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Josh-D. S. Davis

Xaminmo / Omnimax / Max Omni / Mad Scientist / Midnight Shadow / Radiation Master

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XBox-360
Josh 201604 KWP
joshdavis
MOTHERBOARD

PROCESSOR(s)
"Xenon" codename, tri-core PPC64 at 3.2GHz,
FSB at 5.4ghz (21.6GB/s),
VMX128 extensions (somewhat compatible with G4 and G5 VMX),
Lockable L2 cache so streaming data won't thrash cache,
PHYsical interface (to GPU) of 1.35GHz x 8B (10.8GB/sec),
Support for PROCEDURAL geometry (one core calculates all of the triangles for something like a sphere, which can be described by a function, thereby saving tons of memory bandwidth)
This is similar to the Cell Processor they're making for the PS3; however, the cell proc is 1 real core and 8 support processors - more than DSPs, probably fully PPC compatible, but more focussed on FP and VMX than general instructions.


GPU
Codenamed Xenos,
500MHz, 332M transistor ATI part related to the R420,
Unified pixel and vertex shaders,
3 parallel groups of 16 shaders,
Direct access to L2 cache,
32GB/s bandwidth to eDRAM daughter die,
22GB/s bandwidth to system memory,
10GB/s bandwidth to CPU.


GPU EMBEDDED DRAM
10MB eDRAM die in same package with the GPU
On-die z, stencil, color, alpha and anti-aliassing coprocessor.
32GB/s bandwidth to the GPU
256GB/s bandwidth to zprocessor


RAM
512M of 128-bit, 700MHz, GDDR3 (22GB/s bandwidth).


STORAGE
12x CAV DVD-DL SATA, standard PC style, internal drive

2.5" 20GB 5400rpm Samsung SATA drive,
13G of the drive is usable on a FATX partition.
Comes in a custom case that snaps on the side.
Replacement isn't possible yet.
There is a magic key, and a safety sticker.

Blu-Ray/HD-DVD will be external, probably USB,
and will be of whichever type wins the war.

There are 2 memory unit ports, which are also USB internally.
They are 64MB Phillips chips.


CONTROLLERS
Front IR port for remote control.
2 front USB ports for wired controllers.
USB 2.4GHz spread spectrum - supports 4 controllers.
Headsets and mini-keyboards plug into the controllers.


NETWORK
RJ11, 100Mbit SMC with BCM5241 PHY chip
USB, rear 802.11abg (on the non-core model).


FIRMWARE
It runs Secure Hypervisor, which means that it's feasible that LPARs could be put on it.
I'm assuming the sHYP is on chip-ROM, but there are ports to hook up additional ROM.
p5 ucode could be pulled and hacked, if someone were l337.

There is an Open Source Hypervisor
which probably is similar in design which might be helpful.
It would be no small task, but just a thought.

It's also feasible that the Xen mods might tie into this, allowing Xen (a linux core) to run as the VMM.

If it's not there, it's feasible that this could run openfirmware.


DEBUGGING
There appears to be an on-chip service processor with JTAG connectors.
Debug bus connects to cpu at 1/4 speed and can pull real-time traces.
Support for external, serial EEPROM for firmware bypass and augment.
Some boxes have an Atmel part near the CPU.


OPERATING SYSTEM
Derived from Xbox OS, which was derived from Windows 2000.
Graphics API will be upscaled DX9.0c, with mods to handle the unique GPU.


LINUX
It's in flux, and the page is presently at Free60 at sunsite, however, the domain name will be moving again (was http://www.free60.org, and may end up as http://free60.dotsrc.org). Anyone able and willing to do FA, including high-res photograpy, of the various chips in an xbox360 can get ahold of the project guy at The Stuff They Need Page.


MORE REFS
XBox360 exposed
Since the 802.11bg and the controllers, and microwave ovens, and home cordless phones, and bluetooth all are in the 2.4-2.45 GHz range, it will be interesting to see whether the wireless controllers crap out, even with channel hopping.
There is a resistor labelled R2D2, which isn't that strange of a name, but I still find it amusing.
Block diagram on wikipedia of various busses for this system.