The Shape of Code

The 1990s was a decade of dramatic improvements in desktop computer capacity and performance. The difference in performance between the newest and current systems was clearly visible from the rate at which compiler messages zipped up the screen. How did the price of these desktop systems change during this period?

Magazine adverts are sometimes the only publicly available source of information about historical products. For instance, the characteristics of IBM PC compatible computers (e.g., price, RAM, clock frequency) over the first 20 years since they were first introduced in the early 1980s.

During the 1980s and 1990s BYTE magazine was the leading monthly computer magazine in the US, with a strong following here in the UK. Each issue contained around 400+ pages, and was packed with adverts from all the major hardware/software vendors. The last issue appeared in Jul 1998. The Internet Archive contains a scanned copy of every issue.

In 1987 Dell Computer Corp started selling cut-price computers direct to customers. Dell ran adverts in every issue of BYTE from June 1988 until the magazine closed. Gateway was another company in this market, and also regularly advertised in BYTE.

The text information present in adverts is often embedded within graphical content. My interest in this information has not been sufficient to manually type it in. LLMs are now available, and these have proven to be remarkably effective at extracting information from images.

The following advert shows how information specific to a particular computer system appears once, along with prices for particular options. Grok correctly populates a csv file containing information on four systems.

I did not attempt to ask LLMs to extract the Dell/Gateway ads from a 400+ page magazine. Manual extraction of the advert pages also gave me the opportunity to scan for other ads (a few companies advertised sporadically, e.g., Micron). Some experimentation showed that Grok returned the most accurate/reliable data.

System configuration information, for Dell and Gateway, was extracted from their adverts that appeared in the June/December issues for every year between 1988 and 1998.

Adverts show the price of particular system configurations. Typically, vendors list prices for minimal systems, along with the incremental price for more memory or a larger hard disc.

The plot below shows the original US dollar prices of 500 systems appearing in Dell/Gateway/Micron/Zeos BYTE adverts during the 1990s (code+data):

These prices have not been adjusted for inflation, and show the numeric values often ending in “99” that appeared in the adverts.

Once a ballpark figure is established in the market for the price of a product, vendors are loath to decrease it. Higher priced systems generally have higher profit margins.

Dell starts by offering systems whose price varies by a factor of four, and then settles into a narrower range of prices (presumably based on feedback from volume of sales). Micro appears to be similarly experimenting around 1996.

In the UK, when the price of low-end systems reached £1,000, rather than continuing to reduce the price, sales outlets started adding a printer to a complete package, keeping the price at around £1,000 (which families were willing to pay). Eventually the cost of a printer was not enough to fill the price gap.

The plot below shows the advertised disk size and amount of RAM installed in 500 systems advertised during the 1990s (the 1.44MB disk is a floppy drive only system; code+data):

The well-known exponential capacity growth is clearly visible.

The data shows that during the 1990 there was no consistent decrease in the numeric value of the advertised price of desktop computers, which fluctuated (more data is needed to separate out the effects of functionality added to top-end systems), while actual prices decreased by 30% over the decade due to inflation. The capacity of the disk and RAM installed in desktop systems increased exponentially (also cpu clock speed; this plot is not shown).

The Hedonic index is a process used by economists to model the interaction of a product’s price and its characteristics.