CompuServe Messages

Dan; First to muddy the waters… ROM is RAM! This just happens to be one of my "buttons." ROM = Read Only Memory and RAM = Random Access Memory. RAM is defined as memory where any memory location can be accessed without regard to any previous access. Basically that means that you can access location 00001 and then 99999 and then 98989 and then 00002 or whatever other order you (or your program) would like to use. Contrast this type behavior with a tape drive where you can't get to the last file without first spooling by all of the previous ones. ROM chips used in almost all computers today are definately RAM. The memory that most of the world refers to as RAM should actually be called Read/Write memory. Now having said all of that: A single memory location is usually considered to be 4 bits wide, 8 bits wide, 16 bits wide or 32 bits wide (recognize that Main Frame computers often use other values, but micros and minis pretty well stick to these). 4 bit data bus computers were never very popular to start with so it is unlikely that you have seen or used one. The size or capacity of the memory is usually express in bytes (kilobytes or megabytes, 1024 byte units or 1,048,576 byte units respectively) regardless of whether the processor accesses the memory a byte (8 bits) at a time, a word (usually 16 bits — now anyway) at a time, or a long word (again usually 32 bits) at a time. The 68030 processor (used in the Amigas 3000 and most accellerated Amigas) can access memory 32 bits at a time. These same chip can also access memory by 8 and 16 bit chunks. Since every memory access cycle takes time, a precessor that is required to access memory that is only 16 bits wide will take about twice as long as one that accesses 32 bit wide memory. Now this does not mean that the processor will run twice as fast but just based upon memory access time you can bet that the programs will run much faster. The chips themselves come as 1 bit, 4 bit, and 8 bit wide devices (standard, I [ MORE ]