DOS ain't dead - Considering MS-DOS (now FreeDOS)

paulrichards

08.08.2011, 03:11

Considering MS-DOS (now FreeDOS) - Part 3 (Users)

OK, this is all getting too hard for my tiny mind.

After consideration I decided to use FreeDOS for a Windows XP dual boot configuration. The major reason for that being that with FreeDOS I didn't have to place it in a partition at the beginning of the HD, as is required by MS-DOS (and I didn't want the complications of an originally C:\ based XP becoming D:\ with issues relating to the XP registry not 'knowing' about D:\)

So I shrunk my XP partition and created a FAT32 partition at the 'end' of the HD, this partition becoming D:

I then tried to boot from the FreeDOS Base CD and got the message "InitDiskWarning : Partition ID does not suggest LBA to access partition C:. Invalid Opcode" + a string of hex digits (obviously FreeDOS can't see the XP C: partition and is looking at the 'new' D: partition, as expected.)

So, checking the documentation for my partition software regarding LBA, it basically stated that I needed to make changes in the BIOS, albeit with dire warnings about possible data corruption. But, being an adventurous sort, I rebooted, had a look in the BIOS and there's no reference to LBA. However there is a reference to having SATA enabled with the message "Disabling SATA may be necessary when a legacy OS is used", MS-DOS being a legacy OS, no doubt.

This is all too complicated and fraught with the danger of data loss - and if I can't modify anything to do with LBA I'm stuffed anyway.

I think I'll stick with DOSBox :-(

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Paul
Melbourne, Australia

DOS386

08.08.2011, 03:34

@ paulrichards

Considering DOS (now FreeDOS) Part 3 - LBA48 and > 128 GiB

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> So I shrunk my XP partition and created a FAT32 partition at the 'end' of
> the HD, this partition becoming D:

Is it a primary partition visible in the MBR, rather than a "logical" partition inside an extended partition ?

> I then tried to boot from the FreeDOS Base CD

What one ?

> and got the message
> "InitDiskWarning : Partition ID does not suggest LBA to access partition
> C:. Invalid Opcode" + a string of hex digits (obviously FreeDOS can't see
> the XP C: partition and is looking at the 'new' D: partition, as expected

BUG :-(

> So, checking the documentation for my partition software regarding LBA, it
> basically stated that I needed to make changes in the BIOS, albeit with
> dire warnings about possible data corruption.

Size of your HD ? I suspect > 128 GiB, so the warn is about LBA48 vs LBA28 ...

> But, being an adventurous
> sort, I rebooted, had a look in the BIOS and there's no reference to LBA.
> However there is a reference to having SATA enabled with the message
> "Disabling SATA may be necessary when a legacy OS is used"

Your PC seem to be to new for CHS vs LBA issues ... but maybe FreeDOS could work with SATA too (via BIOS) ?

Anyone tested FreeDOS with LBA48 and > 128 GiB disks ? I don't have such stuff :-(

The other solution is to get another HD, and put FreeDOS onto it (HD0 XP | HD1 FreeDOS).

---
This is a LOGITECH mouse driver, but some software expect here
the following string:*** This is Copyright 1983 Microsoft ***

paulrichards

08.08.2011, 03:51

@ DOS386

Considering DOS (now FreeDOS) Part 3 - LBA48 and > 128 GiB

Post reply

> Is it a primary partition visible in the MBR, rather than a "logical"
> partition inside an extended partition ?

Yes, both the C and D partitions are primary.
>
> > I then tried to boot from the FreeDOS Base CD
>
> What one ?

The ISO image which contains just the base OS (as opposed to the 128MB Live CD which contains a lot of additional tools etc)

> > and got the message
> > "InitDiskWarning : Partition ID does not suggest LBA to access partition
> > C:. Invalid Opcode" + a string of hex digits (obviously FreeDOS can't
> see
> > the XP C: partition and is looking at the 'new' D: partition, as
> expected
>
> BUG :-(

A bit basic that one.

> Size of your HD ? I suspect > 128 GiB, so the warn is about LBA48 vs LBA28
> ...

No, my hard disk is 112 GB.

> Your PC seem to be to new for CHS vs LBA issues ... but maybe FreeDOS could
> work with SATA too (via BIOS) ?

My PC (laptop) is just under 5 years old.

> Anyone tested FreeDOS with LBA48 and > 128 GiB disks ? I don't have such
> stuff :-(

> The other solution is to get another HD, and put FreeDOS onto it (HD0 XP |
> HD1 FreeDOS).

I can't be bothered :-)

---
Paul
Melbourne, Australia

paulrichards

08.08.2011, 12:36

@ paulrichards

Considering DOS (now FreeDOS) Part 3

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Well, I tried again to install FreeDOS into partition D: and, for some reason, this time it worked :ok:

Looking at partition D:\ (using Windows Explorer from XP on C:\) I see a folder called FDOS and 2 files: FDCONFIG.SYS and KERNEL.SYS. I'm assuming that this is what I should see.

Now my problem is how to ensure that I get the option to boot into FreeDOS when I start my PC. I'm not familiar with Boot Managers. I've downloaded GAG but am chary of doing anything with it in case I screw up my existing XP installation.

So I'd appreciate any advice on how to get to a boot menu that allows booting into either XP or FreeDOS.

TIA

---
Paul
Melbourne, Australia

paulrichards

08.08.2011, 23:37

@ paulrichards

Considering DOS (now FreeDOS) Part 3 - SOLVED

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> So I'd appreciate any advice on how to get to a boot menu that allows
> booting into either XP or FreeDOS.
>
Well, this was easier than I thought. GAG has a 'boot from floppy' option whereby there is no need to change the MBR on the C:\ drive. So after initially writing GAG to a floppy and rebooting, GAG then recognises XP and FreeDOS. This info is saved back to the floppy and it's then a question of choosing one or the other at reboot. What GAG seems to do is set the 'Active' flag to whichever partition/OS is chosen. So after booting into FreeDOS if I then want to use XP next time I reboot GAG from the floppy and choose XP.

One question: when I look at the D:\ FreeDOS partition from XP I see a folder FDOS + files KERNEL.SYS and FDCONFIG.SYS. When I boot into FreeDOS and do a DIR I see AUTOEXEC.BAT, amongst other files. So why is AUTOEXEC.BAT not visible in Windows Explorer? Is it created 'on the fly' during the FreeDOS boot process?

Thanks to all who have responded to my meanderings so far :clap:

---
Paul
Melbourne, Australia

DOS386

08.08.2011, 23:39

@ paulrichards

Considering DOS (now FreeDOS) Part 3

Post reply

> Well, I tried again to install FreeDOS into partition D: and, for some
> reason, this time it worked

:-)

> Looking at partition D:\ (using Windows Explorer from XP on C:\) I see a
> folder called FDOS and 2 files: FDCONFIG.SYS and KERNEL.SYS. I'm assuming
> that this is what I should see.

YES.

> Now my problem is how to ensure that I get the option to boot into FreeDOS
> when I start my PC. I'm not familiar with Boot Managers.

Just add FreeDOS into existing BOOT.INI ?

PS: you might be able to put the FreeDOS partition at disk begin. XP doesn't reportedly change boot volume letter anymore once installed - so if it is C: then it will remain C: - untested.

> So why is AUTOEXEC.BAT not visible in Windows Explorer?

H attribute ? ".BAT" extension ? ???????????????????

1. ATTRIB -S -H D:\*.* /S /D

2. Exploiter sucks, don't trust it, don't use it - get a good FM :hungry:

> Is it created 'on the fly' during the FreeDOS boot process?

AFAIK NO.

---
This is a LOGITECH mouse driver, but some software expect here
the following string:*** This is Copyright 1983 Microsoft ***

paulrichards

09.08.2011, 04:18

@ DOS386

Considering DOS (now FreeDOS) Part 3

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Thanks for your input. Dual booting between XP and FreeDOS is working fine via GAG. :ok:

---
Paul
Melbourne, Australia

Rugxulo

Usono,
10.08.2011, 04:48

@ paulrichards

Considering DOS (now FreeDOS) Part 3

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> Thanks for your input. Dual booting between XP and FreeDOS is working fine
> via GAG. :ok:

I got a similar issue today. Basically, I'm not sure FDISK is choosing the right partition code (0xB FAT32 instead of 0xC for FAT32 INT32X). But I could be way off (this stuff is incredibly arcane and confusing). But FreeDOS kernel 2040 seemed to just assume LBA anyways and still worked for me, so perhaps it's more tolerant than older kernels (e.g. 1.0 CD from 2006 using 2036).

As DOS386 mentioned, XP uses BOOT.INI, but for later Windows (Vista, 7) they used BCD, which needs something like EasyBCD (free for private use) to configure.

But you could also try BOOTMGR, which fits entirely in your boot sector (512 bytes) and lets you save a backup to file in case you want to "go back" later on. It works quite nicely!! But yeah, if you want to use a GAG floppy, that's fine too.

paulrichards

10.08.2011, 06:27

@ Rugxulo

Considering DOS (now FreeDOS) Part 3

Post reply

> But you could also try
> BOOTMGR, which
> fits entirely in your boot sector (512 bytes) and lets you save a
> backup to file in case you want to "go back" later on.

Rugxulo: thanks for that. Reading the install instructions, it states "You should run `bootmgr.com' from plain DOS, not from a MS Windows DOS box, nor under any multitasking environment".

Not sure how to do this since I need, in my case, GAG to get into a DOS environment and (Free)DOS can only see my XP D:\ drive (as its C:\ drive) so I'm not sure how it can modify the MBR of the 'real' C:\ partition (NTFS)

---
Paul
Melbourne, Australia

Rugxulo

Usono,
10.08.2011, 14:32

@ paulrichards

Considering DOS (now FreeDOS) Part 3

Post reply

(BTW, I hope I'm even halfway understanding this correctly, much less explaining it as mhc / Michael H. Tyc would be the guru to ask.)

> Rugxulo: thanks for that. Reading the install instructions, it states "You
> should run `bootmgr.com' from plain DOS, not from a MS Windows DOS box, nor
> under any multitasking environment".
>
> Not sure how to do this since I need, in my case, GAG to get into a DOS
> environment and (Free)DOS can only see my XP D:\ drive (as its C:\ drive)
> so I'm not sure how it can modify the MBR of the 'real' C:\ partition
> (NTFS)

It doesn't need to read NTFS, it only has to read/write raw sector 0, which is where the (only) MBR w/ partition table resides. Each partition can have its own boot sector, too, which is good for chain loading (or whatever).

It's not that using GAG via floppy is a bad idea, far from it! But sometimes you can't use a floppy, sometimes they go bad, yadda yadda ... I just wanted to mention another (easier?) way in case you ever needed to use something else.

To be honest, I just like BootMgr, it's so well done, so small (NASM ftw!), so any chance to use it is cool with me. And it's just easy enough to use (unlike most boot tools) that I can (mostly) wrap my head around it! ;-)

paulrichards

10.08.2011, 15:40

@ Rugxulo

Considering DOS (now FreeDOS) Part 3

Post reply

> > To be honest, I just like BootMgr, it's so well done, so small (NASM ftw!),
> so any chance to use it is cool with me. And it's just easy enough to use
> (unlike most boot tools) that I can (mostly) wrap my head around it! ;-)

I understand that - I have just found GAG to be very easy to use, (all this MBR stuff confuses me :-) ) my USB floppy drive works well so I'll stick with it, but thanks anyway.

---
Paul
Melbourne, Australia

DOS386

17.08.2011, 09:20

@ paulrichards

Considering DOS (FreeDOS) Part 3 | GAGA real/unreal "C:\"

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> GAG to get into a DOS environment and (Free)DOS can
> only see my XP D:\ drive (as its C:\ drive)
> so I'm not sure how it can modify the MBR of the 'real' C:\ partition (NTFS)

There is no "real" or "unreal" like "C:\" partition. There are 2 partitions:

* "part0" NTSC
* "part1" FAT

Under XP "part0" becomes "C:" and "part1" becomes "D:" ( no "\" ).

Under FreeDOS "part0" is ignored and "part1" becomes "C:"

MBR is NOT part on any partition so you can write into it in DOS (and doing so can be useful).

Both partitions do have a PBR, you could write into the PBR of "part0" in DOS too (but probably no point).

---
This is a LOGITECH mouse driver, but some software expect here
the following string:*** This is Copyright 1983 Microsoft ***

paulrichards

17.08.2011, 23:02

@ DOS386

Considering DOS (FreeDOS) Part 3

Post reply

> MBR is NOT part on any partition so you can write into it in DOS (and doing
> so can be useful).

I'm a bit confused here :confused:

So where is the MBR held if not on part0 or part1?

If I boot into FreeDOS and try and install BootMgr from FreeDOS, where does it find an MBR to modify?

---
Paul
Melbourne, Australia

Rugxulo Usono, 18.08.2011, 01:59 @ paulrichards	Considering DOS (FreeDOS) Part 3 Post reply
	> So where is the MBR held if not on part0 or part1? > > If I boot into FreeDOS and try and install BootMgr from FreeDOS, where does > it find an MBR to modify? If I tried explaining it, I'd probably tell it wrong. Just read here: http://en.wikipedia.org/wiki/Master_boot_record

paulrichards

19.08.2011, 05:34

@ Rugxulo

Considering DOS (FreeDOS) Part 3

Post reply

> Just read here:
>
> http://en.wikipedia.org/wiki/Master_boot_record

OK, thanks.

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Paul
Melbourne, Australia