What is the function in Windows similar to Inode in Linux?

In NTFS file metadata is stored in the MFT records, which is the analog of inode in Windows. Each record has its own unique ID which is the equivalent to inode number. You can check this with fsutil file queryfileid

PS C:\>  fsutil file queryfileid .\Windows\
File ID is 0x0000000000000000003f000000023994

You can also open a file with its ID by using the API OpenFileById()

You can get more detailed information (including the file ID) with fsutil file layout which can be considered the rough equivalent of stat in Unix

PS C:\>  fsutil file layout .\Windows\

********* File 0x003f000000023994 *********
File reference number   : 0x003f000000023994
File attributes         : 0x00000010: Directory
File entry flags        : 0x00000000
Link (ParentID: Name)   : 0x0005000000000005: HLINK Name   : \Windows
Creation Time           : 07-07-2018 7:13:52
Last Access Time        : 22-07-2018 3:50:13
Last Write Time         : 13-07-2018 14:43:09
Change Time             : 13-07-2018 14:43:09
LastUsn                 : 14,010,547,632
OwnerId                 : 0
SecurityId              : 269
StorageReserveId        : 0
Stream                  : 0x010  ::$STANDARD_INFORMATION
    Attributes          : 0x00000000: *NONE*
    Flags               : 0x0000000c: Resident | No clusters allocated
    Size                : 72
    Allocated Size      : 72
Stream                  : 0x030  ::$FILE_NAME
    Attributes          : 0x00000000: *NONE*
    Flags               : 0x0000000c: Resident | No clusters allocated
    Size                : 80
    Allocated Size      : 80
Stream                  : 0x090  :$I30:$INDEX_ROOT
    Attributes          : 0x00000000: *NONE*
    Flags               : 0x0000000c: Resident | No clusters allocated
    Size                : 400
    Allocated Size      : 400
Stream                  : 0x0a0  :$I30:$INDEX_ALLOCATION
    Attributes          : 0x00000000: *NONE*
    Flags               : 0x00000000: *NONE*
    Size                : 16,384
    Allocated Size      : 16,384
    Extents             : 4 Extents
                        : 1: VCN: 0 Clusters: 1 LCN: 2,017,244
                        : 2: VCN: 1 Clusters: 1 LCN: 2,280,708
                        : 3: VCN: 2 Clusters: 1 LCN: 2,285,170
                        : 4: VCN: 3 Clusters: 1 LCN: 16,203,332
Stream                  : 0x0b0  :$I30:$BITMAP
    Attributes          : 0x00000000: *NONE*
    Flags               : 0x0000000c: Resident | No clusters allocated
    Size                : 8
    Allocated Size      : 8
Stream                  : 0x100  :$TXF_DATA:$LOGGED_UTILITY_STREAM
    Attributes          : 0x00000000: *NONE*
    Flags               : 0x0000000c: Resident | No clusters allocated
    Size                : 56
    Allocated Size      : 56

There's no such thing on FAT file system although you can consider the first position of the file in the file allocation table its ID (until the file is moved due to defragmentation)

The concept of a inode is used in Unix based File System. NTFS may have some type of index identifier used internally in the MFT, but Windows doesn't have a built-in command to show this. I don't know if your just curious or you are trying to accomplish something like create a hard link in Windows. I administer Linux Desktops and Servers every day, and the only thing useful for looking at a inode number for me, is to confirm a hard link.

Source: http://commandwindows.com/fsutil.htm

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