Nope, American comma. Now that you mention it, it seems high to me as well. I just figured out why:
That is cached or buffered reads.[0] The buffer appears to be a small amount of memory that sits on the HDD. In addition to housekeeping, it seems mostly useful for read-ahead, which seems like it helps a little bit when you are accessing the same part of the HDD repeatedly (i.e., usually). On my HDD it is 8 GB.
RAM is faster than cache though. My RAM has a peak transfer rate of 10666 MB/s (DDR3 1333). Stuff sits around in your RAM after being loaded until something else needs the space. So buffers help with initial loads from the HDD. But after that, RAM is king.
For sequential reads/writes to my actual disk, the speeds are 15,000 KB/s to 50,000 KB/s (faster for larger files).
So yeah. SSD still the way to go for any form-factor that can handle it. But it's nice to know that SD cards have gotten to the point where they rival and sometimes beat HDDs in terms of real-world performance. The range of possible applications for the Pi and its ilk just expanded in my mind.
That is cached or buffered reads.[0] The buffer appears to be a small amount of memory that sits on the HDD. In addition to housekeeping, it seems mostly useful for read-ahead, which seems like it helps a little bit when you are accessing the same part of the HDD repeatedly (i.e., usually). On my HDD it is 8 GB.
RAM is faster than cache though. My RAM has a peak transfer rate of 10666 MB/s (DDR3 1333). Stuff sits around in your RAM after being loaded until something else needs the space. So buffers help with initial loads from the HDD. But after that, RAM is king.
For sequential reads/writes to my actual disk, the speeds are 15,000 KB/s to 50,000 KB/s (faster for larger files).
So yeah. SSD still the way to go for any form-factor that can handle it. But it's nice to know that SD cards have gotten to the point where they rival and sometimes beat HDDs in terms of real-world performance. The range of possible applications for the Pi and its ilk just expanded in my mind.
Yay, learning!
[0]http://en.wikipedia.org/wiki/Disk_buffer