UIQ 2.x devices incorporate several different and separate memories.
- 1. ROM Drive Z:
The Z: drive is called ROM drive. It contains the operating system - the Symbian OS 7.0 / UIQ software. This memory is based on Flash chip and is read only. Users cannot modify its contents. This memory can only be erased and re-written during the firmware update process either by authorized service centres or (in case of Sony Ericsson Pxxx smartphones) via the Sony Ericsson Update Service.
- 2. ROM drive A:
A: drive is another read only ROM drive. This disk contains "customization" software, depending on your country and/or operator, like Web browser's home page and default bookmarks, default themes, standard ringtones, default color scheme, MMS templates, startup and shutdown animations, etc. These contents depend on your CDA version. You cannot modify this disk's contents.
- 3. User storage disk C:
Disk C: is like hard disk in your desktop computer. You can use it to store different kinds of files and install 3rd party applications. The system uses it to store its settings and databases (like Contacts database or Calendar database). You can freely modify its contents, but you should avoid modifying the System folder, which contains system data and settings required for the device to boot and work. The size of this disk in P800 is about 12 MB and about 16 MB in P900. P910 has much larger disk C: - about 64 MB. Disk C: is based on Flash memory, which means that its contents are fully secure even if you remove the battery as Flash chips preserve their contents without any current supplied.
- 4. Storage memory card D:
Disk D: is the Memory card (Memory stick Duo in SE P-series phones, Secure Digital in A92x and TriFlash in A1000/M1000). Basically, it serves as an expansion of the internal storage memory (disk C:). You can use it to install third party applications and store different kinds of files and documents. Both P800 and P900 support MS Duo memory cards up to 128 MB, the P910 supports Memory Stick PRO Duo cards (currently up to 2 GB).
- 5. Operating memory - RAM
This is a separate memory that acts exactly like RAM memory in your PC. You can't install any applications or data in it. This memory is used for execution of the operating system and applications. Both P800 and P900 contain 16 MB RAM of which about 6-8 MB is free for executing user applications and the rest is being used by the operating system itself. The P910 (as well as Motorola A92x/A1000 phones) has 32 MB RAM of which about 21 MB is free for the user. If you see "Not enough memory" message, it means that there are some applications running in the background (Symbian OS is a multitasking operating system capable of running many applications and processes simultaneously) and you have to close some of them to provide free memory for the application you are trying to launch. This can be done using so-called "task managers" showing list of tasks running in memory and letting you close them. Good examples of such applications are TaskMan, SMan, Switcher etc.
Users very often mix up different kinds of memories. For instance, many users try to remove data from C: drive when they see "No memory" message. This message usually applies to insufficient RAM memory and has nothing to do with free space on C: or D: disk.