V5 introduces 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.
It was not until late 2001 that the Microsoft Xbox became the second console with (non-standard) USB and DVD support.
Later hardware revisions had better compatibility with PlayStation games (Metal Gear Solid: VR Missons works on most silver models).
After an apparent manufacturing issue caused some initial slowdown in producing the new unit, Sony reportedly underestimated demand, caused in part by shortages between the time the old units were cleared out and the new units were ready.
The PS2 also supports PS1 memory cards (for PS1 game saves only) and controllers (the PS2's Dual Shock 2 controller is essentially a slightly upgraded PS1 Dual Shock).
One of them includes the old EE and GS chips, and the other contains the newer unified EE+GS chip, otherwise being identical.
The machine's future continues to be uncertain, with North American and European launches considered to be distant if at all.
Although Sony placed little emphasis on online gaming during its first year, all that changed because of the launch of the online-capable Xbox.
Developers also complained that it was difficult to develop for the system, with little in the way of reference material from Sony for its exotic architecture.
In September 2004 Sony unveiled the third major hardware revision (V12, model number SCPH-70000).
When it was released, the PS2 had many advanced features that were not present in other contemporary video game consoles, including its DVD capabilities and USB and IEEE 1394 expansion ports.
