The PlayStation 2 (abbreviated "PS2") is Sony's second video game console, the successor to the successful PlayStation and the predecessor to the PlayStation 3 as part of the PlayStation series. Its development was announced in March 1999 and it was released a year later in Japan.

The PS2 is part of the sixth generation era, and is the best-selling console to date, having reached over 127 million units in sales by the end of 2007. On November 29, 2005, the PS2 became the fastest game console to reach 100 million units shipped, accomplishing the feat within 5 years and 9 months from its launch. This achievement occurred faster than its predecessor, the PlayStation, which took 9 years and 6 months to reach the same benchmark.

Only a few million people had obtained consoles by the end of 2000 due to manufacturing delays. After its release, it was difficult to find PS2 units on retailer shelves. Another option was purchasing the console online through auction websites such as eBay, where people paid over one thousand dollars for a PS2. The PS2 initially sold well partly on the basis of the strength of the PlayStation brand and the console's backward compatibility, selling over 980,000 units by March 5, 2000, one day after launch, in Japan. This allowed the PS2 to tap the large install base established by the PlayStation - another major selling point over the competition. Later, Sony gained momentum with new development kits for game developers and more PS2 units for consumers.

A notable piece of advertising for the PS2 launch was accompanied by the popular "PS9" television commercial. 9 was to be the epitome of development, toward which the PS2 was the next step. The ad also presaged the development of a portable PlayStation (first released in Japan on December 12, 2004).

Many analysts predicted a close three-way matchup between the PS2 and competitors Microsoft's Xbox and the Nintendo GameCube (GameCube being the cheapest of the three consoles and had an open market of games); however, the release of several blockbuster games during the 2001 holiday season maintained sales momentum and held off the PS2's rivals.

Although Sony, unlike Sega with its Dreamcast, placed little emphasis on online gaming duri

In addition to PS2 software, the PS2 can read both CDs and DVDs and is backward compatible with PlayStation games. The ability to play DVD movies was an added incentive for consumers to be able to justify purchasing the PS2 (the MSRP was US$300 in October 2000). The PS2 also supports PlayStation memory cards (for PlayStation game saves only) and controllers, although the memory cards only work with PS1 games and the controllers may not support all functions (such as analog buttons) for PS2 games.

The PlayStation 2's DualShock 2 controller is cosmetically similar to the original DualShock.The PS2's DualShock 2 controller is essentially an upgraded PlayStation DualShock; analog face, shoulder and D-pad buttons replaced the digital buttons of the original. Like its predecessor, the DualShock 2 controller has force feedback, which is commonly called the "vibration" function. The standard PlayStation 2 memory card has an 8MB capacity and uses Sony's MagicGate encryption. This requirement prevented the production of memory cards by third parties who did not purchase a license for the MagicGate encryption. The memory card can store PlayStation game saves, but PlayStation games cannot read from or write to the card - it can only be used as a backup.

The console also features USB and IEEE 1394 expansion ports. Compatibility with USB and IEEE 1394 devices is dependent on the software supporting the device. For example, the PS2 BIOS will not boot an ISO image from a USB flash drive or operate a USB printer, as the machine's operating system does not include this functionality. By contrast, Gran Turismo 4 is programmed to save screenshots to a USB mass storage device and print images on certain USB printers. A PlayStation 2 HDD can be installed in an expansion bay on the back of the console, with some exceptions (see Hardware revisions below).

With the purchase of a separate unit called the Network Adapter (which is built into the slimline model), some PS2 games support online multiplayer. Instead of having a unified, subscription-based online service like Xbox Live, online multiplayer on the PS2 is split between publishers and run on third-party servers. Most recent PS2 online games have been developed to exclusively support broadband Internet access. Xbox Live similarly requires a broadband Internet connection.

All online PS2 games released in and after 2003 are protected by the Dynamic Network Authentication System (DNAS). The purpose of this system is to prevent piracy and online cheating. DNAS will prevent games from being played online if they are determined to be pirated copies or if they have been modified. Recently, however, methods have been developed to get around this protection by modifying key files in the pirated game.

Also, some unofficial hacks have been made on the PS2 software allowing it to be used as a fully-functional web browser or messenger when connecting to a certain network. The PS2 can also run Linux.

Three of the original PS2 launch models (SCPH-10000, SCPH-15000, and SCPH-18000) were only sold in Japan, and lacked the expansion bay (Dev9) of current PS2 models. These models included a PCMCIA slot instead of the Dev9 port of newer models. A PCMCIA-to-Dev9 adapter was later made available for these models[citation needed]. SCPH-10000 and SCPH-15000 did not have a built-in DVD movie playback and instead relied on encrypted playback software that was copied to a memory card from an included CD-ROM (normally, the PS2 will only execute encrypted software from its memory card, but see PS2 Independence Exploit). V3 had a substantially different internal structure from the subsequent revisions, featuring several interconnected printed circuit boards. As of V4 everything was unified into one board, except the power supply. V5 introduced minor internal changes, and the only difference between V6 (sometimes called V5.1) and V5 is the orientation of the Power/Reset switch board connector, which was reversed to prevent the use of no-solder modchips. V7 and V8 included only minor revisions to V6.

Assembly of the PS2 moved to the People's Republic of China during the development of V9 (model numbers SCPH-50000 and SCPH-50001). The upgraded console added an infrared port for the optional DVD remote control, removed the IEEE 1394 port, added the capability to read DVD-RW and DVD+RW discs, added progressive-scan output of DVD movies, and added a quieter fan. V10 and V11 were only minor revisions to V9.

The PS2 standard color is matte black. Several different variations in color have been produced in different quantities and regions, including ceramic white, light yellow, metallic blue (aqua), metallic silver, navy (star blue), opaque blue (astral blue), opaque black (midnight black), pearl white, Sakura purple, satin gold, satin silver, snow white, super red, and transparent blue (ocean blue).

In September 2004, Sony unveiled its third major hardware revision (V12, model number SCPH-70000). Available in November 2004, it is smaller, thinner, and quieter than the older versions and includes a built-in Ethernet port (in some markets it also has an integrated modem). Due to its thinner profile, it does not contain the 3.5" expansion bay and therefore does not support the internal hard disk drive. It also lacks an internal power supply, similar to the GameCube, and has a modified Multitap expansion. The removal of the expansion bay has been criticized as a limitation due to the existence of titles such as Final Fantasy XI, which require the use of the HDD. The official PS2 Linux also requires an expansion bay to function. Currently only the modified MultiTap is sold in stores, meaning that owners of older PS2s must find a used or non-Sony MultiTap in order to have 4 or 8 players during a single game. Third-party connectors can be soldered into the unit giving hard drive support, however IDE connections were completely removed in the V14 revision, thereby eliminating this option.

Comparison of the Slimline PlayStation 2 design with the PlayStation 2, with an Eye Toy on top.There are some disputes on the numbering for this PS2 version,[citation needed] since there are actually two sub-versions of the SCPH-70000. One of them includes the old EE and GS chips, and the other contains the newer unified EE+GS chip, but otherwise they are identical. Since the V12 version had already been established for this model, there were some disputes regarding these sub-versions. Two propositions were to name the old model (with separate EE and GS chips) V11.5 and the newer model V12, and to name the old model V12 and the newer model V13. Currently, most people use V12 for both models, or V12 for the old model and V13 for the newer one. The slimline version was discontinued on July 1, 2008.

The V12 model was first released in black, but a silver edition is available in the United Kingdom, Germany, Australia, United Arab Emirates and other GCC Countries, France, Italy, South Africa, and most recently, North America. It is unknown whether or not this will follow the color schemes of the older model, although a limited edition Pink PS2 has become available since March 2007.

V12 (or V13) was succeeded by V14 (SCPH-75001 and SCPH-75002), which contains integrated EE and GS chips, and different ASICs compared to previous revisions, with some chips having a copyright date of 2005, compared to 2000 or 2001 for earlier models. It also has a different lens and some compatibility issues with a different number of PlayStation games and even some PS2 games.

In the beginning of 2005 it was found that some black slimline console power transformers bought between November and December 2004 were faulty and could overheat. The units were recalled by Sony, with the company supplying a replacement model made in 2005.

Later hardware revisions had better compatibility with PlayStation games (Metal Gear Solid: VR Missions operates on most silver models); however, the new Japanese slim models have more issues with playing PlayStation games than the first PS2 revisions.[citation needed]

The mainboard of the new silver slim PS2(model SCPH-79000).In 2006, Sony released the latest hardware revisions (V15, model numbers SCPH-77001a and SCPH-77001b). It was first released in Japan on September 15, 2006, including the Silver limited edition. After its release in Japan, it was then released in North America, Europe, and other parts of the world. The new revision uses an integrated, unified EE+GS chip, a redesigned ASIC, a different laser lens, an updated BIOS, and updated drivers.

In July 2007, Sony started shipping a revision of the slimline PlayStation 2 (SCPH-79000) featuring a reduced weight of 600 grams compared to 900 grams of the SCPH-77001, achieved through a reduction in parts. The unit also uses a smaller motherboard as well as a custom ASIC which houses the Emotion Engine, Graphics Synthesizer, and the RDRAM. The AC adaptor's weight was also reduced to 250 grams from the 350 grams in the previous revision.

Another refinement of the slimline PlayStation 2 (SCPH-90000) was released in Japan on November 22, 2007, with an overhauled internal design that incorporates the power supply into the console itself, with a further reduced total weight of 720 grams.