entire data files, while deleting and editing are used for individual records in a data file. COMPUTER  SYSTEM  SOFTWARE Up  to  now,  we  have  been  discussing  computer hardware (the computer and its peripheral devices) and the manner in which these devices work and are able to talk  (communicate)  with  each  other.  But  what  about this  thing  called  software?  Do  we  really  need  it?  We most certainly do! Software plays a major role in data processing;  for  without  software,  we  could  not  direct the   computer   to   perform   simple   addition.   It’s   the software that makes everything happen. Or, putting it another way, it brings the computer to life. At this point, we briefly describe the general types of software used in computers. Software  can  be  defined  as  a  set  of  computer programs,  procedures,  and  associated  documentation concerned  with  the  operation  of  a  data  processing system.  Basically,  there  are  two  types  of  software: systems software and applications software. SYSTEMS  SOFTWARE Systems  software,  often  referred  to  as   systems programs,  consists  of  supervisory  and  support  modules (programs)  designed  to  coordinate  the  capabilities  of the  computer  itself.  These  include  programs  such  as operating  systems,  assemblers,  debug  routines,  text editors,   compilers,   library   maintenance   routines, utilities, linkage editors, and I/O drivers. Operating Systems An   operating   system   is   a   collection   of   many programs used by the computer to manage and control its   own   resources   and   operations.   These   programs control   the   execution   of   other   programs. They schedule,  assign  resources,  monitor,  and  control  the work  of  the  computer,  allowing  it  to  carry  out  tasks independently of most human intervention. Assemblers and Compilers Both   assemblers   and   compilers   are   language translators.   They   are   usually   designed   for   specific machines   and   specific   languages.   They   translate computer programs written in assembly language into machine  language. A   language   translator   for   an assembly  language  is  called  an  assembler   program. Most   high-level   language   translators   are   called compiler  programs.  These translators are designed to convert the artificial languages used by programmers, such as COBOL or FORTRAN, into a machine-usable code after it is entered into the computer. Utilities Utilities are programs or routines that have general application.  They  may  be  separate  programs  or  they may   be   routines   or   programs   included   with   the operating system to further aid the user by performing standard  functions.  Sort,  merge,  and  copy  programs  are typical  examples.  Other  examples  are  text  editors  to allow  programmers  to  enter,  add,  delete,  or  change program  statements;  linkage  editors  to  put  together compiled  programs  and  routines;  and  debug  routines  to help programmers find errors. APPLICATIONS  SOFTWARE Applications   software   consists   of   programs designed  to  solve  specific  classes  or  types  of  problems. For example, word processing programs help us prepare correspondence,   instructions,   messages,   and   so   on. Spreadsheet programs enable us to store and manipulate numbers   in   numerical   tables. Database   programs enable us to store and retrieve large amounts of data in various report formats. Some software is ready to use and   may   be   purchased   from   retail   stores   and government contracts. This software is called  off-the- shelf  software   (COTS).  If  COTS  is  not  available  to solve Navywide or individual user problems, the Navy may   write   its   own   programs.   Some   programs   are designed and written by one of the Navy’s central design agencies and distributed to AIS installations for use. If no Navy-developed software will solve an individual problem,  you  or  your  automated  information  system (AIS)  installation  may  write  a  program  in  one  of  the many programming languages. PROGRAMMING   LANGUAGES Almost any type of application you can think of can be   programmed   in   one   or   more   of   the   many programming  languages.  Just  as  we  humans  speak  in many different languages, computers also speak (use) many  different  languages.  We  can  divide  programming languages  into  three  categories:  machine  languages, assembly languages, and high-level languages. Machine Languages A machine language consists of a combination of 0s and 1s that is used to indicate OFF and ON states of 3-2