FRM,  and MEM,”  LOTUS  adds  “WK1,  PRN,  and PIC.” It is important to devise a naming scheme that is comfortable for you. Your command may have already addressed   this   area   and   come   up   with   descriptive naming  conventions. If  so,  of  course,  you  will  use those.  Whatever  method  you  use,  be  sure  that  it  is indeed  a  method  and  NOT  just  haphazard  naming  of files. When working alongside the end users, be sure to pass along what you have learned. When they go to the filing  cabinet,  be  sure  they  know  exactly  which  file drawer to open and which file folder to retrieve from that drawer. Most people are familiar with organizing file folders in the drawers of a filing cabinet. You might want to use this analogy as a starting point, explaining to the users how they can organize their disk files in much the same manner. Explain how they can organize their work (files) into groups of files called directories. Directories File directories, like the folders that are filed away in drawers by category, or like the yellow pages of the phone  book,  provide  you  a  way  to  organize  and  find files by category and name. Most  operating  systems  give  you  the  option  of creating  either   single  or multiple-file   directories, regardless of whether your system uses floppy or hard disk. Disks with only one directory are said to be of the unstructured  or flat type.  Disks  having  more  than  one directory are said to be  hierarchical  or tree  structured because   they   contain   a   root   directory   and   several subdirectories, each subdirectory containing files with common subject matter. We use the term  tree  structure because this type of directory takes on the appearance of an upside down tree with the trunk of the tree or root directory  located  at  the  top  and  all  the  branches  or subdirectories  located  below. Let’s assume you have a floppy disk that contains 50 files  with  only  a  main  or  root  directory,  as  shown  in figure 2-16. Upon displaying the directory (using the DIRectory command), you notice the files are listed in random sequence, usually in the order of their creation or  when  last  updated. We  call  this  an  unstructured directory. Looking more closely, you realize a number of  things.  First,  that  better  organization  is  needed. Second,  that  most  of  the  files  listed  can  be  grouped together   by   categories: supply,  3-M,  personnel, disbursing,  food  services,  and  division  management. Finally,  you  see  that  there  are  really  two  types  of Figure  2-16.—Unstructured  disk  file  directory. categories: files  that  deal  with  user  applications  and those that deal strictly with division matters. Using the tree-structured approach, you can divide your disk into smaller units by subdirectories, as shown in  figure  2-17.  In  this  example,  E5  Christmas,  as  the primary user of these files, decided to organize her files by   setting   up   a   separate   directory   called E5CHRISTMAS.   Within   the   E5CHRISTMAS directory,  she  set  up  several  subdirectories.  They  are identified by <DIR> following the name and they have no  extensions.  Notice  also  that  some  files,  those  that relate   to   division   matters,   are   included   in   the subdirectory  along  with  the  subdirectories  that  relate  to user  files.  Because  E5  Christmas  uses  the  division  files frequently, she wanted to be able to access them directly from  her  directory. Subdirectories, like other files, appear as entries in the  directory;  however,  you  can’t  see  a  listing  (or  a display) of all the files in all the subdirectories at one Figure  2-17.—Tree-structured  disk  file  directory. 2-27