The set of arithmetic operations that a particular ALU supports may be limited to adding and subtracting or might include multiplying or dividing, trigonometry functions (sine, cosine, etc.) and square roots. Therefore, any computer can be programmed to perform any arithmetic operation-although it will take more time to do so if its ALU does not directly support the operation. An ALU may also compare numbers and return Boolean truth values (true or false) depending on whether one is equal to, greater than or less than the other.
I/O is the means by which a computer exchanges information with the outside world. Devices that provide input or output to the computer are called peripherals. On a typical personal computer, peripherals include input devices like the Personal computer input devices Keyboard, Mouse, Terminals, Touch-sensitive screens, Bar-code scanners, Optical data readers, Point-of-sale (POS) devices, Magnetic ink character recognition devices, and output devices such as the display and printer. Hard disk drives, floppy disk drives and optical disc drives serve as both input and output devices. A graphics processing unit might contain fifty or more tiny computers that perform the calculations necessary to display 3D graphics. Modern desktop computers contain many smaller computers that assist the main CPU in performing I/O.
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A microprocessor is a silicon chip containing millions of microscopic transistors. This chip functions as the computer's brain. It processes the instructions or operations contained within executable computer programs. Instead of taking instructions directly off of the hard drive, the processor takes its instructions from memory. This greatly increases the computer's speed.
Processor has a clock speed which is measured in gigahertz (GHz). CPUs also typically have two or three levels of cache. Cache is a type of fast memory which serves as a buffer between RAM and the processor. The processor's socket type determines which motherboard it can be installed on.
There are two primary manufacturers of computer microprocessors.
Intel and Advanced Micro Devices (AMD):
Intel's desktop CPUs include:-
Celeron, Pentium, and Core. Intel makes Celeron M, Pentium M, and Core mobile processors
AMD's desktop processors include:-
Sempron, Athlon, and Phenom AMD make mobile versions of its Sempron and Athlon, as well as the Turion mobile processor which comes in Ultra and Dual-Core versions.
2.2 Backing Storage
Backing storage devices are where you can store data permanently. This means that data is held when the computer is switched off and can be loaded onto a computer system when required.
The hardware that stores the data is called backing storage media. The media are put into backing storage devices.
The data stored on backing storage media can either accessed randomly or sequentially. Random access means that the computer can go directly to a piece of data. If the access is sequential then the computer has to go through every item of data until it gets to the one it is looking for.
A peripheral is a device attached to a host computer, but not part of it, and is more or less dependent on the host. It expands the host's capabilities, but does not form part of the core computer architecture. Make it easy to add external devices, called peripherals,
For example, USB Drivers, Magnetic disks, USB hubs, etc..,
2.4 Memory, mother Boards, Ports, Case and Power supply:
Information is stored permanently on a chip
Contains startup instructions and other permanent data
Special low-energy kind of RAM
Used for phones, portable computers, and handheld computers.
Information travels between components on the motherboard through groups of wires called system buses,
Typically have 32 or 64 wires
Connect to storage devices in bays
2.5 Power Supply:
A power supply unit (PSU) is the component that supplies power to the other components in a computer. More specifically, a power supply unit is typically designed to convert general-purpose alternating current (AC) electric power from the mains (100-127V in North America, parts of South America, Japan, and Taiwan; 220-240V in most of the rest of the world) to usable low-voltage direct current (DC) power for the internal components of the computer. Some power supplies have a switch to change between 230 V and 115 V. Other models have automatic sensors that switch input voltage automatically,
Always on Time
Marked to Standard
There are 3 types of power supply in common use:
AT Power Supply - still in use in older PCs.
ATX Power Supply - commonly in use today.
ATX-2 Power Supply - recently new standard.
The voltages produced by AT/ATX/ATX-2 power supplies are:
+3.3 Volts DC (ATX/ATX-2)
+5 Volts DC (AT/ATX/ATX-2)
-5 Volts DC (AT/ATX/ATX-2)
+5 Volts DC Standby (ATX/ATX-2)
+12 Volts DC (AT/ATX/ATX-2)
-12 Volts DC (AT/ATX/ATX-2)
2.6 Mother Boards:-
a motherboard is the central printed circuit board (PCB) in many modern computers and holds many of the crucial components of the system, while providing connectors for other peripherals. The motherboard is sometimes alternatively known as the main board, system board, or, on Apple computers, the logic board.
The early pioneers of motherboard manufacturing were Micronics, Mylex, AMI, DTK, Hauppauge, Orchid Technology, Elite group, DFI, and a number of Taiwan-based manufacturers.
The most popular computers such as the Apple II and IBM PC had published schematic diagrams and other documentation which permitted rapid reverse-engineering and third-party replacement motherboards. Usually intended for building new computers compatible with the exemplars, many motherboards offered additional performance or other features and were used to upgrade the manufacturer's original equipment.
3. Operating Systems:
3.1 An overview of functions
What is an operating system?
A program that is executed by the processor that frequently relinquishes control and must depend on the processor to regain control.
A program that mediates between application programs and the hardware
A set of procedures that enable a group of people to use a computer system.
A program that controls the execution of application programs
An interface between applications and hardware
The operating system does the following tasks:
a. Memory Management - It keeps a record of where data and programs are stored in main memory.
b. Human Computer Interface - This is how the user interacts or communicates with the computer system and vice versa. Most systems use a Graphical User Interface (GUI) the most common of which is a WIMP.
c. Error Reporting - It tells the user if there is a problem with any part of the computer system.
d. File Management - Controls where on backing storage files are stored and can locate files to load into main memory.
The most effective filing system is a hierarchical filing system. In this system you have a root directory that can hold files or sub-directories which can in turn store files or sub-directories.
3.2 Comparisons between selected OS:
Linux & Windows:
The majority of Linux variants are available for free or at a much lower price than Microsoft Windows.
Microsoft Windows can run between $50.00 - $150.00 US dollars per each license copy.
The majority of Linux variants and versions are notoriously reliable and can often run for months and years without needing to be rebooted.
Although Microsoft Windows has made great improvements in reliability over the last few versions of Windows, it still cannot match the reliability of Linux.
Linux has a large variety of available software programs, utilities, and games. However, Windows has a much larger selection of available software.
Because of the large amount of Microsoft Windows users, there is a much larger selection of available software programs, utilities, and games for Windows.
Linux is and has always been a very secure operating system. Although it still can be attacked when compared to Windows, it much more secures.
Although Microsoft has made great improvements over the years with security on their operating system, their operating system continues to be the most vulnerable to viruses and other attacks.
Although it may be more difficult to find users familiar with all Linux variants, there are vast amounts of available online documentation and help, available books, and support available for Linux.
Microsoft Windows includes its own help section, has vast amount of available online documentation and help, as well as books on each of the versions of Windows.
3.3. System to other OS:
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The introduction of the Intel 80386 CPU chip with 32-bit architecture and paging capabilities, provided personal computers with the ability to run multitasking operating systems like those of earlier minicomputers and mainframes.
The alternative CP-67 system for the S/360-67 started a whole line of IBM operating systems focused on the concept of virtual machines. Other operating systems used on IBM S/360 series mainframes included systems developed by IBM: COS/360 (Compatibility Operating System),
Microsoft Windows is a family of proprietary operating systems most commonly used on personal computers. It is the most common family of operating systems for the personal computer, with about 90% of the market share.
Unix-like systems run on a wide variety of machine architectures. They are used heavily for servers in business, as well as workstations in academic and engineering environments. Free UNIX variants, such as GNU/Linux and BSD, are popular in these areas.
Mac OS X is a line of partially proprietary graphical operating systems developed, marketed, and sold by Apple Inc., the latest of which is pre-loaded on all currently shipping Macintosh computers. Mac OS X is the successor to the original Mac OS, which had been Apple's primary operating system since 1984
The machine components to the requirements in the case study for the accounts job, the selected components are
4.1 SYSTEM CONFIGURATION:
Deluxe ATX cabinet
15 slot passive backplane (PICMG)
300 watt heavy duty power supply
NUPRO 842LV Single Board Computer
Intel P4-2.8GHZ-533FSB CPU
256MB DDR266 memory installed
Integrated 10/100 Ethernet controller
Integrated 3D AGP/2D/3D Graphics Engine
Seagate Digital 80GB IDE Hard Drive
56X CD ROM Drive
Dual USB pin headers provided on SBC
Ubundu (Linux) open source
Cost-140$ + 20$ for the accounting software, This cost only for the sub-system not for the application software, operating system & accounting software's, if u are using the Linux based OS Ubundu (open source), open office software for other office works,
4.2 Performance of the Selected System:
The Intel P4 computers are enough source for the small client works & accounting works because you are choosing the ubundu (Linux) with the open office (open source software's), which includes the basic accounting work spreadsheets, excel works, so you need to buy only particular accounting software of your need, Laser printer for clients documents printing work & internet connection for online help providing across the nation. Intel's most advanced, most powerful processor for desktop PCs and entry-level workstations, is based on Intel Net Burst micro architecture. The Pentium 4 processor is designed to deliver performance across applications and usages where end-users can truly appreciate and experience the performance. These applications include Internet audio and streaming video, image processing, video content creation, speech, 3D, CAD, games, multimedia, and multi-tasking user environments. The Pentium 4 processor delivers this world-class performance for consumer enthusiasts and business professional desktop users as well as for entry-level workstation users,
P4 computers is the Best computers for the accounting office because there is no other work like multimedia, application development etc., in earlier computer is invented for the calculation works, so basic computers is best for the office, 256MB of SD ram enough for the clocking speed & cache memory, VGA card is necessary for the some flash Based files in accounting software, That the reason to buy the Graphics card, 56X CD-ROM for copy the working files into the system, Then USB hub provided for the copy the files from system to USB disk, the security measures of the system is high because Linux based OS is highly secured operating system in the modern computer field, if you buy windows based OS, then you need to buy the Anti-virus software, that the reason to select Linux based OS, Which freeware & highly secured OS.
P4 computer with Linux Based OS (Cost-100$)
Laser printer (Cost-40$)
4.3 Functions & Features of Different types of OS:
An operating system is a software component of a computer system that is responsible for the management of various activities of the computer and the sharing of computer resources. It hosts the several applications that run on a computer and handles the operations of computer hardware. Users and application programs access the services offered by the operating systems, by means of system calls and application programming interfaces. Users interact with operating systems through Command Line Interfaces (CLIs) or Graphical User Interfaces known as GUIs.
Real-time Operating System: It is a multitasking operating system that aims at executing real-time applications. Real-time operating systems often use specialized scheduling algorithms so that they can achieve a deterministic nature of behavior. The main object of real-time operating systems is their quick and predictable response to events. They either have an event-driven or a time-sharing design. Some examples of real-time operating systems are Chimera, Lynx, MTOS, QNX, RTMX, RTX, and VxWorks.
Multi-user and Single-user Operating Systems: The operating systems of this type allow a multiple users to access a computer system concurrently. Time-sharing system can be classified as multi-user systems as they enable a multiple user access to a computer through the sharing of time. Single-user operating systems, as opposed to a multi-user operating system, are usable by a single user at a time. The common examples of multi-user operating system include VMS, UNIX, and mainframe operating systems which include MVS system.
Multi-tasking and Single-tasking Operating Systems: When a single program is allowed to run at a time, the system is grouped under a single-tasking system, while in case the operating system allows the execution of multiple tasks at one time, it is classified as a multi-tasking operating system.
Distributed Operating System: An operating system that manages a group of independent computers and makes them appear to be a single computer is known as a distributed operating system. The development of networked computers that could be linked and communicate with each other, gave rise to distributed computing.
Embedded System: The operating systems designed for being used in embedded computer systems are known as embedded operating systems. They are designed to operate on small machines like PDAs with less autonomy. Windows CE, FreeBSD and Minix 3 are some examples of embedded operating systems.
4.4 Complete computer system is suit in the given task:
Multi-tasking and Single-tasking Operating Systems is the suitable OS for the P4 computers & it is the Best selection for the Office works Because of the more workers at a same time in a office, so it is best suitable operating system for the system specified in the given task.
The operating systems thus contribute to the simplification of the human interaction with the computer hardware. They are responsible for linking application programs with the hardware, thus achieving an easy user access to the computers.
5. Testing Strategies:
Possible issues which is uncovered in the testing & manage the issues:
You also might find that your system problems are caused by a hardware malfunction and that you must open the computer case to perform repairs.
First I need to show the common pc errors and solutions, here I show the software errors & error messages on the screen & solutions of that,
5.1 Peripheral diagnostic
Many types of diagnostic software are used with specific hardware products. This software can be integrated into the hardware, included with the hardware purchase, or sold as a separate product. Many network interface adapters, for example, are equipped with their own diagnostics, designed to test their own specialized functions. Depending on the network adapter, these tests might require you to boot with a DOS disk or they might function within Windows.
5.2 Operating system Diagnostic
When Windows encounters severe problems such as malware that corrupts or interferes with system operation, bugs in drivers or other low-level software, inconsistencies in data necessary for operation, or even hardware defects, the system is halted or shut down in a condition that is technically called a bug check. Bug checks are also known as stop errors, kernel errors, trap errors, fatal system errors, and system crashes, and because the error information is normally displayed on a blue text-mode screen, they are also informally known as blue-screen. When these errors occur, in addition to the blue-screen text, Windows normally saves a memory dump file and then automatically restarts the system.
A large number of commercial third-party diagnostics programs are available for PC systems. These commercial programs are used by technicians to perform testing of new systems (often called burn-in testing) or testing of existing systems either in the shop or in the field.
Here are some of the programs available:
5.3 Testing Tools for Physical components:
In some cases, you must use specialized devices to test a system board or component. This test equipment is not expensive or difficult to use, but it can add much to your troubleshooting abilities. These are the tools used to check the mother board, hard disk & other physical components
Electrical Testing Equipment
Loopback Connectors (Wrap Plugs):
Outlet (Receptacle) Testers
Memory Module Testers
5.4 Preventive Maintenance:
The average PC user doesn't think much about problems that can arise with a computer until a problem actually occurs in the system. Once a failure happens, repairs can be both costly and time-consuming. The good news is that there are some preventive measures that you can take to decrease the likelihood of running into problems with the computer's smooth and efficient operation and also to lessen any damage that does occur despite best efforts to avoid failures.
Why proper computer maintenance is important?
Because it will increase the speed of your PC
Prevent errors, which will save money
secure your data and information
5.5 Health & Safety requirements of System:
1. Always update your system. Whether you are a Windows or a Linux user it is suggested that you do a weekly update for you systems to keep up with the latest patches that your system provider can offer.
2. Have reliable anti-virus software installed in your system. Be sure to update your anti-virus and have a weekly scan check for viruses in your computer systems.
3. Have tune-up software installed in your system and have it run weekly. This software helps you in cleaning your system making it more efficient and accelerates your system's performance.
5. Always keep a backup for your important files. In this way you can be sure that if your system fails, you still have a chance to restore the files you have lost.
6. User Documentation for System:
Here I provide the user documentation for the selected system; the selected system is Intel p4 system, so we provide the user manual for the machines,
User manual for Intel P4-2.8GHZ- CPU is found at source of the internet, source available at-
Source: [online at: http://software.intel.com/en-us/articles/intel-pentiumr-4-processor-optimization-reference-manual/]
The Laser printer (Samsung ML-2010 series) user documentation is available at
Source: [Samsung ML-2010: http://www.samsung.com/us/support/downloads/ML-2010/XAA]
The user documentation of the ubundu (Linux) OS is available at
Source: [ubundu guide: http://ubuntu-manual.org/]
6.1 Communication centre for the user documentation:
The user manuals are distributed through the internet & paper document, internet is the big communication center for the providing of the documentation to the customers, because of the documentation is difference for every devices & software's, the unfamiliar customers are also easy to know about internet usage so internet is the big communication medium of user manuals, Services and resources available on the internet are expending phenomenally and are receiving global acceptance day by day. Amateurs and professionals alike look towards e-resources to be updated about latest developments in their fields and acquire an edge over others by staying informed and develop new sets of skills. One such rapidly growing online service is of web-based business. Over the last two decades, the internet has become both an inevitable repository of information and a mode of communication.
7. Test Plan:
Test Plans for checking the software & Hardware components using standard:
Activity 1: Determine problems and make recommendations
You have been called to a PC system that will not load the operating system. What diagnostic tool will you examine to help determine the problem?
The Device Manager to look for resource conflicts
A drive checking tool to look for file corruption
A POST tool to look for errors in the booting process
A system information tool to check on system updates
When you turn it on the screen remains blank and you hear a series of beeps. You know the system has a gigabyte motherboard. What do you do?
Turn the computer off and ensure all device cables are seated correctly
Check for the documentation that accompanied the system
Visit the manufacturer's website and look for supporting documentation
All of the above
You have determined that the system has suffered from a user accidentally entering the CMOS setup tool and modifying settings. What would you recommend?
Enter the CMOS tool and select 'Restore Factory Settings'
Recommend protecting the CMOS with a password
Educate the user about the computer's booting sequence
All of the above
Activity 2: Understand diagnostic tools
The purpose of booting in 'Safe' mode is to minimize the chances of the operating system failing through only loading core services.
The system log will record information about which system services have started and which have failed.
Activity 3: Use diagnostic tools
A user complains that their USB memory stick is not recognized on their Windows XP system. It should appear as a disk drive in Windows Explorer. They suggest that the driver may need to be installed. What tool would you use?
CMOS/BIOS configuration tool
A new video card and monitor is added to a PC, but does not allow you to access the range of settings you expect. What diagnostic tools could you use to check the device?
The Device Manager
Activity 4: Check disk
The computer you have been sent to examine is reported to have 'lost' and 'corrupted' files on its hard disk drive. Examine the boxes shown in the screenshot below (from the computer) then answer the following question.
The option selected for this disk check will not:
Attempt to find 'lost' or 'corrupted' files
Check the FAT entries against the contents of the drive
Attempt to fix 'lost' or 'corrupted' files
Identify a faulty hard disk drive
Check your understanding
Do you think you already have an understanding of system diagnostic tools? Try and answer the following questions to check your understanding.
A diagnostic tool will tell you what is wrong with a computer system that is malfunctioning.
The POST tool will tell you:
What operating system is installed
The software drivers of all devices are correctly installed
The major hardware components of the system are functioning
The printer is online and working
The CPU type and speed is displayed after the POST is complete.
The system log provides information about the:
Loading of the operating system and its services
Status of each device and the resources it uses
CPU type and speed in MHz
Type and number of hard disk drives installed
A device driver is written for a specific device and a specific operating system.
A computer's RAM is first checked by the operating system when it loads.
Tools and their functions
Drag a line from each tool to the corresponding function.
Power On Self Test
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Allows resources to be viewed or configured
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Checks keyboard is present and no keys are stuck
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Maintains hardware configuration of the system
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Checks FAT and media integrity
7.1 Security Policy of the System:
A computer security policy defines the goals and elements of an organization's computer systems. The definition can be highly formal or informal. Security policies are enforced by organizational policies or security mechanisms. A technical implementation defines whether a computer system is secure or insecure. These formal policy models can be categorized into the core security principles of: Confidentiality, Integrity and Availability. For example the Bell-La Padula model is a confidentiality policy model, whereas Biba model is an integrity policy model.
No amount of technology will keep your business secure if there's no overall company policy specifying how digital assets are to be protected. It should be part of the hiring procedure for every new employee that they read and acknowledge by signature their acceptance of this policy. It's vital that every person using company computers and/or accessing company data understands the rules relating to the company's digital assets.
Security policies should also include:
â€¢Standards to use when defining rules and actions or consequences to support the computer security policy goals and definitions. These standards may also provide specifications for acceptable solutions performance and work together to provide a layered security solution.
â€¢Guidelines that support the security policy's objectives and administrative goals. It's often helpful to have these guidelines mirror current best practices as they relate to the different security threats and recommended responses.
Because your business, and the security threats to your business, is in a constant state of flux, your security policy must be a living document that changes as the business, environment and technologies change. It should be reviewed and updated at least once a year to make sure all aspects remain applicable and current.
General Policies - High level policies defining who is responsible for the policies along with business continuity planning and policies.
User Policies-Define what users can and must do to use your network and organization's computer equipment. It defines what limitations are put on users to keep the network secure such as whether they can install programs on their workstations, types of programs they can use, and how they can access data. Some policies include:
A computer system consists of hardware and systems software that cooperate to run application programs. Information inside the computer is represented as groups of bits that are interpreted in different ways, de-pending on the context. Programs are translated by other programs into different forms, beginning as ASCII-text and then translated by compilers and linkers into binary executable ï¬les. Processors read and interpret binary instructions that are stored in main memory. Since computers spend most of their time copying data between memory, I/O devices, and the CPU registers, the storage devices in a system are arranged in a hierarchy, with the CPU registers at the top, followed by multiple levels of hardware cache memories, DRAM main memory, and disk storage. Storage devices that are higher in the hierarchy are faster and more costly per bit than those lower in the hierarchy.