Notice the emphasis here is on the mobile DJ world, as the software for MP3 utilization is currently embryonic in relationship to the needs of the beat mixing club jock. At an average size of 10 megabits per minute of recorded music, and should you carry only 1,000 songs to every engagement, and assume an average of 4 minutes per track length, you would need a hard drive capable of storing 40 gigabits minimum and there'd be no more room for expansion. As most laptop computers feature hard drives between 4 and 8 gigabits, it becomes mathematically evident that laptops were never considered as an alternative storage compared to CDs. The frequencies have been surgically removed, not squeezed into a smaller package that can be re-expanded at a later time. That being said, let's press on.
Laptops are now a viable storage media.
As the MP3 file is a computer data file, it can only be played through a computer or new walkman-type players. You cannot make a CD of 150 songs in MP3 format and play it through your DJ CD players. There are many MP3 player programs out there, some smooth, some glitzy, some expensive, some free, some functional and some not well thought out. Designing space shuttles while playing MP3s is not recommended. SCSI hard drives.