Q82747: How Windows Prints to a Network
Article: Q82747
Product(s): Microsoft Windows 95.x Retail Product
Version(s): WINDOWS:3.1,3.11
Operating System(s):
Keyword(s):
Last Modified: 24-SEP-1999
3.10 3.11
WINDOWS
kbprint kb3rdparty kbnetwork
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The information in this article applies to:
- Microsoft Windows versions 3.1, 3.11
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SUMMARY
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Microsoft Windows version 3.1 uses a network device driver to manage printing to
network servers by integrating many network printing utilities into Windows.
Printing enhancements that are not supported by the network driver and that rely
on hooking MS-DOS calls or ROM BIOS calls may not work correctly when Windows
prints directly to the port. Using LPT1.DOS (or LPT1.OS2) passes printer output
through MS-DOS to these enhancements; however, being terminate-and-stay-resident
(TSR), these enhancements may create problems in Windows unless the program
takes the usual precautions necessary to make a TSR program compatible with
Windows.
MORE INFORMATION
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The most common MS-DOS enhancement for printing is the network printer
redirection, which allows a network user to print documents on a printer
attached to a server. Examples of printer redirection utilities include the NET
USE command in Microsoft LAN Manager and the CAPTURE command in Novell NetWare.
Windows handles network redirections using a Windows network driver, a program
that Windows uses to manage the network. These drivers make printing over the
network transparent to the user and also allow the user to connect and
disconnect to network printers.
If you have a network for which a network driver is not installed by Windows
Setup, contact your network vendor to determine if a Windows driver is
available. Windows 3.1 installs a driver for all major networks, including
Novell Netware, Microsoft LAN Manager, Microsoft MS-Net, Banyan Vines, 3Com
3+Share and 3+Open, Artisoft LANtastic, and IBM DOS LAN Requester. In some
cases, the driver ships with the network software and not Windows itself.
When you print a document on a network, Windows calls the network driver to
determine if the port in use is connected to a network printer. If so, the
network driver is expected to open a file handle to the network device. If the
network driver reports that the device is not connected to the network, Windows
prints to the port using the Windows COMM driver. The COMM driver does direct
port input/output (I/O); it does not call MS-DOS or the BIOS. Therefore, a
printing enhancement not supported by the network driver is bypassed by Windows.
Printing enhancements work by hooking either INT 21h writes or INT 17h, the BIOS
functions to control the printer. The COMM driver cannot use INT 17h because of
performance considerations; calling INT 17h from Windows would require multiple
protected-to-real mode transitions for each byte of output.
Remote spooling enhancements such as Novell's RPRINTER do not require any special
support on the machine that creates the printout; the network driver supports
connections to network printers whether they are on a server or on another
workstation. There are known problems with earlier versions of RPRINTER that
were corrected by Novell. If you encounter problems with RPRINTER in Windows
3.1, contact Novell for the latest version.
The only caution for using RPRINTER or LANSpool is not to print to the same port
as a local port through the Windows COMM driver. This causes the output to be
mixed randomly with the output from RPRINTER. If the workstation running
RPRINTER needs to print to the same printer, connect the port over the network.
Printing is not as fast in this case, but the output is correctly sequenced.
There is no explicit support in Windows for non-network printing enhancements
that hook MS-DOS or ROM BIOS function calls. In general, the way to use these
enhancements is to cause Windows to use MS-DOS calls instead of the Windows COMM
driver. This is the reason for LPT1.DOS and LPT1.OS2 (new Windows 3.1 users see
the former). Connecting to these ports causes Windows to print using MS-DOS
calls instead of the Windows COMM driver. Alternately, you can turn off the Fast
Printing Direct To Port check box in the Connect dialog box. (To access this
dialog box, open Printers icon in Control Panel.) In general, printing
performance and error condition handling are poorer; however, printing
enhancements see the output to the printer when they are passed through MS-DOS.
Printing enhancements are TSR programs. Like all TSR programs, they require
special precautions to avoid problems in Windows. If a printing enhancement
fails in Windows, by crashing or causing incorrect output, it may be
incompatible with Windows because it does not handle multiple MS-DOS Virtual
Machines (VMs) or critical sections. Some enhancements may work if no MS-DOS VMs
are open; try printing from a Windows application without any MS-DOS
applications or MS-DOS prompts running.
Additional query words: 3.10 3.11
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Keywords :
Technology : kbWin3xSearch kbZNotKeyword3 kbWin310 kbWin311
Version : WINDOWS:3.1,3.11
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