Computing Cg1

Only available on StudyMode
  • Download(s) : 91
  • Published : March 15, 2013
Open Document
Text Preview
Protocols
networks consist of hardware/software that work together to exchange info. Only possible if agreed rules/procedures governing communication are in place , these are called protocols HTTP (Hyper Text Transfer Protocol) Stand method of transferring data between web server and browser FTP (File Transfer Protocol)- allows files to be transferred across the internet WAP (wireless application protocol) – open international standard for app layer network communications. Mainly to enable access to internet from mobile or PDA. SMTP (simple mail transfer protocol) – for sending e-mail between servers & computers POP3 (post office protocol) - downloads email from server to computer VoIP ( voice over ip) – allows internet to be used as phone HTTPS (secure HTTP) identical to http but signals browser to use added encryption4 IrDA ( infrared) – short range communicating by infrared light Bluetooth - wireless technology, allows phones computers and devices to talk over short distances up to 100 meters

Hardware and communications

Connecting portable devices
portable devices useful at home, working, meetings or travelling. Can connect to network or sync to a host computer e.g microsoft activesync for windows mobile device. Personal digital assistant (PDA) – Calculation, clock, calendar, address book, internet, emails, photos video recording, word processing, bar codes, radio/music player, games, GPS, can be connected to wireless network via wireless network connection. Other devices can also be connected by USB. Wi-fi replaces wired lans, allows you to move freely. Check emails everywhere. Places offer wi-fi airports, coffee shops, centers of education etc

Benefits of wireless
lack of cables allows networks in places it couldnt before e.g historic buildings, public areas, outdoors, on the road
Wireless security
having wirless connect means should protect data etc techniques include : WEP – wireless encryption protocol
WPA/WPA2 – Wireless proctected areas
MAC filtering – will only accept connections of known computers No security – foolish but easy to set up
WEP & WPA/WPA2 will require some form of network key to gain access
Wireless Standards
wi-fi has own set of protocols
802.11a, 802.11b, 802.11g and 802.11n standard as laid down by the IEEE (Institute of Electrical and Electronic Engineers). letter after the number indicates the particular revision and also the speed and frequency at which the network will operate. Wireless networking in use

Equipment
Usb wireless adapter
PCI wireless adapter
wireless router
wireless access point

File Processing

Master files
permanent files kept up to date by applying transactions that occur during the operation of buisness. Have 2 basic types of data : data of permanent nature such as pay roll file , employee name, address etc data that changes every time transactions are applied, gross pay to date, tax paid

Transaction files
contain details of all transactions occurring in the last period period maybe time since buisness opened morning, week or even month sales transaction file might have details of all sales made that da, once processed it can be discarded employee transaction files could be details of hours worked

File organisation
files stored on magnetic media can be organised in a number of ways, same as manual system advantages/disadvantages to each type of file organisation and chosen method will depend on several factors how the file is to be used

how many records processed when updated
whether individual records need to be quickly accessible
Defining a file
database is collection of files
file – organised collection of related records
record is a collection of related fields
field = single data item stored in particular format
data in file must be...
tracking img