Michael Dell talked everything from big data and cloud computing to touchscreen PCs at the Dell World conference yesterday, with the Texan reserving special mention for bring-your-own-device (BYOD) and Windows 8.Talking at the conference, the Dell CEO first dismissed any suggestions of the ‘post-PC’ world, instead insisting that businesses are still using these devices for the bulk of their work.“There are about a quarter billion PCs sold every year and the installed base of PCs is about a billion and a half. Overwhelmingly, PCs are how business gets done in the world today.”"And now with Windows 8, we’re on the cusp of the next revolution of