Объясните код

class ISuperblock
{
public:
    virtual ~ISuperblock();
 
    virtual int             ConnectToDevice(class IBlockDevicePartition * Device) = 0;
 
    // Mount service
    virtual class IBlockDevicePartition *   GetDevice(void) = 0;
    virtual class Inode         *   GetRootInode(void) = 0;
    virtual class ISuperblock       *   GetParentSuperblock(void) = 0;
    virtual const ino_t             GetParenInode(void) = 0;
    virtual void                    SetParent(class Inode * inode) = 0;
 
    // Controls how many objects use Superblock
    virtual void            AddReference() = 0;
    virtual void            DelReference() = 0;
    virtual const int       GetReferenceCount(void) = 0;
 
    // Inode service
    virtual class Inode *   GetInode(int nInodeNumber, int nParenNumber ) = 0;
    virtual class Inode *   MakeInode (unsigned short uid, unsigned short gid, unsigned short mode) = 0;
    virtual int     RemoveInode(class Inode * inode) const = 0;
    virtual int     ReleaseInode(class Inode * inode) = 0;
 
    // Directory service
    virtual typeDirentry *      ReadDir(class DirectoryHandler * dir) = 0;
    virtual int         InsertDirectoryEntry (class Inode * where, class Inode * which, const char *szName) = 0;
    virtual int         DeleteDirectoryEntry (class Inode * where, const char *szName) = 0;
    virtual bool            IsDirectoryEmpty ( class ISuperblock * sb, class Inode * inode_dir) = 0;
 
    // Symbolic link service
    virtual int         MakeSymbolicLink(class Inode * inode, const char * szLinkTo) = 0;
    virtual class Inode *   GetSymlink (class IProcess * process, class Inode * node) = 0;
 
    // File system name and status service
    virtual int         StatFS( statfs_t * stat) = 0;
    virtual char *          GetFileSystemName(void) = 0;
 
    // Prepare Inode to read/write operations
    virtual int         OpenNode(class Inode * inode) = 0;
    virtual int         CloseNode(class Inode * inode) = 0;
 
    // Disk blocks service
    virtual block_t         AllocateFreeBlocks(int nCount) = 0;
    virtual int         ReleaseBlock(block_t nBlock) = 0;
    virtual block_t         GetBlockNumberByIndex(class Inode * node, unsigned int nIndex) = 0;
    virtual int         SetBlockNumberByIndex(class Inode * node, unsigned int nIndex, block_t nBlockNumber) = 0;
    virtual int         TruncateInode(class Inode * inode, unsigned int nSize = 0) = 0;
 
    // Flushing service
    virtual int         FlushInode( class Inode * inode, FlushMode_t flush_mode ) = 0;
    virtual int         FlushDiskCaches(void) = 0;
 
    // File path service
    virtual int         GetCurrentDirectoryName (class IProcess * process, class Inode * inode, char * dirname) = 0;
};