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Archive for the ‘IT Essentials’ Category

Blue tooth classifications

Class 1 – Range of 100m

Class 2 – Range of 10m

Class 3 – Range of 1m

Each uses Adaptive Frequency Hopping (AFH)

Fire walls


Free standing, uses it’s own hardware

Costs more

Multiple computer use

Little impact on computer performance


Availible as 3rd party software, cost varies

Included in Windows XP

Only protects the computer it is on

Uses the CPU, can slow computer speeds

Wireless network stuff

The domain is the bigger network, a work group is a smaller group within the domain, information can be shared between only these computers.

SSID – Service Set Identifier

The default wireless network name so that wireless devices can detect other devices in a wireless network, it must be manually entered when the SSID broadcast has been disabled on the wireless router or access point.

MAC address filtering

A security technique in which only identified MAC addresses can connect to a wireless network, used on wireless LAN’s

WEP – Wired Equivalent Privacy

First generation security for wireless, crap, it is easy to break it’s encryption making it pretty much useless.

WPA – Wi-Fi Protected Access

2nd generation of WEP, has much stronger encryption


A security layer for wireless systems, once it was made an official standard WPA2 was released

WPA2 – Wi-Fi protected access 2

The improved version of WPA which uses the entire 802.11i standard and provides goverment grade security. It can be enabled in two versions:

Personal – Password authentication

Enterprise – Server authentication

LEAP – Lightweight extensible Authentiation Protocol

CISCO’s wireless security, addresses weaknesses in WEP and WPA

WTLS – Wireless Transport Layer Security

Security for mobile devices which uses a smaller amount of bandwidth. Uses WAP (Wireless Applications Protocol)

 Hub – receives data, sends to all ports

Switch – Sends to intended port, more sophisticated than a bridge

Routers – Connects entire networks to each other e.g. internet

WAP – Wireless Access Points, Uses radio waves to connect wireless devices to the network

Printer and scanner hazards

Weight read instructions for two or three man lifting

Clothes that may shift it, from desks for example or shoes that don’t protect your feet if something drop on them

Jewelery that may drop into slots or scratch flatbeds

Heat from being turned on may remain for hours after being turned off

Packaging that should be removed


Serial attached SCSI (sas)

Point to point

Can take 65535 devices

No terminators

SATA (old)

Half duplex- Info goes one way at a time

Consumer market

1-2m cables

SCSI (new)

Full duplex- Info goes both ways at the same time

Better error handling

Critical server applications

10m cables

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