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how to set up LPT1 in Dos guest?

Posted: 3. Mar 2017, 06:27
by eag
I have Windows 7 host, with VirtualBox5.1.14, with guest VM running FreeDOS1.2. Printer is connected to parallel port on host. How do I get it to work in VM? Someone else posted that he successfully did this using the following commands:
VBoxManage modifyvm "My VM Name" --lptmode1 "LPT1:"
VBoxManage modifyvm "My VM Name" --lpt1 0x378 7
1. WHERE do I run these commands? VirtualBox documentation says VBoxManage commands are run "from the
command line of your host operating system". Huh? Command line of Windows machine would be the cmd prompt. But VirtualBoxManage is not a Windows command. Surely it has to be a VIrutalBox command, no? But I can't find a command line within VirtualBox.

2. How do I find out the base address and IRQ of parallel port in my DOS VM, needed as parameters in the second command?

Sorry if I'm being thick. I'm very new to this. Thanks, eag.

Re: how to set up LPT1 in Dos guest?

Posted: 3. Mar 2017, 07:20
by socratis
The VBoxManage command resides in the VirtualBox directory, so typically you have to enter the following in order to execute it:
  • cd "C:\Program Files\Oracle\VirtualBox\"
    VBoxManage ...
or "combine" them:
  • "C:\Program Files\Oracle\VirtualBox\VBoxManage" ...
or you can put that directory in your path environment variable (search on how to) and execute it from anywhere.

In another post I directed you to the HowTo section of the forums (great starting place for questions). In the "Board index ‹ General ‹ Howtos and Tutorials ‹ Generic Advice" section there a tutorial: Enabling and Configuring Parallel (LPTx) Ports. Did you stumble upon it?

Re: how to set up LPT1 in Dos guest?

Posted: 3. Mar 2017, 20:15
by eag
Aha. OK, got that now, and followed instructions on the tutorial. Thanks for pointing that out. Unfortunately, when I now attempt to start the VM, I get the following error, which prevents the VM from starting:

HostParallel #0:Could not get direct access to
the host parallel port!
(rc=VER_INTERNAL_ERROR_3)
(VERR_INTERNAL_ERROR_3).

Parallel device 0 cannot attach to host driver
(VERR_INTERNAL_ERROR_3).

Someone else on this forum reported (and ultimately resolved) this error, but his problem was that his device was attached to LPT2. My printer really is on LPT1, and yes, it works on the host. Any idea on what this error might signify (other than that it ain't working), and whether there is any hope? Thanks, eag