It looks like the UMD is here to stay. Speaking to PocketGamer about the UMD format, Koller revealed that Sony will never "walk away" from its base.
Koller was keen to highlight the many strengths of the format, notably its size, form factor and portability. The same can be said for the cartridge solution employed by Nintendo for the DS, but Koller also raises one further key advantage.
"Duplication of UMDs is much easier, cheaper than cartridges," he said. "We've really optimized time and cost by going with a disc-based format."
The UMD does, however, have one major drawback, as Castlevania series creator Koji Igarashi points out.
"The slowness of the seeking speed of UMD is a weakness," he states, "To tell the truth, I was a little worried at first because I was told that the loading time was long when I started working on PSP. But thanks to programmers, we were able to achieve considerably fast loading times. We can overcome [loading times] by technique - it is the programmers' chance to show what he can do."
Despite the apparent backing for the UMD format, Sony is expected to announce a slimmer PSP in the near future, a device which is rumoured to feature solid state storage which would dramatically improve load times.