot.
Adjust to best parameter value.Use such UFD to make usb boot disk.
This is a fundamental solution. |
|