Jim Pappas

Comparing SSDs to Tomatoes

TomatoA few years ago The SSD Guy posted an analogy that Intel’s Jim Pappas uses to illustrate the latency differences between DRAM, an SSD, and an HDD.  If we look at DRAM latency to be a single heartbeat, then what happens when we scale that timing up to represent SSDs and HDDs?  How many heartbeats would it take to access either one, and what could you do in that time?

I still think it’s a pretty interesting way to make all these latency differences easier to understand.

Just recently I learned of a Rich Report video of a 2015 presentation in which Micron’s Ryan Baxter uses a different and equally interesting analogy based on tomatoes.

Tomatoes aren’t the first thing that comes to my mind when I think about SSDs, but this video may change my way of thinking!

The tomato slide, 9:30 into the presentation, is Continue reading

Understanding Storage Delays

Jim PappasJim Pappas of Intel, a fellow member of SNIA (the Storage Networking Industry Association) shared a really intuitive way to understand storage delays at the last Storage Developer Conference (SDC).  It’s very simple.  First consider these two facts:

  • The difference between the speed of system memory and that of a hard disk drive (HDD) is roughly 6 orders of magnitude, or 1 million times
  • SSDs split the gap.  An SSD is about 1,000 times faster than an HDD, and is about 1,000 times slower than system memory.  Memory access times are measured in nanoseconds (ns), SSDs in microseconds (µs) and HDDs in milliseconds (ms)

The problem with understanding this (ns, µs, ms) is that Continue reading