Cannot access Com1

[ukdodger]

Ok Ok.. so I've lined up all the ports to be com1 in XP, settings and in W7 and uninstalled com4 in W7 so now only Com1 is showing.

BUT now com1 in W7 has a yellow triangle which is code 12 and means a conflict of resources. I've run a registry cleaner, rebooted and it's still there. I tried disabling a USB-Serial port in W7, rebooted and that made no difference. There is software on the net that claims it can fix this but none of it is from MS so I'm scared to use it. I ran the MS 'Mrfixit' and it couldnt. Attempting to intall a driver fails. Any ideas?

So near..

[jorgensen]

Thanks jorgensen. But what does this mean - Add the driver (e.g. FTDI USB <-> Serial)' and where do I get the driver?
And would you expand on this:
'From the menu or status bar of VirtualBox frame check the Serial Port in the USB section.
Install the USB driver in the guest'
Where is the Status bar and how do I instal a driver in the guest?

You can add the USB adapter to the USB section in the guest settings, and if so, the USB adapter will be attached to the guest when launched - check the manual for this.

Alternative you can attach the USB adapter after the guest is launched.
1: From the Virtualbox menu bar at the top of the guest, select Devices->USB->???? (you have to guess the driver name of USB adapter)
2: From the Virtualbox status bar at the bottom of the guest, right click the USB icon and select the USB driver.

You install the corresponding USB serial driver at the guest as you did in the host, where you need to access the setup file from a shared folders, CD, Internet download, etc.

In the XP device manager make sure to remove the standard COM ports, and set the USB serial driver to the required port number - check the USB serial driver manual for this.

[andyp73]

p.s. As someone who wrote serial port using software for DOS and then Windows from its earliest days, I would never have assumed that nothing other than COM1 or COM2 could exist, so I would not accept that assertion without checking it.

I don't have access to the application in question but as someone who has developed BIOS and other low level software for PC hardware manufacturers I know that there were plenty of applications from the DOS/Windows 3.1 era that did assume there would only be ever COM1 and COM2 and worse wrote to them using hard coded IO port values.

Which is why I think the best option is still as we described in the early posts that the first serial port is enabled in the VM so that the application in question sees a COM1 at an address and IRQ where COM1 has always lived and let the host worry about all the USB stuff.

That said, I have two USB-RS232 adapters one using an FTDI chip and one from Prolific and there are some subtle differences in the way the behave.

Andy.

[mpack]

and worse wrote to them using hard coded IO port values.

Oh, we all did that on DOS. The BIOS/DOS functions were polled, making them completely useless for >1200 or so. They were also written for the 8250 and couldn't benefit from FIFO modes on the 16550A, so even at 1200 the overhead was intolerable. The PC architecture had standard I/O base addresses for the first four comm ports. From memory they were 3F8, 2F8, 3E8, 2E8. But only two IRQs, so those had to be shared (4,3,4,3). You could also let the user configure a base address and IRQ, in fact the API was quite similar to what VBox provides now.

Programmers used DOS for disk access (files). You didn't use it for anything else, not if you didn't want to be laughed off the magazine review pages. There was no downside to directly accessing the hardware - we're talking about a single tasking OS, so it isn't like something else could conflict.

That all changed when Win3 came out: it ran apps in a protected mode, so I'm not aware of anything accessing UART base addresses directly there.

[ukdodger]

Well I finally got it to work. In case anyone else would like to know here is the working configuration:

Virtualbox

Guest settings/Serial ports:

Enable Serial port = checked
Port number = COM1
Port Mode = Host pipe (It wouldnt work with 'Host Device')
Path/file path = COM5

Windows XP:

Device manager:

Ports (COM & LPT) = COM1

****************************

Windows 7 settings

Device manager:

Ports (COM & LPT) = COM5

(with this serial/parallel cable and using the Prolific chip. Other serial/parallel drivers didnt work.)

http://www.amazon.co.uk/gp/product/B004 ... _i=desktop

I never could find how to remove the yellow exclamation mark from COM1 in W7 so I deleted it.

Thanks to everyone for there input