Architecture of the Playstation 2

Edit: why am I talking about the PS3 cell? This article is about the PS2. :facepalm: please ignore, too late to delete?

Unmentioned is perhaps the coolest fact, about how it all went down:

The leading lady of chip design Lisa Su (presently President & CEO of AMD) parlayed her existing chip-design experience first doing Silicon-on-Insulator research at MIT, then spending some years fixing some copper interconnect emerging-problems at Texas Instruments, before first working for IBM, where she launched an Emerging Products Division at IBM (2001)[1], & focusing on low power chip design among other things.

She became IBM's chief point of contact with Sony in their collaboration to develop what became the PS3 (2006) Cell chip. And is largely credited with the design.

Afterwards She became VP of Semiconductor R&D at IBM before leaving for a CTO position at Freescale in 2007 (bought by NXP in 2015, in turn almost bought by Qualcomm, but China did not sign off fast enough). She joined AMD as SVP & GM of AMD in 2012, & became CEO in 2014.

Thank you Lisa. You continue to light the way. On a personal note, it is so nice to see some absolutely badass engineers given a role in companies, allowed to lead the way. It feels like this world rarely knows what it's doing, but you have the deep background, the in-the-trenches engineering chops, & the wide swarth of experience that makes you a true & genuine veteran of this field, & your work & developments have been ongoingly leading for the industry, each time. Thank you again Lisa.

[1] https://en.wikipedia.org/wiki/Lisa_Su#2000%E2%80%932007:_IBM...

Cell was a disappointment in the PS3 though. It was such an underperformer that the SPEs couldn’t be used for their intended role as a GPU and got shanghied into being used like SMT cores, while a whole separate GPU chip had to be added into the design at the last minute to compensate. The Cell’s weak CPU performance, strange programming model, and weak developer tooling was a problem for pretty much the whole generation.

The much more traditional XB360 tri-core plus GPU design was widely considered the better design and Sony reverted to a similarly traditional design the next generation as well.

It was a highly heterogeneous design, and yes the world has adapted to those much better now than they did in 2007 (and maybe it would have been more successful with better tooling), but there are also prior heterogeneous designs like Saturn that were also widely considered a mess apart from rare cases where developers were skilled enough to effectively utilize them. The tasks where it succeeded (like the oft-referenced air force supercomputer) tended to be embarrassingly parallel workloads (matrix math, password cracking, etc) that didn't have a high degree of dependencies in their processing workflow. That is pretty much the lowest-hanging fruit for a heterogeneous throughput-oriented system, if it couldn't do even that it would be fully useless, but merely doing that doesn't make it good.

I guess maybe think of it like a GPGPU - but a GPGPU would have been a terrible choice to use as your control CPU for a console even if it did allow higher degrees of processing in some narrow use-cases. Just not how that type of programming is usually done. Maybe at best you can say it was mis-understood and mis-applied by Sony but it really just wasn't as great a chip for most things as people thought at the time. Wasn't a great GPU, wasn't a great CPU, wasn't good enough to be the first "APU" to bridge to having both one one chip as originally intended.

It clearly was designed for HPC/supercomputing situations where someone understood the architecture. Probably still was held back by the tooling and documentation anyway. I know it was in some supercomputers, but there probably is a reason that 10 years later nobody is designing follow-on processors or inspired by that particular architecture.

People at the time jerked off heavily about it, both in HPC and the PS3, and I get that it powered a lot of people's fond childhood memories, but I think in hindsight it pretty much was a failed design and an architectural dead end. You can say that maybe APUs took some inspiration from it but the cost-savings of an integrated CPU+GPU are pretty much an obvious goal, and later processors used a much more standard CPU and GPU that happen to live on the same chip and have some coherent memory access protocols. They share nothing in common with the Cell's SPE/ring concept. Nobody ever used that in a design ever again, for a reason.

I have a... heavily modified Browser 2 install on an insanely large (for a PS2) 1TB HDD. Between that and some other tools you can install and run full games onto the console. I even figured out how to make custom Browser icons for them, although in practice selecting one game out of even a decently-sized PS2 collection is ungodly slow. It's still cool as a retro hobby project, if you're willing to jump through the hoops to get a working setup.

AFAIK the official purpose of Browser 2 was to support PSBBN and distributing software through it. They never launched that service outside of Japan. Hell, most of the games that supported the HDD got that functionality stripped out of it in the US. PS2 games could install themselves to the hard drive for faster load times, much like the later install features on Xbox 360 and PS3. However, as far as I am aware this was exclusively for online service games in the US and Europe. On the original Xbox, Microsoft was already trying DLC and digital distribution (no, seriously, it had it, but you needed a special Arcade disc to run games). So I have to wonder how Sony wound up sleeping on something they were already doing for a whole generation.

There also exists the "Fortuna" exploit (and also recently reimplemented and documented as open source "OpenTuna"), which uses a buffer overflow in the memory card icon reading code, providing a disc-less exploit for the later models of PS2 (including the "PS2 TV", aka the Sony Bravia KDL-22PX300 television set including a built-in PS2 console)

With FreeMCBoot and Fortuna, all PS2 consoles can be exploited from boot time. With FreeDVDBoot, it provides a convenient entrypoint to install the aforementioned exploits.

There is a work-in-progress port of the newer Linux 5.x kernel to the PS2: https://github.com/frno7/linux