The Personal Jukebox (also known as PJB-100 and, to some extent Music Compressor) was the first ever hard disk MP3-Player to hit the market in late 1999, which makes it the great-grandfather of today's players like the Apple iPod. Production has since been discontinued, commercial distribution has also almost ceased. The original design was developed by Compaq Research (SRC and PAAD groups) starting in May 1998. Compaq did not release the player themselves, but licensed the design to HanGo Electronics Co., LTD. of South Korea. HanGo first presented it at the COMDEX trade show on November 15, 1999. Various versions of it were produced in the following years, the original one having 4.86 GB of hard disk space and a non-backlit LCD. Later versions sported a backlit LCD and were fitted with bigger disks (up to 60 GB were commercially available). The PJB can be upgraded with standard 2.5 in (64 mm) laptop hard drives with relative ease, although this operation was never originally intended to be carried out by the end-user. Its 24 bit DSP, stable firmware and intuitive, easy-to-use GUI made it an immediate success with a (relatively small) group of users, who consider it to still be a top (if not the top) MP3-player today. Compaq Research also published an SDK for the unit, that enabled users to develop a variation of tools, drivers and applications for many different operating systems (Windows, Mac OS and Linux).

History

Development

The PJB was created as a personal audio appliance prototype by Compaq Systems Research Center (SRC) and Palo Alto Advanced Development group (PAAD). The Project started in May 1998 and a final product was brought to market in November of 1999. The PJB was the first-ever hard-disk-based MP3-player to actually be available to the end-user (other vendors had hard-disk players announced but failed to introduce them in time).

The "100" in the "PJB-100" name was chosen from the capacity of the original 4.86 GB hard drive in the first Personal Jukebox. With this drive, the unit was supposed to be able to hold about 100 popular (45 minute) music CDs encoded at 128 kbit/s. The name was kept for the later models with bigger hard drives, even though these could technically store a much larger capacity of albums.

The impact of the unit was significant as it changed the focus of future digital music player development. It was the first MP3 portable to garner a "Milestone" product designation from MP3 Newswire, which they defined in their January 2000 review of the PJB-100 as "any product whose breakthrough innovations are so significant, they influence the future course of its industry".

Licensing, marketing and distribution

For reasons that are hard to fathom, Compaq decided not to manufacture the PJB themselves. Instead they licensed the design to the electronics company HanGo Electronics Co., LTD. (also known as Remote Solution Co., LTD.), out of Kimcheon City , Kyongbuk, Korea, who called it "Personal Jukebox - PJB-100". The license from Compaq to HanGo was worldwide exclusive; nobody else could license the technology from Compaq during the term of the HanGo license, although HanGo had a distribution agreement with the Korean company HyTek . HanGo also manufactured the HyTek units, but rebranded them as "Personal Jukebox - (Music) Compressor".

HanGo took the unit into mass-production and first introduced it to the public at the Las Vegas COMDEX in November 1999. The first units were sold in a special auction held by MP3.com, with bids exceeding $1000. Some lucky winners were enjoying the first PJBs before the end of 1999. The first auction-won units were hand-built by the Compaq engineers who designed it, and had single-digit serial numbers.

HanGo's California-based marketing and sales department went under the name of HanGo Remote Solution, Inc. . David Ahn , a Korean living in the United States, owned a 30% stake in this company. Ahn had been HanGo's sales representative in the United States since 1997 and had, for that purpose, formerly founded and headed HanGo Electronics, Inc. (which changed its name to Remote Solution in 2000). HanGo Electronics, Inc./Remote Solution's business eventually failed and the company folded in December 2002. RemoteSolution is now repositioned as a division of Remote Control Systems, Inc.

The campaign for the PJB was "Can I? Yes, you can!". It showed a large stack of CDs next to the small unit, representing the amount of music that the device could hold. The PR agency in charge of press work and the actual product launch was Media Perspectives of Charlotte, North Carolina.

Distributors included MP3FactoryDirect in the U.S. (which seems to have folded) and Swiss-based UHU Distribution (Portacomp AG) in Europe as well as from online-retailer ThinkGeek and probably a few others more. The Compressor was available from Hammacher Schlemmer (and only for a limited period and in minor capacity, while the PJB-100 was widely available from various distributors). Those distributors usually also provided support, repairs, accessories and hard-disk upgrades. The firmware kept being developed by Compaq. What the PJB lacked, was any form of advertisement or marketing. Even though it was the superior product at its time of release, less units were sold than inferior products that were both more buggy, less well designed and provided far lower audio quality.

Models

As development on 2.5 in (64 mm) hard-disk-drives progressed, various models of the PJB were commercially available. A major difference was that later versions had a backlit LCD.

Following hard-disk size-models were available:

• 4.86 GB
• 6 GB (June 2000, replaced 4.86 GB model)
• 10 GB (replaced 6 GB model)
• 20 GB (February 2001, replaced 10 GB model)
• 30 GB
• 40 GB (April 2002)
• 60 GB (August 2002)

The PJB was available in various colors (not all colors were available from all distributors):

• black with black buttons
• titanium with black buttons
• translucent light blue with grey buttons
• translucent dark blue with gold buttons
• translucent red (very rare and only at the beginning of distribution)
• translucent dark green with silver buttons (uncertain if this version was available from distributors at all)

Specifications

Physical specifications

Measurements: 150×26×80 mm (5.9×1×3.15 inches) (W×H×D)

Weight: 280 g (9.9 ounces), 304 g (10.7 ounces) including battery

Audio specifications

Playback: MPEG-1 Audio Layer 3 MP3 at bitrates of 8 to 320 kbit/s (playback support for WAV is in the firmware, but is not implemented - it was used by the developers before the MP3 decoder was licensed from Fraunhofer IIS)

Audio signal-to-noise ratio (S/N): >90 dB

Audio Total Harmonic Distortion (THD): <0.1%

Frequency response: 20 Hz to 20 kHz

Audio output power: >50 mW at 32 ohm impedance

Hardware

Digital signal processor (DSP)

The "heart" of the PJB is its Digital Signal Processor. It controls the hard-drive, buttons, LCD, USB interface and handles MP3-decoding for playback. The PJB uses a 24 bit Motorola 56309 DSP running at 33 MHz. The MP3-encoder/decoder code (which is about 2 MB in assembly DSP code) was licensed from Thomson and Fraunhofer IIS.

Memory

The PJB has 12 MB of DRAM and 1 MB of flash memory. 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. Therefore the hard-disk doesn't have to be powered on all the time, which helps saving battery-life and also makes the unit more robust in the face of rough treatment, since when the hard-disk is powered-off, the ramp-loaded heads are retracted from the disk surface. The flash memory houses the firmware as well as the bootstrap.

Communication interface

To up- and download data, the PJB is equipped with a USB 1.1 Type-B-connector. Inside is a Philips PDIUSBD12 USB peripheral controller, which averages a raw throughput of about 400 kB/s. Early prototypes used Ethernet instead of USB for data transmission, which was significantly faster than USB 1.1. It was replaced by a USB port because USB was more common than Ethernet on standard home computers back in 1998.

Display

The PJB has a big LCD (even for today's standard) with a resolution of 128×64 pixels. 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 character set the PJB uses internally is ISO-Latin-1 (ISO-8859-1), with some minor variations. One of the developers recently explained this by stating that "it's missing some of the symbols in the range 160 to 255 (because I got bored when I was creating them :-). Upper case accented characters are rendered unaccented, because that looks better within the font's 9 pixel height. There are some strange glyphs in the range 0 to 31, used for the various symbols on the screen."

Hard drive

The real innovation when the PJB was developed and first introduced was its 2.5" laptop hard-drive on which to store music, opposed to the then state-of-the-art technology of flash-based storage that other mobile music players featured. While these players could store between 32 and a maximum of 128 MB at the time, the first PJB could store 4.86 GB of music. While various models were commercially available and quickly updated, whenever bigger drives became available, it was (and still is) possible to replace the hard-drive for the end-user (although voiding the warranty in that case). Therefore users upgraded their models with bigger drives (30, 40, 60, 80 even 100 GB) as soon as fitting models were on the market. Not every 2.5" drive can be used in every PJB, while some others can be, but drain the battery very quickly.

A minor modification (a green or blue wire soldered to a specific place on the mainboard, see this picture) was made in later-model PJBs. The most important factor for models not having this modification is that the drive used must have separate logic and motor pins (pins 41 and 42, both are used for powering on the drive). While the logic pin is always supplied by the PJB, the power pin is only supplied when there is need to spin the drive up and buffer data into memory. If the pins are internally shorted together, the drive still consumes power when powered off, hence draining the battery very quickly. Models having the modification seem to have fewer problems with higher power consumption. The modification was HanGo's solution to the problem that fewer and fewer new drives were being designed with this split logic/motor pin-assignment. The problem is that it is not easy to tell which units have the modification and which do not. It has been suggested that models that came with a 20 GB IBM/Hitachi drive have the modification, while earlier models do not.

Detailed instructions on how to modify the motherboard to enable using any of the hard drives listed below (and maybe a good number of others more) can be found here (PDF file at the pjb-100 Yahoo! group, free registration or a Yahoo! account necessary).

Physically, only drives with a height of 9.5 mm fit into the PJB (although the older 12.5 mm drives are not produced anymore today anyway). Finally, large cache sizes (above 2 MB) seem to consume more power as well. Drives with higher rotation-speeds (5,400 or 7,200 opposed to 4,200 RPM) consume more power, since the drive needs more power to spin up - this does not improve anything in the PJB and will just drain the battery faster. The manufacturer used drives by IBM (later Hitachi) and the Toshiba MK-GAx series.

Following drives are reported to work (although not all work on the units without the modification mentioned above):

• IBM Travelstar DJSA-220 (20 GB)
• Hitachi DK23CA-20 (20 GB)
• Toshiba MK-2016GAP (20 GB)
• Toshiba MK-2016MAP (20 GB)
• Toshiba MK-3017GAP (30 GB)
• Toshiba MK-4018GAP (40 GB)
• Toshiba MK-4018GAS (40 GB)
• Toshiba MK-6021GAS (60 GB)
• Toshiba MK-8025GAS (80 GB)
• Toshiba MK-1031GAS (100 GB) (one user reported having this hard-drive working in his unit on January 12, 2005)

Buttons/controls

The PJB has 6 buttons on the front:

• left/previous/rewind
• right/next/forward
• up
• down
• play/pause
• stop/power off

Volume is adjusted by a wheel on the unit's right side. It does not do this in an analog way, but digitally (it can be turned indefinitely). It also is possible to click/push the wheel, which pauses playback and turns the unit off after about one minute. When the unit is powered off and the wheel is pressed for a few seconds, playback resumes. This also works when the buttons are locked, which helps a lot when carrying it on the belt or in some other locations where it cannot be as easily accessed (for example a car or in a bag).

On the same side is also a small switch, which can lock and unlock the unit’s entire button controls (except for the wheel, see above).

Between the wheel and the locking-switch is a standard 3.5 mm jack for connecting headphones, speakers etc. Above the locking-switch is the jack for the provided AC adapter. Above that is the USB-B-connector used for up- and downloading data onto the unit.

Battery and power supply

The PJB is not powered by regular dry cell batteries like most other players at the time of its development, but by a provided UR-110 3.6 V/1350 mA Li-Ion battery. HanGo also sold a more powerful 1600 mA battery to be used in the PJB. Strangely, some users have repeatedly reported problems when using other-branded, higher-capacity batteries with some hard-drives having a cache of 8 MB or more, although a reason could not be determined and it apparently does only happen with certain combinations of hardware revisions/hard-drives/batteries.

The PJB includes a 5 V power supply which powers the battery and also enables playback without a battery in the unit at all. The charging control circuit for the battery is built into the PJB itself, not the power supply, so the use of a replacement power supply requires only the proper voltage (5vdc), polarity (center +) and sufficient current capacity (2.5A).

Accessories

Included accessories

Compared to other players, the PJB included a huge amount of useful high-quality accessories. It varied a bit from distributor to distributor, Swiss distributor UHU/Portacomp AG included the following accessories:

• KOSS PortaPro headphones (considered one of the best portable headphones on the market today)
• Leather case with belt clip
• 5 V power supply with converters for European and American power outlets (except UK)
• 1350 mW/3.6 V Li-Ion battery (see the battery section
• USB 1.1 compliant A-B connector cable
• Cinch-Audio cable 3.5 mm to RCA
• Manual (in German and English)
• CD with drivers and Jukebox Manager software (Windows, Mac OS/OS X, Linux)

Optional accessories

Various accessories were offered by different distributors (among them various headphones and speakers, also for use with other audio hardware than the PJB and replacements for the included accessories):

• 1600 mW Li-Ion Battery
• Waterproof neoprene bag for use of the PJB on a beach or pool
• Audio-cassette adapter for playback on car/home stereos
• Swan-neck car-holder
• Various magnetic mounts to attach the PJB within a car
• Power-supply-adapters for car cigarette-lighters

Firmware

Features and version history

The current firmware version, which surfaced in December 2003 is v2.3.3-alpha, the latest stable (rock-solid!) version is v2.3.2, which was introduced in mid-2001. In the beginning, the functions provided by the player were pretty 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. New firmware versions came out regularly, but were mostly bug-fixes with very little new functions being introduced.

Later versions added some of the most requested features:

• Files could finally be redownloaded to the PC
• Browse-while-Playing was implemented (meaning while one track was playing, another could be selected without the current stopping)
• Some (hidden) games were included (see the easter eggs section)
• Create-playlists-on-the-fly, is included in the 2.3.3-alpha version, which means whole (temporary) playlists can be created during playback (which is great if DJ'ing with the unit)

Following versions of the firmware were available:

• v2.1.6 (original version)
• v2.1.8 (September 6, 2000)
• v2.1.10 (March 17, 2001)
• v2.2.0 (April 3, 2001)
• v2.3.0 (May 19, 2001)
• v2.3.1 (June 5, 2001)
• v2.3.2 (June 19, 2001)
• v2.3.3-alpha (December 30, 2003)

Sets, discs, tracks

To understand navigation on the PJB one must know that its file system does not allow for variable folder-depths. Instead, all data on the PJB is organized hierarchically in three levels, called Sets, Disc and Tracks. There can be a number of Sets each including a number of Discs, each including a number of Tracks. What each represents is completely up to the user. A Set could be the name of the artist, a character, a genre, the title of a sampler or a soundtrack, etc. Following this example, a disc could be the name of the album/single or of the artist.

Here is an (abbreviated) example of how a PJB user could organize his music collection:

• Atrocity
  • Werk 80
    • Tainted Love
    • Der Mussolini
    • Wild Boys
  • Gemini
  • Todessehnsucht
• Black Sabbath
  • Paranoid
    • Paranoid
    • Iron man
• All Artists - A
  • Abba
    • Money, Money, Money
  • Alice Cooper
  • Apocalyptica
• Grunge
  • Nirvana
    • Floyd the Barber
  • Pearl Jam
• Pulp Fiction Soundtrack
  • Kool & The Gang
    • Jungle Boogie
  • Dusty Springfield
    • Son of a Preacher Man
• Audio Books
  • J.R.R. Tolkien - The Lord of the Rings
    • A long awaited party

This method of course has some advantages and disadvantages. For most people, three levels of organization are sufficient, although occasionally a fourth level would be useful. If you think through a good system of organization before uploading and keep to it, even very large collections can be easily managed. A problem might be that if another person is searching for a specific track and does not know the method of organization it might be a little hard to find the sought track. Here players like the iPod have the search advantage, since all kinds of tags (artist, genre, album) can be searched dynamically.

User interface and navigation

The PJB's large display shows all the relevant information at the same time. It is divided into seven lines and looks like this:

The lines are selected with the up/down buttons while Sets, Discs, Tracks and various playback options are selected with the Left/Right buttons. The Play and Order options interact with each other. This Track/Repeat will play the current track indefinitely. Everything/Shuffle will randomly play every track on the unit, which is one of the favorite modes with many PJB owners. One of the lacking features of the PJB is a proper equalizer, instead it is just possible to increase the bass level in two steps.

Later versions of the firmware include Browse-while-Playing and creating Playlists-on-the-Fly. Both is achieved by pressing and holding down the Play button. This brings up a new line with following options: Play now, Add to playlist, Add to playlist and play, Play after current track, Play after current disc. Discs and Tracks can be added to playlists. If any of the playlist options is selected, a temporary Set "Online Playlists" is created as the last set, and any selected disc is added as Disc. Selected tracks are added to an "Online Playlists" Disc within this Set.

As mentioned before, volume can be adjusted in 21 levels by the wheel on the unit's side, which can also be used to pause a track or to power the unit on, when pressed and held down.

File system and table of contents (TOC)

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. Instead, a unique file system is used, which, while losing the mounting ability, is optimized for the structure of MP3 files (having a cluster size of 128 kB, which equals about 8 seconds of 128-kBit-encoded MP3-music). Therefore managing actions like defragging become unnecessary.

Another option this sort of internal file management brings, is also one of the most interesting and useful of the PJB: Cue points and gapless playback. For instance, if the user rips and uploads a live CD, it sounds like one continuous stream if played on a CD-player. On the other hand. classic computer file systems and some of the design weaknesses of the MP3-format would now force a "gap" of silence to be heard between the single tracks. The PJB allows (if the right method of uploading is used) to store all of these tracks as one continuous stream. Single cue points are used to mark the beginnings and ends of what the PJB display as Tracks. Therefore, if the Disc is played back sequentially, the record will sound as intentioned - gapless.

Another interesting thing that the file system allows for, is the linking of Tracks into various Discs/Sets. 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. This may help to preserve a good amount of disk space and allows for more tracks to be stored on the disk.

All of this info is stored in the TOC (table of contents). 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. A copy of the TOC is always stored on the unit as well, so errors and damage to the original TOC can usually be fixed without the user having to worry about it (in most cases, users don't even notice anything having been wrong).

While the TOC is conceptually very well designed, it (or rather a design weakness in the firmware) is also the reason for one of the PJBs most annoying limitations: the TOC and additional memory used to set up data and navigation structures (the TOC in a parsed form) must not exceed 1436 kB. While this may sound a lot for a plain text-file, it really is not, when long (full) names for Discs and Tracks as well as a fair amount of linked tracks are used. While it is no problem to have an 80 or 100 GB disk in a PJB, not all of the available space might really be usable because of these TOC-size limitations. One of the original developers recently stated that changing the TOC-size at the expense of disk or buffer memory space would only require a trivial change in the firmware code, although certain reasons probably will prohibit this from ever happening (see the future firmware updates section). The space the TOC/parsed TOC take up can be displayed, along with the free space, by pressing a button combination on newer firmware versions.

Easter eggs/games

Later versions of the firmware (from 2.3.1 up) include an easter egg screen, when a certain combination of buttons is being pressed (the exact combination differs between versions). In this screen, the user can choose between three different options:

• play the game Minesweeper
• play the game Sokoban
• display the credits (of the developer team at Compaq Corporate Research)

The user can also choose whether the music playback should continue, or if special sound effects should be used.

Software

Software development kit

Another unique feature the PJB offers is that the original developers at Compaq Research also designed an SDK (Software Development Kit) for the unit and published it under the Open Source GPL license in 2000. This means anybody with programming skills or interests can develop drivers, tools and software applications for virtually any operating system used today and can also further develop the actual SDK. Some great programs and ideas to be used for the PJB have surfaced since its introduction.

Drivers

As mentioned, the PJB does not integrate itself as a USB mass storage device into modern operating systems, like most of today's players do (and to be fair, there was no USB Mass Storage Rationale available at the time of development). Therefore special drivers are required to make the operating system recognize an attached PJB. Drivers for Microsoft Windows and Mac OS were included, while drivers for Linux were quickly developed by the open source community using the provided SDK.

Jukebox Manager (Windows, Mac OS)

The included management tool for the PJB is the Jukebox Manager (the latest Windows version is v1.5.6). It is a pretty basic application which can create/delete/manage Sets, Discs and Tracks (when uploading, the user can choose which ID3-tag will represent which level). It can also encode CDs directly onto the PJB and query the CDDB for the proper disc/track information. Finally it can update the firmware. 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. The Jukebox Manager does not make use of some of the firmware’s later features, such as downloading tracks back to the computer and does not provide advanced features such as mass-uploading, synchronizing or creating playlists from M3U-playlists.

pjbExploder (Windows)

Development of the pjbExploder was started by Enea Mansutti in 2001 and is an open source project under the GPL, with its development page residing on SourceForge. It is one of the few projects for the PJB which still is actively developed. The latest version currently available is v1.0.42.

It is the tool to use for managing the PJB on a Windows-PC today. It has the same uploading capabilities of Sets/Discs/Tracks as the Jukebox Manager, but also provides additional features, such as mass-uploading, synchronizing, a playlist manager, creation of CUE-sheets, advanced search and sorting options, uploading of non-MP3 data files as well as the ability to re-download tracks to the PC or the playback of tracks on the PJB via the computer's audio hardware (mind you, through USB-interface only, not through an attached audio-cable) in real-time. Starting with version 1.0.42 it also optionally installs the correct PJB drivers for Windows 2000 or XP, eliminating the need for JBM or the drivers to be installed first.

MP3Loader (Windows, discontinued)

MP3Loader Was a shareware project by Robert Valentino and was popular for its mass-uploading capabilities, either representing fixed directory structures as Set/Discs/Tracks, or using M3u-playlists to generate the structure on the PJB.

Jukemon (Mac OS X)

A tool for Mac OS X that was developed to replace the Jukebox Manager, which would only run on the classic Mac OS. It also implements the PJB's USB drivers, so when using Jukemon, no additional drivers for the PJB are required. It's a full Cocoa application using all of the APIs features. It can up- and download files to and from the PJB, interprets ID3-tags accordingly and also uses them to enable the creation of Sets or Discs named after more than one tag. It has a function to enable gapless playback (if the files are encoded to be gapless) and also features debug output to the console. It is also open source under the GPL.

OpenPJB/PJB Tools/pjbsdk and minor projects

The OpenPJB/pjbsdk Project on SourceForge tries to provide a base for all (open source) PJB applications, while also further developing the SDK. They also provide the PJB Tools, a collection of tools for the command line of various operating systems, published under the GPL (including documentations and a modified version of the SDK). While not as comfortable to use as applications with a GUI, they are a very useful and mighty bunch of tools providing basic up- and downloading options for both Sets/Discs/Tracks and the TOC. The PJB Tools include the following files:

• pjb
• pjbcom
  • pjbcom ActiveX Control: A subproject of pjbcom providing an ActiveX control for Windows
• pjbdocs
• pjbsdk
• pjbwmu

At the files section of the pjb-100 Yahoo! group, users have also posted some very interesting projects created with the help of the SDK. These range from Perl scripts loading music onto the PJB via M3U playlists to Excel-sheets displaying the contents of the unit's TOC and even a fully functional web-browser interface to manage the PJB written in JavaScript. There are also some helpful code-snippets and SDK-related documentation located there.

Linux projects

There are also various Linux projects operating on SourceForge (some under the banner of the OpenPJB project). 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. Some of the projects include:

• Jukebox Manager (KDE)
• GNOME/Gtk+ GUI Personal Jukebox Manager (GNOME)
• Emacs PJB Manager
• PJB File System for Linux (Kernel 2.3/4, 2.6)
• PJB VFS module (for use with Nautilus)
• pjmirror (written in Perl to synchronize the PJB with data on the PC)

Future outlook

(Open source) firmware updates?

With the introduction of Playlists-on-the-Fly in v2.3.3-alpha, a major step towards final user-happiness was achieved. The version seems pretty stable, which doesn't come surprising since the preceding version v2.3.2 is considered virtually rock solid by most of the user base. Some major problems make it unlikely though, that any future updates will be provided: The firmware was always written by people at Compaq and provided to HanGo (this was originally intended as a solution for the transitional phase of the licensing process, but it seems that HanGo never took up developing the firmware and the original developers kept doing it in their spare time from other projects, since most of them had enjoyed the PJB project so much). Most of the original developers do not work for Compaq/HP anymore (at least those who publicly talked about the PJB in the user group don't). HanGo has ceased producing the PJB - most distributors don't even sell it anymore. Compaq was bought by Hewlett-Packard and the two companies merged their product lines - what became of the PJB design and firmware source is unknown to the public. Compared to other players, there were never huge amounts of the PJB sold (which might also be because HanGo provided virtually no marketing for the product and it was almost exclusively sold by distributors, not retailers), therefore there is a relative small user base demanding any updates.

So if no one is willing to develop the firmware at HP and no one cares about it anyway, why not open source it and have some skilled programmers, who are in love with the unit, keep developing it? Unfortunately, there are some reasons that would prohibit that as well: The code used for decoding MP3 in the PJB is owned by Fraunhofer IIS (the encoding algorithms original developers) and is considered one of their "crown jewels" - they would not be happy seeing this part of the firmware become public domain.

Those fears were confirmed in March 2005, as one of the original developers was kind enough to provide necessary contact information for the person at HP research believed to be in charge of the original PJB resources these days. On request, about the possibility of HP improving the firmware, or licensing it under some sort of agreement to a (limited) circle of developers for a binary-only release to the public, the person stated that "[...] Unfortunately, for a variety of business reasons, HP has no plans to update the firmware for that product ourselves, nor are we planning to devise license conditions under which third parties could update the firmware. [...]". This pretty much killed any remaining hope for official improvements to the product in the future. Some time before this, some of the original developers still interested in the project tried similar approaches to employees of HP, but got rebuked in similar ways.

If an agreement with HP could have been reached, it might have been possible to remove some of the nit's current limitations such as the limited TOC-size, or implement some other interesting features, such additional games like Tetris (although one of the original developers stated that they had originally tried getting permission from the license-owners of the game and were denied permission to implement it).

Another option might be to try to create new firmware from scratch. One of the original developers shed some light on the issue and said that the MP3 encoder would have to be completely rewritten in DSP assembly code, which is not a trivial effort. The same goes for other formats that might be considered, like Ogg Vorbis. WAV or FLAC playback might be achievable, although this would also require some assembly code to be written for the specific DSP used in the PJB. It would also require some knowledge that is public domain, such as the DSP toolchain and documentation, as well as some debugging hardware, which is hard to come by these days.

New models based on the design

The design of the PJB (concerning both hardware and firmware) was revolutionary in its day, and still seems well thought-through after almost five years on the market. Following release of the original PJB-100 product, Compaq Research continued work according to their roadmap, which anticipated the use of smaller hard drives: 1.8" as in the original iPod and 1.0" as in the iPod Mini. Based on discussions with Toshiba about their upcoming 1.8" drives, the PJB team produced a largely complete design of a second-generation PJB, including industrial, mechanical and electronic design and a port of the firmware to the new hardware. The result bore an uncanny resemblance to the original iPod, and was offered to the Compaq product group in Houston in late 2000, but as with previous attempts, this was again rejected. The management of Compaq Research then stopped the project, since producing designs to be licensed to other companies was not the proper mission of the Research Division. Ironically, Hewlett-Packard later struck a deal with Apple to sell a rebranded iPod as their own hard-disk based MP3-player in 2004, even though they had a nearly complete design with all the necessary intellectual property (for example: US Patent 6,332,175, see the external links section) and know-how sitting on the shelf. This seems sad, but given the entire PJB team had gradually departured, it would have been very difficult to revive the project.

Some years ago, HanGo announced a successor to the PJB, called the PJB-300, but would not comment on any further details. Since they never followed the announcement up with any more details or even a release date, it is largely considered vaporware these days. Whether the new model would have been based on the same design as the PJB-100, and would have had further improvements over it, or was just a naming convention for a completely different product will probably never be fully resolved.

In an e-mail to the person believed to be currently in charge of the PJB resources (see the above section on future firmware updates) at HP in March 2005 some further bad news (or at least, no big encouragements) concerning the possibility of any new units being developed off the original hardware design were given. The contacted person merely stated "[...] As for potential new products based on the design of the Personal Jukebox, I'm afraid that it is not my place to discuss HP's product plans [...]"

But maybe one day somebody at HP will remember the great design of the unit and will develop a worthy successor of the PJB for the mass-market.

External links

General information, discussion and support

• The new and improved PJB-100 User Group at Yahoo! Groups - largest active community, some original developers post there, support, discussion, questions, file section includes all of the firmware, manuals and documentation for the PJB (free registration required, new posters must be approved by moderator to keep the group spam free)
• Original PJB-100 User Group at Yahoo! Groups - Active from 2000-2005 (closed because the original moderators had left and spam was becoming a problem) it contains more than 17,000 messages and a great number of files (drivers, firmware, manuals, pictures and some very interesting programs and code-snippets) on or for use with the PJB
• PJB-100 official development site at Compaq Research
  • Emulation of PJB user interface in JAVA at above site
  • Detailed presentation of the PJB-100 at above site (PowerPoint format)
• PJB-100 Info Site - includes FAQs, manuals, photos, links to official reviews and software projects
  • Info on hard-disk upgrades from above site
• Ultimate PJB-100 FAQ
• Pimp my PJB! - Some pictures from a user who adapted and modded his PJB to build it into his car
  • Info on this mod at the pjb-100 Yahoo! group
• Motherboard modification instructions - Instructions on how to modifiy the PJB's motherboard so that larger hard-drives work in older units (at the pjb-100 Yahoo! Group, PDF format)

PJB-100 software projects and developer info

• pjbExploder (Windows) project home page
• Jukemon (Mac OS X) project home page
• OpenPJB Project multi-platform command line tools and SDK
• Jukebox Manager (Linux/KDE) project home page
• pjbmanager (Linux/GNOME) project home page
• Firmware downloads - various official and unofficial firmware and software versions for Windows, Mac OS/Mac OS X and Linux (including pjmirror not found anywhere else) at the site of European distributor UHU/Portacomp AG (see below)
• File System info - a description of the PJB's file system and other technical info for developers (PDF)
• Patent #6,332,175 - this patent covers one of the key technologies of the PJB: Buffering data into RAM and playing it back from there

Distributors (just support and accessories these days)

• PJB-100 page of European retailer UHU/Portacomp AG including a lot of information and firmware/software for various operating systems

Articles/reviews about or including info on the PJB-100

• Video interview with a HanGo representative from the 2001 CES in Las Vegas about the PJB-100 (WMV format)
• MP3-Portable speichert 70 Stunden Musik - October 29, 1999. Article from German heise Newsticker on the PJB-100 (in German)
• 1200 Song MP3 Portable is a Milestone Player - January 11, 2000. MP3 Newswire review of PJB-100 from Archive.com
• Introducing the world's first MP3 player - January 21, 2005. CNET article on the PJB-100 being the world's first 'iPod'