HP UPD - Microsoft Driver Isolation Mode FAQs

2
OVERVIEW
This white paper describes the advantages of Microsoft® driver isolation mode, how it works, which
systems it supports, and how to use it with the HP Universal Print Driver (UPD).
Background
Microsoft
®
Windows Server versions 2000, 2003, and 2008, along with client versions Windows
XP
®
and Windows Vista
®
, utilized user-mode version 3 print drivers that operate in the print spooler
process spoolsv.exe. If any driver utilizing spoolsv.exe fails, all print operations dependent on the
print spool service fail.
To solve this problem, Windows 7 and Windows Server 2008 R2 introduced isolation of print
drivers. Drivers configured in isolation mode run in an independent PrintIsolationHost.exe process
which proxies print services to spoolsv.exe. In the event of driver instability or failure, the
PrintIsolationHost.exe fails independent of the Spoolsv.exe.
Driver isolation applies to usage of the print driver in the spooler context, not use of the print system
(for example, opening the user interface). Two or more drivers can be defined to share a
PrintIsolationHost.exe process, or a single driver can be defined to a dedicated PrintIsolationHost.exe
process. A driver can only be defined for one mode, while the server supports all three modes in
combination.
What are the driver isolation mode settings for Windows 7 and
Windows Server 2008 R2?
No Isolation—The driver runs in Spoolsv.exe (the same as for Server 2003, Windows Vista,
Windows XP, and Server 2008 SP2). All drivers set to no isolation share Spoolsv.exe. The failure
of one driver could cause the failure of the entire print system.
Shared—Drivers share the same PrintIsolationHost.exe, separate from Spoolsv.exe, but not
separate from other drivers within the shared PrintIsolationHost.exe process. The failure of one
driver could cause the failure of all drivers sharing the isolated process, but would not cause
failure to Spoolsv.exe.
Isolation—Each driver runs in its own PrintIsolationHost.exe process, separate from Spoolsv.exe,
and separate from other drivers in isolation. Failure of one driver would not impact other drivers.
Each print queue does not operate in its own instance of the PrintIsolationHost.exe. Instead,
multiple queues using a single driver utilize the same instance of isolationhost.exe.
Would a failure in the Spoolsv.exe cause dependent
PrintIsolationHost.exe processes to fail?
For installed print drivers defined to run in Shared or Isolation mode, PrintIsolationHost.exe is
dependent on the underlying Spoolsv.exe. The PrintIsolationHost.exe process will become operational
again when Spoolsv.exe recovers, but print job context might be lost during the spooler’s stop and
restart process.
What is the default isolation mode for HP drivers shipped with the
Microsoft operating system?
Shared isolation mode is the installed default for HP drivers shipped inbox with Microsoft Windows 7
and Server 2008 R2 operating system installation media.