Introduction to UNIX
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Lesson - 1


 INTRODUCTION TO UNIX 

MENU

Introduction to UNIX|Topics to Learn |1-0|8,42
   #                Topic
  ---              -------
   1   -    The UNIX Operating System
   2   -    UNIX Software Residence
   3   -    UNIX System Characteristics
   4   -    UNIX Versions and Evolution
   5   -    Lesson Review
   0   -    Return to the Main Menu

TOPIC1

The UNIX Operating System

P1

Introduction to UNIX|The UNIX Operating System|1-1.1|7,48
     An operating system is the program that 
manages the resources of a computer.


     An operating system is the software on a 
computer which is independent of any particular 
application.

P2

Introduction to UNIX|The UNIX Operating System|1-1.2|6,54
     UNIX is an operating system which has been used 
very successfully on a broad range of computer systems.


     UNIX is one of the most popular multi-user
operating systems.

TOPIC2

UNIX Software Residence
Introduction to UNIX|UNIX Software Residence|1-2.1|12,54
     The services of certain operating system 
functions are required many times each second.
Under UNIX these functions are constantly kept
in the primary memory.  The memory resident 
portion is called the UNIX kernel.


     Most operating system functions need to be
accessed only occasionally.  These include UNIX 
commands, utilities, and most user-written programs.
These are kept on the disk (secondary storage) and
are invoked upon demand by the user.

TOPIC3

UNIX System Characteristics

P4

Introduction to UNIX|UNIX System Characteristics|1-3.1|13,54
     UNIX is a multi-user operating system because 
on most UNIX systems several users may be logged on 
at one time, each performing a different task. 


     UNIX is a multi-tasking operating system because 
a user under UNIX can run more than one program at 
one time. 


     Some UNIX systems have more than one processor 
executing programs simultaneously (in parallel), thus 
UNIX has the capability of handling parallel processing.

TOPIC4

UNIX Versions and Evolution

P5

Introduction to UNIX|UNIX Versions and Evolution|1-4.1|14,66
     The primary versions of UNIX on the market today are:

        (Bell-Type)
                -   Version - 6 (1975)
                -   Version - 7 (1978)   
                -   System - III (1982) 
                -   System - V (JANUARY 1983)
                -   System - V, release 2.0 (1984)
                -   System - V, release 3.0 (1986)
          
        (Berkeley-type - BSD)
                -   BSD 4.1   (1979)
                -   BSD 4.2   (1983)
                -   BSD 4.3   (Early 1986)

P6

Introduction to UNIX|UNIX Versions and Evolution|1-4.2|11,56
     All UNIX systems are based on the system developed 
at Bell Laboratories.


     Newer versions usually added more features, but 
in doing so, the system grew in size.


     Efforts at Bell Laboratories focused on the greater 
commercial utility of the system, while at U.C. Berkeley 
they focused on improving the system's performance.

P7

Introduction to UNIX|UNIX Versions and Evolution|1-4.3|11,54
     There are several systems running both the Bell 
and the Berkeley types, one of them is "Pyramid 90x" 
from Pyramid Technology, which uses the operating 
system called "OSx".


     In such systems, System V and 4.3 BSD co-reside.


     The most successful Unix derivative is Xenix, 
from Microsoft Corporation which in the early 1986 
accounted for over 60% of all Unix licenses.

P8

Introduction to UNIX|UNIX Versions and Evolution|1-4.4|12,54
     A UNIX operating system usually contains at
least two shells.  A shell is a program that processes
your requests.  It is a command interpreter.


     The standard UNIX shell, sh, is called the
Bourne Shell.
                                    

     The default prompt under sh is a dollar sign:

 $ 

P9

Introduction to UNIX|UNIX Versions and Evolution|1-4.5|7,54
     The shell that usually comes with Berkeley 
versions of UNIX, csh is called the C-Shell.


     The default prompt under csh is a percent sign:

 % 

P10

Introduction to UNIX|UNIX Versions and Evolution|1-4.6|15,54
     Most UNIX systems have several other shells 
available, including the visual, restricted,
uucico, and korn shells.


     Under both sh and csh, a user or a system
administrator may change the default prompt.
It may be changed to a name, initials, number 
or phrase. For example:

                  {henry}:  
                  {ec}:  
                  35:  
                  Type in Command>
                  What next Dave?  

TOPIC5

Lesson Review