The Forrest Curve

[Note: I originally wrote this in the early 1990s so some of the references are dated. Nevertheless, the point I’m trying to make is more true now than ever.]

The Forrest Curve
Jon Forrest

There is a phenomenon sweeping the computer industry that is having a profound but largely unrecognized effect. I claim that companies ignoring this phenomenon will suffer a slow and painful death. What’s more, there’s absolutely nothing that can be done to escape it. In this article I first describe this phenomenon and then spend some time trying to figure out what it means.

Simply and briefly stated, my hypothesis is that fewer and fewer computer users think their computer is too slow. I’ve invented what I call the Forrest Curve to illustrate this.

Here’s the Forrest Curve:

                   | \
                   |  \
    "slow"         |   \ /\
    factor         |    v  \
                   |        \ /\
                   |         v  \
                   |             \   /\
                   |               v   \
                   |                    \

                   -- time --

This is a curve with a general downward slope, having occasional upward blips. The curve approaches but never hits 0. Neither axis is drawn to any scale nor can be used to derive any specific numeric values.

The “slow” factor is the number of people who think their computer is too slow. I admit that this isn’t a very objective measurement but you can get a feel for it by the amount of grumbling about computer speed that takes place in your office.

I’m also not being very specific about exactly what constitutes a “computer”. I claim it really doesn’t matter. Taken as a whole, the whole pile of stuff sitting on someone’s desk (or lap), is what I consider to be a computer. A more detailed examination wouldn’t change the Forrest Curve.

Note that I’m including the entire population of computer users in this graph, many of whom know very little, if anything, about what their computer is really doing or how it works. But, even if I were to confine this graph to “software professionals” the graph would merely have a higher origin point. The general shape wouldn’t change.

I also recognize that there is a class of users that can and will always be able to consume any amount of computer resources. These guys are why the Forrest Curve never goes to zero. In spite of their needs they can’t reshape the Forrest Curve because they don’t have enough money to spend anymore.

Every so often something comes along that causes a temporary perturbation in the Forrest Curve. Some examples might be relational databases, X-windows, Windows NT, multimedia, handwriting and speech recognition, and so on. This is natural. There will always be such cases and they admittedly can cause high blips in the Forrest Curve. Sometimes these blips are partially flattened by special purpose hardware but the problem is that special purpose hardware usually has a short lifespan and is doomed to financial failure due to lack of economy of scale. The rest of the time general purpose hardware will catch up. The one exception I can see here is that the hardware necessary to handle digital video is special purpose now but will soon be a commodity, once consumer television goes digital.

Another implication of the Forrest Curve that we’re already seeing is the shrinking, if not outright elimination, of the distinction between a workstation and a PC. A while ago you could think of a workstation as a kind of special hardware gizmo that was only bought for a select few. The rest of us got PCs. But now, with 450Mhz Pentium IIs, the PCI bus, fibre channel disks, and all the rest, it’s gotten to point where the main difference between a workstation and a PC is the size of the monitor, the lack of IRQs in workstations, and maybe the amount of memory you can stick in a PC.

The Forrest Curve implies that the folk myth claiming that people’s requirements for computing power expands to consume all available computer cycles is no longer true. I’m not convinced that it ever was true, although I have more faith in its corollary about disk space. Meanwhile, although Moore’s Law, which states that the power of microprocessors doubles every 18 months, seemingly operates independently, the Forrest Curve does predict that Moore’s Law will start to spread out as the cost of producing ever faster microprocessors rises.

Another factor I recognize is that having an infinitely fast computer on your desk doesn’t do you any good unless it runs the applications you need to run. I’m choosing to ignore this issue.

Let’s assume you accept the Forrest Curve. What does it mean?

It means that computer vendors are going to have a tougher and tougher time selling computers. This is because people above the curve only need a new computer when something breaks. This happens less and less often. Even most disk drives, which are about the most mechanical part of a computer system, come with at least a 3 year warranty.

It means that computer purchasing decisions are no longer made based on price/performance or just performance, like in the dark ages. Now, when somebody decides to buy a new computer it will be price alone, or maybe price and service, that determines which computer to buy. The service aspect should not be ignored. Some people consider it very important to know that they can call somebody to come to their home or office to fix stuff and are willing to pay a fair amount for this. Other people feel that it’s important to buy name brands no matter what the quality of the name brand is. For those of us who are more enlightened, if our application requires 25 MIPs to run, and we’re trying to decide whether to buy the 30 MIP machine or the 50 MIP machine to run it, the number of people who’d pay much extra for the 50 MIP machine is very small. Let’s face it, nobody is going to turn down a faster computer but the people making the purchasing decisions will have a harder and harder time justifying the extra cost of a faster system for most people. This is especially true in environments where large numbers of computers are bought for non-technical people.

In earlier versions of this document I had the following sentence right here: “It means that companies like DEC and SGI that are trying to produce the fastest computer are slowly committing suicide because there will be fewer and fewer people who need to buy computers this fast.” Two points for me. As of this writing, DEC is gone and SGI is fighting for its life. On the other hand, companies like Sun, and virtually all PC companies, are doing the right thing by concentrating on staying just below the Forrest Curve by selling computers that are fast enough at the lowest price. Although Sun’s approach might have been an accident it has kept them profitable during some extremely hard times in the industry. Ironically, it may turn out that Sun will start to suffer too unless it can sell SparcStations at PC prices or increase their performance to rise above the Forrest Curve for a little while.

So, except for breakage, to be successful the computer industry is going to have to concentrate on selling to people who don’t currently have a computer. How many people is that in modern society? Maybe the laptop industry will thrive because it isn’t affected by the fact that so many people already have computers since most people who buy laptops already have at least one computer.

Maybe computer vendors can postpone hitting the Forrest Curve by concentrating their marketing and sales efforts into the Second and Third World but I bet the Forrest Curve still applies there, but with a lower origin point. Plus, I wonder how much money there is to be earned there, given hard currency and other non-technical problems. But, even if these places are exploited, the Forrest Curve is merely spread out a little. There’s simply no way of escaping it.

Another way to explain the Forrest Curve is as just the commoditization of computer technology. Assuming your application runs on a certain computer architecture, there’s little any vendor can do to add enough value to get you to buy their system instead of somebody else’s. For all intents and purposes, the different brands of computers are all the same, just like different brands of flour and sugar, and buying a computer will be similar to buying baskets in Tijuana. The only way for computer vendors to survive is to remember this, and to remember that price and service will be what makes or breaks them. Caveat Vendor!

[Update 9/2022]

I originally wrote this article back in the early 1990s. It’s now Sept. 2022, roughly 30 years later. Is the Forrest Curve still valid?

I think it is. The huge I/O speedups caused by solid state disks, RAM price reductions, CPU speed increases, and multi-core CPUs have together contributed to making desktop PCs more powerful than most people need, just as the Forrest Curve originally predicted.

However, the Forrest Curve does have a major fault. It originally described only desktop computing. It didn’t anticipate mobile devices, such as cell phones and tablets, which didn’t exist then. These devices connect to the Internet at a slower speed than desktop PCs and are severely limited in how much power they can use. But, the Forrest Curve, when applied to mobile devices, still applies. How often do you hear people complaining about the cell phone being too slow? If you do, chances are that the complaint is actually about how fast the phone connects to the Internet, not the speed of the phone itself.

Another development that the Forrest Curve didn’t anticipate is using graphics processors for general purpose computing. The number of people who do this is small, but the processors make it possible to do things significantly faster than before. Crypto-currencies, like Bitcoin, wouldn’t have been feasible without them. Plus, computer gaming is dependent on them.

Copyright 2022 Jon Forrest.
All rights reserved.

This document may be published in any forum for any reason provided the document is not modified in any way.

Last updated (9/18/2022).

Posted on December 18, 2015, in Uncategorized. Bookmark the permalink. Leave a comment.

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