How hard drives work
Linc
OwnerDetroit Icrontian
Wonder what goes on inside that silver box that keeps all your data? Learn how current hard drives operate, and how solid state devices operate differently.
Most people have thousands upon thousands of megaybytes of data on their computer, and indeed the hard drives we used today to store all that information have grown by astronomical amounts since the early days, but have you ever wondered just how a hard drive actually works?
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Great read Thrax
"Higher rotational velocities can significantly increase data read and write time"
Surely it either increases read/write SPEED, or DECREASES the time taken
I have a question regarding spindle speed vs areal density.
Is it true that the maximum data rate read from the platter to the buffer (and visa versa) by a single read head, is proportional to SPINDLE SPEED x LINEAR TRACK DENSITY.
So potentially the figure of performance for a disk drive is SPINDLE SPEED x SQUARE ROOT(AREAL DENSITY).
In another words: A disk with twice the spindle speed is twice as good as the same disk with double the areal density instead.
COOL.
So potentially the figure of performance for a disk drive is SPINDLE SPEED x SQUARE ROOT(AREAL DENSITY).
Now ... Correcting my Math in conclusion ... Doh:
In another words: A disk with twice the spindle speed should be equivalent in performance to the same disk with four times the areal density instead.
Thrax replied:
It is true, however as the spindle RPMs increase, the track density must decrease due to reliability concerns.
Now thats straight. Thanks.
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thanks
Hard drives put data wherever there's a physical space on any of the platters that's large enough to hold the binary in question. Once the data is broken down into small chunks called blocks, the file system (like FAT32 or NTFS) records where those blocks have been placed, and should they get shuffled around, where they have gone.
It's easiest to imagine that a hard drive is a big filing cabinet with a master index on the side that lists where every page of every document is stored. A hard drive might not put all the pages in the same drawer, but instead you can read the index and see what drawer each page is saved in.
A hard drive will attempt to store the entirety of a file on a single platter (it's faster this way), but it won't hesitate to store it on multiple platters if the need arises. As far as I am aware, a hard drive can only read from one armature at a time, though I'd be happy to see if I could get you an official answer from a hard drive manufacturer.
The biggest speed boost for a mechanical drive comes from increasing the drive's areal density, or how many bits of data can be stored per square inch. The higher the density, the less distance an armature has to cover to load an entire file.