DOCUMENT:Q154052 09-AUG-2001 [winnt] TITLE :Explanation of X86 Boot Drive Limitations PRODUCT :Microsoft Windows NT PROD/VER:3.5 3.51 4.0 OPER/SYS: KEYWORDS:kbsetup ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Workstation versions 3.5, 3.51, 4.0 - Microsoft Windows NT Server versions 3.5, 3.51, 4.0 ------------------------------------------------------------------------------- SUMMARY ======= During Setup, Windows NT can only be installed within the first 1,024 cylinders of the boot drive. This is due to Interrupt 13 limitations on x86 computers. MORE INFORMATION ================ When starting an x86 based computer, Ntdetect.com retrieves and stores Interrupt 13 information. This information is supplied by the computer's BIOS. Only information for the first two disks in the system is saved. This information about the drive layout is then passed to the operating system during initialization. The amount of space that the operating system files can use to boot the system is limited in Windows NT to the first 1,024 cylinders of disk 0. This means that Ntldr, Boot.ini, Ntdetect.com and the Windows NT operating system files must be within this boundary. If the disk controller is using a 32 sector/64 head translation scheme, this boundary will be 1 GB. If the controller uses 63 sector/255 head translation, the limit will be 4 GB. If there is a secondary controller that does not have BIOS enabled, Windows NT will default to 32 sectors/64 heads. In some cases, such as duplexing, this may cause identical drives on different controllers to be interpreted as being slightly different in size. Additional query words: prodnt ====================================================================== Keywords : kbsetup Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT351search kbWinNT350search kbWinNT400search kbWinNTW350 kbWinNTW350search kbWinNTW351search kbWinNTW351 kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS351 kbWinNTS350 kbWinNTS351search kbWinNTS350search Version : 3.5 3.51 4.0 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.