The terminology used is a bit different from what you'd find in the Unix world, however in terms of having an integer that uniquely identifies a file, NTFS and some Windows API expose the concept of "file IDs" which is similar.

You can query the file ID of an open handle via GetFileInformationByHandle. See nFileIndexHigh, nFileIndexLow; this is the high and low parts respectively of the file ID which is 64 bits.

NtCreateFile can also open a file by its ID. See the FILE_OPEN_BY_FILE_ID flag. You need a volume handle to open by file ID.

Windows has "FileId"

Yes, it does. Generally called FileId (AKA file ID, AKA FileID). Try this in a Win8 command shell:

C:\>fsutil file | findstr /I fileid queryFileID Queries the file ID of the specified file C:\>fsutil file queryFileID Usage : fsutil file queryFileID <filename> Eg : fsutil file queryFileID C:\testfile.txt 

Reference:

• https://learn.microsoft.com/en-us/windows/win32/api/winbase/ns-winbase-file_id_info

  FileId

  The 128-bit file identifier for the file. The file identifier and the volume serial number uniquely identify a file on a single computer.

• https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/fsutil-file

Yes. NTFS uses a B-Tree indexing system. Every file in the MFT has a 64 bit File Index Number. This number, called the File ID, uniquely identifies the file ONLY WITHIN ITS VOLUME. I.e., two files on two separate volumes on the same PC may have the same File ID. See this MSDN article for more details.

https://msdn.microsoft.com/en-us/library/windows/desktop/aa363788(v=vs.85).aspx

regarding your second question, "how does windows internally manage files", see this technet article:

https://technet.microsoft.com/en-us/library/cc781134(v=ws.10).aspx

There are two things here. The term INode, and a file-system implementation that uses either INode terminology or something like INode in its place.

All Windows file-systems(FAT*,NTFS) I know of, use Inode-like structures in actual implementation.

To further simplify the answer

(Think of INode as a block of metadata about a file.)

INode as term : No windows file system dont have it.

INode as concept : Windows will have some other structures, similar in property and usage but used with different name

This question is more about filesystems than a particular OS I believe. Each filesystem handles files differently (and each OS can support multiple filesystems).

http://pcnineoneone.com/howto/filesystems1/ has a pretty good writeup on FAT and NTFS, which are two popular filesystems with windows.

Inodes are a POSIX concept. Modern Windows versions use NTFS. An in-depth description of NTFS: Inside NTFS