Q: I am very confused about the meaning and significance of the Service Packs. Can you explain them, please?

Service Packs confuse a lot of people. They contain bug fixes that are cumulative, meaning that Service Pack 2 includes the fixes in Service Pack 1, and so on. For example, the following list contains the bug fixes in Service Pack 2 for Windows NT 3.51.

Q112665: UPDATE.EXE Starts Setup Help if Space Exists in Directory Path

Q128567: Landscape Orientation Reversed with PostScript Driver

Q129670: GSNW Not Releasing Session to NetWare Server

Q129724: Macintosh Client Has Slow Access to Windows NT 3.5x SFM Volume

Q130226: Banner Always Printed When Using GSNW Print Gateway

Q130783: STOP Msg: 0x0000003F NO_MORE_SYSTEMS_PTES Repetitive I/O on MIPS

Q130932: Desktop Remains Active at Logoff

Q130979: User Environment Variables Set Before Default Home Directory

Q131073: Datagram Sends Fail if Route Is Not in IPX Cache

Q131241: FTPSVC Orphans Connections, Uses Up Virtual Memory

Q131428: DHCPADMN Reports Error 14 After You Select Local Machine

Q131689: PostScript Jobs Do Not Print Correctly Over SFM and AppleTalk

Q132085: Applications Hang When Opening Files When CSNW Is Installed

Q132394: Streaming Mode NPMCA.SYS NIC Sleeps on Transmit

Q132511: Windows NT 3.51 Hangs on Shutdown with Some S3-Based Video Cards

Q132722: Server Instability After Reboot Caused by NDIS Driver Problem

Q132896: FTP Client Scripts Terminate Without Completing

Q132903: Err Msg Using NetBIOS over TCP/IP (NETBT.SYS): STOP 0x0000000A

Q133112: NetWkstaSetUid2 API Returns Access Denied

Q133128: Printing from Windows NT 3.51 to an HP4 at 600 DPI Is Slow

Q133252: Windows NT 3.51 GSNW Help Reports the File Is Corrupted

Q133280: FTPSVC: Delay Receiving FTP Directory Annotation and Prompt

Q133303: WINFILE.EXE Application Error When Associating a Searched File

Q133306: Maximum Disk Space of 1.99 GB Displayed for NetWare Volume

Q133384: Event ID 2019: Nonpaged Memory Pool Empty

Q133410: The Breakpoint "\{,,\} ." Cannot Be Set

Q133488: LPR Printing Fails After Setting Up Security

Q133701: Forward Slash May Be Ignored as a Path Delimiter in 3.51

Q133757: Performance Monitor SQLServer-Log Object Corrupted

Q134250: No Compaq Netflex Drivers in Windows NT 3.51 for RISC Platforms

Q134285: STOP Msg: 0x0000007B or "0x4,0,0,0 Error" in WinNT 3.51 Setup

Q134286: Windows NT 3.51 Lsar-LookupSids Errors from Big Endian Servers

Q134386: Computers Using QVision Display Driver Lock Up

Q134427: Dr. Watson Access Violation Occurs Sending Mail Attachments

Q134701: Uninitialized Pointers in DHCPSSVC.DLL Cause Access Violation

Q134765: Unknown Software Exception When Application Calls OpenGL

Q134959: Cannot Copy Icons from a Common Group to a Personal Group

Q134968: NetWare Connections Remain Connected After You Log Off

Q134969: Faxing from 16-bit Program Using Separate Memory Space Fails

Q134985: Browsing & Other Traffic Incur High Costs over ISDN Routers

Q134988: Access Violation in glsb-CreateAndDuplicateSection API on PowerPC

Q135065: Windows NT 3.51 Hangs on Shutdown

Q135275: Windows NT Backup: Incorrect Date in "Tape Name" Text

Q135277: WINS Records of Multi-homed Computers Do Not Replicate

Q135291: Print Manager: Owner Appears as System Printing from Macintosh

Q135308: Disk Administrator Corrupts Partitions

Q135471: Cannot Reconnect to OS/2

Name Space Resources on NetWare Server

Q135548: PIF Editor Reserve Shortcut Keys Settings May Be Ineffective

Q135553: IOCTL_NDIS_QUERY_ALL_STATS Causes STOP Msg in Windows NT 3.51

Q135621: NetWare Transaction Tracking System (TTS) Not Detected

Q135667: STOP 1E When Using File Manager and Services for Macintosh (SFM)

Q135692: "List Name From" List Box Shows Only 20 Trusted Domains

Q135724: Deleted Disk Space Not Released on Converted NTFS Volume

Q135774: Performance Monitor Counters Produce Unlikely Results

Q135777: Unable to Connect Using Cabletron EISA F70XX FDDI NIC

Q135856: RIP Table Does Not Update When New RIPX Response Is Received

Q136023: Batch Files Stop Executing with Windows NT Version 3.51

Q136024: Tape Hardware Data Compression Disabled After Running NT Backup

Q136334: Access Violation in LSASS.EXE During User Password Change

Q136336: Windows NT Fails Because of an Access Violation in WINLOGON

Q136375: NTFS Directory Corruption with More Than 100,000 Files

Q136402: IniFileMapping for 16-Bit Windows Apps Fails in Windows NT 3.51

Q136472: NE3200 NIC Driver Can Lose Locally Administered Address

Q136627: Layered Drivers Never See WINSOCK IRPs for the TCP/IP Device

Q136780: WinFax Pro Software Causes 16-bit Applications to Hang

Q136782: Unable to Connect to AT&T Advanced Server for UNIX Printer Share

Should you apply a particular Service Pack? Look at the list, and see whether any of the bugs are relevant to you. If not and if your system is functioning well, I see no reason to apply the Service Pack, particularly on a production machine. Service Packs are not typically regression-tested as other releases are. If you are concerned about a specific application and the Service Packs, ask the application vendor. (For more information see, "Loading Service Packs," in the February issue of Windows NT Magazine.)