Server Operating System NewsFlash

The Server Operating System NewsFlash Weekly Newsletter is located inside the MCP Secure Web Site. Here I have collected and condensed some interesting problems. If you encountered any of these problems, please contact Microsoft Product Services to obtain the fix. Further information is at http://www.microsoft.com/support/supportnet/overview/overview.asp.

File Transfer Between Computers are Slower Than Expected

File transfer between Windows NT computers with similar names (for example, TEST and TEST1) is sized 512 bytes instead of 4,096 bytes or larger.

The redirector (rdr.sys) on the workstation (e.g. TEST1) incorrectly mark a connection to a remote server (e.g. TEST) as "loopback". This is because the remote server's NetBIOS name is a subset of the local NetBIOS computer name. In loopback connections, the file transfer is only at 512-byte increments.

Taken from Server Operating System NewsFlash Weekly Newsletter Vol 5, Issue 38 Sept 23, 1999.

NetWare Migration Tool May Not Migrate Long File Name Permission

When a folder with long folder name is migrated from NetWare into Windows NT using nwconv.exe, the permissions might not migrate correctly.

Taken from Server Operating System NewsFlash Weekly Newsletter Vol 5, Issue 36 Sept 9, 1999.

Windows NT 4 Supports Maximum of 7.8 GB System Partition

The system partition is the partition that contains the necessary files (NTLDR, NTDETECT.COM, BOOT.INI) to boot up the system. Although in theory, Windows NT 4 can support partitions of up to 16 EB, system partition is limited to 7.8 GB.

When an Intel-based computer first boots, the first process that occur is called the bootstrap process. This process has inherent hardware and software limitations beyond which Windows NT cannot operate.

During the bootstrap process, the only mechanism available to Windows NT (or any other OS) to access the drive is a set of functions in the BIOS known as Interrupt 13 (INT13). The INT13 functions allow low-level code to read from and write to the drive by addressing a specific sector on the drive. The BIOS in virtually all modern computers supports "Logical Block Addressing," which allows INT13 functions to address the first 7.8 GB of drive space independent of the drive's physical geometry. The INT13 functions are the only means available to the operating system to gain access to the drive and system partition until the operating system loads additional drivers that allow it to gain access to the drive without going through INT13. Therefore, Windows NT 4.0 cannot use a system partition larger than 7.8 GB. In fact, the entire system partition must be entirely within the first 7.8 GB of the physical disk. Windows NT can use a 7.8-GB system partition only if the partition begins at the start of the physical drive.

Other operating systems, such as Microsoft Windows 95 OEM Service Release 2, Microsoft Windows 98, and Microsoft Windows 2000, can boot from larger partitions because these operating systems were written after the computer industry defined a new standard for BIOS INT13 functions (the "INT13 extensions") and implemented this new functionality on manufactured motherboards. Because Windows NT 4.0 was written before this new standard was invented, Windows NT 4.0 is unaware of this new technology and is unable to use its features.

When you are installing Windows NT 4.0, you can create a system partition with a maximum size of 4 GB. This occurs because Setup first formats the partition using the FAT file system. If you want to use an NTFS partition, the partition is converted to NTFS after the first reboot. The FAT file system has a file system limitation (unrelated to any BIOS limitations) of 4 GB. When you perform an unattended installation, use of the ExtendOEMPartition directive in an Unattend.txt file can expand the system partition to a maximum of 7.8 GB.

In the future, additional limitations may come into play as well. Although the NTFS file system can address 16 exabytes of disk space in a single partition, current disk-partitioning schemes store partition information in structures that limit partitions to 2^32 sectors, or 2 terabytes, in size. The ATA hardware interface uses 28-bit addressing, which supports drives that are 2^24 sectors, or 137 GB, in size. These limitations may apply to partitions other than the system partition as well.

Another factor to consider when you are troubleshooting partitioning problems is that hard disk manufacturers often use "decimal megabytes" (1 megabyte = 1,000,000 bytes), whereas Windows NT uses "binary megabytes" (1 megabytes = 1,048,576 bytes). Using both definitions of a megabyte in calculations can often account for "lost" disk space. Also, this article assumes a sector size of 512 bytes in all calculations. Although a 512-byte sector has become a de facto industry standard, it is possible that disk manufacturers could produce drives with a different sector size. This would result in a corresponding change in partition limits. Partitions are based on cylinder, head, and sector calculations, not on byte calculations. Therefore, a change in bytes per sector causes a change in bytes per partition.

Taken from Server Operating System NewsFlash Weekly Newsletter Vol 5, Issue 36 Sept 9, 1999.