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Jet 80

 

John Rehn, who was in the team that developed Jet 80, adds the following;

The things I mostly worked with at the Jet 80 was the system (bios) and the network. The network occurred in two versions. JetNet, which was a network that was built around a fairly advanced file management system (name?). On this was laid a CPM 2.2 emulator. This was in itself a downgrading, because Jet otherwise run with CPM 3.0. Moreover, this worked very well and we sold a number of systems to a country in Southern Africa (name?) via SIDA (an abbreviation for Swedish International Development Cooperation Agency). Later came a CPM 3.0 compatible network, JetNet2. Most of this was made by a company in Östersund (for relocation money).

What I made, was the transport layer for these networks. The SIO, which was a very capable communications circuit from Zilog, was good to work with. We used two twisted pair, clock and data. HDLC protocol. RS485 standard. We did run in 800 KB/s and although this, our system worked almost as fast as the PC 10MB/s network. To this, we were able to connect 32 systems, with a 10 MB hard drive as file server (at the first version).

To this we could mix floppy supplied "slaves" with terminals without a mass storage. In these, we put the Jet 80 card in the foot on an Amplex display (80 x 24). The systems cost a pittance compared to IBM's network. And everything was built into the computer from the beginning, no extra card needed to be purchased. The drawback of these networks was the lack of communication between the terminals. All traffic was going to/from the server, which most often was equipped with a printer. Supreme for classroom sets. What was "killing" this was the talking about the computer Compis, that would be standard in all Swedish schools, and that became the end of purchasing the Jet. But of Compis became nothing.

You could also buy a graphic terminal and a video card that was designed by Peter Löthberg (the Swedish Internet guru).

Kent Olsson, who was in the team that developed the operating system of Jet80, adds the following;

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