Changing LPT Port Address

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Hazardsneon
Posts: 12
Joined: 20. Dec 2012, 19:35

Changing LPT Port Address

Post by Hazardsneon »

I made a virtual harddrive from an XP machine that was used to run a piece of hardware that requires a parallel port. I had this working on a different computer but needed to move the VM and now I can't get it to connect to the parallel port hardware.

The first thing I forgot was to enable the parallel port according to this post : viewtopic.php?t=54187

Now it seems like it is down to the point that the software that controls the hardware can't recoginze the I/O resources that are on my win10 computer. Right now the parallel port has an address space starting at E010 but the old software must not be able to go that high.

It doesn't look like there is a way to modify the LPT address on the win10 side.

Is there away to keep the address E010 on my host but make it look like 0x387 on my VM client?
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: Changing LPT Port Address

Post by mpack »

LPT devices are simulated, as all other virtual devices are. So the memory and IRQ resources used by actual host devices is not relevant. All you care about is the device name on the host (e.g. "LPT1").

The LPT address and IRQ VM settings have to do with how simulated features are presented to the guest, and as the tutorial tells you, you almost certainly have no reason to change that.

The linked tutorial actually explains this in great detail in the 3rd post.
Hazardsneon
Posts: 12
Joined: 20. Dec 2012, 19:35

Re: Changing LPT Port Address

Post by Hazardsneon »

Ahh. It probably would have helped if I read step 1 instead of jumping right to the solution :) That makes a lot of sense now.

However, I have it setup correctly now but my hardware is still not being recognized.

My guest sees the LPT port with the 0x378 address location but the associated software still can't recognize the hardware.

It is just strange because I have this working on another computer but I suppose that the hardware is different. The win10 host that I have it working on is a laptop plugged into a dock with a parallel port. The win10 host that I am trying to get working is a desktop and I installed a Startech PEX1P2 PCIe Parallel port card.

Would you happen to have any suggestions?
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: Changing LPT Port Address

Post by mpack »

Sorry, as I say in the tutorial - I have not had a parallel port in any PC of mine for a very long time, so I have no personal experience to add to the tutorial. The only reason I wrote the tutorial is because no-one else volunteered anything better.

The only thing is to be sure you have the correct host LPT identified, and make sure nothing else is using it because LPT and COM ports cannot be shared by two different apps (both standards date from the 1960s, which running multiple apps in parallel was not common). Failure to do this may not stop the VM from running, it would just stop it successfully communicating.

Parallel ports worked fine for printers, but I always dreaded trying to get other devices (JTAG programmers, ZIP drives) working because even on physical hardware there was enough variation that some devices (or apps) worked on a given PC, but didn't work on the apparantly identically specced PC next to it. Thankfully the need for such kludgery was killed off by USB.
Hazardsneon
Posts: 12
Joined: 20. Dec 2012, 19:35

Re: Changing LPT Port Address

Post by Hazardsneon »

Just as an update. I found out that this PC has an internal Parallel port that I just needed the adapter cable to bring out to one of the PCI slots.

However, even with using the integrated Parallel Port, with the standard 0x378 address, I still have no luck.

I will try to update with a fix if I ever get this running.
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