A new category of handheld devices has recently emerged that are even smaller than current portable models, with their main advantages being increased portability and affordability relative to their counterparts.
Current portable technology is held back by batteries that are heavy and bulky, but store relatively little power.
Current portable DVD players offer bright, clear video display, Dolby Digital sound and batteries powerful enough for a double feature.
By contrast, my current portable Mac has more than 500 times the memory -- and I was able to double its storage the other week for $39.
Current portable TVs can only pick up terrestrial transmissions, which means there is relatively little sport, much of which has moved on to satellite and cable channels; they also have large aerials and do not work well on the move.
"It doesn't matter because it goes on all the time anyhow," Mr. Perez said. Louis Smith, 48, who said he had been homeless all his adult life, called the current portable toilets repugnant but said he has seen the pay toilets in San Francisco and found them a big improvement.
