Tuesday, December 11, 2012

Is it a time to focus from moor’s law to storage law?


Overall performance of computers (PC or Server) depends on many factors, people usually move to a faster processor. Comparatively memory/storage has become bigger bottleneck in recent years, due to the volume of data we store. The below table describes about the latency of each memory/storage technology.

Memory
Capacity
Latency
CPU Registers
Bytes
< 1 ns
Cache
kb/mb
< 10 ns
RAM
GB
< 100 ns
Hard Disk
TB
3 – 10 ms
Tape
PB
NA


Especially the hard disk latency. The evolution of hard disk technology - disk latencies have only marginally improved over the last years (≈ 10% per year). But throughput (i.e., transfer rates) improve by ≈ 50% per year. Hard disk capacity grows by ≈ 50% every year. Over the time the capacity of the memory grow faster, transfer speed grow moderately but latency grow very minimum. Throughput can be increased rather easily by exploiting parallelism, i.e Use multiple disks and access them in parallel. Solid-State Disks (SSDs), mostly based on flash memory chips, have emerged as an alternative to conventional hard disks. SSDs provide very low-latency but costly. HDD as a price of about $0.10 per GB – 10x cheaper than flash, this situation will change in coming years.


Related “If you’re not using SSD, you are doing it wrong

No comments: