DOS tips & tricks
You can install Microsoft DOS 7.10 by using this patched bootdisk. If you want an open-source DOS version look for FreeDOS. They both work fine for me, except that FreeDOS somehow doesn't run QuickBasic.
Having both DOS versions on the same partition with XP's bootmanager
Install Freedos with the supplied setup program on a FAT (16/32) partition on your first harddisk. When you're asked if the Master Boot Record is to be overwritten answer no to preserve the XP bootmanager. When finished change to the drive where you installed FreeDOS and enter sys a: c: fdimage.bin, where c: is the drive where you installed FreeDOS. This will create a file called fdimage.bin containing the bootsector for booting FreeDOS. Add a line for this to boot.ini like this:
c:\fdimage.bin=" FreeDOS "
Now if you also want MS DOS 7.10 it gets a little more trickier. I don't know if there is a DOS program like dd that can do the things that are needed to but I'll assume you have access to a Linux box.
Download the patched bootdisk mentioned earlier and write the image to a floppy disk with an utility like rawrite. Write the MBR to a file by entering dd if=/dev/hda3 of=mbr.bin bs=512 count=1 in Linux as root (substitute /dev/hda3 with the partition where the bootmanager resides, recognisable by a boot.ini file in the root directory).
Now boot with the bootdisk you created. Enter sys a: c:, remove the floppy disk and check if DOS 7.10 was properly installed. Now boot into Linux and write this bootsector to a file by entering dd if=/dev/hda3 of=msdos710.bin bs=512 count=1. Copy the msdos710.bin file to the directory where the bootmanager resides and add it to boot.ini. Now restore the original bootsector you backed up with dd, by now swithing the parameters for if= and of= from the command used to back it up.
It is perfectly possible to let FreeDOS and MS Dos 7.10 use the same CONFIG.SYS and AUTOEXEC.BAT but it is also possible to let them use seperate ones. Rename the CONFIG.SYS file for FreeDOS to FDCONFIG.SYS. Edit this file to contain the following line (among the rest of your configuration ofcourse):
The fdcom.com is the command.com file from FDOS\BIN, renamed so it doesn't interfere with the command interpreter from MS DOS 7.10. You probably guessed that the AUTOEXEC.BAT for FreeDOS should now be renamed to FDAUTO.BAT. That's it.
Listening to MP3
First of all, you have to get your soundcard working. If you don't have a Creative or Gravis compatible soundcard you're out of luck because they usually don't work. Note that a lot of would-be soundblaster compatible cards only offer 8-bit playback by running a TSR driver. For me it was reason enough to get my hands on a real Soundblaster from Creative.
The MP3 player I use is MPXPlay. It supports many formats like MP3, CD Audio and OGG and has a nice interface. Study the command line switches for soundcard detection if you don't hear sound. I recommend using mpxplay -bp -idl if you have a 'fast' computer (say, faster than 200 MHz).
Watching DivX movies!
I was really surprised when I learned this is possible in DOS but it is. The program is called QuickView Pro. Subtitles are supported and it also views MPEG, VideoCD, JPG, MP3 etc. etc. An important drawback is that it is shareware and shows reminder that you have to register on top of the movie every now and then.
Browsing the internet
Yes it's true: you can get access to the internet in good old DOS! It took a while for me to find out but it wasn't even that hard. You'll have to get what is called a packet driver. If you use a NIC (network) card to connect to the internet you have to indentify precisely what kind of brand and model number it has and search for that on the internet. For example I searched for "realtek rtl-8139 packet driver". The packet driver should be a small .COM or .EXE file.
If you connect to the internet with a modem you should download a PPP packet driver, like LSppp. If you you have an ASDL connection use PEPA. I have tested neither of these last two programs because I have a router at home and use a gateway to connect to the internet.
Now that you have a packet driver you can use most of the available internet software for DOS. An excellent graphical browser I recommend is Arachne. As this browser can be quite slow when run from disk it is advisable to run it from a RAMDISK. A RAMDISK is a virtual drive in your computers memory. To be able to make a RAMDISK get XMSDSK. Now zip your whole arachne directory in one big ZIP file by entering:
pkzip -exx -r -P arachne.zip arachne\*.*
Open an editor and save the following as c:\arachne.bat (or some other bat file)
c:\utils\xmsdsk.exe 10000 r: /y /t
pkunzip -d c:\arachne.zip r:\
In this bat file I assume that the drive letter R is free, which is fair I think. A RAMDrive of approx 10 MB is created, you can change this to whatever size you want ofcourse, the size is in KB.
Extra tip: don't settle for 60 Hz, adjust the refresh rate. This can be done by running a program in your autoexec.bat, for example VBEHz. It only effects graphical modes. For this program to work your video card must be VESA 3.0 compliant. It doesn't work with my Matrox card, but there's VBEXT.EXE which does the same trick for Matrox cards. It is said to be included on the driver CD but since I didn't find it I include this link.
Turning your computer off in DOS
Ofcourse you can just turn of your computer any time if you see the command prompt but I mean turning of the power by just entering a commmand. I use atxoff.com for this. When you run the program the computer will power off at once. For this to work you need an ATX motherboard/powersupply, which is standard for modern computers.
Accessing NTFS and Linux partitions, Long File Names
There's a free, read-only NTFS driver at http://www.sysinternals.com. It mounts all NTFS partitions found and assigns drive letters. You can run programs and access files, inluding compressed ones.
For Linux partitions (ext2) there's LTools (opposite of MTools, dos utilities for linux)
To support Long File Names on FAT drives there's DOSLFN, a very small TSR program.
Making a bootable (rescue) CD
If you don't want to mess with your hardisk you can also make a bootable CD. Collect all the software you want to include on the CD and add it to a compilation in Nero (best burning software for windows). Find yourself a suitable bootdisk at www.bootdisk.com and write it to a floppy disk by running the .EXE. You can also use this patched win 98 se bootdisk. You can use dd to write this image to a floppy disk. Change autoexec.bat and config.sys files if necessary. Try if the floppy disk boots correctly and if the necessary hardware is working, notably your CD-ROM. Now select your floppy drive as input source for the bootable partition in Nero and burn the CD.
My config files: