You may hear the terms router, switch and hub used interchangeably. They look alike on the outside, but they’re very different on the inside. Hubs are dumb devices that simply repeat everything they hear. When one computer sends a signal to the hub, the hub sends the identical signal back out to all of the other ports on the hub.

Hubs enable computers on a network to communicate. Each computer plugs into the hub with an Ethernet cable, and information sent from one computer to another passes through the hub. A hub can’t identify the source or intended destination of the information it receives, so it sends the information to all of the computers connected to it, including the one that sent it.

A hub can send or receive information, but it can’t do both at the same time. This makes hubs slower than switches. Hubs are the least complex and the least expensive of these devices.

Switches work the same way as hubs, but they can identify the intended destination of the information that they receive, so they send that information to only the computers that are supposed to receive it. Switches can send and receive information at the same time, so they can send information faster than hubs can.

If your home network has four or more computers or you want to use your network for activities that require passing a lot of information between computers (such as playing network games or sharing music), you should probably use a switch instead of a hub. Switches cost a little more than hubs.

Switches are much more intelligent devices that analyze each packet coming in. The switch determines where the traffic needs to go and transmits it only on the port connected to the destination computer. This is a much more efficient use of the network’s bandwidth, and it also prevents unauthorized users from intercepting traffic on the network. Until recently, switches were much more expensive than hubs, but recent advances in switch technology have made hubs all but obsolete.

Routers enable computers to communicate and they can pass information between two networks—such as between your home network and the Internet. This capability to direct network traffic is what gives the router its name. Routers can be wired (using Ethernet cables) or wireless.

If you just want to connect your computers, hubs and switches work well; however, if you want to give all of your computers access to the Internet using one modem, use a router or a modem with a built-in router. Routers also typically provide built-in security, such as a firewall. Routers are more expensive than hubs and switches.

If you’re building a new LAN from scratch, an all-in-one unit that combines a router, Ethernet switch, and wireless access point is your best value. It is also the most compact and simplest to install, since all of the cables will connect to a single, centrally located unit.

http://helpdeskgeek.com/networking/router-vs-switch-vs-hub/

* Navigate to /private/var/mobile/Library/AddressBook
* There will be two files save them on your computer.

How to backup Calendar:

* Navigate to /private/var/mobile/Library/Calendar
* Copy Calendar.sqlitedb to your computer

How to backup Notes:

* Navigate to /private/var/mobile/Library/Notes
* Copy notes.db and notes.idx to your computer

http://www.kaskus.us/showpost.php?p=131341301&postcount=4128

Stop 0×000000ED (UNMOUNTABLE_BOOT_VOLUME)
Stop 0×0000007B (INACCESSIBLE_BOOT_DEVICE)

These two errors have similar causes and the same troubleshooting steps apply to both of them. These stop codes always occur during the startup process. When you encounter one of these stop codes, the following has happened:

1. The system has completed the Power-On Self-Test (POST).
2. The system has loaded NTLDR and transferred control of the startup process to NTOSKRNL (the kernel).
3. NTOSKRNL is confused. Either it cannot find the rest of itself, or it cannot read the file system at the location it believes it is stored.

When troubleshooting this error, your task is to find out why the Windows kernel is confused and fix the cause of the confusion.

Things to check:

• The SATA controller configuration in the system BIOS If the SATA controller gets toggled from ATA to AHCI mode (or vice versa), then Windows will not be able to talk to the SATA controller because the different modes require different drivers. Try toggling the SATA controller mode in the BIOS.
• RAID settings You may receive this error if you’ve been experimenting with the RAID controller settings. Try changing the RAID settings back to Autodetect (usually accurate).
• Improperly or poorly seated cabling Try reseating the data cables that connect the drive and its controller at both ends.
  Hard drive failure Run the built-in diagnostics on the hard drive. Remember: Code 7 signifies correctable data corruption, not disk failure.
• File system corruption Launch the recovery console from the Windows installation disc and run chkdsk /f /r.
• Improperly configured BOOT.INI (Windows XP). If you have inadvertently erased or tinkered with the boot.ini file, you may receive stop code 0×7B during the startup process. Launch the recovery console from the Windows installation disc and run BOOTCFG /REBUIL

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Teguh Aditya – http://card.ly/tguh

This totally spookes you out. Look at it with a couple of friends around. You’ll be surprised to hear conflicting replies about the direction!

THE Right Brain vs Left Brain test … do you see the dancer turning clockwise or anti-clockwise?  

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Teguh Aditya – http://card.ly/tguh

I’ve managed to kill it today thanks to an article in the VMWare communities forums.

The key thing I gleaned from this post was the existence of the following command to get the VMID:

vm-support -x

Before running that however I ran vm-support -h and one of the options is:

-X <wid> grab debug info for a hung VM

So having run vm-support -x to get the VMID I ran the vm-support -X command.  It asks a couple of questions:

Can I include a screenshot of the VM xxxx? [y/n]:
Can I send an NMI (non-maskable interrupt) to the VM xxxx? This might crash the VM, but could aid in debugging [y/n]:
Can I send an ABORT to the VM xxx? This will crash the VM, but could aid in debugging [y/n]:

The key thing here for me was question 3, because after about 5 minutes I got a notification from VirtualCentre that the VM had been switched off.

Source : http://sisutcliffe.posterous.com/vmware-esx-and-a-vm-stuck-in-an-inconsistent

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Teguh Aditya – http://card.ly/tguh