### Economics of PC Storage part 2 - Hard Disks

#### By rmd on Feb 16, 2006

A more interesting way to measure Hard Disk value is GigaBytes per Dollar

Assuming that the GB per $ performance of hard drives can be represented as a quadratic we get

the red dotted line.

lm(formula = Size/Price ~ Size + I(Size\^2), data = mytable)

Residuals:

Min 1Q Median 3Q Max

-0.36294 -0.14051 0.02323 0.13648 0.38674

Coefficients:

Estimate Std. Error t value Pr(>|t|)

(Intercept) 6.514e-01 1.517e-01 4.295 0.000202 \*\*\*

Size 1.173e-02 1.169e-03 10.030 1.33e-10 \*\*\*

I(Size\^2) -2.052e-05 2.030e-06 -10.107 1.13e-10 \*\*\*

---

Signif. codes: 0 '\*\*\*' 0.001 '\*\*' 0.01 '\*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 0.1907 on 27 degrees of freedom

Multiple R-Squared: 0.7923, Adjusted R-squared: 0.7769

F-statistic: 51.5 on 2 and 27 DF, p-value: 6.093e-10

Solving the quadratic we get the best price performing hard drive would be 286GB, sadly nobody makes such a drive but by eyeballing the graph the sweet spot is between 250GB to 320GB with a price performance above 2GB per dollar. Giving us a reasonable margin to build our OpenSolaris Appliance and still beat the comercial products 0.33 to 0.62 GigaBytes per dollar.

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*T*: OpenSolaris Qube ]