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Rockbox Ports are now being developed for various digital audio players!

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Author Topic: flash memory vs ram in rockbox  (Read 1722 times)

Offline scharkalvin

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flash memory vs ram in rockbox
« on: October 05, 2007, 12:30:21 PM »
As we all know, flash memory is limited in the number of write cycles before the device dies.  If you constantly update your database, would this lead to early demise of the flash memory?  In the manual, under database settings, there is an option to keep the database in ram.  However, I didn't see this option available in a recent build for the e200 (this weeks build).  Is this not available for the e200?

Also, if I replace the disk memory in my ipod mini with a flash card, how does rockbox treat this?  IE: do rockbox ports for flash based players try to conserve writes to the flash (treat it less like a disk)?  Do ports to disk based players tend to not conserve on write cycles to the disk (bad if you replaced the disk with a flash device).
I would think that the storage media would be a write/read mostly device, and the only time that software would write to the device would be when adding/deleting/modifing files.  Modifing files would only happen during a database update, or a configuration change.  You shouldn't need to modify the database unless you add/delete music files (right?).
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Offline Chronon

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Re: flash memory vs ram in rockbox
« Reply #1 on: October 05, 2007, 01:40:15 PM »
I wouldn't worry about it too much. . . read more here.

In short:
Quote
As a rule of thumb: if you just write 10 or so data bytes to the Flash Variable table a few times per minute, your application can run for 10 years, before the guaranteed maximum erase/re-write cycle time is reached.

I believe that the analysis on that page assumes a USB drive with flash storage plus microcontroller to allow wear-leveling.  I would guess that the implementation of wear-leveling would be pretty standard in flash-based DAPs.  Compact Flash definitely employs wear-leveling.
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Sansa e280, Gigabeat F40, Gigabeat S60, Sansa Clip+, iPod Mini 2g

Offline dedalus

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Re: flash memory vs ram in rockbox
« Reply #2 on: October 05, 2007, 03:33:26 PM »
Is the wear-levelling routine transparent to the firmware? ie is it something the devs need to concern themselves with when developing for flash-based players or does having the memory working at all assume that the (presumably hardware-controlled) wear-levelling is working with it?
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Offline bluebrother

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Re: flash memory vs ram in rockbox
« Reply #3 on: October 05, 2007, 03:53:43 PM »
It's a hardware controlled thing as the software doesn't know anything about the internal organization of the flash memory.
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Rockbox Utility development binaries (updated infrequently) · How to ask questions the smart way · We do not estimate timeframes.

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