The goal of this page is to take annual size and pricing data for hard disks each year going back to 1992 and use it to determine any trends over the period.
The graphs on this page are generated from data collected from issues of APC magazine and retail web sites. The data is broken down into half yearly intervals and records the best price found for each drive size advertised. At this point, I have only studied what I'll call IDE interface drives. (IDE has had other names over the years but I really don't care, hopefully we all should know what kind of disks I'm talking about). IDE drives have nearly always been the most popular type and it is still the most popular drive type today.
I have made a FAQ for people that have questions about my methodology.
Improvement In Bang Per Buck
If you did take a look at the data, you can see that, for each half year, the drive with the best $ per megabyte figure has been highlighted in red. I call this drive with the best bang for buck the sweet spot. By calculating the percentage improvement, year on year, of the sweet spot using the figure from the first half of the year, I have come up with this graph which charts the history the annual improvement rate of bang per per buck.
Some interesting points:
There is a very consistent period of improvement appearing in the 4 years from 93 to 97 . Over this period there was 30 fold increase in the amount of storage you could buy for the same money.
The slowest period of growth occurred in 93 with only a 6% improvement over 92.
Over the last 5 years there has been a dramatic slow down in the improvement rate. This is possibly because hard drive technology is approaching the superparamagnetic limit. Hard disk manufacturers are having trouble squeezing more and more bits into the same area. It could also be attributed to lack of market demand. The only popular application requiring vast amounts of storage today is video and it seems video content owners are doing their best to make sure you wont be able to easily record it.
The 15 year trend shows about a 90% annual improvement in bang per buck for hard drives. If this were to continue for the next 6 years then by 2013 we could expect to pay only 1 cent (AU) per gig. Given that today 1c US is about 1.06c AU then 1c US per gig mark would be also be crossed in 2013.
In order eliminate the huge boom period from 94 to 97 from possibly distorting the estimate, a measure of the 11 year trend shows an annualized improvement rate of 75%. Projecting again to when we can expect 1 cent per gig gives 2014 for Australian currency and the same for US currency.
Lastly, to show how below ordinary the last 5 years have been, a look at the 5 year trend reveals the annualized rate to be only 42%. That gives 2018 for the 1c per gig mark for, respectively, the AU and US currencies. The bad news is that this 5 year rate is expected to continue for at least another year.
Annual Sweet Spot Capacity Increases
I was going to use the data to show the growth trend in the largest capacity drive available over time. The data isn't very suitable for this as the largest drive available at the time might not be advertised in APC , due to the fact that not many readers and therefore buyers, are interested in purchasing bleeding edge, lower economy hard drives. Advertisers only advertise drives they think they can make the most profit on and that usually means products that sell in volume.
What I decided to do instead is analyze the growth in size of the drive positioned at the “sweet spot”. Many buyers are interested in getting a drive the most Gigs per dollar and so it might be of interest to know how large this drive might become over time.
I chose two specific trends to look at. The whole 16 years and the last 5 years.
The 16 year trend averages out at a whopping 94% increase in size per annum. There was a lot of fluctuation between 93 and 96 with no increase or a reduction in the size of the sweet spot drive in 93 and 95. The was made up for by a massive improvements in 94 and 96. After that the growth rate falls away dramatically. Expecting an average 94% annual increase in drive sizes to continue would seem optimistic. The shorter term average is significantly less.
Taking the 5 year trend gives an annual growth rate of only 33%. The sweet spot in the first half of 2008 is 500GB. Extrapolating the 29% trend means that 1 Terabyte drives could be in the sweet spot in 2011.
The graph shows a clear declining (and disturbing) downward trend. If the trend continues, we cant really expect substantial yearly size increases in the future. If we combine this with the fact that disk space is expected to continue to get cheaper per megabyte then our future may contain very cheap drives indeed. This is because the cost per megabyte would be decreasing at a faster rate than the number of megabytes would be increasing. The result is falling prices per disk. Because of this, RAID may become a much more common solution for people wanting large amounts of storage.
Annual Sweet Spot Price Trends
This next chart shows the price of the “sweet spot” drive in each year.
The long term trend is clearly downwards. If you ignore the data from years 94, 95 and 98 then you end up with a very consistent curve.
It works out to be about a 10% decrease in price decrease each year. This is probably the most consistent trend on this page and one that has not changed much in recent years. From this, it seems safe to say that the sweet spot pricing for hard disks will cross below the $100 mark in about 2012, 4 years from now at which point the drives should be in the Terabyte range.
You can find the 2006 version of this page here.
Ideas welcome
I'm looking for corrections, comments, alternate analysis of the results or even ideas of new ways to look at the data. If you have any of these then please send me a mail to matt21811@yahoo.com.au with your contribution. Thanks!