also could be directly upgraded to Windows XP Professional on IA-32-based systems only. Service packs Windows NT 4.0 received seven service packs during its lifecycle, as well as numerous service rollup packages and option packs. Only the first service pack was made available for the MIPS architecture, Service Pack 2 was the final release for the PowerPC architecture, and Service Pack 6 was the final release for the Alpha architecture. Service Pack 6a (SP6a) is the last released service pack for Windows NT 4.0. Service Pack 7 was planned at one stage in early 2001, but this became the Post SP6a Security Rollup and not a full service pack, released on July 26, 2001, 16 months following the release of Windows 2000 and nearly three months prior to the release of Windows XP. In addition to bug fixes, the service packs also added a multitude of new features such as Ultra DMA mode for disk drives along with bus mastering, newer versions of Internet Information Services, user accounts and user profile improvements, smart card support, improved symmetric multiprocessing (SMP) scalability, clustering capabilities, COM support improvements, Event Log service, MS-CHAPv2 and NTLMv2, SMB packet signing, Syskey, boot improvements, WINS improvements, Routing and Remote Access Service (RRAS), PPTP, DCOM/HTTP tunneling improvements, IGMPv2, WMI, Active Accessibility and NTFS 3.0 support among others. Resource Kits Microsoft released five revisions of the Windows NT 4.0 Workstation and Server Resource Kit (original release plus four supplements) which contained a large number of tools and utilities, such as desktops.exe which allowed the user to have multiple desktops, as well as third-party software. Security Microsoft stopped providing security updates for Windows NT 4.0 Workstation on June 30, 2004, Windows NT 4.0 Server on December 31, 2004, and Windows NT 4.0 Embedded on July 11, 2006, due to major security flaws including Microsoft Security Bulletin MS03-010, which according to Microsoft could not be patched without significant changes to the core operating system. According to the security bulletin, "Due to the fundamental differences between Windows NT 4.0 and Windows 2000 and its successors, it is infeasible to rebuild the software for Windows NT 4.0 to eliminate the vulnerability. To do so would require re-architecting a very significant amount of the Windows NT 4.0 operating system, and there would be no assurance that applications designed to run on Windows NT 4.0 would continue to operate on the patched system." Between June