Class 5 Computer Software

Outline System Software Application Software (“Applications”) Markup languages for Internet (HTML, XML) User Interface Client-Server hardware & software Managing software acquisition

Software (Computer Program) & Types Instructions that manage computer hardware. System software Operating system (MS Windows, Mac OS, Linux) Drivers (connects pieces of hardware & software - !!) Application software (“Applications”– watch out for language mess!)* Web browsers, Microsoft Office User interface (screens for users to input data and get output). Access to data and system’s functionality Should be easy to use (but!...) 1

HTML & XML* HTML – mark-up language for designing user interface (screens) on the Web*. Used for controlling look of screens. XML - mark-up language used for defining content of files (e.g., every part a document can be defined) Useful for transfer of files between different systems on Internet Easy to read and format Weak on security 2

User Interface Both hardware and software concept – all details below belong to User Interface, including the content of the screen (a window displaying the output, clickable icons, images, colours…) Today, User Interface is a very important part of an IS, and it should be easy to use. 3

4 Client-Server Model The model of arranging hardware & software in which one computer serves data storage and processing operations (SERVER) to another computer (CLIENT). Server and Client can share storage and processing operations. If most of work done by server, client is “thin” (Thin Client). Model can get complex with multiple clients an servers (tiers). Client to Data base Multi-tear Client-Server Model

Methods of Acquiring Software 1. Build software in house. Pro: customized to internal needs, technical expertise nurtured Con: Expensive (staff, development technology, maintenance cost) 2. Outsource development of custom solutions to a software vendor Pro: Save on staff and development tools Con: Lock in a vendor – dependence, no own technical expertise, maintenance cost 5

Methods of Acquiring Software 3. Buy off-the-shelf software (one size fits all) Pro: Cheaper than in-house and outsourcing Con: No support to specific internal needs (one size may not fit all) 4. Rent A) Application Service Provider (hosted service) B) Web Services/Cloud Computing (processing, storage served) Pro: cheapest, no hardware cost, no maintenance cost, trendy tech. Con: dependence, no own technical expertise, privacy & security 6

Methods of Acquiring Software 5. Use Open Source software (OS)* OS = Source code (code of a programming language) is accessible to everybody. Supports some basic functions. Accessible for free in a basic version and modifiable Ex. : Linux (operating system), Open Office (like MS Office) Pro: Affordable, innovative Con: Support uncertain, no warranty, product life uncertain, requires staff who can understand it and link it with other software as needed. 7

Total Cost of Ownership (TCO) In managing systems acquisition, don’t consider just capital investment but TCO TCO includes capital investment in software and hardware, training, recurring costs for licenses & maintenance, operating costs (salaries, facilities & energy), downtime (opportunity costs), disposing of used equipment… Maintenance costs can be large 8 Development… Use stage: Discard maintenance, operations, opportunity…