SYSTEM ANALYSIS 3 rd AUGUSUT 2005 WEDNESDAY LOWER SIXTH COMPUTING LESSON Prepared by: T.Fina

WHAT IS A SYSTEM ANALYSIS?  A system analysis is a study of the overall organisation and implementation of an I.T. system.  A system analyst is the person who works on a system analysis.

STEPS IN SYSTEM ANALYSIS  (1) Fact finding  (2) A feasibility study  (3) An analysis phase   (4) System design   (5) Testing   (6) Implementation  (7) Documentation  (8) Evaluation

SYSTEM LIFE CYCLE Feasibility Study Analysis Phase Fact Finding System DesignImplementation Documentation Evaluation Testing

(1) FACT FINDING 1  Fact finding is concerned with finding about the existing system.  It may be that computers are already used but not to their full extent or it may be that a manual system exists which needs computerising.  There are 4 main ways of finding out about existing systems:- i. asking questions (interviewing people); ii. Getting people to fill in carefully designed questionnaires; iii. Sitting with various people to observe how the job is done at the moment; iv. Inspecting any bits of paper, screen displays and files which are used in the present system.

(1) FACT FINDING 2  The final step in fact finding is to produce a report which describes the existing system and its shortcomings, together with some description of the output needed from the new system.

(2) FEASIBILITY STUDY 1  The feasibility study looks at the chances of being able to solve a particular problem at a reasonable cost.  The feasibility report is the document produced at the end of the study and will give an idea of the time the project likely to take, along with some estimate of cost.  The aim of the feasibility study is to see whether it is possible to devise a system that can be implemented and will work at reasonable cost.

(2) FEASIBILITY STUDY 2  The feasibility study ends when a decision has been reached whether or not to proceed with the project.  The following are usually included in a feasibility study: A description of what the system is required to do (called the objectives of the system). Some preliminary design so that the costs may be estimated.

(2) FEASIBILITY STUDY 3 Some alternative designs so that the most suitable one can be chosen. A cost/benefit analysis; this looks at the benefits and makes sure that they outweigh the costs. The costs of a system are not just the costs of thehardware and the software needed. The conclusion, which states whether it is worth going ahead with the project and which design has been chosen.

(2) FEASIBILITY STUDY 4  The feasibility report is written report given to the directors and is really a summary of the results of the feasibility study.  Usually the report is written but it can also be given in the form of a spoken presentation. FEASIBILITY REPORT

(3) ANALYSIS PHASE 1  In the analysis phase the feasibility study is used to design the new system.  To perform the analysis, the systems analyst will need to look at the system in greater detail than for the feasibility study.  When the present system is investigated, the system analyst will find more weaknesses in it.

(3) ANALYSIS PHASE 2  Included in the analysis phase are: Detailed objectives of the proposed system. Facts about the parts of the old system being replaced by the new system. Any constraints on the system. An update of the cost/benefit analysis based on the new information An update of the plan for further development of the system.

(4) SYSTEM DESIGN 1  If the directors of the company are convinced that a new system will be worth having, work can be started designing the new system.  Further investigation should be undertaken to consider what inputs, processes and outputs will be needed.

(4) SYSTEM DESIGN 2 Output Input Data Preparation Code Design File Design Hardware Configuration Software Used

(4) SYSTEM DESIGN 3 OUTPUTWhat output is needed? We must than look at what needs to be on these documents and screens. How frequently do these documents need producing? What is the volume of output? INPUTWhere does the data come from? What data needs to be input into the system? How much data needs to be entered and how often it needs entering? Which input device should be chosen? DATA PREPARATIONInvolves getting the raw data into a form that can be processed by the computer. Verification & validation are included in data preparation. CODE DESIGNWe can use codes to save time typing and also save storage space. Codes need to be carefully designed if they are to be useful. FILE DESIGNWe need to decide how many files are needed and then to design the structure of each of the files. HARDWARE CONFIGURATION If more than 1 computer is used, it makes sense to network them. Includes deciding on the type of computer & on peripheral devices. SOFTWARE USED Decide what software to use. We could use off-the-shelf software or custom-written software.

(5) TESTING  Before it is introduced the new system must be thoroughly tested.  The testing of a system may be broken down into 5 stages: (i) the system is tested with data that contains no errors to see if it produces the correct results. (ii) Known errors are now introduced into the data to see how the computer will process it. (iii) We now start trying to process very large amounts of data to see how the system copes with this. (iv) Some processing is only done now and again. E.g. we might need a stock report at the end of the month so this will need to be fully tested. (v) Extreme data should be entered to make sure the range checks included in the validation program will work.

 How you implement a new system really depends on its size.  Solutions range from a microcomputer or tow, to a system that uses a number of networked PCs or even a system based on larger computers.  Systems may be introduced into an organisation in 3 ways: (i) Direct Implementation (ii) Phased Implementation (iii) Parallel running (6) IMPLEMENTATION 1

 (i) DIRECT IMPLEMENTATION With direct implementation the users decide to start using the system on a given date. In practice this method is only used for small computer systems since in larger ones problems reveal themselves during the first month and the result can be havoc. (6) IMPLEMENTATION 2

(6) IMPLEMENTATION 3  (ii) PHASED IMPLEMENTATION With phased implementation, each job is introduced separately rather than all jobs being introduced in one go, as with the previous method. E.g. we may decide to look at the order processing first and get this run ning before we deal with other areas of the business.

(6) IMPLEMENTATION 4  (iii) PARALLEL RUNNING With parallel running, the new system is run alongside the existing system. If the new system fails, then because we still have the old system, we can use that until the problems are sorted out. Parallel running provides an ideal opportunity to compare the results from the new system with those of the old system, since both systems will be in operation at the same time.

(7) DOCUMENTATION 1  Documentation is of 2 types: (i) User documentation (user guide) (ii) Technical documentation

(7) DOCUMENTATION 2  (i) User Documentation A user guide or manual is documentation that the user can turn to for learning a new procedure or for dealing with a problem that has arisen. The guide should detail what to do in exceptional circumstances. E.g. if the system fails to read a disk or data is sent to the printer without it being switched on and the machine is locked, a user will need to know what they have to do.

(7) DOCUMENTATION 3  (ii) Technical Documentation Technical documentation is used to explain a system to a specialist, either a programmer or a system analyst. Since these people understand computer jargon this guide does not need to be as simple as the user guide. This documentation is extremely important since it might be used by someone new to the project and there may be no one around who was involved with the original project.

(8) SYSTEM EVALUATION  After a project has been implemented, it should be reviewed periodically to make sure that it is still meeting its objectives.  A good way of evaluating a solution is ask the users of the system.  They will be able to tell you if a system does what they originally wanted or if there are any improvements needed.

TEST YOURSELF… submit on 6 Aug 05  Using the words in the list below, copy out and complete sentences A to K, underlining the words you have inserted. The words may be used more than once. Outputfact findsystem analystparalleldocumentationanalysis feasibility studytrainedevaluateddesignfeasibility report A. A …………….. is the person who looks at the manual system to see which parts to computerise. B. She looks at the manual system in terms of 3 stages: input, process and ……… C. To begin with, she will perform a ………. In order to find out a variety of facts about the business. D. Going on from this, she will then perform a …… which will then look at whether an alternative system would be feasible. E. When she has completed this, she will submit a ……….to the directors of the company. F. If the directors are happy with the report, they will give the go-ahead for the system and the analyst can start to………..the system. G. Detailed systems………………then follows where outputs, inputs, files, software etc are all decided. H. The personnel involved with the new system will need to be…………………………. I. Also, …………..will need to be written. J. There are 3 ways that a system can be implemented: …………………………..running, phased implementation and direct implementation. K. After a system has been in use for some time, it needs to be……………to make sure that the objectives of the system are still being satisfied.

DISCUSSION GROUP  1. John, the head of mathematics at a large comprehensive school, decided to take early retirement and start up a tutorial agency matching tutors to students. He advertises nationally for both tutors and students. He does the marketing and advertising while his wife deals with all the paperwork. The business has been a huge success but the amount of paperwork now generated is getting them both down. They are using a manual system at present but would like a new computerised system.  (a) the head of information technology at his old school suggests that they need to perform a feasibility study which will cover hardware, software, staffing and operating costs. Explain why such a study will help John and his wife select the best system  (b) Explain the steps involved in a feasibility study  (c) John and his wife have now performed a feasibility study and have decided to buy a Pentium computer with a 1000 MB hard disk and a tape streamer. They have also chosen a laser printer. Explain how they might go about choosing the correct supplier for this equipment.  (d) Once they have decided on a system, how should they go about getting their new system up and running?