How does the ROM(Read only memory) store data in it?

Question

Does the ROM store data magnetically or? how does it store data?

Answer 1

Wow, guy above doesnt have a clue, Transistors are actually used in RAM(whihc disapears when the PC is turned off)

Harddisks use magnetic discs, thers a small head that uses a magnet to read and write. its pretty  safe form external magnets as its ina pretty thick case.

CD's are either stamped pits and gorroves in aluminium then read with a laser, or on home made re-wrtaible CD's the laser burns marks into the disk, so it acts like pits and grooves.

Flash drives use NAND transitors, so the memory can stay written, and its jsut a case of sending a small elctrical charge thouoght to see what the data is. Newer Hard drives called SSD's use similar technology.

Answer 2

It's basically hard-wired into the circuitry (like with transistors).  It can't be magnetic because if it was magnetic, it could easily be erased with another magnet (and then it wouldn't be read only!)

Edit for the guy below me: how can I not have a clue if you just restated the same things I said.  Basically that magetical drives can be re-written and that Flash Drives (A type of EEPROM) is made with NAND transistors?  On top of that, you didn't even answer his question.

Answer 3

If you are talking about ROM of a computer, here is the answer. The ROM is a memory which cannot be changed. Now when we do changes on the BIOS which resides on the ROM, it gets saved not on the ROM. There is something called BIOS image. I guess in the BIOS you have seen an option called "set to default" which will put your BIOS back to the factory settings.

  Now the changes that you do on the BIOS is saved on a chip called NV-RAM which holds the BIOS image. The changes that you do on the BIOS is actually saved here. To run the NV-RAM you have the CMOS battery, i.e the reason when there is no CMOS battery your computer is a little cranky.

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