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This is the least expensive, and fastest way of making mask ROM [3] as it only needs one mask with data, and has the lowest density of all mask ROM types as it is done at the metallization layer, [3] whose features can be relatively large in respect to other parts of the ROM. This is known as contact-programmed ROM.
If we ignore both these effects, then the average memory access time becomes an important metric. It provides a measure of the performance of the memory systems and hierarchies. It refers to the average time it takes to perform a memory access. It is the addition of the execution time for the memory instructions and the memory stall cycles.
A module of any particular size can therefore be assembled either from 32 small chips (36 for ECC memory), or 16(18) or 8(9) bigger ones. DDR memory bus width per channel is 64 bits (72 for ECC memory). Total module bit width is a product of bits per chip and number of chips. It also equals number of ranks (rows) multiplied by DDR memory bus width.
The most common word size is 8 bits, meaning that a single byte can be read or written to each of 2 m different words within the SRAM chip. Several common SRAM chips have 11 address lines (thus a capacity of 2 11 = 2,048 = 2 k words) and an 8-bit word, so they are referred to as 2k × 8 SRAM .
The byte, 8 bits, 2 nibbles, is possibly the most commonly known and used base unit to describe data size. The word is a size that varies by and has a special importance for a particular hardware context. On modern hardware, a word is typically 2, 4 or 8 bytes, but the size varies dramatically on older hardware.
Original CD-ROM drives could read data at about 150 kB/s, 1× constant angular velocity (CAV), [1] the same speed of compact disc players without buffering. As faster drives were released, the write speeds and read speeds for optical discs were multiplied by manufacturers, far exceeding the drive speeds originally released onto the market.
It is one type of read-only memory (ROM). PROMs are used in digital electronic devices to store permanent data, usually low level programs such as firmware or microcode. The key difference from a standard ROM is that the data is written into a ROM during manufacture, while with a PROM the data is programmed into them after manufacture. Thus ...
In 1967, Dawon Kahng and Simon Min Sze at Bell Labs proposed that the floating gate of a MOSFET could be used for the cell of a reprogrammable ROM (read-only memory). [3] Building on this concept, Dov Frohman of Intel invented EPROM in 1971, [3] and was awarded U.S. patent 3,660,819 in 1972. Frohman designed the Intel 1702, a 2048-bit EPROM ...