Yes, we all heard of the new Palm OS Handheld called the Tungsten T5. It sports 256 MB of Flash Memory-what was that once again? NAND Flash used as RAM is the new buzz feature that is busily discussed and that has generated a lot of strain on developers. You may ask why a subtle change in memory architecture causes the developer mailing lists to go havoc and bubble with information. Didn’t we have that with the Palm III-it used DRAM instead of the SGRAM for the storing of data? There was no fuzz that time!
I agree on this, but the change from RAM to NVFS/NAND Flash memory is much greater than the change from one type of RAM to another.
Flash is a different type of memory that doesn’t loose its data when power is removed. However, most types can only be written(and sometimes read) in sectors-that means that you cannot change a single bit or byte at once, as you can do with RAM. You can only specify the sector address, and out flows a stream of serial data. Thus, it is rather difficult to run a program without a RAM buffer!
In addition, it is much slower than real RAM -and thus the TT5 has a shadow ram of 32MB! 16MB of it are used as storage space for the OS. The remaining 16 MB of RAM are subdivided into a cache for writing and reading data and into 4MB of dynamic stack. Just remember that the Tungsten T3 has 12MB for stack and operating systems-while the T5 must work with chintzy 4MB. Big background tasks will now consume the memory that the foreground app needs-didn’t we have that with then Tungsten T? In addition, the whole write cache is sized only 10MB-so you cannot open a PRC file or a single database record that has more than 10MB even if there is enough storage free. Imagine this-the good old m515 can handle PRC files bigger than the T5. With data records, the problem isn’t as bad-as only the record that is currently being used resides in the cache! However, huge PRC files or reading and using more than 10 MB of data at the same time may become a problem!
In addition, many PalmOS applications use one database with many little records-the PalmOS allows up to 64k with only little performance penalty. However, on the TT5, each record resides in an own sector and munches up at least 512 bytes(I am not 100% sure about this number). Thus we now have the same sector problem that the FAT file system has had for many years on the PC-but now on the Palm!
Concluding, there is an old German saying: Weniger kann oft mehr sein! Translated, it means as much as less can be more! However, this is definitely not true with the new T5 and its memory architecture!
If you want further information, just scan the PalmOS Mailing List for the words Big issues with the T5.
Additionally, the following pages may be helpful:
PalmONE Pluggedin program
Red Mercury Flash answer page
As always, I am looking forward to interesting comments!