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> The RAM myth is a belief that modern computer memory resembles perfect random-access memory. Cache is seen as an optimization for small data The post doesn't
by shmerl 2y ago
> The RAM myth is a belief that modern computer memory resembles perfect random-access memory. Cache is seen as an optimization for small data
The post doesn't seem to answer what the memory actually resembles. If it's not resembling a random access memory, then what is it resembling?
- zahlman 2y agoIt resembles a hierarchy wherein a small fraction of memory - a "cache" region - can be accessed much faster than the rest. With careful planning, the programmer can increase the odds that the necessary information for the next step of an algorithm, at any given point, is within that small region. (This is a simplification; there are actually several layers of cache between a CPU and the most general part of the RAM.)
- rcxdude 2y agoIt resembles sequential access memory with relatively fast seeks and a cache (ok, multiple layers of caches). Reading sequential, predictable addresses gives you much more throughput than random access, and reading a value that was recently accessed (or adjacent to such) is much lower latency than something that was not. There's further wrinkles in multicore systems as well, because then accesses to memory recently written to by another core can be slower again.
- dare944 2y agoI can only conclude the word myth was chosen for attention. Modern CPU memory systems (with or without their caches) certainly resemble idealized RAMs.