Introduction
Hardware is known to represent the visible, physically tangible part of a computer system. This is similar to the physical structure of humans. Without software, hardware is practically useless. If there is no blood flowing through man, man is as good as dead.
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Hardware + Software + Human = Computer System
Goal
After completing this unit, you will be able to:
Describe the term software and different types of software (eg B. System software vs. application software).
Describe the features of the operating system.
Distinguishes between standard packages and custom software.
Software
Software is a term used to describe programs, instructions, manuals, related documentation, or programs that make a computer perform various tasks. Blood flows through computer systems. Compared to hardware, the software used in a particular computer is relatively easy to change, an attribute that gives computers flexibility.
Just as humans have two types of blood cells that perform different functions, computer systems also have two types of software that perform different functions. The former is called system software, and the latter is called application software. All other types of software fall into these two broad categories.
SYSTEM SOFTWARE
System software is the programs that come with your computer to help you use your hardware.
We are saying they are preparing the computer. These are non-hardware utilities, computer programs and routines that facilitate the operation of your computer. This broad classification can be further divided into custom application programs and standard application packages. These two will be explained in detail later.
How the System Software Works
Batch Processing
Jobs (programs + data) are entered and stored in a batch queue on disk and run one at a time under control of the operating system. Jobs can wait in the batch queue for minutes to hours, depending on the workload. Cannot be changed while editing. Remote Order Entry: Refers to batch processing where orders are entered at a terminal remote from the computer and transferred to the computer.
Multiprocessing
This is a term used to describe the situation that occurs when a computer system has two or more processors that share some or all of their memory. In such cases, two programs can be processed simultaneously.
Multiprogramming
This happens when more than one program in main memory is apparently being processed at the same time. This is achieved by alternating the execution of the program in blocks of short processing time. H. Another program may be executing some logic commands while one program is being saved. All of these appear to be happening at the same time. This is because your operating system (OS) shields you from the intricate details of what's going on inside your computer. Interactive computing: This occurs when computers and terminal users can communicate with each other.
e. With user-friendly software. This is a very common form of computer use in our time. Conversational mode: This is an interactive computer operation in which responses to user messages are instantaneous.
Multi-Access
This occurs when the computer allows multiple users to interact at the same time. H. If multiple devices can communicate with her one CPU. Multiplexers are used to allow the CPU to communicate with many devices. Time sharing: In this case, processor time is divided into smaller units called time slices, which are shared among users in turn to allow multiple accesses. Each of the devices in the multiple access system 5 is serviced in such a way that it appears that the CPU 1s is only servicing the particular device. This impression can be achieved by time division or frequency division. Timeshare belongs to online processing mode.
Online Systems
These are interactive in nature. In particular, a system is said to be online if devices external to the computer (without human intervention) can communicate directly with the CPU, and the computer itself can take alternative actions such that the external devices affect data processing. will be broken. Operation inside the computer. Actors and interrupts are involved
An interrupt is a signal from an external device, or internal to the CPU itself, that requests the CPU to perform an action. When an interrupt is internal to the CPU it is called a trap. Real-Time Systems: If the exchange of information between an external device and a computer is fast enough that the computation of the results can have an immediate and desirable effect on the computer of which the device is a part, such an online system can: They are called real-time systems. A real-time system, on the other hand, can be defined as a computer system that can process data fast enough to influence the activities that are currently taking place. These systems often require multiprocessing and front-end processors. Response time is important in determining whether a system is real-time or online. For some applications, such as time reservation systems, response time is paramount to avoid overbooking seats, so such systems need to work in real time.
Network
This is a more sophisticated network of computer systems and other devices that are physically or remotely connected, all working together and accessing a common pool of data through communication lines (telephone lines). computing format. Networks allow computers to exchange, share, store, and protect information. It also makes it easier to share expensive hardware and software. A network can be a local area network (LAN) or a wide area network (WAN).
LAN is configured to cover a small area of about 10km2. When it covers a city, it is called a Metropolitan Area Network (MAN).
Wide area networks span cities, countries, or regions.
TYPES OF SYSTEM SOFTWARE
Various types of system software are:
Operating Systems
Translators
Utilities
Database Management System (DBMS) processors and their vast array of capabilities solved the need for more sophisticated modes of operating computers.
Here are some of the problems I had with previous generation computers:
Setup Time: This was necessary for each job to be placed on the machine and the computer to be completely idle during this time. For example, changing the ribbon spool in the ribbon unit, changing printer stationery, etc.
Manual Intervention: Required to investigate error conditions and take corrective action. Again, the machine is idle during this time.
Imbalance between processor speed and other peripherals: This means that the central processor was idle for a long time while the peripherals were running.
Analysis reveals that in a computer with many units, only a small part is working at any given time. What is needed is a “super controller” to run these massive facilities simultaneously and optimize system operations. It turns out that this task can only be performed by some kind of internally stored program. This program became known as the
Operating System. From the previous discussion, we can see that the operating system controls how software uses hardware. This control ensures that your computer not only behaves as you intended, but it also behaves systematically, reliably, and efficiently.
The
operating system works exactly like the human central nervous system. It controls, coordinates and links all activities of computer systems. Also known as Computer Resource Manager. It shields the end-user from the details of the computer's hardware layer, which makes using the computer much easier and user-friendly. User-friendly means that the operating system does not need to understand the complex electronic wiring and inner workings of the computer as a basis for computer use.
Important functions of the operating system:
Scheduling, queuing, and loading of programs or subprograms to provide a continuous sequence of operations and to provide appropriate responses to events.
Controlling hardware resources, especially controlling the selection and operation of input/output and storage devices.
Synchronizes the entire computer system, giving the impression that virtually all jobs are running at the same time.
Protection of Hardware, Software and Data from Improper Use.
Call to main memory. programs and subroutines as and when required.
Passing of control from one job (program) to another under a system of priority when more than one application program occupies the main memory
Provision of error correction routines
Furnishing a complete record of all that happens during processing (usually in the form of printed log)
Communication with the user, usually by means of a Console. The user communicates with the operating system through a Job Control Language (JCL), which is translated and executed by an interactive command interpreter.
There exists various types of operating systems From our understanding of the different uses of computers, especially in terms of customized and multi-purpose or general purpose computers, Operating systems are often described in terms of the methods by which they operate the system and the mode of access they provide to the users.
TYPES OF OPERATING SYSTEMS
SINGLE PROGRAM OPERATING SYSTEM
The majority of small micro-computer based systems have monitors which allow a single user to operate the machine in an interactive, conversational mode and normally only allow one user program to be in the main memory and processed at a time i.e there is no multiprogramming of user programs There exists a number of well-established operating systems which fall into this categories. Examples include CP/M (Microcomputer Control Program) manufactured by Digital Research and MS DOS (Microsoft Disk Operating System) manufactured by Microsoft. The operating system is designed for his two main modes of use, offline and online. In offline mode, batches of programs are loaded and run according to a simple OS with commands from the operator. This type of OS program is commonly known as a disk operating system (DOS) because it is stored on disk. This includes various versions of Windows operating systems that support graphics and multimedia capabilities. In online mode, data is processed as it is received
The concept of multiprogramming allows several different programs to be processed simultaneously.
SIMPLE BATCH SYSTEMS
These are systems that allow multiple programming of batch programs, but offer little opportunity for interaction or multiple access. Many commercial computers in the 1960s and 1970s were of this type.
Multi-access and time-sharing systems
Most operating systems fall into this category. However, such systems have a wide range of complexities. Larger microcomputers and smaller minicomputers have many operating systems available for different machines from different manufacturers. Operating systems that are growing in popularity include Windows 98/XP, UNIX, and XENIX. On large mainframe computers, operating systems are usually unique to each machine manufacturer.
Real-Time Systems
The operating system should be tailored to the type of real-time system used.
A more complex multi-access timesharing system that allows each user to freely select system functions. Also, multi-access users have a clerical role rather than a programming role. These systems often access large databases.
Process Control Systems B. Systems for controlling chemical plant operations Changes need to be responded to as quickly as possible and reliability is essential.
Real-time process control systems vary greatly in size. A large system like the one just described is an extreme example.
At the other extreme are the embedded Real-time systems used in microprocessor-based instruments and monitoring device e.g. the control system in a service station's petrol pump.
Networks- Network operating systems provides network functionality, supplying network protocol support, file and print sharing and other network-centric activities. Most network Operating systems have quite a bıt in common in terms of the services they provide. The complexity of the network however determines which operating system is most appropriate Operating Systems used on networks include Windows 95, Windows 98, Windows NT. Novell NetWare, LINUX, UNIX, and XENIX etc
TRANSLATORS
A translator is a program which converts statements (program or instructions) written in one language to statements in another language especially to machine language
There are three types of translators
Assemblers
Compilers
Interpreters
THE ASSEMBLER
This is a program, which translates assembly language into machine code. A machine language instruction is generated for each source instruction. The resulting program cannot run until the assembly process is complete.
Assembler functions
Convert mnemonic opcodes and symbolic addresses to machine addresses.
Injects the appropriate machine code for macros, including links necessary for closed subroutines.
Allocate memory space.
Detects and displays invalid statements in the source language.
Creates an object program on disk if necessary.
Generates a printed listing of the source and object programs with comments.
Compiler
Compiler translates high level language into machine language
A compiler converts an entire source program into machine code, or an object program, before loading the object into main memory and executing it. The resulting program cannot be run until compilation is complete.
How the Compiler Works
The
translates source program instructions into machine code.
Contains a link to a closed subroutine.
Allocate an area of main memory.
Generates the object program on card, tape, or diskette as desired.
Make printed copies of the source and object programs as needed.
Tabular list of errors found while compiling the program. Use of words or statements that are not in the language's vocabulary. Rules of syntax or vocabulary.
Interpreter
Interpreters are easier to understand than compilers. Both compilers and interpreters are commonly used to translate high-level language programs, but they do so in two distinctly different ways. A compiler converts an entire high-level language source program into a machine code object program before the object program is loaded into main memory for execution.
This is in contrast to the interpreter, which processes the source program statements statement by statement, completely transforming and executing each statement before proceeding to the next. Interpreters rarely produce object code, instead relying on built-in routines. However, some intermediate code is usually generated temporarily. When to use the compiler
You only have to compile the same program once. However, the object program can then be loaded directly into main memory and executed. When using an interpreter. A source program is compiled each time the program is run. Execution performed in this manner can be ten times slower than execution of an equivalent object program. Interpreters are widely used. It's easier for beginners than compilers, especially for the BASIC programming language on small computers.
Using INTERPRETER
Processing user commands on interactive systems.
Debug the program while it is running (1. i.e. fix program errors). H. For each line of code before implementation.
Processing of software written for or by another computer. In this case, an interpreter is essential.
Connect two different machines together for operation, or
simulation to replicate the behavior of the old model if software written on the old model and not yet converted needs to run on the new model. Enable
4. The interpreter can also be used to simulate new machines that have not yet been deployed, but on which the software has already been written. It is a useful service for computer users by providing functions to perform common tasks more routinely Nature
Controlling hardware resources, especially controlling the selection and operation of input/output and storage devices.
Synchronizes the entire computer system, giving the impression that virtually all jobs are running at the same time.
Protection of Hardware, Software and Data from Improper Use.
Call to main memory. programs and subroutines as and when required.
Passing of control from one job (program) to another under a system of priority when more than one application program occupies the main memory
Provision of error correction routines
Furnishing a complete record of all that happens during processing (usually in the form of printed log)
Communication with the user, usually by means of a Console. The user communicates with the operating system through a Job Control Language (JCL), which is translated and executed by an interactive command interpreter.
There exists various types of operating systems From our understanding of the different uses of computers, especially in terms of customized and multi-purpose or general purpose computers, Operating systems are often described in terms of the methods by which they operate the system and the mode of access they provide to the users.
TYPES OF OPERATING SYSTEMS
SINGLE PROGRAM OPERATING SYSTEM
The majority of small micro-computer based systems have monitors which allow a single user to operate the machine in an interactive, conversational mode and normally only allow one user program to be in the main memory and processed at a time i.e there is no multiprogramming of user programs There exists a number of well-established operating systems which fall into this categories. Examples include CP/M (Microcomputer Control Program) manufactured by Digital Research and MS DOS (Microsoft Disk Operating System) manufactured by Microsoft. The operating system is designed for his two main modes of use, offline and online. In offline mode, batches of programs are loaded and run according to a simple OS with commands from the operator. This type of OS program is commonly known as a disk operating system (DOS) because it is stored on disk. This includes various versions of Windows operating systems that support graphics and multimedia capabilities. In online mode, data is processed as it is received
The concept of multiprogramming allows several different programs to be processed simultaneously.
SIMPLE BATCH SYSTEMS
These are systems that allow multiple programming of batch programs, but offer little opportunity for interaction or multiple access. Many commercial computers in the 1960s and 1970s were of this type.
Multi-access and time-sharing systems
Most operating systems fall into this category. However, such systems have a wide range of complexities. Larger microcomputers and smaller minicomputers have many operating systems available for different machines from different manufacturers. Operating systems that are growing in popularity include Windows 98/XP, UNIX, and XENIX. On large mainframe computers, operating systems are usually unique to each machine manufacturer.
Real-Time Systems
The operating system should be tailored to the type of real-time system used.
A more complex multi-access timesharing system that allows each user to freely select system functions. Also, multi-access users have a clerical role rather than a programming role. These systems often access large databases.
Process Control Systems B. Systems for controlling chemical plant operations Changes need to be responded to as quickly as possible and reliability is essential.
Real-time process control systems vary greatly in size. A large system like the one just described is an extreme example.
At the other extreme are the embedded Real-time systems used in microprocessor-based instruments and monitoring device e.g. the control system in a service station's petrol pump.
Networks- Network operating systems provides network functionality, supplying network protocol support, file and print sharing and other network-centric activities. Most network Operating systems have quite a bıt in common in terms of the services they provide. The complexity of the network however determines which operating system is most appropriate Operating Systems used on networks include Windows 95, Windows 98, Windows NT. Novell NetWare, LINUX, UNIX, and XENIX etc
TRANSLATORS
A translator is a program which converts statements (program or instructions) written in one language to statements in another language especially to machine language
There are three types of translators
Assemblers
Compilers
Interpreters
THE ASSEMBLER
This is a program, which translates assembly language into machine code. A machine language instruction is generated for each source instruction. The resulting program cannot run until the assembly process is complete.
Assembler functions
Convert mnemonic opcodes and symbolic addresses to machine addresses.
Injects the appropriate machine code for macros, including links necessary for closed subroutines.
Allocate memory space.
Detects and displays invalid statements in the source language.
Creates an object program on disk if necessary.
Generates a printed listing of the source and object programs with comments.
Compiler
Compiler translates high level language into machine language
A compiler converts an entire source program into machine code, or an object program, before loading the object into main memory and executing it. The resulting program cannot be run until compilation is complete.
How the Compiler Works
The
translates source program instructions into machine code.
Contains a link to a closed subroutine.
Allocate an area of main memory.
Generates the object program on card, tape, or diskette as desired.
Make printed copies of the source and object programs as needed.
Tabular list of errors found while compiling the program. Use of words or statements that are not in the language's vocabulary. Rules of syntax or vocabulary.
Interpreter
Interpreters are easier to understand than compilers. Both compilers and interpreters are commonly used to translate high-level language programs, but they do so in two distinctly different ways. A compiler converts an entire high-level language source program into a machine code object program before the object program is loaded into main memory for execution.
This is in contrast to the interpreter, which processes the source program statements statement by statement, completely transforming and executing each statement before proceeding to the next. Interpreters rarely produce object code, instead relying on built-in routines. However, some intermediate code is usually generated temporarily. When to use the compiler
You only have to compile the same program once. However, the object program can then be loaded directly into main memory and executed. When using an interpreter. A source program is compiled each time the program is run. Execution performed in this manner can be ten times slower than execution of an equivalent object program. Interpreters are widely used. It's easier for beginners than compilers, especially for the BASIC programming language on small computers.
Using INTERPRETER
Processing user commands on interactive systems.
Debug the program while it is running (1. i.e. fix program errors). H. For each line of code before implementation.
Processing of software written for or by another computer. In this case, an interpreter is essential.
Connect two different machines together for operation, or
simulation to replicate the behavior of the old model if software written on the old model and not yet converted needs to run on the new model. Enable
4. The interpreter can also be used to simulate new machines that have not yet been deployed, but on which the software has already been written. It is a useful service for computer users by providing functions to perform common tasks more routinely Nature
APPLICATION SOFTWARE
An application program is software intended for a specific practical use. This broad classification can be subdivided into two categories: custom application programs and standard application packages.
TYPES OF APPLICATION SOFTWARE
CUSTOM APPLICATION SOFTWARE
These are programs, such as written programs, with associated documentation specially designed (custom-made) to perform a specific task. Other examples of custom application programs include payroll programs and matrix product programs.
Standard Application Packages
These are software packages containing related documentation used to solve common everyday problems.
Helps many users who may have the same kind of problem. Manufacturers and software developers create standard programs to solve these everyday problems and sell them to many needy users.
Classification of standard application packages
Graphics package. Corel Draw, ISIS Draw, Print Artist, etc.
Computer Aided Design Packages. For example: AutoCAD, ArchiCAD, etc.
statistical packages. B. SPSS
word processing packages such as Microsoft Word and WordPerfect.
TYPES OF APPLICATION SOFTWARE
CUSTOM APPLICATION SOFTWARE
These are programs, such as written programs, with associated documentation specially designed (custom-made) to perform a specific task. Other examples of custom application programs include payroll programs and matrix product programs.
Standard Application Packages
These are software packages containing related documentation used to solve common everyday problems.
Helps many users who may have the same kind of problem. Manufacturers and software developers create standard programs to solve these everyday problems and sell them to many needy users.
Classification of standard application packages
Graphics package. Corel Draw, ISIS Draw, Print Artist, etc.
Computer Aided Design Packages. For example: AutoCAD, ArchiCAD, etc.
statistical packages. B. SPSS
word processing packages such as Microsoft Word and WordPerfect.