by Sony; Samsung; Nike
Hi-MD
For Example
Filling your Hi-MDs takes a few scant moments with Sony's MZ-NH1, sitting pretty in its combination USB 2.0 cradle and battery charger.
Vitals
Takes 1GB Hi-MD discs; 3.25 x 3 x 0.59 inches; in-cord remote. $400; sony.com
Inside the Tech
Record
A red laser creates nonreflective bumps on a flat, reflective data track on the memory layer. It creates bumps smaller than it can read.
Play
The "switching" layer, when heated with a red laser, magnifies the memory layer below it. Nonreflective bumps = 0s; reflective spaces = 1s.
Max Capacity
1GB
Avg. Price per MB
$0.01
Claimed Lifespan
30-plus years
Who Wants It
The music enthusiast who's always swapping out tunes and needs a durable device.
HARD DISK DRIVE
For Example
The Samsung Napster Yepp YH-800, one of the first micro jukeboxes that links to a music service.
Vitals
1.5GB hard drive; 2.25 x 2.25 x 1 inches; FM tuner; 10-hour rechargeable battery. $300; samsungusa.com
Inside the Tech
Record
The write head moves over a spinning platter coated with magnetic iron-oxide particles to polarize them in a sector on one of tens of thousands of tracks.
Play
The read head detects the presence or absence of a magnetic charge and converts it into the 1s and 0s we love so much.
Max Capacity
40GB*
Avg. Price per MB
less than $0.01
Claimed Lifespan
5-plus years
Who Wants It
The audio pack rat who's going to pamper a device that stores his entire music collection.
FLASH MEMORY
For Example
The Nike Philips MP3Run packs in an FM radio and provides time, distance and pace data on demand via a Bluetooth sensor you wear on your shoe.
Vitals
256MB internal flash memory; 2.8 x 2.8 x 1.1 inches; 12-hour rechargeable battery. $350; nikerunning.com
Inside the Tech
Record
A positive charge applied to the control gate of a transistor pulls electrons through a thin oxide layer into the floating gate, creating a negative charge there.
Play
When a voltage is applied to the control gate in read mode, electron-filled floating gates are read as a 1; neutrals are 0s.
Max Capacity
8GB
Avg. Price per MB
$0.05
Claimed Lifespan
50-plus years
Who Wants It
The gadget lover who wants the smallest and lightest audio player with some aesthetic mojo.
