simultaneously. An example of multitasking is to have the  network  server  transfer  a  message  (using  a  program called E-mail) from one PC to another, save a 50-page document to hard disk, and send a report to a printer, in rapid   succession.   Only   systems   with   multiple processors, such as a system with two 386 or 486 microprocessors,   can   process   information simultaneously. Network  system  software  provides  utility programs, such as electronic mail (or e-mail). E-mail gives network users the ability to send messages to one another over the network. If for some reason you needed to send a message to all the network users, E-mail is capable of sending your message to multiple users. Other utility programs sort, merge, and print files. Network  system  software  also  provides  data protection. This includes  data  security/integrity  and backing up of files. Data security is a must if you are to limit  access  to  sensitive  and  classified  information. Data  integrity  prevents  files  from  being  updated  by more than one user at a time. There are a number of ways you can control access to information on the network. One way is to divide the shared hard disk into several  different  sections,  similar  to  making  logical partitions.   Once   the   different   areas   have   been established, you can specify how the user can access them. Generally, the different levels of access can be designated for either private, shared, or public use. They are defined as follows: . PRIVATE USE Only one user is allowed to access and make changes to the data in this area. For example, all of PO1 Smith’s work is located in the area \SMITH. Only PO1 Smith has access to this area, and only she can make changes. . SHARED USE All users are allowed to access and make changes to the data in this area. For example, a shared area called \ADMIN could contain correspondence that can be updated by all  the  command’s  Yeomen. . PUBLIC USE All users are allowed to access this  area;  however,  they  cannot  make  any changes to the data. For example, the area called \DIRECTIV contains all command directives. You would want your users to be able to view the data but not be able to make any changes. Security  and  data  protection  are  provided  by identification and password security. When the users log  on  the  system,  they  must  enter  their  correct identification  numbers  along  with  their  passwords  (as  a double check) to gain access to information. Another reason why data must be made secure is to prevent unintentional damage that can result when more than one user accesses and changes the same information at the same time. In a case such as this, neither user would know what the other had done, and the result would be corrupted  data.  To  prevent  this,  network  software  often provides you with some type of  locking  capability. This locking  feature  prevents  others  from  accessing  the file or record when you are working on it. To ensure a well-managed (network), the data must not only be secure, it must also be backed upon a regular basis. Files must be backed up if all the information on the network server’s hard disk is to be saved in the event of a hard disk failure, a sudden power surge, or loss of power. Tape backup systems are very effective in that not only the tapes but also the tape units themselves can be  stored  off-site,  which  provides  for  additional security. APPLICATION SOFTWARE In addition to network system software, users of (network) require application software  to carry out their  specific  requirements.  You  are  familiar  with  many of   the   application   software   functions/packages available.  They  include  word  processing  programs, database   management   programs,   spreadsheet programs,  computer  aided  design  (CAD)  programs, tutorials, and so on. Application software shared on a network is different from the software you use on your individual or stand-alone PC. It is specially designed to work on a network—to handle the demands of many users and to share resources while serving many users. It can also provide data security features, such as file or record locking and password recognition. Because network versions of application software are designed to be used by many users, a network software license agreement often costs more than a standard license. Before leaving this section, you need to know a few other things about network software. Network system software features often vary from one network system to another. The system software can also dictate what hardware components  CAN and CANNOT be used, and how the network CAN or CANNOT be configured. SOFTWARE   INSTALLATION Before  installing  software  on  an  individual’s  PC  or on the network server, you will need to know the minimum  system/hardware  requirements  for  that 1-7