It is unprecedented the level of popularity this system achieved during the noughties, at the end of its lifespan (2013, after 13 years!) the game library was filled with 1850 titles .
Mr Moskeeto (2001). Whenever someone argues about the abundance of PS2 games, I remember this one.
What happened here is really impressive. The PS2 doesn't have a 'programmer-friendly' architecture, (as seen from the perspective of a PC programmer) yet with such an amount of games developed, I too wonder if there were more factors involved (such as 'licensing reliefs', low distribution costs, cost of development, small form factor and what not).
Development ecosystem
Sony provided the hardware and software to assist game development.
On the software side, there was the PlayStation 2 SDK which included :
- The Emotion Engine toolchain: A set of C and C++ compilers, assemblers, linkers and debuggers used to control each element of the EE. The main CPU was mainly programmed using C/C++, however, performance-critical components like the vector units were programmed using assembly (microcode/macrocode) instead.
- The pack also included an 'Emotion Engine simulator' which could roughly test out the code without sending it to the real hardware, although the simulator wasn't as accurate as the physical EE chip.
- All of these tools worked on Linux, Solaris and Windows. The latter variant ran under the Cygnus environment.
- Low-level libraries: Interfaced many system functions (using BIOS calls).
- 'Analysis' tools to profile performance usage.
- Additional tools to connect with the official development hardware.
On the hardware side, Sony provided studios with dedicated hardware to run and debug games in-house. The initial devkits were bare boards stacked together to replicate the unreleased hardware of the PS2. Later kits (named Development Tool), had a more presentable appearance, enhanced I/O and combined workstation hardware (running RedHat 5.2) with PS2 hardware to build and deploy the game in the same case .
The combination of the Devkit, the official SDK and CodeWarrior (a famous IDE) was one of the most popular setups.
Medium
The disc drive can read both DVDs and CDs, so games could be distributed using either format, but for obvious reasons, you will find most titles in DVD format.
Kingdom Hearts II (2005). Typical retail game box and disc.
DVDs can hold up 4.7 GB of data in the case of DVD-5 (the most common 'sub-format') or 8.5 GB in the case of DVD-9 (dual-layer version, less common) . There's actually a third format, DVD-10, which is double-sided but no commercial games ever made use of it.
Due to the type of medium used, not only games could be played, but also movies. Now, this requires a decoder to be able to read the DVD movie format, and for that, the PS2 initially included the required bits installed in the memory card (after all, the card is just a storage medium) but later models came with the DVD software pre-installed in the BIOS ROM.
In terms of speed, CD-ROMs are read at 24x speed (so 3.6 MB/s) and DVD-ROMs are read at 4x speed (5.28 MB/s) .
Network service
As you have seen, the networking features of these consoles weren't standardised until later revisions, which arrived four years later after the first release. Similarly, game studios were in charge of providing the necessary infrastructure if they decided to provide online services (like multiplayer). In later years, Sony deployed the Dynamic Network Authentication System or 'DNAS', it wasn't an online server, but an authentication system to prevent pirated games from connecting online.
An unusual kind of game
Apart from all these games with their fancy graphics, Sony released a Linux distribution based on 'Kondara' (which is in turn based on Red Hat 6) available in two DVDs (the first disc is called 'Runtime Environment' and the second one is called 'Software Packages') along with a VGA adapter, USB Keyboard and Mouse; plus some developer manuals. The pack was known as Linux Kit and you could run the OS by booting the first DVD and then proceed like any old-school Linux environment. You obviously needed a Hard drive fitted in the console to install the Linux distro. Once installed, the first DVD was always required to boot this OS.
Linux Kit included compilers targeting the EE (gcc 2.95.2 with glibc 2.2.2) and assemblers targeting the vector units, along with a window system (XFree86 3.3.6) 'accelerated' in the Graphics Synthesizer . Overall, this sounds like an interesting environment. In fact, one of the research papers I read to write this article was carried out using this setup.