Read-only memory (usually known by its acronym, ROM) is a class of storage media used in computers and other electronic devices. Because data stored in ROM cannot be modified (at least not very quickly or easily), it is mainly used to distribute firmware (software that is very closely tied to specific hardware, and unlikely to require frequent updates).
Modern semiconductor ROM chips are not immediately distinguishable from similar chips like RAM modules, except by the part numbers printed on the package.
In its strictest sense, ROM refers only to mask ROM (the oldest type of solid state ROM), which is fabricated with the desired data permanently stored in it, and thus can never be modified. However, more modern types such as EPROM and flash EEPROM can be erased and re-programmed multiple times; they are still described as "read-only memory" because the reprogramming process is generally infrequent, comparatively slow, and often does not permit random access writes to individual memory locations, which are possible when reading a ROM. Despite the simplicity of mask ROM, economies of scale and field-programmability often make reprogrammable technologies more flexible and inexpensive, so that mask ROM is rarely used in new products as of 2007.
Modern semiconductor ROM chips are not immediately distinguishable from similar chips like RAM modules, except by the part numbers printed on the package.
In its strictest sense, ROM refers only to mask ROM (the oldest type of solid state ROM), which is fabricated with the desired data permanently stored in it, and thus can never be modified. However, more modern types such as EPROM and flash EEPROM can be erased and re-programmed multiple times; they are still described as "read-only memory" because the reprogramming process is generally infrequent, comparatively slow, and often does not permit random access writes to individual memory locations, which are possible when reading a ROM. Despite the simplicity of mask ROM, economies of scale and field-programmability often make reprogrammable technologies more flexible and inexpensive, so that mask ROM is rarely used in new products as of 2007.
الأحد مايو 08, 2011 5:27 am من طرف Samer Al Sayegh
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الثلاثاء مايو 03, 2011 8:15 pm من طرف هيثم فرج
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الإثنين مايو 02, 2011 4:11 am من طرف hanin
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الخميس أبريل 28, 2011 5:55 pm من طرف Samer Al Sayegh
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الإثنين أبريل 25, 2011 6:03 pm من طرف Samer Al Sayegh
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الإثنين أبريل 25, 2011 4:08 am من طرف hanin
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الإثنين أبريل 25, 2011 12:56 am من طرف Samer Al Sayegh
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الأحد أبريل 24, 2011 12:40 am من طرف Samer Al Sayegh
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الأحد أبريل 24, 2011 12:38 am من طرف Samer Al Sayegh