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Is there a difference between the terms OS and ROM?

Discussion in 'Android Lounge' started by ballhands76, Oct 22, 2010.

  1. ballhands76

    ballhands76 Newbie
    Thread Starter

    If so what is it, and which one is made accessible by Android being open source? (Yup, I'm a newbie.)

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  2. ballhands76

    ballhands76 Newbie
    Thread Starter

    Perusing the web, I get the impression that a phone's ROM is an image of an OS that's been installed to a phone, so the two terms are roughly equivalent - is this correct?
  3. fangorious

    fangorious Guest

    OS == Operating System. It is the software that runs the system. Windows is an Operating System, as are Mac OS X, Linux, and Solaris. Android devices run the Linux OS. Linux is open source, and Google maintains that openness with Android.

    ROM == Read Only Memory. It usually describes a piece of hardware, a memory chip that you normally can't write to. Device manufacturers will typically use ROM to store the OS to help ensure the devices maintains a known state and is thus more reliable and easier to support.

    Rooting your phone is a way to give yourself enough access to write to protected parts of the file system and alter the OS. People tend to use the phrase ROM in these types of forums to refer to a complete image that contains an OS which you can load on your phone.
    ballhands76 likes this.
  4. AndroidSPCS

    AndroidSPCS Android Expert

    ballhands76 likes this.
  5. takeshi

    takeshi Android Expert

    As discussed above, they're roughly equivalent but there are some distinct differences. "Image" would be more equivalent to ROM than OS, IMO.

    Can you explain what you mean by "made accessible"?
    ballhands76 likes this.
  6. Member243850

    Member243850 Guest

    Howzit ballhands76!

    When some1 says ROM they technically mean EPROM / EEPROM (electronically erasable programmable read only memory)

    ROM is only for reading and not for writing / or reprogramming... the correct term is EPROM. Like a CD or DVD...

    Today EPROM chips can "read" and "write" like transflash / usb stick :)

    Hope this helps dude ;)

    ballhands76 likes this.
  7. ballhands76

    ballhands76 Newbie
    Thread Starter

    I think I get it. Thanks to everyone for all your help!

    takeshi, what I meant was which exactly is open-source, the OS or the ROM, in case there was a difference. I take it that the OS is open-source and modifiable, and a modified OS can theoretically be installed as a ROM image on a phone.
  8. snapper.fishes

    snapper.fishes Android Expert

    For most intent and purposes, ROM and OS are the same on an android. The same goes for firmware.

    The Android OS is definitely open source. But are manufacturer roms open source? Possibly not. Google allows individual companies to customize the android OS interface, and those modifications are not open source.
    ballhands76 likes this.
  9. This is old as dirt, but I want to thank the original asker as well as all these helpful responders. I was just confirming this theory myself.
    funkylogik likes this.
  10. dan330

    dan330 Extreme Android User

    some clarification...
    ROM .. the TERM is used in many areas and with different meanings.

    OS = Operating System

    some OS are open source.
    Android is an open source OS.

    Android OS is packaged into a file with other needed parts .. to be loaded on to devices.
    this file is called a ROM. (I don't know what the letters stand for here)

    some developers take the open source Android OS.. change it up ... customize it.
    repackage it into a custom ROM to be loaded into specific mobile devices.
    #10 dan330, Dec 9, 2014
    Last edited: Dec 11, 2014
    funkylogik likes this.
  11. kbkjamar

    kbkjamar Lurker

    #11 kbkjamar, Sep 10, 2019
    Last edited: Oct 3, 2019
    ocnbrze likes this.
  12. ocnbrze

    ocnbrze DON'T PANIC!!!!!!!!!

    yes...you got it.

    once the custom rom is flashed it becomes the os, but we still call it by the name of the rom and not what os the rom is based on.

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