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I am going to install MS DOS 6.22 and Windows 3.11 on my new Lenovo IdeaPad U410 laptop just for fun and just to prove myself I can do it.

I want to ask if I can expect some problems? And if so then which ones? The only think I care about is not to harm my hardware and not to harm other partitions. I am not expecting MS-DOS to take advantages of using of my big RAM and I am not going to access my other partitions from MS DOS.

Will the MS DOS be kind to other unknown partitions and to new hardware?

I simulated it using VirtualBox and everyhing was ok. Now I am about to try it with real hardware. Is everything going to be the same as virtualized?

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Only point to watch is the size of the partition, you would be advise keeping under 32gb. – Ian Mar 17 '13 at 20:08
You need to have a MBR partition table and have to install it inside a primary partition. – FSMaxB Mar 18 '13 at 16:44

Yes, you might run into some issues.

Your BIOS might need to support IDE emulation for SATA drives (hard disk and CD), otherwise DOS might not see the drives as well. Even if thats the case, there still is a chance it wont work with modern hardware. Even, if it does work, the hard drive, FAT16 will limit volumes to 2GB.

If your Lenovo IdeaPad U410 has any "funky" hardware, especially core components, you might not be able to install DOS as there wont be any drivers for it. For example, your keyboard and mouse might not work. If this is the case, you could use a USB keyboard, as long as your BIOS supports legacy USB support (all I have seen do).

But the real question is: Will 16 bit code, which DOS and Windows is written in, run natively on a 64 bit processor? Im not sure about that.

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Yes, the x64 instruction set is fully backwards compatible with its 32- and 16-bit predecessors. – Marcks Thomas Mar 17 '13 at 23:29
@MarcksThomas Or more accurately, x86-64 CPUs implement Intel's 16- and 32-bit instruction sets as well. Actually, I'd be surprised if even modern UEFI POST implementations aren't done in 16-bit code (although other parts of the UEFI firmware might not be). – Michael Kjörling Apr 8 '13 at 14:52

You tagged the question with virtualbox. If you are using a type 2 hypervisor like that, there will be no effect on your host operating system. The MS-DOS virtual machine will not even be aware of the host machine.

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he said he simulated it in virtualbox, he is going to install it directly on the laptop. – Keltari Mar 17 '13 at 21:14
That edit came after my answer. – Patrick S. Mar 17 '13 at 23:42

DOS is pretty kind to unknown partitions, since there are proggies (like Novell Netware), that use DOS as a boot block, and then mount an unknown partition. It certainly lives quite happily beside things like BOOTMGR, HPFS and NTFS.

DOS pretty much expects to find an IDE layout, with disks of up to four primaries.

DR-DOS does not booting from partitions other than 1. You can't create two primary partitions, and install drdos on the second one. But PC-DOS and MS-DOS don't seem to mind. You can't start dos from an extended partition either.

It's best to install DOS on a partition less than 120 MB, because the way Win9x works, it will try to convert the partition into a fat32 partition.

Some versions of DOS will bork, if there are several primary partitions, and the first partition on the extended partition is not a fat16 one.

Some of the more recent computer hardware uses different kinds of setup, which not only affects DOS, but even later operating systems like WinXP. You might see if you can see your dos partition from a dos boot diskette, before doing drastic things.

Otherwise, it's back to the virtual machines for DOS.

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"It's best to install DOS on a partition less than 120 MB, because the way Win9x works, it will try to convert the partition into a fat32 partition." Wow, what a lousy reason. I suggest making DOS partitions as near 2GB as possible (being less than 2GB, not over). The initial release of Win95 doesn't support FAT32, and I've used Win98 on FAT16 numerous times without issue. Simply avoid converting to FAT32 if that's undesirable. MS KB182751 shows Win95 needs 120MB+, Win98 needs 140MB+, so an artificial 120MB limit isn't the preferred amount! – TOOGAM May 24 at 11:59
Other programs will try and convert fat16 into fat32 if it's over 126 MB, i have encounted this often enough to know. In any case, the extended partition should have a fat16 as the first partition too, otherwise some DOS versions get confused. – wendy.krieger May 24 at 13:57
I maintain: My experience counters this cliam. I can imagine Windows Setup possibly doing that during an upgrade. Any other program that would do such a conversion without prior approval is an absolutely shocking concept. And, 120MB is an insanely low amount; that's only barely big enough for some of the minimal installs of Win9x, leaving no room for programs or other data. It's not even big enough for most Win9x installs. Bundled hard drives were getting to be about 200+MB by Summer 1992. Even if you're right that such auto-conversion happened, 120MB can't conceivably be the right limit – TOOGAM May 24 at 17:25
Plus95 did things like that in its default setup. I never said that 120 MB was a limit. I said that it was the largest partition that many automatic fat convertors ignored. 120 MB is only small if you load it with lots of other stuff. Windows 9x was always installed elsewhere (g:\ or something), and most of dos apps were over the e:\ drive. very rarely went into c: – wendy.krieger May 24 at 22:30

There may be multiple issues.

You mentioned Windows 3.11. As I recall, there can be some issues with Win 3.1 (which I've used) on systems with too much RAM. 256MB is okay. More than that can be iffy. In particular, I seem to recall needing to edit a configuration file, possibly just for installing Internet Explorer. When I was looking for a new system, quite a while ago, I recall documenting some RAM Limits I found, which will affect DOS, Windows 3.x, and newer Windows versions. I recall that some of the workarounds mentioned there didn't work real well.

HIMEM.SYS might want no more than 64MB of memory. That can often be worked around by using the /EISA switch, but, even still, MS KB 116256 mentions not being able to report more than 4GB of memory. So, yeah, I imagine that your 8GB laptop may encounter some issues.

You may need to adjust the "system startup" settings. (By this, I'm thinking of BIOS settings. However, newer systems may use UEFI.) In particular, SATA drives may need to use IDE/Legacy mode. Also look for Legacy/ISA settings in sections related to IRQs/PnP. DOS is really designed to work with BIOS, so a BIOS system may be more preferable than (U)EFI.

If your hard drive is too large, that may cause some issues. Anything that is 127.5GB or more will require LBA48 which isn't supported by these operating systems. If you apply newer patches (like those made by third parties, designed for Win98/ME), I think you could potentially be fine using a drive as large as 4TB, but of course you won't be using that much for DOS. DOS will want to only be using partitions under 2GB each, unless you're using a DOS variation that supports FAT32. (In general, as long as you're not violating important limits like the limit on a drive's size, DOS won't care how big your non-DOS partitions are, or the extended partition. Since this question is about the topic of newer hardware, I'm not referring to old limits related to things like outdated BIOS chips.) I do suggest placing DOS partitions first on the hard drive, as other operating systems are often better at loading from later parts of the hard drive. Each FAT32 is best to keep at some at 133,693,376 KB (slightly under 127.5 GB).

DOS FDisk may not like drives that are too large. Expect trouble if using a drive that is over 64GB, unless you use the FDISK from the downloadable update at MS KB Q263044. Even then, expect trouble that is cosmetic (for FDISK and FORMAT), but things will actually work fine. Alternative: use third party software (like XFDISK, or Ranish Partition Manager).

Other hardware problems are not too likely. In other words: I don't anticipate DOS being likely to break your hardware. However, hardware being completely unsupported is quite likely. USB may not be supported. You might be able to use a USB keyboard; that may require setting some sort of Legacy/Compatibility option in BIOS. Same comments can be made about a USB mouse; I would suggest trying a newer mouse driver (CuteMouse comes to mind). For other USB devices, including memory sticks, you may have some luck by adding some drivers/software that has been made well after DOS has been discontinued. I suggest becoming familiar with the FreeDOS website. (Besides distributing FreeDOS, the website also mentions lots of newer drivers/software that work fine with MS-DOS. The site has highlighted new software releases in a News section, but also lots of software buried in sections under FreeDOS software area.)

I've had troubles running XFDisk on a friend's system that used a 64-bit CPU. I suggest trying to boot DOS off of removable media before spending a lot of time trying to re-partition and install DOS onto the hardware.

In general, DOS doesn't know/care about the concept of hardware being virtualized. You may find that some of your real hardware may work easier when using DOS directly, compared to trying to get it to work in a virtual machine. The biggest exception to that might be USB keyboard/mouse, which some "virtual machine" software might emulate in a way that works nicer than the real things.

Some of the MDGx Windows 98 + ME •still• alive Campaign may also point to some newer resources, which may be helpful for trying to do newer activities (like using newer hardware) with this older operating system.

For games, many DOS programs were designed for sound cards that may not work as well on newer systems. Even if your system was a desktop, the lack of ISA support will rule out "Gravis UltraSound" and many other classic cards. You might, or might not, be able to get "Sound Blaster" support. If so, consider yourself lucky. Naturally, the fact that your system runs fast may cause some software to be unhappy. Software which might be particularly prone to such problems may be games, multimedia (media players), and maybe communications. Software which simply works with keyboards and hard drives will probably not be too unhappy about the unfathomable speed.

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