Current Computer and Associated Technology Activities
In addition to working with mainframe computers education of career activities, Terry was an early adopter of personal computers. In the late 1970's, prior to the introduction of the IBM PC in 1981, computer hobbyists were building small computers using components, literally individual computer chips. In 1978 Terry build a S-100 Bus computer using a Z-80 processor chip and a motherboard from a company called DataSpeed whose business it was to provide car racing teams with real-time data from their cars. The final step in the construction was hand soldering the 25 leads for the Parallel Printer Port.
The computer ran an early (pre-MS DOS) operating system called Control Program/Micros or CP/M. The authors of CP/M in 1979 released a multi-use version called MP/M which allowed multiple dumb terminals to access the computer in the manner of a network. Terry had three terminals in his home, each with access to the Wordstar text processing software and all the files on the computer.
The tradition of building his own PCs has continued to the present time. Terry built and maintains eight desktop computers in his home, networked gigabit Ethernet in every room and supporting both an archival server and an SQL server was well as the home automation system. Several of the PC's are used for Terry's citizen science activities. There are also three commercially made PCs. He also has been experimenting with single board computers such the Raspberry-Pi in conjunction with his home automation and amateur radio activities.
Desktop Personal Computers
* These eight computers were constructed by Terry. PCs were constructed using:
The advantage of building desktop PCs as they can incrementally upgraded. The recent upgrades are:
Single Board Computers - Raspberry Pi 3B+ and Raspberry Pi 4B
Our house has a wired Cat 6 Gigabit Ethernet network with primary and spare connections in multiple locations in each room using a multi-level star topology with one master and seven second/third-level Netgear Gigabit switches. All PCs except the Microsoft Surface Laptop are connected via the wired network. We also support three vLANs, comprised of separate- secure, guest, and Internet of Things (IoT) WiFi networks. We generally have between 50 and 60 IP addresses in use on the various networks at any given time.