ReactOS on USB.

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alexei
Posts: 137
Joined: Wed Oct 19, 2005 5:29 pm

ReactOS on USB.

Post by alexei »

It's way "sub-optimal" solution, but it's pretty simple to make SCSI driver that would actually call Int 13h AH=42h/43h to do disk I/O.
That would allow to run ReactOS from USB right away!
Please do it ASAP :)
Many people would like to try ReactOS from USB stick!

Alexei

GreatLord
Developer
Posts: 926
Joined: Tue Nov 30, 2004 10:26 am
Location: Sweden

Post by GreatLord »

alexei it is not so simple as you think

1. we need a working usbstack for usb memory stick
2. we need a usb memory stick loader
3. we need 3 diffent usb protocoll

to start reactos to freeldr are not a real problem
the real problem is freeldr take over the system and loading in ntoskrnl.exe then all driver we need being loading and start.
But we need here a usb stack and protocools and small plug and play
detector to detect usb device then a driver for the usb device as well
after we got all this then reactos is avail boot from usb device. but not
before we got thuse part in place. ReactOS is base on NT and not on DOS
if it was DOS it is pretty simple as u desciver it. But it is not in our case.

h-a-l-9000
Posts: 9
Joined: Mon Dec 26, 2005 3:44 pm

Post by h-a-l-9000 »

Couldn't there be a VDM driver like the VESA one that lets the BIOS access the storage device? It wouldn't be fast but could make ROS start on much like anything without special driver.

alexei
Posts: 137
Joined: Wed Oct 19, 2005 5:29 pm

Post by alexei »

GreatLord wrote:alexei it is not so simple as you think
we need...
No, we don't :) To be precise, we can live without it for a while :)
If you ever track NT loading from USB (or HDD) you would know that it uses Int 13h to access the drive from the very beginning (MBR code) to the point where all boot-time drivers already loaded and started. Also, you probably know that there are a lot of drivers that substitute HDD with some kind of "emulator". To name a few: RamDisk, EWF, SDI, Filedisk.
Modern BIOSes already have USB stack implemented. It allows them to provide unified access any HDD (PATA/SATA/SCSI/USB) via Int 13h calls.
When you select booting from USB-HDD in BIOS setup, the USB drive becomes accessible as drive 80h, which by Int 13h specification is supposed to be 1st HDD. The driver can call int 13h instead of "talking to" HDD controller, though 16-bit thunk is obviously needed to call BIOS interrupts.
As a future perspective it would be better if ReactOS had unified HDD driver that would initially use BIOS (or EFI) and then switch to using appropriate driver for the specific device PATA/SATA/SCSI/USB/Firewire. That would also allow not to use "special" NTLDR (EWFLDR) to support EWF, etc. Unified HDD driver would also superseed NTBOOTDD functionality.
And, as a final note, "Portable NT" is one of the MS worse nightmares, so they made their solutions accordingly :(
Sorry, if my initial post sounded incompetent to you.

Alexei

oiaohm
Posts: 1322
Joined: Sun Dec 12, 2004 8:40 am

Post by oiaohm »

Portable NT is not there worst nightmare.

They all ready produce Portable Editions of XP for high end business to repair machines. If you live in the right places you can make your own USB XP disk. Most likely when reactos is more drive friendly close to the same method might be copy able. http://www.tomshardware.com/2005/09/09/ ... ur_pocket/

Open Source Portable NT damages there means to limit provision of Portable Editions ends. Not much really. Thinking its stuffed in ever country where making you own is legal. Not much difference.

alexei
Posts: 137
Joined: Wed Oct 19, 2005 5:29 pm

Post by alexei »

oiaohm wrote:Portable NT is not there worst nightmare.
They all ready produce Portable Editions of XP for high end business to repair machines. If you live in the right places you can make your own USB XP disk. Most likely when reactos is more drive friendly close to the same method might be copy able. http://www.tomshardware.com/2005/09/09/ ... ur_pocket/

Open Source Portable NT damages there means to limit provision of Portable Editions ends. Not much really. Thinking its stuffed in ever country where making you own is legal. Not much difference.
Facts:
- OS build with "XP Embedded" is not allowed on desktpo.
- "Windows Fundamentals" will not be available through retail or OEM.
- Both MS "Preinstallation Environment" and Bart's PE do not have persistent registry, therefore can't be used as regular OS.

I've never heard of "Portable Editions of XP" with full XP functionality.
Does it exist?

OK, I agree, ReactOS is the worse MS nightmare :lol:

Alexei

hto
Developer
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Joined: Sun Oct 01, 2006 3:43 pm

Post by hto »

IRC is a better place to talk with developers.

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