Systems Analysis Flashcards
stages of system analysis
analysis, design, implementation, installation, evaluation, maintenance
analysis
problem is defined and requirements are established.
data (origin, uses, characteristics, volume) procedures (how errors handled, what where when how), problems with current software, future (development plans and expected growth rates)
design
pseudocode, what will it look like:
inputs (frequency and methods), data structures (how data held and accessed), output (medium and sequence) hardware (appropriate configuration), security (against hacking and corruption, processing (algorithms and modular structure), UI (menus, screens, dialogues)
installation
install and more testing- so weaknesses and omissions arise
implementation
coding, documentation (user, system and technical doc) testing and errors traced and corrected
evaluation
on effectiveness, usability, maintainability: critical examination 3-6mo after, allows staff to learn, get used to and understand software. Air views and discuss improvements and shortcomings by users. Online queries discussed in month end period routine reports
modular programming
program divided into separate self contained, specific well defined, tasks which can be WRITTEN and tested individually and subdivided further into smaller modules
black box testing (functional testing)
carried out independently of PROGRAM CODE and how ALGORITHM works. looks at program SPECIFICATION and creates test data covering all inputs, outputs and program functions. test outputs against expected outputs
white box (structural testing)
dependent on CODE LOGIC and derived from program structure and source code. code is STUDIED and and tests are devised testing every possible path at least once using TRACE TABLES/dry running, but doesn’t detect missing functions. ensures all parts work as intended
alpha testing
testing done within the software company/software developers in-house testing team as the program is being developed, revealing omissions and errors in the SYSTEM REQUIREMENTS DEFINITION. May use emulators. they may take up the role of the users
why may programmers have missed something out
not specified carefully enough
developers overlooked/misunderstood
beta testing
giving package which is not yet finished to potential third party users, agreeing to use and report any problems, exposing it to normal, real use and detects problems and errors NOT ANTICIPATED by developers. sent out when confident after SEVERAL MODIFIED beta versions
what takes place in a post implementation review
assessment of every aspect against preset criteria
discuss errors made during system development
discuss unexpected benefits and problems
compare systems actual performance against anticipated performance
waterfall lifecycle model
input from users at very beginning and end
each step completed INDIVIDUALLY one at a time from beginning and end and each stage provides specific outputs which lead to next stage
can return to previous stage but have to work down in same order
adopted from manufacturing industry where any modification to hardware = cost implications so every stage has to be right before moving on
spiral model used for…
large scale projects that take years to deliver where REQUIREMENTS and tech may change