Windows NT 3.5

Windows NT 3.5 is an operating system developed by Microsoft, released on September 21, 1994. It is the second release of Windows NT.[3]

Windows NT 3.5
A version of the Windows NT operating system
Windows logo - 1992.svg
Logo of Windows 3.1x
Windows NT 3.5.png
Screenshot of Windows NT 3.5
Source modelClosed source
Released to
September 21, 1994; 25 years ago (1994-09-21)[1]
Latest releaseService Pack 3 (3.5.807) / June 21, 1995; 25 years ago (1995-06-21)[1]
PlatformsIA-32, Alpha, MIPS, PowerPC[2]
Kernel typeHybrid
LicenseCommercial proprietary software
Preceded byWindows NT 3.1 (1993)
Succeeded byWindows NT 3.51 (1995)
Support status
Unsupported as of December 31, 2001

One of the primary goals during Windows NT 3.5 development was to improve the operating system's performance. As a result, the project was codenamed "Daytona", after the Daytona International Speedway in Daytona Beach, Florida.[4] Like many other older Windows versions before 1996, Microsoft stopped supporting Windows NT 3.5 on December 31, 2001. Support for Windows NT 3.51 Workstation also ended on that date.


Windows NT 3.5 comes in two editions: NT Workstation and NT Server. They respectively replace the NT and NT Advanced Server editions of Windows NT 3.1.[5] The Workstation edition allows only 10 concurrent clients to access the file server and does not support Mac clients.[6]

Windows NT 3.5 includes integrated Winsock and TCP/IP support.[7] (Its predecessor, Windows NT 3.1, only includes an incomplete implementation of TCP/IP based on the AT&T UNIX System V "STREAMS" API.) TCP/IP and IPX/SPX stacks in Windows NT 3.5 are rewritten.[8] NetBIOS over TCP/IP (NetBT) support as a compatibility layer for TCP/IP was introduced as also the Microsoft DHCP and WINS clients and DHCP and WINS servers.[9][10]

Windows NT 3.5 can share files via the File Transfer Protocol, and printers through the Line Printer Daemon protocol. It can act as a Gopher, HTTP, or WAIS server,[11] and includes Remote Access Service for remote dial-up modem access to LAN services using either SLIP or PPP protocols.[12] Windows NT 3.5 Resource Kit includes the first implementation of Microsoft DNS.[13]

Other new features in Windows NT 3.5 include long filenames of up to 255 characters, Object Linking and Embedding (OLE) version 2.0 and support for input/output completion ports.[14] Microsoft updated the graphical user interface to be consistent with that of Windows for Workgroups 3.11. NT 3.5 shows performance improvements over NT 3.1, and requires less memory.[3]


A lack of drivers for PCMCIA cards limited NT 3.5's suitability for notebook computers.[11]

To install Windows NT 3.5 on a computer that has a sixth-generation or later x86 processor,[15] one has to modify files on the installation CD-ROM.[3]


In July 1995, Windows NT 3.5 with Service Pack 3 was rated by the National Security Agency as complying with Trusted Computer System Evaluation Criteria (TCSEC) C2 criteria.[16]

Source codeEdit

In 2020, the full source code of Windows NT 3.5's Build 782 was leaked and made available online in 4chan.[17] The source code was originally uploaded to[18], but it has been taken down by Microsoft. The source code still remains in the Internet Archive[19].


  1. ^ a b Adams, Paul (4 August 2009). "Windows NT History". if (ms) blog++;. Microsoft.
  2. ^
  3. ^ a b c "Microsoft Windows NT 3.5". Old Computer Museum. Old Computer Museum. Retrieved 22 September 2013.
  4. ^ Russinovich, Mark; Solomon, David A. (8 December 2004). Microsoft Windows Internals (4 ed.). Microsoft. ISBN 978-0-7356-1917-3. The first release of Windows NT was larger and slower than expected, so the next major push was a project called "Daytona", named after the speedway in Florida. The main goals for this release were to reduce the size of the system, increase the speed of the system, and, of course, to make it more reliable.
  5. ^ "Microsoft Windows NT 3.5". Old Computer Museum. Old Computer Museum. Retrieved 22 September 2013.
  6. ^ "Microsoft Windows NT 3.5 Server". Old Computer Museum. Old Computer Museum. Retrieved 22 September 2013.
  7. ^ "TCP/IP in Windows NT 3.5". Yale University. 9 April 1995. Retrieved 22 September 2013.
  8. ^ How to Optimize Windows NT to Run Over Slow WAN Links w/TCP/IP
  9. ^ "TCP/IP in Windows NT 3.5". Yale University. 9 April 1995. Retrieved 22 September 2013.
  10. ^ DHCP (Dynamic Host Configuration Protocol) Basics
  11. ^ a b "TCP/IP in Windows NT 3.5". Yale University. 9 April 1995. Retrieved 22 September 2013.
  12. ^ "Files Needed to Set Up Windows NT 3.5 and 3.51 RAS". Microsoft. Microsoft. 1 November 2006. Retrieved 22 September 2013.
  13. ^ DNSSETUP.EXE for Beta DNS Service included in
  14. ^ Russinovich, Mark (1 November 2006). "Inside I/O Completion Ports". Sysinternals. Microsoft. Archived from the original on 20 February 2007.
  15. ^ "Windows NT 3.5 Setup and the Pentium Pro Processor". Microsoft. 1 November 2006. Retrieved 4 September 2009.
  16. ^ "Windows NT Server 4.0 – Maintain – Revision 1.1". Microsoft. 1998. Retrieved 4 September 2009.
  17. ^ Xbox and Windows NT 3.5 source code leaks online
  18. ^ NT-782.7z at (archived 26 May 2020)
  19. ^ Windows NT 3.50 (Build 782) - Source Code at the Internet Archive

External linksEdit