Mira and Atie decided to play truant for the first time today, so here I am on my own in this class. Technically, Lyn and Fareha are with me, but well… Today’s topic for Compsci 111 lecture is.. urm… Software. Looking at the first slide, I was like “Hrm… Free stuff.”

• Software - usu. include -all data we’re working with
• Data & instruction, initially separated
• known also as programs
• loaded from secondary storage into primary memory
• runs (executes) from RAM
• Software is loaded (HDD - RAM) - Read/Write CPU executes instruction (CPU)
• Read up in CPU very rapidly
• FILE FORMATS:
• all data stored in binary numbers
• organised in chunks (of related dtaa)
• method of encoding - dep. on software, = file format
• FORMATS - define the way numbers r interpreted
• EXTs - a dot followed by letters at the end of a file
• Windows OS use ext to determine file format n decide which apps to use to open a file

Why are standards needed? (standardised agreement)

• OS - open standard - published freely to the public, free to use, maintained by a non-profit orgs (xml, html, uml)
• But open x mean all good
• Proprietary standard - intellectual prop of an entity (indivisual/comp), use is usu through license
• risk for users: vendor lock-in

Proprietary Software

Software that has restrictions on using/copying

• all rights retained by owner
• owner enforces restrictions

License:

• commercial
• freeware
• sharewre
• semi free (usu non-profit org)

Freeware

• software dist free - no agreement abt dist, access to source code
• types: loss leader (given away with loss as sales promo), adware, donationware, postcardware
• abandonware: not legally recognised (IE, iTunes, Adobe Reader)

Shareware

• on the idea of ‘try b4 buying’
• trial period: purchase license/upgrade to comm ver
• nagware: reminder messages to license software
• crippleware: softwr lacks the advanced features until licensed (word processor that can’t save of print - (HAHA! Sounds like OFFICE 2007, doesn’t it??)

Open Source/Free Software

• freedom to use n study the work
• to copy n share the work with others
• change the work
• distribute changed and therefore derivative works
• copyright prevents these acts - explicit permission is required, free software license gives permission
• Richard Stallman - free software foundation (FSF), GPL (GNU General Public License) - legal doc that gives permission :P, Copyleft

Kinds of Software

• App software - helps user complete task
  System software - needed to run the comp
• OS - manages all the hardware resources for apps (CPU, RAM..)
• device drivers: help OS control hardwre
• diagnostic and maintenance tools - for analysis, troubleshooting n optimisation

OS

• low-level software - allow the use of system
• default interface when no app is running
• manages the system

Continued in notebook.