SYS_READAT Read from an open file (with offset)
SYS_WRITE Write to an open file
SYS_WRITEAT Write to an open file (with offset)
+SYS_TRUNCATE Change the size of an open file
SYS_IOCTL Perform an IOCtl Call
SYS_SEEK Seek to a new position in the file
SYS_READDIR Read from an open directory
SYS_GETCWD Get current directory
SYS_MOUNT Mount a filesystem
SYS_SELECT Wait for file handles
+SYS_MMAP Map a file into this address space
+SYS_MUNMAP Unmap a file
+SYS_MARSHALFD Create a reference to a FD suitable for handing to another process
+SYS_UNMARSHALFD Accept a marshaled FD
+