Fooling the processor

Many a times when we use linux this can be done more easily in windows and vice-versa. So is it possible to run two operating systems together one at a time? Yes using Emulators it is possible. These emulators fools the processor and runs 2 operating systems.

Once upon a time when pen drive is something every person having computer has. And due to falling prices now a days its not even expensive to use a pendrive. So thought of using Qemu along with accelerator kemu and twiking with autorun.inf file, what i made was just inserting a pendrive and then your ubuntu starts without booting the pc.

I don't know much advantages of it. There are many. But memory becomes half the size is the biggest disadvantage.

Connecting two Computers

After I upgraded my Desktop computer I was left with 2 lan cards on my Desktop. I always wanted to Connect my laptop with my Desktop. The prime reason to do this was to get internet connection on my laptop without shelling extra bucks on it.

Desktop has dual boot with Ubuntu and XP
Laptop has only XP in it.

eth0 of Desktop goes to Internet Connection and has a static ip with subnet 255.255.255.0 . I got a CAT5 with crossover crimping done. Connected my lappy with Desktop with it. Made Desktop as a Default gateway for Laptop.

So now eth1 on my Desktop had 10.0.0.1/24 as IP Set and eth0 of Laptop had 10.0.0.2/24 as IP.
I thought this can be done only by setting up proxy server SQUID (or anything else) on Ubuntu. But one of my senior helped me out with two small commands to forward internet connection on the private network.

$ echo 1 > /proc/sys/net/ipv4/ip_forward
$ iptables -t nat -A POSTROUTING -j MASQUERADE

But now the problem starts. I tried reversing the ends of the CAT5 wire. Tested it in my college labs but there was no problem in the wire. But both the computers were not able to ping each other. If I diagnosed after going to XP it did show me that all the NIC are working properly they could ping to themselves and
as far as connection is concern it even showed me that the LAN connection is up and running fine which means there was no "Network Cable Unplugged message".

But ping 10.0.0.1 would give me "Request Time Out"
This meant that the packets are going but there is no acknowledgement from the opposite machine. I tried it with all possible ways

• Switched the connections of wire.
• Tried with different OS.
• Upgraded the drivers of NIC. (which was hopeless decision)
• Tried with various ips like 192.168.0.1/24
• Then tried changing the subnetmask.
• Few said it might be because of compatibility problem with all NIC since all were from different companies.
  

After all these things I tried with changing connection Value of the LAN CARD. From auto-negotiation I made it to 10T Base Full Duplex. Thats it.
"Request Time Out" budge to "Reply from 10.0.0.1............................" message. And then my joy had no happiness.

I rebooted my Desktop to Ubuntu again. Tried with the ip_forwarding commands. Set my options on laptop. Changed the DNS to the same as DNS of laptop and yes. My browser showed some signs of connection and it displayed a website.

Hence there was successful connection between laptop and Desktop.