Holborn 9100, an almost-forgotten Z80 multi-user PC from Holland

The Holborn 9100 was released in 1981 by Dutch computer manufacturer Holborn. The appearance was designed by an industrial design office named Studio Vos and developed by Hans Polak and Henny Beavers. The name comes from the phrase "born in Holland." There were two main versions, a larger one with a proprietary multi-user operating system named Holborn OS with support for a light pen, and a smaller machine with the operating system CP/M and no light pen support. These versions were split into four different models released: the 9100, 7100, 6500, and 6100. The systems consist primarily of a combined desktop monitor, terminal, and keyboard with an external unit housing two 8-inch floppy drives and an optional hard drive. The 6500 series had a detachable keyboard. The computer was primarily marketed to small companies for administration and bookkeeping purposes. The lower-numbered models were produced after the release of the 9100. Around 200 machines were produced, with 50 of them being the larger models. Due to the high price of the system at the time at 30,000 guilder or $10,000 USD (equivalent to $30,591 in 2023) and competition from IBM, the system was a commercial failure and caused the manufacturer to go bankrupt in 1983. The most popular version was the 6100. It is estimated that around 20 systems survive.