MS-DOS, LPT and IRQ

I'm just testing VPC in a XP Home enviroment. I need to
run some old MS-DOS 6.22 applications for a special
communication hardware (CAN) at the LPT. The software
uses the ports and the IRQ of the LPT. VPC LPT port
access works fine, but no interrupt is dedected. Booting
pure MS-DOS and using this software or running windows
specific software for this hardware shows, that the ports
and the IRQ works fine (LPT = standard bidirectional, LPT
as plug & play or legacy, use all interrupts of the
connection).
I didn't found any comment about the LPT IRQ in this
forum or the documentation, but the information, that a
parallel port ZIP drive will work. I think, the ZIP guest
software will also use the interrupt. So the question is,
what else can I do, is there a problem of using XP Home
or is the use of LPT IRQ no part of VPC?

Thanks

JUB

 

VPC uses IRQ7 for the parallel port.

How do you have LPT1 configured on the host? Set it to standard, or
bi-directional.

Steve Jain, Microsoft MVP for Virtual PC for Windows
Website: http://www.essjae.com
*** All posts are provided AS-IS, no warranty, no QoS ***

 

The notebook BIOS it is set to bi-directional, port
0x0378, irq 7. The host OS (XP Home, SP 2) says printer
port LPT1, resourcen 0378-037F, irq 7, use every
interrupt, Legacy recognation on (off changes nothing).
VCP says LPT1 = physical LPT1.

In the guest OS MS-DOS 6.22 the application can access
the LPT ports. The initialisation of the hardware is ok,
I can send messages through the CAN-Bus, but I didn't
receive any message. The receive process is interrupt
driven. The other side says, that the hardware accept the
message. I can poll received messages. So it seems to be
only an irq 7 problem.

COM1 and its interrupt works fine with an other MS-DOS
application in VPC. The application use the COM1
interrupt in the same way.

I tried VPC now on an other system with WIN 2000, same
result. On both systems, booting MS-DOS direct, the
application run correct.

JUB

 

The notebook BIOS it is set to bi-directional, port
0x0378, irq 7. The host OS (XP Home, SP 2) says printer
port LPT1, resourcen 0378-037F, irq 7, use every
interrupt, Legacy recognation on (off changes nothing).
VCP says LPT1 = physical LPT1.

In the guest OS MS-DOS 6.22 the application can access
the LPT ports. The initialisation of the hardware is ok,
I can send messages through the CAN-Bus, but I didn't
receive any message. The receive process is interrupt
driven. The other side says, that the hardware accept the
message. I can poll received messages. So it seems to be
only an irq 7 problem.

COM1 and its interrupt works fine with an other MS-DOS
application in VPC. The application use the COM1
interrupt in the same way.

I tried VPC now on an other system with WIN 2000, same
result. On both systems, booting MS-DOS direct, the
application run correct.

JUB