Judgement of my posts ain't made here but do suggests some knowledge you have in your brain.
You're obviously permitted to have a look around, but of course, itchy fingers aren't entertained - so don't take what's not yours. ;)
CONTROL UNIT
A control unit is one of the two components of the central processing unit. The function of the control unit is to extract information which is stored in the memory and to decode and execute those instructions.
Functions of Control Unit:
A control unit can be described as a sort of circuitry that supervises and controls the path of information that runs over the processor and organizes the various activities of those units that lie inside it.
• It carries out many tasks such as decoding, fetching, handling the execution and finally storing the results.
• It controls the execution of instructions in a sequential order.
• It guides the flow of data through the different parts of the computer.
• It interprets the instructions.
• It regulates the time controls of the processor.
MEMORY UNIT
The memory unit is the principal storage of the computer. All the data and instructions that the computer needs at a moment are stored here.
Functions of memory unit:
A computer memory unit is the storage where data and instructions go when entered into the computer.
ARITHMETIC LOGIC UNIT (ALU)
Arithmetic logic unit is that part of the computer which performs the different logic operations and arithmetic calculations like addition, subtraction, multiplication and division. It is the high speed digital circuit that solves calculations and does comparisons.
Functions of Arithmetic Logic Unit:
• Almost all the actions of the computer are done by it. It gets its data from a certain computer memory called processor register . After the data gets processed, its results get stored in output registers of the arithmetic logic unit .
• The arithmetic logic unit can perform integer arithmetic operations like addition, subtraction, etc.
The difference between types of primary memory and their uses (RAM, ROM).
Memory may be one of two types, known as RAM and ROM respectively.
COMPUTER RAM
RAM stands for Random Access Memory, which means that any memory location can be directly accessed by referring to its address.
Short for Random Access Memory, RAM, also known as main memory or system memory, is a term commonly used to describe the memory within a computer. Unlike ROM, RAM requires power; if power is lost, all data is also lost.
Uses of RAM:
Data and programs are transferred into and out of RAM, and the data in RAM is processed according to the instructions in the program.
COMPUTER ROM
There is a type of memory that stores data without electrical current; it is the ROM (Read Only Memory) or is sometimes called non-volatile memory as it is not erased when the system is switched off.
Uses of ROM:
ROM is used to store some of the operating system commands, and the instruction set of the computer.
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- The program used in a computer
- a set of instructions for the computer to carry out task.
Computer software, or just software is a general term primarily used for digitally stored data such as computer programs and other kinds of information read and written by computers. -Wikipedia-
Software is a collection of instructions that enables a user to interact with the computer or have the computer perform specific tasks for them. Without any type of software the computer would be useless.
-ComputerHope-
System Software
System software is use to control the computer or hardware.
- it is where you save the data
- control the hardware
- install or run other programmes
It includes the combination of the following :
- device drivers
- operating systems
- servers
- utilities
- windowing systems
The purpose of systems software is to unburden the applications programmer from the often complex details of the particular computer being used, including such accessories as communications devices, printers, device readers, displays and keyboards, and also to partition the computer's resources such as memory and processor time in a safe and stable manner.
Example : Microsoft Windows XP, Microsoft Windows Vista, Linux, OSX (AppleMac)
Application Software
Application software is to do a specific and to solve problems. It is a subclass of computer software that employs the capabilities of a computer directly and thoroughly to a task that the user wishes to perform.
There are two types of software :-
- Ready made (off-the-shelf) software
- User-written software
Ready Made software
- display on shelf
- less error
- fully tested
- cannot modify
- cheaper
User Written software
- overlooked by programmer
- more expensive because may hire specialist
- may contains more error
- can request some special features
- programmer can create their own program using this
Advantages of using ready made packages :
- An important advantage is that users do not need any special technical skills or ability to use them. Designed to be user-friendly.
- They cost much less than writting your own software.
- They are easily available. It is buy what you want.
- Suitability of the computer.
Disadvantages of using ready made packages :
- They are rigid and their functions cannot be changed.
- Some of them may not suit your specific requirements.
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What is a system software?
System software is a computer software designed to operate the computer hardware and to provide and maintain a platform for running application software.
What is operating system?
Operating system is a software that controls the operation of the computer, directs the input and output of the data, keeps track of files and controls the processing of the computer programs.
The purposes of operating system
An operating system is the framework that allows you to communicate with computer hardware in an interactive way.
Without this, you would not be able to tell the computer to do anything and it would have any instructions to follow. This is why it is important for a computer to have an operating system .
Its roles include managing the functioning of the computer hardware, running the applications programs, serving as an interface between the computer and the user, and allocating computer resources to various functions. -WikiAnswers-
The file management tasks that are done by a computer operating system :
- Manage the information on the disk in file management which the user can save the information disk.
- Control the hardware to make the system to run such as tasks management input and output control.
- Run the program or system, example for the user to log in and out of the system.
- User account management for the user to manage their accounts to prevent any unauthorized use.
- The user can do multitasking for example all window applications, the user can open as many window applications as he wants, it will be display on the taskbar.
BATCH PROCESSING
- Batch processing : a group of documents must be collected and compile and process as a group.
Characteristics of Batch processing
This requires the operating system to work through a series of programs that are held in a queue.
The operating system is responsible for scheduling the jobs according priority and the resources they require.
Example of use of batch processing : A large company would use batch processing to automate their payrolls. This would find the list of employees, calculate their monthly salary (with tax deductions) and print the corresponding payslips. Batch processing is useful for this purpose since these procedures are repeated for every employee each month.
REAL-TIME PROCESSING
- Real-time processing : a real time system accepts data and process it immediately when a change is made due to transaction occuring and respond to user input.
Real-time operating systems are designed to respond to an event within a predetermined time. These types of operating systems are found within environments where computers are responsible for controlling systems.
Examples of use of real time processing : Robotics, manufacturing, special military applications.
SINGLE -USER OPERATING SYSTEM
- Single-user : it is to designed to manage the computer so that one user can effectively do one thing at a time.
It is most commonly used when talking about operating system being usable only by one person at a time.
MULTI-USER OPERATING SYSTEM
- Multi-user : is an operating system that allows concurrent access by multiple users of a computer
Batch processing systems for mainframe computers are considered as multi user system to avoid leaving the CPU idle while it waits for an I/O operations to be completed.
MULTI-TASKING OPERATING SYSTEM
- Multi-tasking : a system that is doing more than one job at the same time.
In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for that task.
Multitasking solves the problem by scheduling which task may be the one running at any given time, and when another waiting task gets a turn. -Wikipedia-
NETWORK SYSTEM OPERATING SYSTEM
- Network system : includes software to communicate with other computers via a network and allows resources such as files and printers to be shared between computers.
It allows user to access data found on the other network such as the internet.
It allows the user to access hardware connected to the network.
It also protects the data and services located on the network.
RANGE OF APPLICATIONS
In Batch processing, inventory and payroll system data supplied and the printing out slips of the workers salary by doing it in one go.
In real time response, Nucleus OS that is ideal for resource-constrained devices (frequency and memory) and for environments where squeezing out every cycle per watt is paramount.
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- icon : a meaningful symbol to represent items for example small pictures
- window : a rectangular portion of a document on the screen.
- menu : a list of options which the user can choose from.
- pointer cursor : looks like a short arrow to point to an item you wish to select.
Examples of GUI : Microsoft Windows 2000, Microsoft Windows 2003
Icons shown below, helping the user for selection instead of typing.
For example :
COMMAND LINE INTERFACE
When you type an instruction which is usually abbreviated in order to get something done. It is not easy to use because have to remember many commands in order to be able to use the software quickly.
People often get the commands mixed up because commands for different software packages are rarely the same. Some people prefer command driven because they can be faster use once you have learnt all the commands.
For example :
UTILITY SOFTWARE
Purpose of disk formatting : by formatting the disk to enable the user to store on more files and documents with more memory space just like a new disk.
Purpose of file handling : it is to manage the file system to sort out nicely.
Purpose of hardware drivers : it is a software use to control the hardware components or drivers.
Purpose of file compression : allows user to make one or more files into a smaller zip file so that more memory is available.
Purpose of virus checkers : to check or detect any viruses attacking the software.
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