Some time ago the long-awaited Service pack 4 to Windows NT version 4.0 was released. Last week Microsoft surprisingly released another Service pack - SP5.

These Service packs are updates to the operating system which fixes security holes and other weaknesses. Microsoft claims that "Service packs keep the product current, and extend and update your computer's functionality. Service packs include updates, system administration tools, drivers, and additional components."

Service packs are cumulative in such a way that any Service pack includes the updates in the former Service pack as well as new fixes. However, some organizations do not want to install a brand new Service pack until it is properly tested. In such situations the need to apply hotfixes may arise.

Unlike Service packs, hotfixes are made to solve one particular problem. Often they are created to fix a security problem which may be used by an intruder to gain access to some resources, crash the operating system or applications. Various Denial of Service (DoS) exploits have been fixed by hotfixes from Microsoft.

Since hotfixes are not created to extend the operating systems functionality but to solve a problem, they do not apply to all configurations. Neither are they tested as thoroughly as the Service packs. The recommendation therefore is to not install hotfixes unless you are exposed to the vulnerability which that particular hotfix is supposed to solve.

More information about

• Microsoft's Service packs to Windows NT
• Microsoft's Hotfixes for Windows NT

Per Olav Førland