About the 770's memory

From Internet Tablet Talk

This information is edited from comments made at Ars Technica by Karoliina Salminen, a member of the team at Nokia who designed and built the 770. Her blog is at http://www.karoliinasalminen.com/blog e mail : karoliina at maemo dot org

The 770 has 64MB RAM as shown in the specs on the Nokia site.

Flash memory in the 770 has nothing to do with memory consumption of applications since the 770 does not swap to flash or run applications inside flash. I use 1GB RS-MMC in my 770. The memory applet in the control panel indicates the available space on flash and not the available memory to run applications. To see how much free RAM you have, go to xterminal and use top, for example. For the amount of RAM being 64MB, at Nokia the 770 team has done a lot of optimization, e.g. we implemented background killing for applications. All applications that are shown on Task Navigator are not running; they are killed, then brought back when user switches on them and their state is restored from flash.

Nokia 770 has: 64MB RAM (which is available to run Linux operating system, UI framework (including maemo-af-desktop) and then applications on top of those) 128MB flash (which is for storing data and applications, in other words, the filesystem) bundled 64MB RS-MMC card for storing data (mp3, videos, documents and stuff) and the applications.

The RAM in 770 is DRAM. It is *not* flash-RAM. The Linux system runs in DRAM, not in flash memory where the filesystem is located in JFFS2 format (JFFS2 spreads the writes around the flash so that one block gets as seldomly writes as possible to minimize the wearing out). The flash is a storage device, in other words a file system (formatted in JFFS2), a similar thing than a hard disk if you like. The device does not have swap currently on flash as it would be 1) slow 2) would wear out the flash because flash has limited number of write times - it is not because of the particular flash memory used in the device but because it is the nature of flash memory. Therefore it runs on DRAM exclusively everything and that is 64MB. Adding flash affects by no means the amount of memory the applications have to run.

It would be possible to put the swap to flash, but it is not that recommended if you are not willing to wear your flash out fast. I may test it sometime soon in my device, however, correct place to continue discussion about using flash for swap filesystem would be in maemo-developers list.

The RAM in Nokia 770 (in other words memory) is 64MB and the (slower) flash memory (analoguous to hard drive, but has no moving parts) is used for the JFFS2 filesystem exclusively where the Linux is installed and where the user can store their applications. If you look at the size of the rootimages (software updates) for 770, their size equals the size of the Flash on the device.

There is a nice page in Wikipedia explaining flash memory: http://en.wikipedia.org/wiki/Flash_memory I am happy to answer to any further questions if any unclear technical issues still would remain.