Toshiba today announced 80 and 120 GB 1.8" hard disk drives that use the Serial ATA (SATA) interface and operate at 5400 RPM.
Currently, Apple's MacBook Air and iPod Classic utilize 80 GB single platter 1.8" hard drives running at 4200 RPM over a Parallel ATA (PATA), though the Air has a solid state drive option. By incorporating the SATA bus and increasing the rotational speed, the performance should elevate to that of standard 2.5" drives used in larger laptops such as Apple's MacBook or MacBook Pro.
Additional Reading: Maximum MacBook Air Drive 80GB for Now
Correction: The original version of this article claimed the 80 GB drive was a single platter drive. This has been pointed out to be not true: both are dual-platter drives at this time.