Personal Jukebox

The Personal Jukebox (also known as "PJB-100" or "Music Compressor") was the first commercially sold hard disk digital audio player. Introduced late in 1999, it preceded the Apple iPod and similar players. 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 the device at the COMDEX trade show on November 15, 1999. Several versions were produced in the following years, the original having 4.86 GB of hard disk space and a non-backlit LCD. Later versions sported a backlight and were fitted with larger disks up to 60 GB. The PJB can be upgraded with standard 2.5 in (64 mm) laptop drives with relative ease, although this operation was not intended to be carried out by the end user. It features a 24 bit digital signal processor.

Compaq Research also published a software development kit for the unit, which enabled users to develop a variation of tools, drivers and applications for many different operating systems.__TOC__

History

Development

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. The PJB was the first hard-disk-based MP3 player made available to the end user (other vendors had announced hard-disk players but had not yet brought them to marketFact|date=February 2008).

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 expected 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 store a larger number of albums.

The PJB-100 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

Instead of manufacturing the player themselves, Compaq licensed the design to HanGo, which called it the "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. HanGo granted a distribution agreement to US company [http://www.hytekmfg.com/ Hy-Tek Manufacturing] of Sugar Grove, IL in 2001. HanGo rebranded the units sold through Hy-Tek as the "Compressor".

HanGo took the PJB-100 into mass production and 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 US$1000. Some winners received their players before the end of 1999. The first auctioned units were hand-built by the Compaq engineers who designed it, and had single-digit serial numbers.

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 public relations agency in charge of press work and the product launch was Media Perspectives of Charlotte, North Carolina. Beyond the launch, the PJB apparently went without advertising or marketing.

Distributors included MP3FactoryDirect in the U.S., Swiss-based [http://www.uhu.ch UHU Distribution (Portacomp AG)] in Europe, and online retailer ThinkGeek. The Compressor was available from Hammacher Schlemmer for a limited period.

The firmware continued to be developed by Compaq through the life of the product.

Models

As development on 2.5 in (64 mm) hard disk drives progressed, various models of the PJB were commercially available. Later versions had a backlit LCD.

The following hard disk sizes were used:
* 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 (may not have actually been distributed)

pecifications

Physical specifications

Measurements: 150×80×26mm (5.9×3.15×1.0 inches) (W×H×D)

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

"Note: The PJB used a 2.5" hard drive and was bulky compared to modern devices based on 1.8" or 1.0" hard disk drives or flash memory."

Audio specifications

Playback: MPEG-1 Audio Layer 3 (MP3) at bitrates of 8 to 320kbit/s and a sample rate of 44.1kHz (playback support for WAV is in the firmware, but is not enabled - it was used by the developers before the MP3 decoder was licensed from Fraunhofer IIS).

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

Audio total harmonic distortion (THD): <0.1%

Frequency response: 20Hz to 20kHz

Audio output power: >50mW at 32 ohm impedance

"Note: There seems to be a minor bug in the firmware and/or hardware design, causing a slight delay of the right audio channel. [http://tech.groups.yahoo.com/group/PJB100-mp3/message/659] A user broke it down to this:"

"The specifics are that the right channel output is delayed 22.7 microseconds from the left channel output. This corresponds with the sample rate, 44.1kHz (1/44100 = 22.7 microseconds). The problem is in the order that the digital audio data is conveyed from the DSP to the DAC, and it could probably be corrected with a little bit of hardware. I verified these timings with an oscilliscope." [http://tech.groups.yahoo.com/group/PJB100-mp3/message/663] "

"The user who originally mentioned this has posted some theoretic fixes to this probem, requiring modifications to the hardware. Thus far, no working technical solution to this issue has been documented or been made available, though."

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 codec (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. The buffer allows the disk to be run only intermittently, preserving battery life. 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.

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. USB was used in production models because it was more common than Ethernet on standard home computers in 1998.

Display

The PJB's LCD has a resolution of 128×64 pixels (2:1 ratio) at a diameter of 3 inches (7.62 mm). 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 Latin-1 (ISO-8859-1), with some minor variations. One of the Compaq developers stated 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."Fact|date=February 2008

Hard drive

While flash 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 the PJB-100 was updated as bigger drives became available, it was also possible for end users to replace the hard drive (although voiding the warranty in that case). Not every 2.5" drive can be used in every PJB, and some that can be used drain the battery very quickly.

A minor modification (a green or blue wire soldered to a specific place on the mainboard, see [http://home.clara.net/wsymonds/toprightpjb.jpgthis 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. It is not easy to tell which units have the modification. 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 [http://groups.yahoo.com/group/pjb100/files/upgradehd.pdf 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.

The 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)
* Hitachi DK23DA-20F (20 GB) (original delivered in PJB)
* 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 [http://groups.yahoo.com/group/pjb100/message/17043 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, 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. 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, in case the main controls cannot be easily accessed.

On the same side is also a small switch, which locks the unit’s controls (except for the wheel).

Between the wheel and lock switch is a standard 3.5 mm jack for connecting headphones, speakers etc. Above the lock 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 HanGo (probably rebaranded Sanyo, hence the same ID) UR-110 3.6 V/1350 mA Lithium ion battery. HanGo also sold a more powerful 1600 mA battery to be used in the PJB.

Some suitable replacements for the original battery (which is no longer being manufactured/distributed by HanGo or Sanyo) are the higher-capacity Sanyo UR-111 (3,7V/1700mAh) as well as the Sharp models AD-MS10BT (3,6V/1850mAh) and MD-MS200. It is still possible as of July 14, 2007 to buy a UR-110 2000 mA from various battery distributors. Since li-ion batteries tend to lose the ability to hold full charge after some years, even buying a stocked version of the original battery is discouraged, since it will very likely not be able to perform very well to begin with, having been in stock for at least three years or more.

In the past, 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 only happens with certain combinations of hardware revisions/hard-drives/batteries.

The PJB includes a 5V power supply which charges 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 (5V DC), polarity (center +) and sufficient current capacity (2.5A).

Accessories

Included accessories

Compared to other players, the PJB included a large number of useful high-quality accessories. Details varied from distributor to distributor, but UHU/Portacomp AG included:
* Koss Porta Pro headphones
* 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 mAh 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 latest firmware version, which surfaced in December 2003 is v2.3.3-alpha; the latest stable version is v2.3.2, introduced in mid-2001. 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. New firmware versions came out regularly, but were mostly bug fixes with very few new functions introduced.

Later firmware versions added some of the most requested features:
* Files could be transferred from player to PC
* The ability to browse without interrupting playback
* Some (hidden) games were added (see easter eggs)
* Temporary playlists can be created during playback with the 2.3.3-alpha firmware, a convenience for DJ'ing with the unit.

The 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)

ets, discs, tracks

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.

User interface and navigation

The PJB's display 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.

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.

The file system allows 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).

The TOC and additional memory used to set up data and navigation structures must not exceed 1436 kB.

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.

oftware

oftware development kit

The original developers at Compaq Research designed an SDK (Software Development Kit) for the unit and published it under the Open Source GPL license in 2000.

Drivers

The PJB does not integrate itself as a USB mass storage device into modern operating systems. 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 developed by the open source community.

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 later continued by Michael Hotchin. It 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 v1.0.46.

This software 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 in real-time.

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.

OpenPJB/PJB Tools/pjbsdk

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).

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)

External links

General information, discussion and support

* [http://groups.yahoo.com/group/PJB100-mp3/ 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)
* [http://groups.yahoo.com/group/pjb100/ 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
* [http://www.research.compaq.com/SRC/pjb/ PJB-100 official development site at Compaq Research]
** [http://www.research.compaq.com/SRC/pjb/emulation.html Emulation of PJB user interface in JAVA at above site]
** [http://www.research.compaq.com/~birrell/talks/pjb-overview.ppt Detailed presentation of the PJB-100 at above site (PowerPoint format)]
* [http://www.mpython.com/pjb/index.htm PJB-100 Info Site] - includes FAQs, manuals, photos, links to official reviews and software projects
** [http://www.mpython.com/pjb/upgrade.htm Info on hard-disk upgrades from above site]
* [http://members.lycos.co.uk/sjw007/ Ultimate PJB-100 FAQ]
* [http://groups.yahoo.com/group/pjb100/files/upgradehd.pdf 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, drivers, firmware and developer infos

* [http://sourceforge.net/projects/pjbexploder/ pjbExploder] (Windows) project home page
* [http://www.xendai.com/jukemon/ Jukemon (including Mac OS X driver)] (Mac OS X) project home page
* [http://sourceforge.net/projects/openpjb/ OpenPJB Project] multi-platform command line tools and SDK
* [http://jukeboxmgr.sourceforge.net/ Jukebox Manager] (Linux/KDE) project home page
* [http://sourceforge.net/projects/pjbapplet pjbmanager] (Linux/GNOME) project home page
* [http://www.pjbox.ch/en/html/content/alte_update.html Firmware downloads] - various official and unofficial firmware versions, software and drvers 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)
* [http://groups.yahoo.com/group/PJB100-mp3/files/Software/Windows%202000%20Drivers/ Microsoft Windows 2000 drivers and instructions] (download from PJB-100 Yahoo! group, registration necessary)
* [http://groups.yahoo.com/group/PJB100-mp3/files/Software/Windows%20XP%20Drivers/ Microsoft Windows XP drivers and instructions] (download from PJB-100 Yahoo! group, registration necessary)
* [https://www.muru.com/linux/pjb-100/ Linux 2.6 drivers] (downloads and instructions for Kernels 2.6.0/2.6.3/2.6.4/2.6.6)
* [http://tech.groups.yahoo.com/group/PJB100-mp3/files/Software/Linux%20Drivers/ Recent Linux 2.6 kernel drivers] (download from PJB-100 Yahoo! group, registration necessary)
* [http://www.hotchin.net/PJB/Docs/pjbfilesys.pdf File System info] - a description of the PJB's file system and other technical info for developers (PDF)
* - this patent covers one of the key technologies of the PJB: Buffering data into RAM and playing it back from there
* - this patent covers a different aspect of buffering data in RAM

Distributors (just support and accessories these days)

* [http://www.ebatts.com/part_b-8702.aspx?equiv=AD-MS10BT Sharp ADMS10BT battery from eBatts.com (2000 mAh)]
* [http://www.atbatt.com/product/5330.asp Amstron Digital Camera Battery for Sharp AD-M10DT from atbatt.com (1850 mAh)]

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

* [http://david.weekly.org/video/CES2001/personal_jukebox.wmv Video interview] with a HanGo representative from the 2001 Consumer Electronics Show (CES) in Las Vegas about the PJB-100 (WMV format)
* [http://www.heise.de/newsticker/meldung/6713 MP3-Portable speichert 70 Stunden Musik] - October 29, 1999. Article from German heise Newsticker on the PJB-100 (in German)
* [http://web.archive.org/web/20031211090946/www.mp3newswire.net/stories/personaljuke.html 1200 Song MP3 Portable is a Milestone Player] - January 11, 2000. MP3 Newswire review of PJB-100 from Archive.com
* [http://reviews.cnet.com/4520-6450_7-5622055-1.html?tag=cnetfd.sd Introducing the world's first MP3 player] - January 21, 2005. CNET article on the PJB-100 being the world's first 'iPod'
* [http://www.theregister.co.uk/2004/01/19/how_hp_invented_the_market/ How HP invented the market for iPod resellers (HP could have capitalized on using the PJB design)] - January 19, 2004 article by Ashlee Vance at The Register
* [http://www.engadget.com/2004/12/17/day-5-of-engadgets-five-days-of-holiday-giveaways-win-an/3#c594087 A heart-warming episode on one of the first-ever PJBs] - December 17, 2004, by jonathan on [http://www.engadget.com engadget.com]