Sunday, 8 September 2013

SCL 3: OPERATING SYSTEM AND FILE MANAGEMENT

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SCL 3: OPERATING SYSTEM AND FILE MANAGEMENT

1.    Operating system used in a desktop/laptop today:

-       Windows 8
-       Windows 7 (Home Premium/Professional/Ultimate)
-       Linux
-       Mac OS


How does operating systems work?

Every time when you turn on your computer, it is nice to think that you are in control. There’s the trusty computer mouse, which you can move anywhere on the screen and summoning up what you want. Although it’s awesome to feel like a director in front of your desktop or laptop, there’s a lot of things happen inside of your system which the man behind the curtain handling all the task that you gave is your operating system.
The operating system (OS) is the first thing loaded onto the computer and without the operating system, a computer is useless. If you like to think with electronic devices, you are probably pleased that operating systems can be found and needed by many devices that we use everyday.
 All desktop computers have operating systems. There are hundreds of other operating systems available for special-purpose applications, including specializations for mainframes, robotics, manufacturing, real-time control systems and so on. In any device that has an operating system, there's usually a way to make changes to how the device works. One of the reasons operating systems are made out of portable code rather than permanent physical circuits is so that they can be changed or modified without having to scrap the whole device.

There are two common things that an operating system does, which are:

1.     It manages the hardware and software resources of the system. In a desktop computer, these resources include such things as the processor, memory, disk space and more.  
  
      2.It provides a stable, consistent way for applications to deal with the hardware without having to know all the details of the hardware.

When you turn on the power to a computer, the first program that runs is usually a set of instructions kept in the computer's read-only memory (ROM). This code examines the system hardware to make sure everything is functioning properly. This power-on self test(POST) checks the CPU, memory, and basic input-output systems(BIOS) for errors and stores the result in a special memory location. Once the POST has successfully completed, the software loaded in ROM (sometimes called the BIOS or firmware) will begin to activate the computer's disk drives. In most modern computers, when the computer activates the hard disk drive, it finds the first piece of the operating system: the bootstrap loader.
The bootstrap loader is a small program that has a single function: It loads the operating system into memory and allows it to begin operation. In the most basic form, the bootstrap loader sets up the small driver programs that interface with and control the various hardware subsystems of the computer. It sets up the divisions of memory that hold the operating system, user information and applications. It establishes the data structures that will hold the myriad signals, flags and semaphores that are used to communicate within and between the subsystems and applications of the computer. Then it turns control of the computer over to the operating system.
The operating system's tasks, in the most general sense, fall into five categories:
·         Processor management
- The heart of managing the processor comes down to two related issues:
   1.  Ensuring that each process and application receives enough of the processor's time to function
        properly.
2.   Using as many processor cycles as possible for real work.
The basic unit of software that the operating system deals with in scheduling the work done by the processor is either a process or a thread, depending on the operating system.

·         Memory management and Storage management
-   When an operating system manages the computer's memory, there are two broad tasks to be accomplished:
1.   Each process must have enough memory in which to execute, and it can neither run into the memory space of another process nor be run into by another process.
2.   The different types of memory in the system must be used properly so that each process can run most effectively.
The first task requires the operating system to set up memory boundaries for types of software and for individual applications.

·         Device management
-          Managing input and output is largely a matter of managing queues and buffers, special storage facilities that take a stream of bits from a device, perhaps a keyboard or a serial port, hold those bits, and release them to the CPU at a rate with which the CPU can cope. This function is especially important when a number of processes are running and taking up processor time.
-          Managing all the resources of the computer system is a large part of the operating system's function and, in the case of real-time operating systems, may be virtually all the functionality required. For other operating systems, though, providing a relatively simple, consistent way for applications and humans to use the power of the hardware is a crucial part of their reason for existing.
·         Application interface
-          Just as drivers provide a way for applications to make use of hardware subsystems without having to know every detail of the hardware's operation, application program interfaces (APIs) let application programmers use functions of the computer and operating system without having to directly keep track of all the details in the CPU's operation.
·         User interface
-          Just as the API provides a consistent way for applications to use the resources of the computersystem, a user interface (UI) brings structure to the interaction between a user and the computer. 
-          The user interface is a program or set of programs that sits as a layer above the operating system itself. The same thing is true, with somewhat different mechanisms, of both Windows and Macintosh operating systems. The core operating-system functions -- the management of the computer system -- lie in the kernel of the operating system. The display manageris separate, though it may be tied tightly to the kernel beneath. The ties between the operating-system kernel and the user interface, utilities and other software define many of the differences in operating systems today, and will further define them in the future.


ADVANTAGES AND DISADVANTAGES

An operating system is a software program that enables  the computer hardware to communicate and cooperate with the computer software. For examples, Windows, Mac OS and Linux. These are the advantages and the disadvantages of them.


Windows:
Ø  Expensive.
Ø  Easy to be use by any stage of ages.
Ø  Theres still lags problems behind its competitors.
Ø  It has a large library of available software and applications.
Ø  Openness to virus attack.


Linux:
Ø  An open source.
Ø  A bit difficult to be use for a beginners.
Ø  Very reliable.
Ø  Rarely freezes.
Ø  Only few computer programs, applications and utilities are available for this OS.
Ø  Some manufacturers do not offer hardware that able to support Linux OS.
Ø  Allowed more advanced users to customise the code as what they wished.
Ø  Less people familiar to this operating system.


Mac OS:
Ø  Mac computers ara more expensive.
Ø  Far less open to viruses and malware.
Ø  It was very rarely to crash, lose datas and also freezes.
Ø  Less computer programs and games are available for Macs.


COMPARISON BETWEEN ANDROID AND WINDOWS 8 IN SMART PHONES



ANDROID
WINDOWS 8
v  Android is an open system that is extremely and easily to be customize.
v Each smart phone that runs on the operating system comes with a specific user interface that is generally easy to use and allows us to customize the look of our device with a variety of skins or themes, wallpapers and the ability to create widgets based on the apps we have on our phones.
v The notification bar on the Jelly Bean operating system has also been redesigned so that it is more noticeable and attractive than the older version.
v Jelly Bean has support for more languages in it’s keyboard.
v Google Now is included in Android's Jelly Bean powered smart phones
·     The user interface is simple and clean and boasts a great metro look that includes live tiles and the ability to customize our home screen with apps of our choice and making them size of our choice from small, medium and large.
·    Windows phones 8 is easy to use and also refreshing change from the other and the older operating systems found in smart phones.
·    Windows phones 8 holds over android's Jelly Bean is that phones that run on it consume considerably less battery power while windows phones provides enough juice to last the user all the day and sometimes into the next.
·    Windows phone 8 also integrates its People Hub with the most popular social networking websites and email hosts.
·    The integration is quite nice and installation of apps such as Facebook, for instance,  are not necessary as it is already built into the phones.



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