Bruce Chubb signal article

I too read the same article in RMC.  Computers have made big changes since the 90s.  I like railroad signals and have scratchbuilt signals for my railroad.  I use the good old outside rail and relays for basic simple red / green aspects.  That is one advantage to 3 rail track.  The old school relay controlled signals are really quite simple.  I do plan to follow the articles in the next issue of RMC.

Steve

Thanks for the heads up. Even though we use insulated rail and relays to trip signals, I always like to look at other systems

By the way, the speeds were (way back in the day):

• IBM PC, PC/XT: 4.77MHz (Later clones ran at 8MHz
• IBM PC/AT-1: 6MHz. You could "over-clock" them to run at 8MHz with no discernible problems. IBM put a trap in the "1A" version to stop the chip swapping over-clock to protect their more profitable entry-level AS400, but that was quickly defeated by a delayed-startup chip kit.
• IBM PC/AT-2: 8MHz (some clones ran as fast as 10MHz)
• PC/MS-DOS could address 640K or RAM, though the AT processor was capable of addressing 16MB if you used Xenix (Unix work-alike). AT's running Xenix were being used instead of entry-level AS400 systems and IBM didn't like that one bit.

I'm seriously dating myself here.

Thanks Matt for the speeds.  All I remember was the buzz of how fast things would be able to get done and how fast those games would play.

I am so ancient that I built a NorthStar computer that used S100 boards and ran BASIC,  Think I had something like 2K RAM and 5" floppy drive.  Hand coded small programs for Z80 CPU (real men and women hand code programs, no sissy assemblers )

Will be interesting to see how this "new and improved" C/MRI works or if clean sheet design and backwards compatiable to his old system.

I'm going to be using the C/MRI system from the 80's just because I already own it. I'm using the third rail for detection, and the signaling logic will come from JMRI. Chubb has a special card for doing the signals, which uses just two output bits to produce a 4 aspect signal, dark, red , yellow and green from a red-green bi colored LED. Not going to get that with relays.

Even though today's computers run at lightening speeds compared to those early monsters, the serial lines still run at the same speeds, I think it's 9600 baud. The processor speed comes into play running the JMRI software preforming the calculations on the data received from the C/MRI hardware.