Bootable USB keys (continued due to lock of unknown origin)

[lo5750ul]

Hi all,

Peter, thank you very much for your post. You are the only one to have touched upon the topic of my question.

I am not simply asking about a BIOS supporting USB; I need to understand the architecture of the USB key - the USB interface, the drive controller, the memory I/O etc. This is not a subject that I feel would find an appropriate answer in the Tech Supprt or General Hardwre forums as I am looking for sub-system designs, IO controls, and circuit design etc.

This is the highly technical forum, and I am looking for highly technical people to help. This is very important, because out of 10 different USB keys we have some that boot, and some that do not.

Thank you all very much in advance.

Note to moderator: If you feel the need to lock this post, please have the courtesy to inform me of your reasons, as I saw no reason for my first post to be locked, and thus do not want to antagonise you any further by making this post.

 

[Lynx516]

If you could rephrase your question into for example. "What is the mechanicsm for and the control systems behind, bootable USB devices" we would be able to help you more and would avoid posts being locked accidentaly.

 

[Peter]

As I said in the original thread, an USB key implements a "Mass Storage" device as defined in the USB standards. www.usb.org for in-depth information on what exactly that implies.

On the hardware side, you typically get a dedicated USB interface/Flash controller combo chip (duh) and one or two FlashROM chips (double duh) There's not much inside them.

 

[lo5750ul]

The problem does not seem to lie in the Host USB to Device USB bus interface, because all the keys enumerate in the same way. The issue lies somewhere inside the key.

For example, I can fdisk (and set the partition active) and format /s the key after booting with a Win98 boot floppy. The key will then boot fine.

If I then use PowerQuest ImageCenter to create an image of the USB key, and use PQIDeploy to put the image back on to the key, PQID reports the key has bad fat entries, and the key will not boot, even though fdisk will show the partition is still active, and all the IO.SYS, MSDOS.SYS & COMMAND.COM files are on the key.

There has got to be something in the drive controller or memory controller that is causing this issue.

 

[Peter]

I'd rather say that the PowerQuest tool is screwing up, in cooperation with the DOS USB mass storage services provided by the board's BIOS.

 

[Mday]

it got locked because this type of discussion is considered off topic.

although, it would be nice to know which ones are bootable...

 

[lo5750ul]

I do not think PQ is causing the problem, because it works fine on some keys and not others. Hence I think there is are issues with the different controllers in the keys. I assumed that this was the right forum because my questions are very technical.

In which forum would this post be better answered?

Cheers.

 

[TerryMathews]

Originally posted by: lo5750ul

In which forum would this post be better answered?

Cheers.

Technical Support.