PalmOne will offer customers a free memory expansion card after the decision to change the memory type in its new Treo 650 smart phone actually reduced the amount of memory available.

The change to Flash memory from DRAM has reduced the amount of memory available by about a third and so PalmOne has decided to give customers a 128MB expansion card to help store people's extra data.

With the Flash memory, small files such as contacts or tasks must be stored in chunks that are much larger than the actual files themselves. So the same files a user stored on a Treo 600 might not all fit on the Treo 650, launched last week.

A PalmOne spokeswoman confirmed the memory issue in a statement. The capacity problem is a design tradeoff caused by the decision to use a new file system that allows users to quickly change batteries and protect their data when power runs out, she said. Treo enthusiast Web sites such as MyTreo.net were the first to highlight the problem.

On the latest version of the popular Treo smart phone, PalmOne made two important changes to the system's design. The device now uses flash memory, rather than DRAM, to store data. Flash memory is non-volatile, which means it can store data without a constant supply of electricity and protect that data in the event of a battery failure or unintended shutdown. PalmOne users have clamored for flash memory for years, and were finally accommodated with the release of the Tungsten T5 and Treo 650.

In order to use flash memory, PalmOne had to switch the file system technology that decides how files are stored. The Treo 650 now uses the NVFS (nonvolatile flash system) file system to store data in clusters. This file system is based on FAT (file allocation table) technology, which was the underlying file system technology for Microsoft's DOS operating system as well as Windows 95 and Windows 98. The Windows NT and XP operating systems use a different technology.

In the Treo 650, NVFS technology stores data in 512-byte blocks. This means that even small 20-byte files, such as a contact's phone number, are stored in 512-byte blocks. Smaller files stored in DRAM on older smart phones and handhelds took up only as much space as the size of the file.

This is inefficient, but FAT-based file systems were designed for PCs that work with larger file sizes and have disk drives in the gigabyte range.

However, the Treo 650 only comes with 23MB of user accessible flash memory - less than the Treo 600, which used 24MB of volatile DRAM to store information. Users are further constrained by the 5MB of storage required for the Documents To Go application, which allows Palm OS users to view and edit Microsoft Office files.

Therefore, a user who wishes to transfer files from an older Palm device to the new Treo 650 might not be able to fit all of their application or data onto the new system, the PalmOne spokeswoman said. A typical address book would take up an additional 800KB of storage space on the Treo 650, the company said in an online support forum.

Third-party applications should not be affected in the same manner as contacts and calendar data, but users should check with their application provider to be sure, according to PalmOne's online support page.

PalmOne believes that the issue will affect only a small percentage of users who have filled their Treo 600 units with data. However, the company will offer a free 128MB SD expansion card to any purchaser of a Treo 650 who requests it. It usually costs around $15.

The company plans to release a ROM upgrade that will improve the efficiency of its flash memory, aspokeswoman said.