Icrontic has posted part two of their article on the Xbox hardware. This time, they take a look at ways to increase performance or just make a cool hack. If you missed part one, read that first.
They were foiled in their attempts to upgrade the hard drive; apparently MS used an obscure password scheme in the ATA-3 spec that prevents red or write access. In the spec, the password is transmitted in the clear, and might be intercepted, but they suspect MS may have encrypted it. They also think the file system is just plain old NTFS.
Despite earlier problems, they were able to replace the ATA/33 cable in the Xbox with an ATA/100 cable; the cable they had tried earlier was defective. The result was as 12% increase in CD ripping performance. (The Xbox can convert CD tracks to WMA files to be played as a custom soundtrack in some games.)
They also cleared up some arguments about the Xbox CPU, where some claim it is a Celeron while others insist it's a Pentium 3:
I would also like to clarify something about the CPU in the Xbox. It is a mobile Celeron. It does have a Coppermine core. It runs at 133MHz front side bus and has 128KB of L2 cache. There was some controversy surrounding this, because of the Coppermine core part. All of the Celeron's that Intel makes nowadays are identical to the Pentium 3, and they all use the Coppermine core (yes that also means they all have Advanced Transfer Cache). There is one major difference, the Celeron has 128KB of cache. Intel's 733MHz mobile Celeron chips (available retail as well) all have a 133MHz front side bus and 128KB of L2 cache -- identical to that in the Xbox. The specsheet for the Celeron is here.
And last, but not least... they plugged a modified USB mouse and keyboard into the Xbox and tried to play Halo. Although the device lights lit up and appeared to function, the game didn't recognize them. Likewise, modified Xbox gamepads show up as unrecognized USB devices when connected to a Windows PC.
On the networking side, they tried out XboxGateway, and talked a bit with one of the developers about how Xbox LAN play works:
It turns out every Xbox has an IP of 0.0.0.1. The machine will start using UDP until it finds the MAC address of another unit. After it finds the MAC address, it starts transmitting data in raw ethernet. This can not be routed. To overcome this situation, several clever people on the TeamXbox forums came up with a workable solution. They used a program called VTUN for Linux, which creates a VPN over the internet. This allowed them to link up Xboxes over the internet and play.
The last page focuses on the DVD drive.