U1T2 - Factfiles Flashcards
What is the purpose of the design stage?
To produce a systems specification. Document includes detail on certain design components.
What should the document in the design stage include?
Data capture methods + forms for system, data inputs + outputs for system (screen designs, report specifications, query designs, storyboards, macros), data processing within system, data structures (database structure, data models, DFDs, normalisation), user interface (screen layouts, buttons, error messages), hardware used to run new system, detailed design of user interface, switchboard, menus), test plan, program code listings + hardware + software config.
What is the purpose of development?
Develop the software package required for info system. Programming code must be produced/features of software package must be developed, data
structures, data checking procedures + user
interface. Must also be evidence of effective use of hardware specification.
What is the purpose of testing?
Ensure system works as described in system specification + is high quality. Should be able to demonstrate all parts/functions of solution work as expected, irrespective of data input. Errors + limitations identified + corrected. Test plan is devised including range of test data ensures it’s structured.
What is a storyboard?
Diagram which shows planned sequence of screen displays in user interface. May be branching diagram showing diff paths available to user. Visual aid, helps with test plan.
What is prototyping?
Involves building a working model/first cut of new system. Gives user ‘look + feel’ experience. User can eval + give feedback to systems analyst. Analyst can make changes + return to user who evals. Means better quality, identify issues early, end user involved, fulfils requirements, saves cost + trains. Process continues as refinements made. Results in fully working system (Evolutionary Prototyping) or produces set of user requirements (Throw-away Prototyping)
How is a system developed with throw away prototyping?
Using alt approach e.g. waterfall method. Prototype produced.
What are 3 diff quality indicators?
Suitability, usability + effectiveness.
What are some suitability questions in terms of quality indicators?
Does system meet all objectives, is it fit for purpose, does system provide required functionality, is it compatible with existing tech/hardware/software/data + is it robust/free from errors?
What are some usability questions in terms of quality indicators?
How fast can user learn to use UI, is UI intuitive, does UI match user’s level of IT competence, how well can user transfer skills + what training required?
What are some effectiveness questions in terms of quality indicators?
Does system perform tasks efficiently + has it been designed to facilitate maintenance, has it delivered promised improvements?
What is system testing?
Making sure system works as described in spec. Follows test plan to test each individual functions works with extreme/invalid data. Ensures system produces correct results for data input.
What is alpha/application testing?
Carried out in-house by members of IT development team e.g. programmers. Includes module, integration + system testing whereby software is tested against module + system specs.
What is beta testing?
Takes place after alpha testing. Software given to number of potential users in pre-release version. Users agree to test system in realistic environment + give feedback to developer.
What is acceptance testing?
Testing software by end user in live environment with real data volumes to ensure it meets user requirements. Feedbacks issues to developer. Gets agreement between user and developer. Proves to customer that system works.
What is the test plan?
Produced at design stage. Detailed document which is used by group of testers. Includes ref to part of system to be tested, test data to be entered + result expected. Testers records if successful/not. Test teams must follow test plan. If expected result doesn’t occur, modified. Data that checks validation rules should be included. Should be created early. Created by analyst. Programmer performs it. Hardware, software + procedures should be tested.
What are the 3 categories of test data?
Normal Data (Includes data that program will accept) Extreme Data (Includes data on acceptability limits) Exceptional Data (Data when entered invalid + not accepted)
Describe what led to the software crisis.
Created when hardware developments (RAM speed, processing power) were growing at much faster speed than software developments. As comp tech more complicated, organisations demanding more complex problems to be solved. Programmers struggled to keep pace with developments.
When did the software crisis become evident?
Projects ran over budget, were delivered late (if at all) + inefficient software. Low quality software which didn’t meet user’s needs. Projects were difficult to manage + codes difficult to maintain. Also impacted maintenance of older software which needed to be adapted to new user requirements. Programmers must spend more time maintaining older software. Expensive to create new software so reluctant to do so. Inadequate documentation.
What are productivity tools
Generic software purchased and tailored to meet user’s needs. e.g. Microsoft 365.
Why might new software have to be produced?
Current system may not be suitable for purpose as requirements may have changed/business may
have expanded.
Current system may be too inflexible/expensive to maintain.
Tech support for old system may not be available/available but expensive.
Tech developments could make current system outdated.
Advances in hardware + OS’s may require it as may not support old system.
What does a computer consist of?
User interface allowing data requiring processing to be entered + outputs results.
What does a user interface allow?
Allows user to interact with computer + software
What is a process?
Activity carried out as part of computer system.
Takes data in form of raw facts + figures + produces info in report.
What does a systems analyst do?
Analyses data processing requirements of organisation
+ documents findings. Conduct feasibility study to find whether system should be computerised
+ which solution suitable + draw up the systems
spec. If fault found during testing reflecting system design then analyst corrects the fault. May have little knowledge of how organisation works.
What is the systems specification?
Criteria against which system testing should be evaluated leading to implementation of system.
What does a programmer do?
Writes source code using programming language. Written from module specs. When program produced, programmer develops test plan + tests it. If bugs present, then programmer debugs it. To allow further development, they produce technical documentation which is used during maintenance stage. Shouldn't write user guides.
What does the project manager do?
Oversees development new system development, schedules project, manages budget, allocated resources (human, hardware + software), monitors progress, identifies + responds to risk + reports back to clients as project progresses.
What is the main point in analysis?
Investigate problems within an information system. Solution to problem can be improvements
within existing system/creation of new info system.
During analysis, what does a systems analyst do?
Investigate present system to establish user requirements. Must understand business purpose + existing system in terms of inputs, processing + outputs. Includes constraints for new system (timescale, cost,
existing hardware + software + staff capability)
Give 4 methods of fact finding.
Interviews, Questionnaires, Observation + Document Sampling.
What do interviews in the analysis stage involve?
Users answer questions from system analyst on one-to-one basis/small groups. Express opinions in detailed
way. Interview may be structured or unstructured
so questions followed up as more facts unearthed from answers. Time consuming + users may also suggest answers analyst wants to hear + not truth. Open ended.
What do questionnaires involve?
Representative group of users complete a set of questions (open or closed) to identify detail on current processes + data. Quicker but inflexible opportunities to respond as answers tend to be
multiple choice. Low return rate from staff, particularly if done by post/e-mail. Spread out staff.
What does observation involve?
Systems analyst shadows users carrying out a process. Analyst sees what user’s role entails. Can get a feel of competence + abilities + time required to do a task, constraints + strengths of current system. Users may respond differently if being observed. Not enough alone.
What is document sampling?
Analyst inspects sample docs (orders, invoices, reports)
to identify current system’s inputs + outputs. Analyst gets idea of volume of data stored seeing how data is
collected + stored. Time consuming if many files. Some out of date.
What are the functional requirements of a system?
Specifies activities a system must perform/provide for users. What the system must do.
e.g. How data is entered into system, outputs (queries + reports) + operations performed by each screen.
What are the non-functional requirements of a system?
Criteria that judges operation of system e.g. Time to update stock database, criteria for usability, security +
access to system, storage capacity, + maintainability, backup of data, recovery procedures,
contingency planning and access restrictions.
What do access restrictions specify?
What data needs protected + what data should be
restricted to a particular user role + level of access such as “read only”. All new computer systems are subject to
legislation such as the Data Protection Act.
What are data flow diagrams?
Shows how data moves through a system + what data is stored. Doesn’t specify what type of data storage
medium is used or how data is stored.
What is a context diagram?
“Level 0” data flow diagram.Sees system as 1 main process, identifies main data source + main data flows into + out of this process. Doesn’t consider data stores .
What is a level 1 DFD?
Breaks down process into sub processes showing how data flows between these. Data stores shown + indication of what data is stored.
What is data archiving?
Storage of info for long period of time. Consists
of info which is still important but not of immediate use/for future reference. Data which must be retained for a period of time to comply with legislation/auditing purposes.
Why is data archiving necessary?
Compressed so takes up less space. Stored on cheaper storage medium (optical discs) Still accessible to end user if necessary so may be indexed for easy retrieval.
Why is backup important?
Makes copies of software/data in case originals lost/damaged. Appropriate backup means if system failure occurs then system/data can be rebuilt accurately. After system failure/data corruption, backup allows corrupt/lost data to be replaced. Should have regular backups.
What are 3 methods of backup?
Full, differential + incremental.
What is a full backup?
Copies all files to provide complete picture of data at given time.
What is a differential backup?
Copies files changed since last full backup.
What is an incremental backup?
Copies files changed since last backup of any type.
What are the advantages of a full backup?
Everything backed up at once + files restored quickly
+ easily as complete files copied from backup.
What are the disadvantages of a full backup?
Most files don’t change so data redundancy in backups, takes longer + security concerns as everything in 1 place.
What are the advantages of a differential backup?
Faster than incremental restore as only uses last full backup + last differential backup, only copies updated files so faster + less space than full.
What are the disadvantages of a differential backup?
Requires more space
than incremental, longer restore time than incremental as all changes copied.
What are the advantages of an incremental backup?
Faster backup as only amended files copied + less storage space as only copy changed files.
What are the disadvantages of an incremental backup?
Recovery process takes longer as all incremental backups required + problems may occur if any incremental backups corrupted.
What is a disaster recovery plan?
Document which details procedures associated with recovery + protection of IT system in event of disaster.
What makes a good disaster recovery plan?
Incorporates set of procedures to support
recovery + continuation of vital tech infrastructure following natural, environmental or
man-made disasters. Also takes into consideration processing + operational needs of organisation + potential problems their IT systems might be exposed to.
What 7 things should be in a disaster recovery plan?
Potential disaster causes (fire, theft, power loss/telecommunication failure)
Assumptions made in plan writing (all staff involved in implementation of recovery plan available to support
implementation)
Plan Scope identifies infrastructure areas covered by plan (Details organisation areas being supported
by identified services + impact of disaster to that area + recovery priority for each area)
Policies to support infrastructure continuity in identified areas.
Staff w/ responsibility for ensuring adherence to each area.
Plan of action (Identifies steps necessary for recovery, steps taken in given time from start to continuing steps)
Revision + testing plan (Tested + reviewed regularly)
What is implementation?
Creates working computer system based on previously produced system design documentation. Includes systems diagrams, interface design creation + spec of verification + validation techniques to be applied to data as it’s input. Puts design elements into practice.
Determines data structures to store data once it’s input, specifying system modules + describes them in algorithmic form before creating the comp system + its associated elements.
What is changeover?
After design, implementation + testing, changeover from old to new system must occur so info system can be tested in real life scenario. Approached depending on system size + processed data nature.
What is parallel running?
Old + new system operate side by side for short time period.
What are 4 different ways of changeover?
Parallel, direct, phased + pilot.
What is direct changeover?
Discontinuing use of old system + immediately replacing w/ new system. No overlap.
