This article was previously published under Q154052
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During Setup, Windows NT can only be installed within the first 1,024cylinders of the boot drive. This is due to Interrupt 13 limitations onx86 computers.
When starting an x86 based computer, Ntdetect.com retrieves and storesInterrupt 13 information. This information is supplied by the computer'sBIOS. Only information for the first two disks in the system is saved. Thisinformation about the drive layout is then passed to the operating systemduring initialization. The amount of space that the operating system filescan use to boot the system is limited in Windows NT to the first 1,024cylinders of disk 0. This means that Ntldr, Boot.ini, Ntdetect.com and theWindows 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 headtranslation, the limit will be 4 GB. If there is a secondary controllerthat does not have BIOS enabled, Windows NT will default to 32 sectors/64heads. In some cases, such as duplexing, this may cause identical drives ondifferent controllers to be interpreted as being slightly different insize.