bios ?
Posted: Thu Apr 07, 2011 3:27 pm
I have a bios that supports booting from usb.
I have 2 usb harddrives one is older then the other.
I can successfully boot my OS that was installed on the older usb hardrive but not the newer one.
I have 2 main questions
Question 1
I am wondering how the bios is able to access and boot from a usb. Does it still use the int 13 extended command in some way. What is the hex value given to a usb hardrive(i.e 80h is primary harddrive ,..etc etc). How does the bios assign numbers to usb devices and access them? ( assuming it is similar to floppy, harddrive, optical drive ,...etc)
Question 2
one harddrive is usb 2.0 but the newer one is usb 3.0 ( I know they should be backwards compatible but would this lead to any problems)
I am wondering if their is away other then trying to find a firmware update for my bios that would work for both devices.
I know both operating systems on the 2 usb harddrives are good because both work on my parents "new computer" which supports booting from usb.
I have 2 usb harddrives one is older then the other.
I can successfully boot my OS that was installed on the older usb hardrive but not the newer one.
I have 2 main questions
Question 1
I am wondering how the bios is able to access and boot from a usb. Does it still use the int 13 extended command in some way. What is the hex value given to a usb hardrive(i.e 80h is primary harddrive ,..etc etc). How does the bios assign numbers to usb devices and access them? ( assuming it is similar to floppy, harddrive, optical drive ,...etc)
Question 2
one harddrive is usb 2.0 but the newer one is usb 3.0 ( I know they should be backwards compatible but would this lead to any problems)
I am wondering if their is away other then trying to find a firmware update for my bios that would work for both devices.
I know both operating systems on the 2 usb harddrives are good because both work on my parents "new computer" which supports booting from usb.