Design Computer Systems

Lesson 2: Computer System Design2011

Mrs. Dyala Rousan

What is a Computer System?

A complete, working computer.  Computer systems will include the

computer along with any software and peripheral devices that are necessary to make the computer function.

Every computer system, for example, requires an operating system.

Common Types of Computer System

BusinessFinancial Systems like

accounting, inventory etc.Scientific and Engineering

SystemsGaming SystemsWorkstations and Servers

Who is Computer System Analysts?

A system analyst is the person who selects and configures computer systems for an organization or business. He/She has to determine the intended purpose of the computers.

This means the analyst must understand the general objectives of the business, as well as what each individual user's job requires. Once the system analyst has determined the general and specific needs of the business, he can choose appropriate systems that will help accomplish the goals of the business.

When configuring computer systems for a business, the analyst must select both hardware and software.

The hardware aspect includes customizing each computer's configuration, such as the processor speed, amount of RAM, hard drive space, video card, and monitor size.

It may also involve choosing networking equipment that will link the computers together.

The software side includes the operating system and applications that are installed on each system.

The software programs each person requires may differ greatly between users, which is why it is important that the system analyst knows the specific needs of each user.

To summarize, the system analyst's job is to choose the most efficient computer solutions for a business, while making sure the systems meet all the company's needs.

Who is Computer System Analysts?

System RequirementsThe system requirements stage

is where you examine the system functions and user interface needed, along with the interface, communications, and appropriate hardware and software requirements.

Client/User RequirementsUsers are those who use the information

system to manage their organizations.Thus their requirements should be

respected while developing any information system.

Consider the following issues:◦ The system: The system must be stable, being

able to meet staff’s requirements and provide accurate information, easy to maintain, quick in identifying and correcting mistakes.

◦ Interface: Suitable with working style of users, stable, easy to control data, flexible.

Function AnalysisThe purpose of function analysis

is to master users’ requirements to the system, i.e. what the system will have to do regardless of how it’s going to do it. The description is then sent to users for their comments and approval.

Computer Timescale

Measurement

Investigation Techniques

Who, What, Where, When, How, and Why?

Investigation Techniques

InterviewsSystems analysts spend a great deal

of time talking with peopleMuch of that time is spent

conducting interviewsConsists of 7 steps

InterviewStep 1: Determine the People to Interview

◦ Informal structuresStep 2: Establish Objectives

◦Determine the general areas to be discussed◦List the facts you want to gather

Step 3: Develop Interview Questions◦Creating a standard list of interview questions

helps to keep you on track and avoid unnecessary tangents

◦Avoid leading questions◦Range-of-response questions

InterviewStep 4: Prepare for the Interview

◦ Careful preparation is essential because an important meeting and not just a casual chat

◦ Limit the interview to no more than one hour◦ Send a list of topics◦ Ask the interviewee to have samples available

Step 5: Conduct the Interview◦ Develop a specific plan for the meeting◦ Begin with good introduction◦ Use engaged listening◦ Allow the person enough time to think about the

question◦ Summarize main points◦ After interview, summarize the session and seek a

confirmation

InterviewStep 6: Document the Interview

◦During the interview, note taking should be kept to a minimum

◦After the interview, record the information quickly

◦After the interview, send memo expressing appreciation, including the main points discussed so the interviewee has a written summary and can offer additions or corrections

Step 7: Evaluate the Interview◦ In addition to recording the facts obtained in

an interview, try to identify any possible biases

Questionnaires and Surveys

◦Keep the questionnaire brief and user-friendly

◦Provide clear instructions that will answer all anticipated questions

◦ Arrange the questions in a logical order, going from simple to more complex topics

◦Phrase questions to avoid misunderstandings; use simple terms and wording

Example of Library Management System A library management system is required to receive

books and magazines number them, store and manage them, produce index of document.

The interview questions should consist of the followings: What are the main jobs of the library

management system? What is the function of each job? How are the jobs currently done? Who does the library serve? and so on

Summarize: The more information you get about the operation

environment of an organization, the more you understand its issues and be able to make realistic questions about the matters you’re interested in.

Computer Systems Selection

Computer user will need to make a choice of what they need from a computer by getting the right deal◦Cost◦Client Requirements◦Maintenance contract / Warranty◦Other requirements◦Compatibility◦Performance

Computer Systems Cost

The more expensive the more advanced hardware technology a PC will have.

The cheaper the PC is, it will be more like basic hardware

Vendors will have different costs◦ Based on brand name (Dell, HP,….etc.)◦ Based on what technology the person is after (more speed,

graphics card,……etc.)

Some people, decide to assemble computers for themselves. ◦ This let them save a lot more than buying a pre-assembled

unit sold in stores. ◦ They could also choose the best parts that they want their

computer to have.

Computer Systems Client Requirements (1/2)

Basic system◦ Emailing◦ Browsing the internet◦ Kids programs and small games

Home entertaining◦ Watching movies/TV with home cinema

system◦ Listing to music, mixing music, composing◦ Playing video games

Computer Systems Client Requirements (2/2)

Business needs◦ Office program (word, excel,….etc.)◦ Graphic design/ web design◦ Developers programs

Others◦ Capacity storage ◦ Different screens sizes◦ Sound system

Some software also has other requirements for proper performance. Internet connection (type and speed) and resolution of the display screen.

Computer Systems Requirements examples

Star-Craft (1998) needed: Windows 95 or NT or superior Pentium processor at 90 MHz

or higher 16 MB RAM 80 MB available in the hard

disk CD-ROM, 2x or higher DirectX 3.0 or higher

Star Wars: The Force Unleashed (2009) needed:

3D Hardware Accelerator - 256MB of memory minimum

Windows XP SP3, Windows Vista SP2, Windows 7

Core 2 Duo or Athlon X2 at 2.4 GHz

2 GB RAM 8x Speed DVD-ROM 23.8 GB + 1 GB Swap File hard

disk space DirectX 9.0c compatible sound

card DirectX 9.0c compatible video

card

examples of system requirement definitions for popular PC games and trend of ever increasing resource needs

Other RequirementsPrinters ScannersWireless card/ Ethernet card Keyboard / mouseWebcamsCPU Cooler

Computer SystemsMaintenance Contracts

Vendors provide warranty contract◦Can extend or buy more warranty

Hardware should be compatible with web servers

Processor upgrade is possibleCompatible with next generation

of softwaresCan be delivered on time (if

ordered online)

Computer SystemsCompatibility

Parts Compatibility◦Hardware parts◦Software versions◦Peripherals

Computer Systems and Systems Integration (SI)

In information technology (IT), systems integration is the process of linking together different computing systems and software applications physically or functionally, to act as a coordinated whole.

The system integrator brings together discrete systems utilizing a variety of techniques such as computer networking, enterprise application integration, business process management or manual programming.

Computer Systems Performance

CPU speed

Computer Systems Performance

Processing power◦The power of the central processing unit (CPU) is a

fundamental system requirement for any software.◦ Intel Pentium CPUs have enjoyed a considerable

degree of popularityEfficiency

◦Hardware & Software are working on their best performance combined

Usability◦Hardware that are easy to use. (optical mouse /

mouse tracker) (media keyboard/ gaming keyboard)

◦Software that meet the needs of users. (not sophisticated)

System SpecificationsComputer Configuration

◦ Installing operating system (OS) that is compatible with the hardware available

◦ Softwares / applications that are compatible with OS and with hardware / peripherals

To get a well configured computer is by getting a laptop. Most are pre-configured with parts suitable for personal use.

There are laptops designed for specific purposes◦ office related work◦ gaming purposes

laptops generally perform great in all aspects of personal computing. It’s the easiest and safest choice in terms of computer configuration.

Other SpecificationsBackup Backups are made to recover data in a

computer crash. If not stored properly data can be read from the backup media. For example:◦External Hard disks◦CD/DVD◦Flash memory

Security◦Anti-virus, Anti-malware…etc◦Pop-up blocker, anti-hacking programs… etc◦Firewalls, Network watch,… etc

Computer SecurityComputer Security is the ability of a system to

protect information and system resources with respect to confidentiality and integrity.

Aspects of Security:◦ Prevention: take measures that prevent your

assets from being damaged◦ Detection: take measures so that you can

detect when, how, and by whom an asset has been damaged

◦ Reaction: take measures so that you can recover your assets or to recover from a damage to your assets

Other SpecificationsTools & Resources

◦Assistance programs (provided by brand name companies)

◦Technical support help◦Drivers download

System documentations◦System startup / tutorial ◦Usage of the system (Manual)◦Updates & troubleshooting (FAQ)