Currently I have seen quite a few post on different forum about confusion between different version of Palm OS, I think it might be a good idea to list a comparison between them, so that user may choose the correct Palm OS machine for themselves.

Different versions of PalmOS:

OS 1.0
– Released in:1996
– Devices:
Pilot 1000, 5000
– Info:
First version of PalmOS

OS 2.0
– Released in:1997
– Devices:
Palm Pilot Personal and Professional

OS 3.0
– Released in:1998
– Devices:
Palm III, Symbol SPT 1500 Series.

OS 3.1
– Released in:1999
– Devices:
Palm IIIx, Palm V, Handspring Visor, Handspring Visor Deluxe

OS 3.2
– Released in:1999
– Devices:
Palm VII

OS 3.3
– Released in:1999
– Devices:
Palm IIIe, HandEra TRGPro.

OS 3.5
– Released in:2000
– Devices:
Palm Vx, Palm IIIxe, Palm IIIc, Palm VIIx, Palm m100, Palm m105, Handspring Platinum, Handspring Prism, Handspring Visor Edge, Handspring Treo 180, Handspring Treo 180g, Handspring Treo 270, Handspring Treo 300, Handspring Visor Pro, Handspring Visor Neo, CLIE S300E, CLIE S500C, CLIE N710C, HandEra 330, Symbol 1700 Series, Kyocera pdQ, Kyocera QCP 6035, Samsung SPH-i330.
– Info:
Featuring all functions collection of pre OS3.5, native 8-bit color and 16 Grey Scale support, Adding different User Interface Enhancement, Command Bar, Masking Record (instead of just Hiding Private records), Color Picker, Slider Control Graphical Buttons, and Notification Manager.
– Reference: http://www.palmos.com/dev/support/docs/palmos35

OS 4.0
– Released in:2001
– Devices:
Palm m500, Palm m125, Palm m130, CLIE 320, CLIE S360
– Info:
Providing New Features like: Secondary Storage (VFS), Bluetooth, Attention Manager, Telephony, Web Clipping Improvement (PQA), Exchange Manager, and Direct 16-bit color support.
– Reference:
http://www.palmos.com/dev/support/docs/palmos40/

OS 4.1
– Released in:2001
– Devices:
Palm m515, Palm m505, Palm i705, CLIE N760C, CLIE NR70, CLIE NR70V, CLIE T415, CLIE SL10, CLIE SJ20, CLIE SJ30, CLIE SJ22, CLIE SJ33, Handspring Treo 90, Kyocera 7135, Fossil Wrist PDA, AlphaSmart Dana Wireless, AlphaSmart Dana version 2, Acer s10, Acer s50, Acer s60, GSL Explore G18, GSL Explore G88.
– Info:
Providing Bug Fix only to OS 4.0, no additional feature added to the OS.
– Reference:
http://www.palmos.com/dev/support/docs/palmos40/os41overview.html

OS 4.2
– Released in:2002
– Devices:
Found in a few Palm m500 machine released in 2002
– Info:
Bug Fix to OS 4.1, Added Graffiti 2.

OS 5.0
– Released in:2002
– Devices:
Palm Tungsten T, CLIE NX60, CLIE NX70V, CLIE TG50, CLIE NZ90, Garmin iQue 3600a
– Info:
Featuring Support of ARM series CPUs, PACE for running OS4 68k programs, Native ARM program support, Sample Sound APIs, Hi-Res (320×320) Screen support, Web Browser 2.0 etc.
– Reference:
http://www.palmos.com/dev/support/docs/palmos50/

OS 5.2
– Released in:2003
– Devices:
Palm Tungsten C, Palm Tungsten T2, Palm Tungsten T3, Palm Tungsten E, Palm Zire 21, Palm Zire 71, Palm Zire 31, Palm Zire 72, Palm Treo 600, Handspring Treo 600, Samsung SGH-i500, Samsung SGH-i530, Garmin iQue 3200, Garmin iQue 3600, CLIE TJ25, CLIE TJ35, CLIE TJ27, CLIE TJ37, CLIE NX73V, CLIE NX80V, CLIE UX40, CLIE UX50, CLIE TH55, CLIE VZ90, PiTech Qool QDA700, Tapwave Zodiac 1, Tapwave Zodiac 2.
– Info:
Bug Fix to OS 5.0, Added SSL support, Graffiti 2 and Limited Collapsible Input Area API .
More Info:
It is to believe that OS5.2.1 officially added the Graffiti 2, and 128MB RAM support on Palm released device.
– Reference:
http://www.palmos.com/dev/support/docs/palmos50/os52overview.html

OS 5.3
– Released in:2003
– Devices:
No known device has been seen released with OS5.3.
– Info:
Featuring QVGA and 1.5x screen resolution, Simplified Chinese Locate, Dynamic Input Area (DIA)
– Reference:
http://www.palmos.com/dev/support/docs/palmos50/os53overview.html

OS 5.4
– Released in:2004
– Devices:
Palm Tungsten T5, Palm Treo 650, Palm LiveDrive, Palm Tungsten E2, Palm Z22, Palm TX , GSL Explore M28, GSL Explore M68.
– Info:
Featuring different resolution support (160×160, 160×220, 176×220 , 320×320 , 240×320 , 320×480), Enhance Bluetooth Library, Bug Fix.
– Reference:
http://www.palmos.com/dev/tech/oses/garnet540.html

OS 6.0
– Released in:2003
– Devices:
Only Prototype Exist.
– Info:
Featuring completely new framework and architecture on Palm OS, Protected Memory, Multi-task, Multi-Thread, etc.
– Reference:
http://www.palmos.com/dev/tech/oses/cobalt60.html

OS 6.1
– Released in:2004
– Devices:
Only Prototype Exist.
– Info:
Added VGA Screen support.
– Reference:
http://www.palmos.com/dev/tech/oses/cobalt60.html

FAQs
Can I upgrade my Palm OS?
First of all, we have to understand where the OS is.

Normally OS are stored in the ROM part of the machine, some machine comes with a Flash-able ROM, and some comes with a Masked-ROM (Cost Saving).

For device that come with a Flash-able ROM, we can access the ROM by different Flashing Tools, for Masked ones, the only way of changing the OS part in ROM is physically remove and change the ROM chip with another preloaded ROM chip.

For Mask-ROM devices, PalmOS do provide another upgrade method.
Packages are provided as Patch, or upgrades are released from different vendor like Sony, Visor etc.
They are stored in RAM instead of the ROM part of the machines, Palm OS will proceed any files in RAM first then ROM.
An example is the Sony Memory Stick Pro upgrades, and the OS3.3 IR upgrades for the Palm IIIe.

Remember as different devices have different hardware (like MS Slot instead of SD slot, different IR port, different CPU, etc) do not try to flash a device ROM into another device, also be very sure the ROM file you are getting is a vaild ones, flashing a faulty ROM WILL make you device non-usable, in many case even non-recoverable.

The following are the list of known upgrades to pre-OS4 machines:
Palm III series with Flash ROM –a paid OS3.5 upgrade CD was provided by Palm, and a developer version of OS4 ROM file exists.
Palm V series – a paid OS3.5 upgrade CD was provided by Palm, and a developer version of OS4 ROM file exists.
CLIE N710C – upgrade service to OS4 was provided by Sony, but then discontinue, an OS4 version ROM file do exist online, featuring direct 16-bit color, and MP3 playback support.
CLIE Series – Sony never releases any OS upgrades for other devices other than CLIEN710C, only bug fix patches was released (As many of the devices are Mask ROM only), check Sony website for more.
Visor series – Mask-ROM was used, only patches to OS was provided, check Palm Support website for more. http://www.palm.com/us/support/
Visor Treo series – Check Palm Support website for Bug fix. http://www.palm.com/us/support/
HandEra 330 – A developer OS4 version exists online, featuring CFIO Bluetooth card, CFIO WiFi card, Bug Fix.

For OS4 machine, there is NO WAY of upgrading to a Palm OS5 as Palm has chosen to change the CPU of the devices, from 68k Dragon ball CPU to the ARM series CPUs.

For OS5 machine, it is to believe that from Palm Tungsten C, hardware should have been powerful enough for running OS6, but since there is no release of OS6 yet, this is still an unknown will there be any upgrades, and only Prototype was known to be exist with running OS6.

And Keep in mind, OS upgrading by ROM is risky, only do what you understand.

Do I need any upgrade?
Please refer to the above table of different feature of different OS version, personally, I do not suggest any upgrades unless you know upgrade do take advantage, for example, as there is no Secondary Storage, Color, Telephony on a Palm V, there is really no point to upgrade unless a software you need to use requires OS4.

What OS to choose from?
Choose from what you really need, there is actually no point of getting the version number race, if the machine already provides the function you need, what are the differences on the version number?

Reference:
http://www.handhirn.de/en/history.php Palm OS Handhelds history
http://www.palmos.com/dev/tech/oses/ Palm OS Software Overview
http://www.palm.com/us/support/ Palm Officials support website

If you found any problem, in-correct information, or something you would like to be cover under this document, please feel free to contact me, I will correct/add them asap.

First version 20051124 by Theo Poon.

To Be Continue………….