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1. bit   2. Byte   3. Code   4. Data   5. Program   6. Chip   7. CPU   8. RAM   9. ROM   10. Computer   11. Peripheral   12. System


Chip that Permanently Holds Instructions & Data.
Acronym: Ro = ct-PHID (pronounced See-tee FID).

ROM (rawm) is an acronym for Read Only Memory. ROM is a hybrid of hardware (chip) and software (instructions), hence is also known as firmware.

Off/on switch patterns in ROM are preset and fixed in position by the manufacturer. Some ROM chips contain basic startup instructions that are activated each time you turn on the computer. Other ROM chips contain instructions for operating certain devices, like your monitor. These instructions are put into ROM because it's quicker than having to go out and get them from the disk every time they're needed.

ROM Features

Read Only
The computer can "read" the switch settings in ROM but can't "write" to it. Hence, any instructions and data stored inside are permanent--they cannot be changed or erased.

Just as volatile means temporary (see RAM), non-volatile means permanent. The switches in ROM are "hardwired" or fixed in position. No power is required to hold its switches On.

ROM vs. Disk
ROM chips are similar to disk media. You can touch and hold them (hardware), yet they contain instructions and data (software). Some portable computers come with software preloaded to ROM, eliminating the need for program disks. However, the advantage of programs on disk is that a new version of the program can be inserted into the computer and used immediately. With ROM, the computer case must be opened to replace the old ROM chip with a new one--something most users are reluctant to do.

ROM is not the same as CD-ROM (Compact Disc-Read Only Memory). A CD-ROM is a foil-coated plastic disc spun in a CD-ROM drive and used for storing large volumes of instructions/data, especially music and video. CD-ROM is called Read Only because it can not be erased or rewritten. However, it more appropriately should have been named CD-ROS, that is, Read Only Storage.

PROM (prawm)
A ROM chip starts as a PROM or Programmable ROM. Once programmed, it cannot be altered.

Imagine a factory worker setting switches in a PROM to OFF and ON. Imagine a second worker pouring "Glue" from a bucket over the PROM switches. Now visualize the switches in the finished ROM chip permanently "glued" in position. Note: This procedure is done electronically, not with glue! Remember, most BrainAids are make believe.


Computer Hardware AcroMap--4 of 5 Terms
Add the new terms to your memory banks. Can you verbally recite what each acronym represents? Observe that ct and ID appear in all three chip types.


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