IBM PC 5150

This week marks a special anniversary, so for today’s “Zscaler Logo on a Weird, Old or Obsolete Device,” I had to highlight the legendary IBM PC Model 5150!

In August 1981 (43 years ago this week!), IBM launched their “PC” line with this machine. Upstart competitors like Apple, Tandy, and Commodore had already launched successful lines of “personal” microcomputers, but IBM’s dominant position in the world of large-scale business computing all but ensured that their machine would be a success, even if they were late to the party.

On a personal level, the IBM PC 5150 was the first computer I ever owned, purchased for the princely sum of $40 from a thrift store in 1993. Having only used Macs previously, I found the PC’s DOS commands confusing and frustrating, but it forced me to dive in and learn how the machine actually worked - effectively putting me on a path that I’m still following today. That PC I had as a kid was thrown away when I left my dad’s house, and I’ve wanted another one ever since. Thanks to a lucky find at a recent Vintage Computer Festival a couple weeks ago, I finally have one again!

Due to a very clever expansion card called a PicoMEM, this IBM PC can boot from a microSD card, and it has a connection to my home WiFi network. By running a clever software package called mTCP, it spent a full week hosting a website - a pretty wild job for a machine with 640kb of RAM and a 4.77MHz processor! Since it only supports text I couldn’t get the Zscaler logo to display as a traditional image. Instead, I used a web tool to render our logo as “ASCII Art,” saved that as a text file, used the IBM’s connection to my home network to download the file from my modern PC via FTP, and then loaded the text in a classic DOS text editing app called Aurora. Easy!

Happy Friday to you all!