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Multibooting and Partitioning Experiments

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saikee:
Sorry I could only log onto this site at the home computer because the site is banned by my office network.

It is nice to talk to someone involved in the inner working of MS systems as I am not IT-related.  I don't mind the discussion at all as I don't think I know that much really.  That is why I always qualify myself by various statements and assumptions so that others in the know can step in if something not factual.  Like you I am interested in the technical side and just able to do it isn't good enough for me.

On the MBR part I think your description is correct as the Bios program only loads the MBR and it is really the code in the MBR that utilises the 64-byte partition table between the 447 and 510th byte.  I used the language loosely as though the Bios would hand over the information to the boot loader.  I suppose in a way it can be correct as once the MBR has been loaded the Bios activities ceases.

On the fat16 partition it is interesting because there are Type 6 for the normal one and type e for the one that use LBA.  I know the type 6 is supported in every MS system and I believe the Type e isn't but I could be wrong on this one.  Can you verify by booting the last official Dos (6.22?) floppy to see if your fat16 partition, created by Win98E, can be seen by it?

You may have a better explanation as you are close to these filing systems that pen drive suppliers adopt fat16 Type 6 for all products below 4Gb and switch to fat32 if the capacity is higher.  Must admit I always stick with the fat16 type 6 because that is what the Dos floppies are capable of handling.

On the VMware side my free version of an installed Linux inside a MS Windows is just a file.  I can't even from one Linux see another guest Linux under the same Host.  If you have done it from an boot up CD that may be something different or you have extra bits and pieces over and above the free VMware server software that I have.

In a real Linux as against a vitual machine one can access any other installed real Linux by mounting their partitions.  What is more one can "change root" into another Linux thereby able to work on another Linux internally.  I believe for someone like you I should describe it as using the kernel of Linux B in combination with a Bash terminal of Linux B.

The partition type is just the 5th byte in the 16-byte partition table but I don't think MS system use it publicly in the partition creation programs even though it is widely utilitised in the Unix-like systems.

Lastly I may as well learn something from you.  It is concerning install a "stand alone" MS system in a logical partition.

The way I understand the MS systems is they seem to share a common MBR up to and including XP and only get changed with Vista.  This is because I always restore a Win2k or xp MBR with a Dos 6.22 floppy and when it come to restore a Dos 6.22 MBR I use a XP installation CD.

I am sure there are difference but the main functionality is the same.

I read that MS MBR's function is primarily to search the 4 primaries and boots the one with the bootable flag switched on.  MS MBR doesn't care what the system inside and I have used this feature to make a XP's MBR to boot up Grub (host in a dta-only primary partition as I can use XP disk management to toggle the active partition).

Now only a primary partition uses the booting flag.  Although booting flag is availabe in the logical partitions but I am not aware any OS uses it.  The booting flag is also pretty loose in the logical partitions because unlike in the primaries where one partition toggled on will automatically toggling the existing one off.  For logical partitions we can set several of them active.  Linux of course never use the booting flag.

The other aspect of logical partition is one can create 63 partitions in a Pata disk and XP and Vista has no objection of mounting them (not 100% sure with Vista but XP has no problem).  Would a MS system installer be able to select any of these partitions for installation?

My puzzle is if a MS system can survive as a "stand alone" OS in a logical partition how does it boot itself?  Everything about its MBR say it cannot be done.

Here is the Microsoft own web page stating the limit of fat16.  I suppose if one can break this limit one can explain it too.

mikiem:
Don't know if it's of any use or even curiosity, Wolf, but since Xp came out in Beta I've been running both 98 SE & XP on the same drive partition... Most of the supporting files work well together, and I've only had a relative few cases where I had to fool with the registry &/or install the same software to 2 folders. Even shared the same folders for Outlook Express so mail was in sync between the 2, which was handy for the 1st year or so.

Since Beta I've been running Vista as well, though that one on a separate partition. Most of the time though I'm still able to use the same program folders for software across all 3 -- if/when an install is required, I just have to be careful to rename the uninstall files accordingly. Much of the time I've also been able to get away without several separate installs... Exporting a program's reg keys under the 2 software sections, then merging with the reg in a different version of windows has worked surprisingly often, and proven invaluable for some older software I still use, where either the install may not run in Vista, or it's been so long I'm not sure where the original discs are.

Again, don't know if any of that is of interest or not -- mostly wanted to point out my experience sharing program folders and partitions, and that it can work well over time (I still use software I installed in '98 in it's original folder etc. in Vista today). Not bragging or whatever, but according to whatever I've read you shouldn't be able to do either, and that's obviously wrong.

wolf.b:
Hi saikee,

I probably should start by explaining what I think might have lead to misunderstandings. I was not careful enough to give enough details on what exactly I have done. This is the hopefully better version:

I have installed Windows 98 SE to E:\WINDOWS when asked by the installer where to intall (default C:\WINDOWS). That will put everything that otherwise lands in C:\WINDOWS now on a different partition. The same goes for files and folders in C:\Programme (German version) which will land in E:\Programme. But the files that the installer puts into the root end up in the root of C:. Theses are things like a lot of *.log, setup.1st, bootlog.txt, backups of files that were there origionally like msdos.sys (now called msdos.dos), command.com (now called command.dos) and so on. Most important are the new files io.sys and msdos.sys. These are necessary to launch E:\WINDOWS\win.com. So strictly speaking, the BIOS reads the MBR, the MBR looks for a single primary bootable partition and if successful, it reads the boot sector of that primary partition. That boot sector looks for files called winboot.sys or io.sys in the root of the same primary partition where it (boot sector) came from. In case of certain (default may be OK) configurations of msdos.sys I think there is need for config.sys, command.com or autoexec.bat to be able to continue. Io.sys will find the path to win.com from msdos.sys and Windows will start.

Short: I have been able to start Windows 98 SE (installed on a logical drive that sits in the last 2 GB of a 250 GB hard drive) in an attempt to check if it is possible. But I have used a primary bootable partition with two files C:\io.sys and C:\msdos.sys to achieve that goal.

Shorter: I boot from C: to start Windows on E:.

I don't know if any of my previous posts were misleading in a way that makes it look as I have "booted" from logical drive E: without using any startup files on primary C:.

In my defense I quote my initial post#1 from the start of the thread:
Most (maybe all) OS for PC run well when they are installed on a logical drive and I boot from a matching DOS floppy. So I thought maybe they also run well when booting from a small primary DOS partition

--- End quote ---

Actually there were a lot more files on C: when I did it. Next experiment was to use a spare primary partition to exclude side effects caused by ntldr loading bootsect.dos (512 bytes) to see if it is still possible. In my case ntldr actually is instructed to load a file called C:\SECTOR\msdos710.bin. I didn't think ntldr would influence the basic possibilities, but I checked anyway. Also I have checked that a floppy with only two files can start this installation on E:. In both cases only two files were able to do it. For completeness let me mention that io.sys is unpatched and original, and this is the content of msdos.sys:

--- ---; MSDOS.SYS
; edited by Wolfgang Bernady
; This version is for MS-DOS 7.10 (Windows 98 SE)

[Paths]
WinDir=E:\WINDOWS
WinBootDir=E:\WINDOWS
HostWinBootDrv=E

[Options]
Logo=0
BootSafe=1
DisableLog=1
DoubleBuffer=2
WinVer=4.10.2222

The only DOS version that in my experiments was able to go straight from MBR code to a logical partition was PTS-DOS 32. I think it uses a special IPL inside the MBR to boot DOS from a logical drive, in my case that was E: again. Unfortunately the demo version of PTS-DOS has got a nasty delay of 60 seconds when it boots and I have not felt overly keen on doing much with it. But it surely boots from a logical drive.

Can you verify by booting the last official Dos (6.22?) floppy to see if your fat16 partition, created by Win98E, can be seen by it?

--- End quote ---
MS DOS 6.22 can not see that particular partition, nor can it see the other partition which was between 12 and 14 GB. Furthermore DOS 6.22 was only able to see my DATA partition (physically first logical drive, sits between 2 and 4 GB, FAT16) after I have changed the 5th byte (partition ID) of the extended partition from 0F hex (Extended LBA) to 05 hex (Extended). Even then it could still not see the 12-14 GB partition nor the 248-250 GB partition (BTW both are type 06 hex FAT16, not type 0E hex). That would have been something. Maybe I could try and use NTFS4DOS to find out what happens then.
 
As for USB pen drives, SD cards, CF cards (I have no other media), I really don't know. But I think you are right that the manufacturers choose FAT16 for compatibility with DOS. This makes me think of a USB format tool, that I have seen recently. It offers FAT, FAT32 and NTFS filesystems for pen drives.

My puzzle is if a MS system can survive as a "stand alone" OS in a logical partition how does it boot itself?  Everything about its MBR say it cannot be done.

--- End quote ---
Sorry, my mistake. It needs a floppy, CDROM, USB boot stick, bootable SD card, network or a small primary hard disk partition to boot first, as far as I know only PTS-DOS 32 boots itself on a logical drive.

Untested: if all partitions located in front of our logical drive are hidden, and Windows was installed to C: then you can probably do without msdos.sys. I think that the paths will default to C:\WINDOWS. So if I install Windows 98 to C:\WINDOWS (primary partition), and copy all the files to the first visible logical drive, and hide the primary partition, (or just convert the primary partition to a logical drive) then I could have a way to lock the computer by taking the boot floppy out. Actually I can think of ways to do that with Win2000, WinXP as well, maybe even Vista, but I don't have Vista. I'm getting carried away here.

The Microsoft Knowledge Base page is currently not available, I will have to look it up later.


Hi mikiem,

I find it very interesting what you write about multiple Windows installations on the same drive. I have a collection of tools that I keep on D:\Tools32 and with some of them I have *.reg files to quickly reinstall/repair their configuration. One of my reasons to keep OS separate was that I was unable to install Win95 to eg E:\WIN95 with programs in E:\Progs95 and parallel to that install Win98 to E:\WIN98 with programs in E:\Progs98. The installation was possible, but I could not figure out how to separate the according %ProgramFiles% folders. That's why I chickened out and ended up with installing unproblematic tools to D: drive and Office or other stuff installed twice on separate E: partitions. Have you got any hints to offer on how one could force Win98 to create and use a folder named Progs98 instead of Programs? It should be possible, because on my installation it is called Programme (long file name with PROGRA~1 as DOS name).
The tools in D:\Tools32 actually work very well even on BartPE and the reg files offer quick and dirty installation. I guess in your case that would be the same with BartPE. I have only a small number of tools that I use like that: file manager, text and hex editors, and a few tiny apps that require no installation. I find it most interesting to hear that it has worked for you over a long period of time. Years back when I tried multiple OS one the same drive I noticed that some programs, when you install them inside one OS, and execute them inside the other, they seem to "repair their installation" (ie create the missing registry entries) and work well afterwards. Other times, I installed the same program for both OS into the same folder. But eventually I gave up, because I was not comfortable any more. Nowadays where hard disks are large, it matters little, but back then it did hurt to waste so much space.

... according to whatever I've read you shouldn't be able to do either, and that's obviously wrong.

--- End quote ---
I'm glad to see that I am not alone. I regard my computer as a toy, I take it apart and put it back together again as I please. And when somebody says "You are not supposed to do ..." I find myself quite often in the process of checking what happens, if I don't listen.

I have to add that the ever present threat of "data corruption" or "data loss" is no problem, as I can not loose anything valuable (I backup my files, then backup my backups, then check if all the backups are ok, then I start experimenting). Also I found that the frequent "data losses" that are happening here are no losses at all. I only loose access to files, partitions and so on, because that is what partition hiding is all about. I know what bytes I change in the partition table to hide or delete partitions, and when I change the bytes back these partitions are unhidden or undeleted. The data itself remains untouched.


Greetings
Wolf

wolf.b:
Hi saikee,

On the VMware side my free version of an installed Linux inside a MS Windows is just a file.  I can't even from one Linux see another guest Linux under the same Host.  If you have done it from an boot up CD that may be something different or you have extra bits and pieces over and above the free VMware server software that I have.

--- End quote ---
I am not sure if I understand everything here. I have got several VMware versions: Player 1.1, 1.4, 2.0. Also workstation version 5.5 from a German magazine with a special trial period of 6 months. I can tell you that somewhere was an option to mount a physical disk. Here I could choose to mount the entire disk or to select one or several partitions. So with the physical disk mounted and the ubuntu iso mounted, this VM booted from CD and gave me access to my physical ubuntu installation.
I know that this is a mere repeat of my previous post. But given this layout, I wonder what you want to add. Would you like me to try starting a second VM with ubuntu and network them. Or would you be interested to see if I can do two separate installations with lets say xubuntu and kubuntu on the same VM but on different partitions of the virtual hard disk. Or maybe two virtual hard disks. And wheather those virtual installations and the physical installation can all see each other with read/write access. At that point I am lost as I don't know what to do at the bash prompt apart from launching midnight commander to look at the file system.
I can not offer support for anything, but I have time to play around. In case you or anybody feels like asking questions similar to this: Has anybody tried using VMware player version 1.4 to install Puppy Linux on a Virtual disk and get access to something. Or has anybody tried InnoTek VirtualBox 1.5.0_OSE to do something else, ...

I invite everybody to just ask questions like that if you want. This is one of the friendly forums on the net where people meet, who like other people as well, not only computers. I am sure that there are a lot of forum members who have looked into multibooting and/or did experiment with partitioning schemes.

A word on how I regard myself: I'm not an IT professional, Computers are a hobby since the days of Sinclair ZX Spectrum. The only area inside my computer that I know well are the bytes number 447 to 510 of cylinder 0, head 0, sector 1, found on the first physical hard disk.


Greetings
Wolf

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