The second entry in the Sony RISC console trilogy.

Console BIOS

Like the original PlayStation the console boots into a BIOS menu system if the console is powered on without a disc, however all regions use the same menu screen layout and format. Now the bios can be upgraded and loaded from the memory card (or at least the frontend application, or the dashboard)

All regions use the same BIOS design but there are variations across the different models due to the revised features.

Video Output

This was the first Sony console to support progressive resolutions officially, with the previous consoles using an interlaced resolution due to standard definition TV being used. With interlacing, the image is split into two fields which alternate at either 50 or 60hz, due to bandwidth limitations. With the advent of RGB and component video, progressive and high resolutions are now possible.

Games that support this will prompt the user to select the video mode on start-up, either from interlaced to progressive mode (480i vs 480p), PAL gamers may also get three options with the third being the ability to run the games in regular PAL 50Hz mode. Not all games provided this but was a welcome addition as PAL gamers could get the opportunity to experience the game in its NTSC 60Hz glory, provided their TV supported NTSC video (Many PAL sets of the time did) Unfortunately many PAL PS2 games did not do this, and were also the kind of games to have botched PAL conversions where the games ran at a slower speed and had banners top/bottom of the screen.

Widescreen (16:9 aspect ratio) was also a lot more commonplace and was an option that could be set in the PS2 BIOS, which the game could detect and display.

High Definition output was also possible, but only three games supported it and required component cables to be used.

Memory Cards

The standard memory cards offered are 8MB in size, whilst larger memory cards were offered they were typically made by third parties. Some games will not recognize larger memory cards, others may save very slowly when saving data to a larger memory card. The largest memory card available is 128MB but with some games refusing to detect a memory card, the largest recommended is 64MB.

Like the first PlayStation many games support only slot 1, with a few games supporting slot 2. FreeMCBoot is capable of booting from slot 2 and is the preferred slot to load from, as this gives more space for games stored on memory card slot 1.

PSone games cannot save to the PS2 memory cards directly, instead, a PSone memory card must be used. In spite of this PSone save files can be saved to the PS2 format cards as a form of backup, but PSone games cannot directly load saves from a PS2 memory card, it must be copied back to an original memory card.

Network Adaptor

This plugs into the expansion bay of the Playstation 2 and is used to provide network and internet connectivity to the PlayStation 2, along with hard drive support for certain games. Only the network function was supported in the US and Japan, Europe did not get official support for the HDD (nice one Sony, as if the PAL format games weren’t bad enough). Early units had an ethernet socket along with a modem telephone connector, whilst later units featured only ethernet.

Selected games supported network play, either local or over the internet. There was no central service like Xbox Live, each game had to have its own central server and infrastructure to implement its online functionality. Typically GameSpy was used to provide the matchmaking, with Sony only providing the DNAS security system to check for authentic and non-modified consoles from being used with the service.

The network adaptor would be built into the slim revisions (SCPH70000 onwards) with the console having a built-in ethernet port.

Game Star Network Adaptor: Thrid party ‘network adaptors’ exist but feature only SATA connectors and have no ethernet support. Mine even had a yellow sticker over the gap where the ethernet socket would have been. In terms of compatibility, they work fine and are recognized in OpenPS2Loader. One side effect is the HDD access light no longer flashes.

Hard Drive

Games that used the hard drive used it in a similar fashion to the original Xbox, where supported games could cache data to the drive and have it load in tandem with the DVD drive, like some sort of RAID. This helped to reduce loading times and reduced stress on the laser. The hard drive cannot be used as a substitute for the memory card.

When the hard disk is spun up and accessed, the power button functions differently due to the hard disk requiring to the spun down when powered off. Pressing the power button will shut the console off, instead of rebooting the console. There is also a HDD access light internal to the console, but can be seen through the front vent. Some users think the console is sparking internally due to the rapidly flashing manor of the LED and the fact it’s not documented or labeled.

Hard disk support was removed with the slim revisions with no provision for support. This means games like Final Fantasy 12 are not compatible with this model on consoles onwards (SCPH 70000)

The hard drive really came into its own with the use of homebrew software, with backup launchers like HDLoader and OPENPS2Loader being released which allow for games to be ripped and run from the hard drive. This has the benefit of faster load times, adding convenience for the player since they don’t have to keep swapping disks and reduced wear on the DVD drive laser, which had a tendency to fail. A side effect was its use of piracy, where games could be downloaded and installed to the PS2 using a PC or over the network cable. Not all games are compatible and some require additional modes or fixes to be enabled.

SATA drives: The original network adaptor featured an IDE connector that was intended for use with an IDE hard drive which was common of the time, with the advent of SATA drives becoming the new standard, getting them to function on a PS2 required either one of the following:

• An IDE to SATA adaptor, this plugged in between the network adaptor IDE ports and the SATA drive interface, this method would only work on laptop-style hard disks and not the larger desktop style hard drives due to the size limitations imposed by the PS2 bay enclosure. It was designed to fit only a 3.5inch hard disk and adding an adaptor would prevent the drive from fitting.
• Converting the network adaptor to SATA, the IDE interface on the network adaptor is interchangeable which meant you could swap it for a SATA interface instead. This involved opening up the network adaptor and replacing the IDE interface for the SATA one instead.
• Using an off-brand SATA adaptor, these are made by a third party but they feature a SATA connector but without any network support. The one I have does not even have an ethernet socket leaving you without any network support

For slim PS2 owners all is not lost as you can use OPL (OpenPS2Loader) to read and load games off an external USB 2 drive, or load games via its built-in ethernet port. This is a lot slower due to the PS2 using a USB1.1 bus which has less bandwidth than the DVD drive and will cause some games to freeze momentarily whilst they wait for the game to load, sometimes even crashing as the game was not designed to be run in this way. An alternative method is to use the network interface and use a basic NAS adaptor. I would advise using some sort of NAS and using the PS2’s ethernet port to load games on the slim models.

Another option was to use the 1394 iLINK port, but since this is only supported on the early larger PS2 models and on those models you would want to use the network adaptor method anyway.

Accessories

Controllers

Dualshock 2: Based on the Dualshock controller for the first PlayStation, new additions are the pressure-sensitive face buttons feature, where the harder you press the face buttons affects how the game reacts. Metal Gear Solid uses this to change how the player handles the gun. In 2006 Sony quietly removed the vibration feature due to a patent issue, which is why the PS3 was initially released without vibration support.

The original PSone controllers are also supported, even for PS2 games but some of the advanced features like analog face buttons may not function in this mode

Eyetoy

A USB web camera that connects via the USB port and is used for certain games. Sort of similar to the Kinect accessory but has little to no tracking capabilities. Certain games include Eyetoy support as an optional feature (Urbz: Sims in the City) which projects the camera image on one of the billboards, other games are reliant on the accessory as it functions as an input device.

USB Devices

• Keyboard/Mouse: Some games (Unreal Tournament) support the use of a USB keyboard mouse as an alternative to the Dualshock controller. This makes it easier to control and gives more accurate aiming
• Mass Storage: Gran Turismo 4 can save photos to a USB flash drive
• Headset: Used for the Socom games, allows voice chat over online play
• Buzz Remote
• Light guns: Guncon 2 for Time Crisis
• Dance Mats
• Some steering wheel controllers plugged into this port, whilst some used the regular controller port.

Connections

AV Multi Out: Used to interface with the TV, this is the same interface used on the original PlayStation, and supports the use of composite video, along with S-Video, component and RGB output. VGA is also a supported standard.

Some PlayStation and PS2 games use non-standard resolutions, which will cause issues when connected to a modern display that does not support these resolutions. Unless a scaler unit is connected when the TV will not be able to display these resolutions. Homebrew software can be used to override the resolution (GSMode)

• Composite: commonly used, and the most basic video output offered, not recommended for today due to the poor video quality, and should really be avoided even back when the PS2 was released
• S-Video, a step up from composite video, is recommended if your TV only has an S-Video socket and no RGB or component
• RF: Avoid, only recommended for very old TV’s
• Scart: This was once the recommended method for connecting your PS2 for Europe/PAL TV sets since they could take advantage of the RGB output (not all TVs support RGB, and some that do have problems handling RGB correctly with the picture being washed out/shifted to the left) Unfortunately the SCART interface is now hard to find on modern TVs, and is no longer recommended unless you have a PAL CRT TV. Sony did not bundle a dedicated SCART cable in Europe, instead a composite to SCART adaptor was offered instead, with the dedicated SCART cable being a premium option
• Component: The recommended option for connecting to modern HDTVs, this supports the use of progressive scan and HD resolutions that some games supports, and is more accessible on modern TVs. If you intend on using your PS2 on a modern TV, thi is the recommended option
• VGA: This was intended to be used in conjunction with the Linux kit for the PlayStation 2, not recommended since many games do not support this.

I recommend having a read on retroRGB for further information on getting the best image quality on a PS2.

1394 iLink: Uses the same protocol as the Firewire/1394 interface, this was used to link two or more consoles together using the 1394 bus, and was an early form of networking intended for the console. This did not take off and was removed on the later revisions of consoles, the ethernet port was its intended replacement.

Processors

Emotion Engine: A large chip designed by Toshiba that consists of:

• MIPS R5900 CPU: Acts the main processor for PS2 software and runs at 294MHz, and at 299Mhz on later versions. This change coincided with the switch to a new IO processor
• Vector Processing Units: Specialised co-processors that are on the same die as the CPU. The clock speed of these processors has been disputed, as they were believed to run at 147MHz (same as the GS) but other sources claim 294MHz, same as the MIPS CPU.
  • VU0: Can function as a co-processor to the MIPS CPU or as its own processor, depending on the game. Could be used as a physics processor, offloading physics calculations from the main CPU
  • VU1: The successor to the GTE on the PlayStation, this generates the polygons and lighting effects. Mainly used for the graphic effects, and is capable of additional effects via software.
• IPU: Onboard MPEG2 decoder (Image Processing unit) used for FMV and DVD video
• GIF: Graphics Interface, main interface to the Graphics Synthesizer

Graphics Synthesizer: The main graphics processing unit, and comes with embedded 4MB eDRAM, since this RAM resides on the same die as the GPU itself, this gives it a massive amount of bandwidth which the PS2 games incorporated into their rendering pipeline.

The VRAM setup was one of the defining features of the PS2, whilst 4MB seems like a small pool of memory compared to the Dreamcast that featured 8MB of VRAM, this memory is applicable to onscreen textures only, with the PS2 being able to store textures in the systems main RDRAM and then call it when it needs it like when the player moves the in-game camera view. This did mean the developer had to be careful with how they managed the game VRAM usage and had to incorporate certain tricks to keep the texture size down. To simplify this, the Dreamcast had to store all textures used for the level in VRAM at once, where the PS2 can store this in its main system RAM, but any textures seen on screen had to be stored in the eDRAM. For some games like FPS or racing games, the PS2 would swap these textures as the player or camera moved. Games that uses fixed camera angles do not benefit as such, like fighting games where the camera focuses on two characters all the time. This sort of technique has resurfaced with the advent of the PS5 and Xbox Series, using the main RAM as the frame buffer and storing off-screen textures and models in the console’s fast SSD, which is fast enough to cope with the bandwidth demand.

Having 9.6GB/s of texture buffer bandwidth and 38.4GB/s frame buffer bandwidth (the Xbox only has 6.4GB/s bandwidth for the systems unified RAM) gave the PS2 a high fill rate which was used in certain SP games for certain effects, like the heat haze effect in Gran Turismo.

PS2 vs PS3 vs PS4 fillrate

A variant of the GS, known as the GS-32 featured 32Mb of eDRAM and was used for the GScube, this hardware is very rare and intended for professional CGI rendering.

The Namco System 256 arcade board *may* use a variant of the GS with 8MB of VRAM, I can’t find any proof of this with the exception of forum posts and the footage I’ve seen of System 256 games (Tekken 5) they don’t look any different from the console counterpart. It’ s more likely to be a revision that’s based on the slim hardware design.

SPU2: The sound processor of the PS2, and is an updated version of the original SPU in the PlayStation, only now two of them giving 48 channels of audio in total.

IO Processor: For Input/Output operations, this is responsible for the USB/1394/controller and memory card ports and relieves the main CPU from this task.

On original models (SCPH10000 – 70000) This is the same as the PlayStation CPU (LSI Coreware R3000) and is used for its backward compatibility mode with the rest of it being emulated on the R5900 CPU (GTE). In PS2 mode it takes over the I/O operations for the USB/1394/controller and memory card ports, relieving the main CPU of this task. In PS1 mode, it becomes the main CPU to run the PlayStation software on.

On later revisions (79000 – 90000), Sony changed the processor for a PowerPC-based processor that took over I/O operations, these are known as Deckard consoles. This meant the emulator had to be changed to accommodate the new processor and also meant that any PS2 software that made extensive use of the I/O processor suffered from compatibility issues. Way to go Sony, as a result there are some PS2 games that suffer from compatibility issues on these models, and some PSone games are no longer compatible or suffer from additional issues. Some greatest hits rereleases maybe recompiled to resolve these issues.

This isn’t the first time Sony has done this as the original PlayStation had a minor GPU change which resulted on some differences in titles, little to no games were broken as a result of this change.

Further Information

Conclusion: The PS2 was a very unique system and possibly the last of its kind. Sony’s next home console would use a standard off the shelf class GPU from Nvidia which would be very similar to what was available for the PC

Games