Kurts Blog of Photography, minicomputers, mainframes, lightwave communications, and just whatever.

More on my Mini-Computer   One of the requirements of having a time-share computer system is having a user interface that makes everything seamless. One point to log in, and commands that allow tasks to be farmed out to the various processors with the user not having to deal with internal details. For example, when the user type print [filename] , he/she shouldn't have to know that the print spooler is on processor 1 even though he is running a program on processor 3. Unix (and by default Linux) works very well for a lot of things. One of the things is does NOT do well is tie multiple processors together for many users. The Primos operating system, DEC's RSTS and a few others do a good job of it. They were written from the ground up as time share operating systems. DEC's RSX-11 was not. MS-DOS also was not. When a user connect to and types on a unix-based operating system, he/she does not actually talk to the operating system. There is a program called a shell tha...

More on my Mini-computer I added some hardware. Here's why. When you have multiple processors, you need to have communications between them. In this case, when I want to start the pdp-11 program I ssh to the processor it runs on (pi5) and start the application. After that I telnet from a different box (thru the ethernet switch) to connect and do whatever. Question: what happens if the ssh connection goes away? For example, I need to reboot the computer the ssh session was started on. Well, then the pdp-11 application dies and corrupts the pdp-11 hard disk. Bad ju-ju. So. What I need is a dedicated console attached just for enabling the pdp computers (pdp-11, pdp-8). How best to do that? I could use a serial console. I got rid of my ADM-31 some time ago and the last time I had a Soroc IQ120 to use was in 1981. They are getting hard to find. Also they are kinda big. What I did is hook up a small car video display used for car entertainment/back-up cameras. This connects ...