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ZIP files changed the way we use computers and they started in Wisconsin

Vintage Desktop PC with Floppy Drive
Виктор Рак
Adobe Stock
Vintage Desktop PC.

We use ZIP files every day in many unseen ways. They make it possible for us to compress files into a smaller package. This compression format revolutionized the way information could spread between computers at a critical time before the internet. 

Bubbler Talkquestion asker John Miller was working at Allen-Bradley when he heard a rumor that some guy who’d worked there was responsible for creating the format.

And, that rumor was right. It all starts in the late 1970s with BBS, the Bulletin Board System.

Jason Scott, a filmmaker who explored the impact of these boards in BBS: the Documentary, says, "From the late 1970s all through the '80s, we see a small explosion in people using home computers to communicate with each other and transfer files, leave messages, download the files that were uploaded and do it with essentially no oversight. Anybody could start one, anybody could call, and it was just wild."

The First page of the Exec PC BBS. It was one of the largest boards in the world, and was based in Milwaukee.
The first page of the Exec PC BBS. It was one of the largest boards in the world, and was based in Milwaukee.

The BBS community was a mix of old-school computer programmers and people just beginning their exploration of the computing world. It was the perfect environment for Phil Katz, a young programmer born and raised in Glendale, Wisconsin.

Friends and colleagues, like Doug Hay, describe Katz as socially awkward, but incredibly intelligent. His talents flourished in this community of people who were creating the building blocks of computer technology and what would eventually become a cornerstone of our society. But of course, computers had to become more accessible for any of that to happen, and one of the major issues was simply transferring information to different computers.

Phil Katz, creator of ZIP and founder of PKWare.
Courtesy of Doug Hay
Phil Katz, creator of ZIP and founder of PKWare.

Hay explains, "When you would transfer a file, like let’s say you wanted to download some kind of a word processor program and there was maybe 80 files total that you had to download. Well, originally with bulletin boards you had to go on there and download 80 individual files and it was a big pain in the butt."

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That could take days. It was also incredibly expensive, as Jim Peterson, chief scientist at PKWare, explains. 

"Storage media, like hard disks and people’s very expensive computers, was very limited on how much information you could store and it was very expensive cause you could buy very small sized discs but they would cost you thousands of dollars," he explains. "Sending information over computer modems was extremely slow, so to reduce the cost for transmission compressing the data was also very important to help save money for both sending information and storing information."

There had to be a way to make files smaller without losing the integrity of the original data; what they needed was a compression algorithm. To put it simply: these algorithms reduce file size by reducing redundancy in the data. 

"So if I say to you: the cat goes up the hill; and then I say to you: the dog goes up the hill — those two sentences only have one word that’s different. So I could take that first sentence without the word ‘cat’ and say: whenever I say this one, single character, that means, ‘the blank goes up the hill.’ And the result is that, especially repetitive files, can go down sometimes 70% or 80%," Scott explains.

ARC was one of the first compression formats to become popular on BBS because it both compressed the size of the files and turned them into a single, downloadable item. The format was free to use and Phil Katz believed he could improve it. So he created his own version called PKARC (Phil Katz ARC), the same name of the company where Hay became the first, full-time programmer. 

But the creators of ARC weren’t too happy, especially with PKARC's branding, which focused on how much better the format was than the original ARC. So the creators of ARC sued and won, but they also lost. The BBS community was mortified that someone would sue another member of the community, and they turned on ARC. Scott says people began changing the ".ARC" files to ".SUE" and users began turning to alternative compression formats.

Zipped folder isolated on white background. 3D illustration.
Destina - stock.adobe.com
Zip files are often shown as a file with a zipper.

Katz teamed up with another programmer to create a new format: PKZIP, which ultimately became ZIP. The BBS community flocked to the new format. Hay was working at the company during the transition.

"As soon as we created the ZIP format, ARC was dead within six months. It was dead. So, [ARC] basically cut [its] own throat by suing us," says Hay.

The company changed its name to PKWare and it’s still based in Milwaukee, but Phil Katz is gone. He died in 2000 at just 37 years old, after a public battle with alcoholism.

It was a tragic end to a man whose life forever changed our world. There are a lot of wild stories about Katz, who did a lot of living in his short, 37 years. Here are some shared by his friend and colleague, Doug Hay:

Phil Katz stories

Today, ZIP compression is a part of our lives in ways Katz could never have imagined. 

Peterson says, "It started as a means to have computer users of the day save storage space. But now it has gotten to be used across every platform by almost every user. It touches almost every computer user’s life countless times every day."

"It is so ubiquitous, it is invisible. That’s how you get apps on your phone, that’s how you get a program, that’s how you get your games on your console," Scott explains.

And it all started right here in Milwaukee. 

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Joy is a WUWM host and producer for Lake Effect.
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