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Grasping RAM, ROM, Flash, User, Built-in, and External Memory


Sep 22, 2010, 1:57 AM

I’m doing a report about Smartphones and the carriers for a non-profit organization called UCAN ( I’m finding your site to be very helpful.

I’m trying to understand the seemingly interchangeable terms for memory that I find at different sites. I see RAM, ROM, Flash, User, Built-in, and External. The first and last a clear. Some phones don’t show a ROM spec but they show a Flash spec. I know that Flash memory is not RAM because it’s slower and I gather that it usually contains the OS + apps. Do some phones have the OS stored in a EPROM (i.e.ROM) instead of flash memory or are ROM and Flash the same?

Some phones show internal USER memory. I assume this to be part of either the flas...

Sep 22, 2010, 3:46 PM
Check out the terms in the Glossary link to the side bar. That should clear up the bulk of what your looking for.

Sep 22, 2010, 4:04 PM
You're right, it helps. Thanks. I now know that ROM is a throwback and is today a misnomer for FLASH memory.

The terms USER Memory and BUILT-IN Memory are not defined. Can you help here?

Sep 22, 2010, 6:46 PM
Built-in memory is generally the total amount of non-ROM storage space on the device.

In the strictest sense, user available memory is a subset of this built-in memory on the device. Some of this non-ROM internal memory still has to be reserved for use by the operating system and actively running applications, so it is partitioned off and only a portion of the internal storage capacity would be made available for actual user data like the address book, media files, etc.

Sep 23, 2010, 1:05 AM
So, apparently then, Built-in and User Memory specs don't refer to actual memory chips or devices. They are either supersets or subsets of the total onboard (excluding microSD plugin devices) memory.

Thanks, both, for your answers.


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