The Components Of Computer Systems Information Technology Essay

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Computer consists of many complicated devices, which have different functions and different reason for being installed. There are some without which computer cannot start up and run. In the following pages I will shortly describe them and state which are necessary for Radio Station. I am also going to choose appropriate requirements for each of them so they fulfil the needs of the given scenario. At the end of this chapter I will propose a system which might be accepted Radio Station as a template for all computers.

The diagram shows a general view of how desktop and workstation computers are organized. Different systems have different details, but in general all computers consist of components (processor, memory, controllers, video) connected together with a bus. Physically, a bus consists of many parallel wires, usually printed (in copper) on the main circuit board of the computer. Data signals, clock signals, and control signals are sent on the bus back and forth between components. A particular type of bus follows a carefully written standard that describes the signals that are carried on the wires and what the signals mean. The PCI standard (for example) describes the PCI bus used on most current PCs.

The processor continuously executes the machine cycle, executing machine instructions one by one. Most instructions are for an arithmetical, a logical, or a control operation. A machine operation often involves access to main storage or involves an I/O controller. If so, the machine operation puts data and control signals on the bus, and (may) wait for data and control signals to return. Some machine operations take place entirely inside the processor (the bus is not involved). These operations are very fast.

Hard Disk Drive:

When you save data or install programs on your computer, the information is typically written to your hard disk. The hard disk is a spindle of magnetic disks, called platters, that record and store information. Because the data is stored magnetically, information recorded to the hard disk remains intact after you turn your computer off. This is an important distinction between the hard disk and RAM, or memory, which is reset when the computer's power is turned off.

The hard disk is housed inside the hard drive, which reads and writes data to the disk. The hard drive also transmits data back and forth between the CPU and the disk. When you save data on your hard disk, the hard drive has to write thousands, if not millions, of ones and zeros to the hard disk. It is an amazing process to think about, but may also be a good incentive to keep a backup of your data.

RAM - Random Access Memory

It is third of very important part of computer system. Without it computer cannot work (it like a heart beat). It is a kind of temporary storage. IF you switch off your system the RAM memory will lost. If we open any programme it's not going CPU first it's going RAM. The CPU fetches the data from the RAM in order to process them. Every programme depends on the Operating System and applications you will be running. IF u want to run the programme RAM is very important than other devices.

There are three kinds of memory available today: SD RAM, DDR RAM and DDR2 RAM. The first one of them is an old technology, practically not mounted in the systems any more. Some of the old machines might require this kind of ram which is still produced by respected company like Kingston and Imation. The second ones are quite new; they have been with us for before two years, now days we can get only DDR2. It is new technology giving the higher bus speed and better performance.

The RAM is installed in DIMM slots on the motherboard. Some mother boards have 4 DIMM slots, but you can find them with less available space.



In practice, data and instructions are often placed in different sections of memory, but this is a matter of software organization, not a hardware requirement. Also, most computers have special sections of memory that permanently hold programs (firmware stored in ROM), and other sections that are permanently used for special purposes.


210 = 1024 bytes


220 = 1024 kilobytes


230 = 1024 megabytes


240 = 1024 gigabytes

Main memory (also called main storage or just memory) holds the bit patterns of machine instructions and the bit patterns of data. Memory chips and the electronics that controls them are concerned only with saving bit patterns and returning them when requested. No distinction is made between bit patterns that are intended as instructions and bit patterns that are intended as data. The amount of memory on a system is often described in terms of larger amounts, as seen in the chart.


Motherboard is essential for any computer system. We can say it is a heart of the computer. Everything is connected with it in order to communicate with other devices. There are many different motherboards available today. When we choose one we have to take into account the types of processors they support. There are many companies producing processors, each of them requires different socket (place on the motherboard to fit the CPU) layout. The other important factor to check is memory. Every motherboard has four or more of slots for memory (RAM) chips. We have to make sure that the amount is enough for us. Another problem arising from memory is it compatibleness. There are different kinds of them and it is up to you to decide which kind you want. The part of motherboard is also expansion slots. They allow you to connect different expansion cards to the motherboard (e.g. TV tuner, sound card, VGA card). Nowadays there are new standards in that area: PCI-E 16x to connect graphic cards and PCI-E 1x to connect other expansion cards...

Most of the new motherboards have some facilities already implemented in them. Almost every time we can find LAN cards, sound cards and Video cards already installed on the motherboard. It is good future, because we can have cheap system with all functionality.


In computers, a monitor is a computer display and related parts packaged in a physical unit that is separate from other parts of the computer. Notebook computers don't have monitors because all the display and related parts are integrated into the same physical unit with the rest of the computer. In practice, the terms monitor and display are used interchangeably.


Modern computer keyboards were modelled after and are still very similar to classic typewriter keyboards. Many different layouts are available around the world but most keyboards are of the QWERTY type.

Keyboards may be wired or wireless but they always communicate with the computer via PS2 or USB connections, usually located on the motherboard. Even though the keyboard sits outside the main computer housing, it is an essential part of the complete system.

Internal Bus Standards

Another important think is bus. Its circuit used by motherboard to transmit data to computer's components Including memory, processor, hard disk, and NIC.

For the Radio Station I chose following requirements for motherboard:

ATX standard

support for Intel Core 2 Duo CPUs (socket LGA775)

support for DDR2 RAM at speeds from 667 to 1066MHz (2-4 sockets)

FSB support from 800MHz to 1333MHz

LAN card (RJ45) with speed up to 1Gb/s supporting IEEE 802.x

Graphic card

Sound card (not essential)

4-6 ports USB

250 GB SATA Hard drive

CPU- Central Processing Unit

It is another very important component of the computer. We can call BRAIN of the computer system. It performs most of the processing. When we run any program on your machine, it contains of some instructions. Those are executed by the CPU.

CPU is the single biggest chip that you can see on the motherboard. It communicates with the other devices via system bus. In the present world we have processors with multiple cores like 2, 3, and 4. We have to decide which is needed for our requirements. The processor's speed is the amount of operation it can perform in 1 second. For the normal use the amount of 2.3GHz should be enough. (But now we can get 3.6GHz.) As I said before in the section about motherboards, there are different kinds of sockets that are available. You have to make sure that your mother board supports the chosen CPU.


PSU - power supply unit

This is another important component; we can get the power of these components. It is cube located at the top back of the computer case. It consists of fan/s and electronics and lots of weir. Different connectors coming from the power supply, that one connect to motherboard DVD-ROM, HDD and CPU COOLER FAN. There are two types of power supply 20 pin and 24 pin.


There are lots of external devices that you can connect to your computer. All external devices connect to the computer's system unit via cables and ports (where a "port" is the slot into which you plug a cable). Unless you're using a portable computer, you probably have several external devices attached to your computer already, including a mouse, keyboard, monitor, microphone, and speakers, as in Figure below.

Whatever external devices we have, they're all connected to the system unit (where the actual "computing" takes place) via cables. Each cable plugs into a specific port on the system unit. The ports are usually on the back of the system unit. But they can be on front or side as well.

Everything has a name, even those little plugs on the back of our computer. Figure shows examples of some ports. But our computer's ports won't necessarily be the same.



Windows is a personal computer operating system from Microsoft that, together with some commonly used business applications such as Microsoft Word and Excel, has become a de facto "standard" for individual users in most corporations as well as in most homes. The original 1985 version of Windows introduced to home and business PC users many of the graphical user interface (GUI) ideas that were developed. There are many kind of windows .Windows 95, 98, 2000, XP .Now we can get VISTA as well


Windows XP's main advantages are due to its popularity, since Microsoft has been the dominant make of operating systems for many years. Some of these advantages include:

1. practically universal hardware support: IF we connect the pen drive it automatically work we don't want installing software (PLUG AND PLAY)

2. Abundance of programs for it.

3. Support. Almost everyone has experience with it, so they will be able to offer support for it, and help you with problems.

4. Its user friendly


1. If u want use this operating system you want install that software

2. This is not an open source operating system

3. Its very poor security than Linux


Linux is a Unix-like operating system that was designed to provide personal computer users a free or very low-cost operating system comparable to traditional and usually more expensive UNIX systems. Linux has a reputation as a very efficient and fast-performing system.


If you have used other operating system you don't want installing in your hard disk you can put the CD and use it

This is the open source software so you can download it free and that has open office, and now you can edit documents and presentations from the popular Microsoft software

Linux has the advantage of the code so it's very security than XP

If you have a Pentium 100 with a 1 GB disk drive, and 16 MB of memory you can use the Linux OP


It's Difficult to handle because all r codlings. If you are contemplating this for your company, you will need to budget some money for training and learning time.

You will want to make sure that you train someone in Linux really well. Alternately, you could hire someone who has experience with Linux. A good Linux administrator needs to be on hand as you start to migrate your systems over. This is a disadvantage financially, at least in the beginning. You may find over time, however, that you only need a temporary administrator to handle the routine tasks.

Some of the latest and greatest hardware we can't use directly so we need drivers coding so its waste of time, One thing you can do is before your purchase, ask if the hardware vendor has support for Linux. Some manufacturers do write their own Linux drivers and distribute them with your purchase, making it very easy to integrate with your existing system.


The typical objectives of a system requirements specification are to:

Provide an overview of the application's context and capabilities.

Formally specify the application's system-level requirements including its:

Functional Requirements

Data Requirements

Quality Requirements


Document any future planned enhancements.

Document any open issues, major things to be completed, and assumptions."

Provide a baseline for:

Application validation

Acceptance of the application by the customer organization

Be a basis for:

Establishing the scope, size, and complexity of the application and its related project(s).

Estimating the associated costs, schedule(s), and progress.

Future extensions and enhancements to the application

The requirements specification is the foundation on which the architecture, design, and implementation are built. At best, a poor requirements specification is a shaky foundation on which to build an application. An incorrect requirements specification is like a foundation built in the wrong place, and we can all imagine how difficult and expensive it will be to move a large shoddy structure that was built in the wrong location. Thus, the requirements specification is one of the most critical documents of an endeavor.

As described above, the contents of this document are very complete and intended for use for large, complex, business-critical or safety-critical applications. Inappropriate contents (e.g., the quality requirement types that do not apply) should be tailored out of the specification and its associated conventions during the process tailoring task.

This is a living document that is developed incrementally and iteratively in parallel with other work products (e.g., requirements executive summary, domain model document and system architecture document).

Different parts of this document are due at different times (i.e., by different milestones).

Some parts of this document should be mandatory and some parts should be optional.

Not all requirements are contained in this document; specifically, required APIs to external applications are specified in the external API specification.

Note that there is typically no need for a separate "software requirements specification" or "hardware requirements specification" on most projects although such documents can be produced if appropriate (e.g., for subcontractors).

Do not concentrate solely on the use cases of the functional requirements. For example, many quality requirements may have a larger impact on the architecture, cost, and schedule than most functional requirements.

Note that the quality requirements are too critical to be specified in a separate "Supplementary Requirements Specification".

Reuse use cases by using a combination of:

The major functions listed in the application vision statement.

The standard mapping from functions to use cases.

Reusable requirements based on functional areas (e.g., Content Management).

Windows 95 or later (Vista.,Xp,and Linux )

900Mhz processor (1.2Ghz for streaming)


6MB Disk space

800*600 screen resolution or higher

1 full duplex soundcard (optional if streaming only)

Optional additional soundcard for track previewing

Optional additional monitor for on-screen instant cart button


ATX standard

support for Intel Core 2 Duo CPUs (socket LGA775)

support for DDR2 RAM at speeds from 667 to 1066MHz (2-4 sockets)

FSB support from 800MHz to 1333MHz

LAN card (RJ45) with speed up to 1Gb/s supporting IEEE 802.x

Graphic card

Sound card (not essential)

4-6 ports USB

2x PS/2

2x PCI, 1x PCI-E 16x and 1x PCI-E 1X

IDE controller

SATA controller (at least 2x SATA)


Intel manufactured

2 cores, 2GHz per core

Fan included








8Mb buffer

Optical drive


CD 48x/52x, DVD 12x/16x (might vary)



Support for SATA


ATX standard

At least 2x5.25", 2x3,25"

Fan included


standard 3 buttons mouse




standard UK keyboard





The table below offers a quick feature comparison. It is only a guide. There is, of course, a lot more to the selection process than can be represented in this table or even this complete article. Another thing that is not shown is what is included with the operating system. For example, Linux and *BSD come with a wealth of development tools, applications and utilities that would cost thousands of dollars if needed for any of the other platforms.

Platform Comparison Chart









Avg. Price

Legacy System


















Windows 3.x










SMB Only













Yes, 2









Yes, Many


















Yes, Many




Hardware and Software Compatibility List

Processor (CPU GHz/L2 cache/front-side bus )MHz

Intel® Xeon® (quad-core) 3.0 GHz /L2 Cache 12 MB/ front-side bus 1333 MHz

Number of processors



1 GB DDR II 667 or 800 MHz

Expansion slots

2 PCI (32-bit/33 MHz), 2 PCI-Express (x8, x1), optional PCI-X or hardware RAID-0, -1, Remote Supervisor Adapter II SlimLine slot

Disk bays

Three Numbers 160 GB hot-swap Serial Attached SCSI Hard Drive Speed 15000 rpm

Network interface

Integrated Gigabit Ethernet

Power supply (std/max)

400W 1/1 or 430W hot-swap redundant 2/2

RAID support

Hot-swap hardware RAID-0, -1, upgradeable to RAID-5


Six USB; Ethernet, two serial, parallel and video

Systems management

IPMI 2.0-compliant mini-BMC2, IBM Director, Alert

Standard Format 2.0, IBM Server Guideâ„¢, optional RSA II SlimLine and Remote Deployment Manager

Operating systems supported

Microsoft® Windows Server® 2003 Server Enterprise Edition and 2008, Windows® Small Business Server 2003, Red Hat Linux®, SUSE Linux


Security policy has to be established in any computer based environment. It prevents the data to be read by unauthorised people. It also prevents system from being hacked. There are some rules that every employee has to have in mind. As experts state the weakest point of computerised system is man. The software itself is very secure, but people tend not to realise the importance of their factor in system security. The major data leakage is due not to know or respect the security policies established within the given company.

The username and password is unique for every employee.

Password must be kept safe. Your password should be known only to you

Do not note our password anywhere.

The different levels of documents security to be set in order to hide them from unauthorised people

Security software to be installed on every machine

The entrance to the building within which are the computers and servers should be controlled.

Every day you must do the back-up from each computer

Every week you must take the back-up from the sever

Don't allow staff to handle the main sever

Don't allow staff to leave the computer switch on

Any unknown person has to be checked for the reason being in the offices.

Employees are expected to wear ID cards in visible places.

Always log off your computer when leaving the office.

Report any suspicious system behaviour to the IT administrator.

The disciplinary actions might be taken if someone is found not complying with above rules.

Printer pool

Print spooling allows you to print a document while a previous one is still printing. The print spooler just queues them up so the printer can print them as it becomes available. When many people need to print large jobs at the same time on a shared printer using a direct IP printer connection. Without an automatic way to process and queue the print jobs, each user must wait for the printer to be available before they can finish printing their job. Each user of a shared printer using a direct IP connection must first wait for the printer to be free and then wait again while the print job is printed. With a print server, each user simply prints their job to the print server where it is spooled and printed as soon as the printer is ready, without requiring the user to wait by his or her computer until the job has finished printing. In fact, once their print job has been spooled on the print server.

When multiple documents are concurrently sent to the printer pool, the first document to arrive will begin printing on the first printer, the second document to arrive will begin printing on the second printer, and so on. If all of the printers are busy, other documents will line up in the queue and then be sent to the first available printer.

Backup Data

Backup refers to the copying of data so that these additional copies may be restored after a data loss event. Backups are useful primarily for two purposes: to restore a computer to an operational state following a disaster and to restore small numbers of files after they have been accidentally deleted or corrupted.

Full backup;

It involves taking a copy of all the data, applications, and system files (including the OS) and storing it to the tape.

Incremental backup;

This is a technique used to cut down on the time taken for a full backup. The first time a backup is made, it is a full backup. The second backup is an incremental backup, which means it will copy only the filed modified since the full backup, and so on.

Differential backup

It is really a compromise between the previous two backup techniques. Each differential backup copy all the files modified since the last full backup.

Back up device

It is very important to purchase and use the correct hardware for the backup process and there are a number of factors that influence the choice of equipment:

Magnetic tape

Hard disk

Solid state storage

I recommend taking into consideration the fact that data availability and network uptime is very critical for the Organization; incremental backup will be the most suitable for Organization.


System testing of software or hardware is testing conducted on a complete, integrated system to evaluate the system's compliance with its specified requirements. System testing falls within the scope of black box testing, and as such, should require no knowledge of the inner design of the code or logic.

As a rule, system testing takes, as its input, all of the "integrated" software components that have successfully passed integration testing and also the software system itself integrated with any applicable hardware system(s). The purpose of integration testing is to detect any inconsistencies between the software units that are integrated together (called assemblages) or between any of the assemblages and the hardware. System testing is a more limited type of testing; it seeks to detect defects both within the "inter-assemblages" and also within the system as a whole.

Software Testing.

Software Testing is the process of executing a program or system with the intent of finding errors. Or, it involves any activity aimed at evaluating an attribute or capability of a program or system and determining that it meets its required results. Software is not unlike other physical processes where inputs are received and outputs are produced. Where software differs is in the manner in which it fails. Most physical systems fail in a fixed (and reasonably small) set of ways. By contrast, software can fail in many bizarre ways. Detecting all of the different failure modes for software is generally infeasible.

Software quality, reliability and security are tightly coupled. Flaws in software can be exploited by intruders to open security holes. With the development of the Internet, software security problems are becoming even more severe.

Many critical software applications and services have integrated security measures against malicious attacks. The purpose of security testing of these systems include identifying and removing software flaws that may potentially lead to security violations, and validating the effectiveness of security measures. Simulated security attacks can be performed to find vulnerabilities.

Functionality (exterior quality)

Engineering (interior quality)

Adaptability (future quality)












Table 1.  Typical Software Quality Factors


Hardware Testing.

A common test platform (CTP), also called an open test standard (OTS), is a set of specifications defining test methods for diverse components of computer and electronic systems to be marketed as complete products. The intent of a CTP is to ensure consistency in hardware and software test procedures from the conceptual and design phases through manufacture and distribution. Computers, computer peripherals and electronic systems often contain complex devices, circuits, programs and interfaces. These must all work together in a variety of applications and conditions. A CTP can be part of an overall quality assurance program. A common standard can reduce the cost of test equipment, optimize the use of available test equipment, increase production efficiency and minimize training costs.

Proposed system for Barry & Co.


When a new computer system is introduced into an organization it's expected to produce certain beneficial effects for the organization and the individuals within that organization. These effects are discussed with reference to ideal systems outlined by some researchers.

In my system I considered overall cost and efficient usage for a small business.

I used comprehensive, affordable accounting software available in the market.

Also hardware sharing scheme via a network has been introduced in order control the budget under the limit and which will keep the environment tidy.

Even though I could go for a heavy accounting package I selected a medium compatible

System which can do a reasonable work load for the Barry & co.