Enable applications to run 2. Enables software to communicate with systems hardware 3. It manages system resources 4. Monitors performance of system 5. Prompts error messages. Multi tasking means an SO can run more than one program at a time Basic systems that are not multi tasking are called single program mode Ox's. User interfaces Can be command driven-blank screen and commands and code used. Can be menu driven- headings and menus Most common is GIG-II-graphical user interface-combines menu driven and icons- Guy's Data capture Data capture turns info into data
Automatic data capture-is fast and accurate BUT manual data capture- is necessary sometimes, and it's cheaper! Data validation and verification Validation-4 checks Range check-checks data is in specified range Presence check-makes sure data is present Check digit-check that numerical data is accurate Data type-checks that text is not where numbers are meant to be. Verification-2 checks Proof reading-read it and make sure that its accurate Double-entry-data entered twice and compared.
Validation problems- mistakes may be allowed if carried out wrong and only makes ere that data is right type-NOT ACCURATE. Verification problems-double entry is time consuming-expensive and proof reading is time consuming and does not eliminate human error. Data processing Real time processing does it instantly Batch processing-all in one go Transaction processing-one off specials Interactive processing-talk to the computer Access to data Serial access-records are stored one after another in creation order Sequential access-records are stored one after another AC. O sensible order Direct access-can go to record directly Implementation and evaluation types of implementation- Direct-straight away and old system goes down but bugs not picked up in testing-bad news! Phased-different parts are introduced one at a time Old system is kept running Parallel-new system is introduced in one go BUT old system stays New system can be tested quickly but all tasks need to be done twice. Evaluation Just checks that the system meets all objectives DIP SOFTWARE-IS good because it creates pro.
Looking documents and the layout can be changed more easily than word processors and the user can control the number f pages more easily than a word processor INTERNET To connect you need a PC connected to a normal telephone line and a modem You use your modem to dial up a computer that is owned by an ISP You need 2 pieces of software- email client and web browser. Internet has 2 main parts-WWW (world wide web) and email. Speed of access depends on 3 things- Modem speed-either Kbps or Kbps Telephone line-either KIDS or ADDS Volume of traffic-more people using the Internet, the slower the speed of access.
Http-hypertext transfers protocol-language that web uses. Http://www. Copybooks. Co. UK Copybooks-domain name Health and safety RSI- repetitive strain injury-aches pains and muscle or tendon damage Spending too long in front of a VADUZ can cause eyestrain and headaches. Circulation and fitness and back problems result from sitting all day in front of a computer Solutions- Take regular breaks, look away from screen walk around and exercise fingers Use correct equipment- a chair with a backrest, a keyboard making it easier to type without straining Good background lighting, good screens and a screen filter to reduce VADUZ glare.