Textbook Notes (369,133)
Canada (162,403)
CIS 1200 (114)
John Saville (104)
Chapter 5

Chapter 5.pdf

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Department
Computing and Information Science
Course Code
CIS 1200
Professor
John Saville

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Chapter Five: Using System Software System Software Basics 2 types of software on your computer  Application Software is a system used for everyday tasks at home  System Software is a set of programs that help run the computer and coordinate instructions between application software and computers hardware devices o System software consists of two programs: operating system and utility programs What does an operating system do?  Operating System (OS) is a group of programs that controls how your computer system functions  manages computers hardware, memory, storage devices, monitor and printer  responsible for the management, scheduling and coordination of tasks  system software includes utility programs. Utility program performs many of the general housekeeping tasks for the computer Do all computers have operating systems?  YES . . . OS is critical. Computer cannot operate without it Are all operating systems alike?  Microsoft Disk Operating System (MS-DOS) (is a single-user operating system) it was the first widely installed operating system in personal computers  Icons are pictures that represent an object  Single user to multitask which means to perform more than one process at a time Types of Operating Systems (OSs) Real-Time Operating Systems Why do machines with built in computers need operating systems?  Real-time operating system (RTOS) allows repetitive series of specific tasks to be performed in an exact amount of time  Require minimal user interaction Where else are RTOSs in use today?  Fuel-injection systems, inkjet printers, VoIP phones, and medical devices What kind of OS controls a simple cell phone?  OS systems that perform one task at a time OSs for Networks, Servers, and Mainframes What kind of OS do networks use?  Multiuser OS (network OS) which enables more than one user to access the computer system at one time by efficiently handling and prioritizing requests from multiple users  Server is the computer on a network that manages network resources such as printers  Examples: Linux and UNIX  UNIX is a multiuser, multitask, OS used as a network OS, primarily with mainframes, although it is often found on PCs What other kinds of computers require a multiuser OS?  Mainframe is responsible for storing, managing, and simultaneously processing data from all users  Supercomputers use these as well OSs for Mobile Devices What kind of OS do smartphones use?  Smartphone has productivity features, in addition to features found on personal media players and cameras, as well it connects to the web  Examples,  blackberry,  Apple’s  Iphone Do gaming consoles and personal media computers require an OS?  Need a system software with system programs, called firmware, that control the device as well as other programs that come with the personal media player of gaming device OSs for Personal Computers What is the Microsoft Windows OS?  Began to work with MS-DOS  Windows XP provided networking capabilities  Windows 7, an OS, builds on security and user interface upgrades that the Windows Vista release provided What is the difference between the various editions of Windows 7 OSs?  Different editions, for home users, business users, and combination users  32-bit and 64-bit versions What is the Mac OS?  Mac OS was the first commercially available OS to incorporate a graphical user interface, with user friendly point-and-click technology Does it matter what OS is on my computer?  Computers platform is the combination of the OS and processor  Microsoft Windows is not meant for a Mac and the Mac would not under stand the Windows OS  Boot Camp, with the newest version of Mac OS X Snow Leopard, allows you to run Windows on a Mac while also running OS X Can I have more than one OS on my computer?  YES, due to the generous size of the hard drives  Linux is an open source OS designed for use on personal computers and as a network OS  Linux OS is based on the central programming code of an OS Where else is Linux used?  Android (new OS developed by Google), and MeeGo (project between Nokia and Intel) Where can I get Linux?  Download for free  Some versions must be purchased What the OS Does  Way to interact with the computer  Manages processor or CPU  Manages memory and storage  Manages systems hardware and peripheral devices  Provides consistent means for software applications to work with the CPU The User Interface How does the OS control how I interact with my computer?  OS provides a user interface which allows you to interact with the computer  Command driven interface is one in which you enter commands to communicate with the computer system  Menu driven interface is one in which you choose commands from menus displayed on the screen What kind of interface do OS use today?  Graphical user interface (GUI) display graphics and use the point-and-click technology of the mouse and cursor Processor Management Why does the OS need to manage the processor?  The  OS  assigns  a  slice  of  its  time  to  each  activity  that  requires  the  processor’s   attention  The OS must then switch among different processes millions of times a second to make it appear that everything is happening seamlessly How exactly does the OS system coordinate all the activities?  Event is an action to which to OS responds  Events can occur sequentially or other events involve two or more devices working concurrently  OS switches back and forth  Interrupt handler is a special numerical code that prioritizes the requests  OS processes a task assigned higher priority before processing a task assigned lower priority (preemptive multitasking)  Stack is a location in the RAM which stores a memo of what the CPU was doing before What happens if there is more than one document waiting to be printed?  The buffer is another temporary location in the RAM which stores a request if the printer is trying to be used while it is already in use  Request then waits in the buffer until the spooler, a program that helps coordinate all print jobs currently being sent to the printer, indicates the printer is available  When more than one print job is waiting than a line is formed so that they can be processed in order Memory and Storage Management Why  does  the  OS  have  to  manage  the  computer’s  memory?  RAM as temporary storage area for instructions and data the processor needs  OS is responsible for coordinating the space allocations in RAM to ensure that there is enough space for all of the pending instructions and data  OS than clears the data from the RAM when it does not need it Does the amount of RAM on a system control the type of OS I get?  Not all applications and devices are compatible with 64-bit system Can my system ever run out of RAM?  Ram has limited capacity, and eventually it will not respond well  As you add and upgrade software and increase your usage of the computer system, you will likely find that the amount of RAM you once found sufficient is no longer enough What happens if my computer runs out of RAM?  If this happens the OS will borrow from the more spacious hard drive for storing data, this is called virtual memory  Swap file is a temporary storage area on the hard drive where data is stored that has not been recently used  The process of swapping data from the RAM to the swap file is know as, paging Can I ever run out of virtual memory?  Thrashing is the condition of excessive paging  Solution to the problem is to increase the amount of RAM How does the OS manage storage?  File-management system that keeps track of the name and location of each file you save and the programs you install Hardware and Peripheral Device Management How does the operating system manage the hardware and peripheral devices?  Device driver is a special program that facilitates communication between the hardware device and the operating system  the  device  driver  translates  the  device’s  specialized  commands  into   commands that the operating system can understand Do I always need to install drivers?  Plug and Play (PnP) is a software and hardware standard that Microsoft created with the Windows 95 OS  PnP  is  designed  to  facilitate  the  installation  of  new  hardware  in  PC’s  by   including in the OS the drivers these devices need in order to run What happens if the device is not Plug and Play?  Printers are not plug and play  When you install a non-PnP device, you will be prompted to insert the driver that was provided with the device  You  can  download  the  necessary  data  from  the  manufacturer’s  Web  site Can I damage my system by installing a device driver?  When you install a driver you system may become unstable  Roll back driver is on Windows and is a feature that removes a newly installed driver and replaces it with the last one that worked Software Application Coordination How does the OS help application software run on the computer?  Application programming interface (API) are blocks of code that the CPU recognizes that application software needs in order to interact with the OS What are the advantages of using APIs?  When writing an application that can communicate with the OS, software programmers only need to refer to the API code blocks  They make it easier for software developers to respond to changes in the OS  Many applications have the same API and therefore the same look The Boot Process: Starting Your Computer  Boot process loads the OS into RAM What are the steps involved in the boot process? 1. CPU activates BIOS 2. BIOS conducts power-on self-test 3. BIOS loads OS to RAM 4. Configuration and customization settings checked, and desktop displays How can I tell if my computer is entering the data process?  Indicator lights and sounds in a Windows OS  On a PC with Windows or on a Mac, you will not hear any beeps or see any keyboard lights. Rather, a PC or Mac logo will be presented Step1: Activating BIOS What’s  the  first  thing  that  happens  after  I  turn  on  my  computer?  Activation of the basic input/output system (BIOS) which is a program that manages the exchange of data between the OS and all the input and output devices attached to the system  BIOS is stored in the ROM (read only memory) chip on the motherboard Step2: Performing the Power-on Self-Test How does the computer determine whether the hardware is working properly?  BIOS first ensures essential peripheral devices are attached and operational (power-on self-test, also known as POST)  BIOS compares results of the POST with the various hardware configurations that are permanently stored in CMOS  CMOS complementary metal-oxide semiconductor is a special kind of memory that uses almost no powe
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