Personal Jukebox

The Personal Jukebox (also known as PJB-100 or Music Compressor) was the first consumer hard drive-based digital audio player.

The PJB was created as a personal audio appliance prototype by DEC Systems Research Center and Palo Alto Advanced Development group (PAAD).

The project started in May 1998, a month before the Digital Equipment Corporation merger into Compaq was completed, and a final product was brought to market in November 1999.

HanGo granted a distribution agreement to US company Hy-Tek Manufacturing of Sugar Grove, IL in 2001.

The DRAM is used to buffer data (between 8 and 12 minutes of music, depending on the bitrate used for encoding) from the hard disk during playback.

When the hard-disk is stopped, battery life is preserved; the ramp-loaded heads also retract from the disk surface, helping to reduce the possibility of damage.

Later versions of the PJB also featured a backlit display (the backlight comes on when the unit is powered on, or a button is pressed and turns off automatically after a few seconds).

The PJB has 6 buttons on the front: Volume is adjusted by a wheel on the unit's right side, using a digital mechanism (it can be turned indefinitely).

It also is possible to click or push the wheel, which pauses playback and turns the unit off after about one minute.

Initially, the functions provided by the player were basic: when music was played back, selecting another track would immediately start this track and stop the current one; playlists had to be created on the computer; files could only be uploaded to the PJB, but not downloaded back to the computer.

Later firmware versions added some of the most requested features: The PJB's disk is not formatted as FAT or FAT32 as is the case with most of the players that were released later, and enables those to be mounted as another drive in an operating system.

Therefore, each track is ideally only stored once on the disc and recurring occurrences of it (for example in playlists or samplers) are just links to the original file.

The TOC is stored in a human-readable text-format and can be downloaded, changed with a text editor and re-uploaded to the PJB again.

If manipulating some values in the Windows Registry, a hidden menu appears, which can be used to debug and, in some cases repair a damaged TOC.

These range from Jukebox-Manager-like applications with a GUI for various window managers to projects making the PJB's file system mountable as a drive in Linux.