ROM or Read-Only Memory (English: Read-only memory (ROM)) is a type of storage medium used in computers and other electronic devices. The information in the ROM cannot be changed or can be done very slowly or difficult to do. So it is mainly used in firmware.
ROM - Read Only Memory
Other non-volatile or power-lost memories that remain are EPROM, EPROM or flash memory. These are sometimes called ROMs but this is incorrect or a misconception because EPROMs or EPROMs can be deleted and re-programmed
History
Many game consoles use interchangeable ROM cartridges, allowing you to play many games with one system.
Rom was used in jacquard looms.
ROMs of ordinary solid state are as old as semiconductor technology. The n-bit address can be input as desired using the combination logic gate as the arbitrary data or value m-bit data output. Mask ROM originated after the discovery of integrated circuits. Mask ROM is actually the sum of some word lines (so that the address has input) and bit lines (so that there is output information). These selectors are added to some transistor switches and reveal arbitrary look-up tables (normal layouts) and predictable propagation delays.
Circuit information is encoded in the mask layout before programming is done during creation. This can lead to some problems such as:
1. It is cheaper to buy only in large quantities, and users have to contact the manufacturers directly for the ROM they wish. Production takes more time as it is done in two stages and both stages are slow. It is unsuitable for research and development because it requires rapid design changes. If a product is not properly prepared or misplaced after sale, the product needs to be changed directly from the manufacturer.
Subsequent developments took steps to address these issues. PROM, invented in 1956, used users to program content once using a high electrical voltage pulse. This solves problems number one and two as a company can easily place PIRM orders and then program them according to their own content. EPROM 3, discovered in 1971, solves the problem. Epirum could be re-programmed or re-used using high levels of ultraviolet light. EEPROM, invented in 1973, solves problem number 4 because EEPROM can be programmed anywhere using any external programming content serial cable. Flash memory was invented by Toshiba in the mid-1980s and released in the early 1990s. It is a type of EPERM that ensures efficient use of chip space and can be re-programmed thousands of times without any damage to the chip.
Although these technologies have improved the performance of ROMs, the Musk ROM was still a popular choice among consumers as a cheap chip (the price of reprogramming devices dropped in the 2000s and the Mask ROM market took over). In fact, it is one of the reasons why new technology ROMs are not only read-only.
The designers of the recently developed NAND Flash (made by Toshiba) claim that they have removed all previous rules, adding that "this is an alternative to the hard disk" [3] which was previously non-volatile primary memory. As of 2006, NAND achieved some of these demands, which were characterized by high levels of endurance, small size, low power consumption, and so on.
Usage for saving programs
Usage for data storage
Since ROM information cannot be easily changed, it contains information that does not need to be changed easily. For this reason, ROM is used to store look-up tables (used for mathematical and logical tasks) on various computers. This is very effective when CPU speeds are low and RAM costs more than ROM.
Note that the old display adapters of personal computers used to store bitmap font data in ROM. This means that the fonts on the display could not be easily changed. The same is true of IBM personal computer XT's CGA and MDA adapters.
In modern day computers, data storage is no longer a matter of ROM. However, flash ROMs now play the role of data storage medium or secondary storage medium. Rom ...
Types Editing
Semiconductor technology
Mask programmed ROMs are integrated circuits that manually encode and store data and are impossible to change after production. Other types of non-volatile solid-state memory allow for change in some cases.
Programmable Read-Only Memory (PROM) or One-Time Programmable ROM (OTP) which is programmed in a one-time ROM with a special device called Piram Programmer. Something is permanently created or removed by providing a high level of voltage to the interconnected link or connection between the chips. As a result, it can be programmed only once.
Erasable programmable read-only memory (EPROM) is exposed to strong ultraviolet light (usually 10 minutes or more) and the program is rewritten. The next time you wipe, you have to hold more energy or longer than the first time you applied it. Repeated exposure to ultraviolet light can damage the ROM or make it unusable. But chronic ROMs can be deleted and programmed to 1000 or more. EPROM recognizes that the ROM has a "window" shaped space through which ultraviolet light enters. After programming it is covered with level so that nothing unwanted happens and for reuse.
Electrically Erasable Programmable Read-Only Memory (EPROM) The structure of its semiconductor is similar to that of EPROM but it can be erased and programmed by applying electrical energy to a specific part or part of it. This does not allow you to open them (computer, MP3 player, camera, etc.). Writing or flashing in EEPR is much slower than RADM.
Electrically Alternative Read-Only Memory (EAROM) is a type of EPROM that can be changed once a bit. Writing is very time consuming and requires high voltage (about 12 volts). This ROM is used on devices that do not require rewriting or require less.
Flash memory is the modern EPROM (discovered in 1984). It can be deleted and written faster than EEPROM as well as long lasting (more than 100,000 cycles). The modern NAND Flash (announced in 2006) has an IC capacity of 32 GB which ensures efficient use of the chip. NAND flash is used instead of magnets in some products
Other technology edits
There are other types of non-volatile memory that are not of semiconductor technology, such as-
Optical storage medium, such as CD-ROM that can only be read. CD-R can be written and read repeatedly, whereas CD-RW can be written and read more than once.