The price deflator for SSD products has been running at around 45%. This means the average selling price is 45% cheaper than last year for a given capacity.

Prices have fallen low enough that by the end of 2019 the important 10 cents per GB may be reached. Already 1TB products are now just below 10 cents per GB. Consider the basic ordinary differential equation.

y(t) = a × ekt

Given we know a 1TB M.2 SSD is $100 now and we expect it to be $55 in 365 days.

55 = 100 × ek×365

Plugging in the values it now becomes easier to understand. So solving for k is easy. So divide both sides by 100 to give:

.55 = ek×365

Taking the natural log of each side gives:

ln(0.55) = k x 365

This gives:

k = ln(0.55) / 365 = -0.00163790959

Now that k is known, it can be used directly to determine the price on any day.

Inflation works the same way, but instead of a lower price, a higher price is used and the same process of finding k is the same.

This type of ordinary differential equation is easy to solve. Any high school student with grade 10 can handle fine.

It’s not hard to set up Excel to calculate a deflator curve for illustration. Long ago with MS-DOS, BASIC would be used to compute the values and draw a curve.

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