types of software systems and their attributes Flashcards
paper 2
types of software
open source
bespoke
off-the-shelf
open source software
software whose source code is visible and can be modified by users
typically license terms promote collaboration and allows sharing for free
open source pros
usually free
if you can program, you can customise to your own needs
open source cons
no right to support it bugs exist
may not have as powerful features as paid for software
bespoke software
software that has been written to order for a specific client
bespoke pros
software can be customised to client’s exact needs
unique software provides unique competitive edge
bespoke cons
can be very expensive
software not immediately available - must be designed etc
off-the-shelf software
general purpose software typically purchased from a retailer
off-the-shelf pros
cheap
readily available on demand
lots of support should exist
off-the-shelf cons
may not solve the problem exactly as you wanted
users tend to pay for features they end up not using
what is a safety critical system
a system in which failure could result in injury or death
fail passive
may fail but has backup measures in place
eg autopilot fails then pilot takes control
fault tolerant systems
can continue to operate on an interim basis but with limited capacity
eg having a redundant system in place split into sections so if one section fails they can activate the redundant system temporarily
fail-safe systems
has manual overrides in place for if failure occurs - eg have a time delay and a warning that allows for human interaction before they become critical
eg medical devices
what is a control system
type of computer system that manages, commands and directs other devices/systems
can be used for:
safety
working remotely
precision
