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3. Hard disk setup

3.1 How do I use my hard disk with dosemu?

First, mount your dos hard disk partition as a Linux subdirectory. For example, you could create a directory in Linux such as /dos (mkdir -m 755 /dos) and add a line like 

   /dev/hda1       /dos     msdos   umask=022
to your /etc/fstab. (In this example, the hard disk is mounted read-only. You may want to mount it read/write by replacing "022" with "000" and using the -m 777 option with mkdir). Now mount /dos. Now you can add a line like 
  lredir d: linux\fs/dos
to the AUTOEXEC.BAT file in your hdimage (see the comments on LREDIR below). On a multi-user system you may want to use 
  lredir d: linux\fs\${home}
where "home" is the name of an environmental variable that contains the location of the dos directory (/dos in this example)(95/8/11).

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Tim Bird (Tim_R_Bird@Novell.COM) states that LREDIR users should be careful when they use LREDIR in the autoexec, because COMMAND.COM will continue parsing the autoexec.bat from the redirected drive as the same file offset where it left off in the autoexec.bat on the physical drive. For this reason, it is safest to have the autoexec.bat on the redirected drive and the physical drive (diskimage) be the same(95/8/11).

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Robert D. Warren (rw11258@xx.acs.appstate.edu) reported (94/4/28) that

I boot off a small hdimage file (less than 1 MB - and twice as large as needs be at that), and the next to last line in my config.sys file on the hdimage boot image is: 

        
        install=c:\lredir.exe c: LINUX\FS\home/dos
This will execute lredir just before the command interpreter runs. And I have successfully run it with both command.com and 4DOS. This eliminates the offset problem using lredir in autoexec.bat.

Uwe Bonnes (bon@elektron.ikp.physik.th-darmstadt.de) adds (95/8/11) that

It is usefull to do: 

        
install=C:\subst.exe g: c:
before that, so you have still access to your hdimage as drive g: Another useful tip in that circumstance is to configure dosemu to use "autoexec.emu" to keep dos and dosemu apart.

3.2 How can I access the hdimage from Linux?

Use the recent mtools, version 3.0 at the time of writing. With a line in /etc/mtools.conf like 


   drive g:  file="/var/lib/dosemu/hdimage" Offset=8832
you can use the mtools on the hdimage, like "mdir g:". "mcopy g:/config.emu /tmp" copies the config.emu file from the hdimage to /tmp/config.emu. You can edit it there and copy it back. Use a drive letter you find sensible. "G:" is only an example(07/2/9).

3.3 Can I use my stacked/double-spaced/super-stored disk?

At this time, compressed drives cannot be accessed via the redirector (lredir or emufs) on a standard kernel. There is a patch for the kernel to mount compressed files under the name "dmsdosfs". Find it on sunsite.unc.edu and its mirrors

http://sunsite.unc.edu:/pub/Linux/system/Filesystems/dosfs/
A good idea is also to look in http://sunsite.unc.edu:/pub/Linux/Incoming for a newer version. However, many people have had success by simply uncommenting the 
   disk { wholedisk "/dev/hda" }        # 1st partition on 1st disk
line in their dosemu config file. Others have had success using 
   disk { partition "/dev/hda1" }
Do that on the risk to loose data on a dosemu crash(97/2/9)!

If your dos partition is already mounted with write access and you try to run dosemu with partition or whole disk access, dosemu will print a warning message and abort. This prevents DOS and Linux from making independent writes to your disk and trashing the data on your dos partition(95/8/11).

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If LILO is installed, the above will not work. However...

Thomas Mockridge (thomas@aztec.co.za) reported (94/8/5) that

To boot dosemu with LILO and Stacker 4.0 I did a little work around...

1. dd the MBR to a file. (or norton utility, etc., first 512 bytes)

2. Boot dos (from full boot not emu), do a fdisk /mbr, make your dos partition active with (dos) fdisk.

3. Copy the new MBR to a file.

4. Replace the original MBR

5. Copy the second MBR to /var/lib/dosemu/partition.hda? (Whichever is your dos partition)

6. Set dosemu.conf 

               disk {partition "/dev/hda? ?"}

7. Start dosemu and and voila! No LILO.

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Holger Schemel (q99492@pbhrzx.uni-paderborn.de) reported (94/2/10) that

Works even fine under dosemu with MS-DOS 6.0. If you have problems, then you have to edit the file 'DBLSPACE.INI' manually and change the disk letter to the letter your drive gets under dosemu.

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Darren J Moffat (moffatd@dcs.gla.ac.uk) also reported (94/3/27)

"...use 6.2 if you can get it!! Just make sure you have a LILO boot disk on hand since dos 6{.2} will change the MBR of the boot HZ."

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