Re: [math-fun] Miss those IBM/DEC blinking lights?
Unlike the DEC blinking lights, the IBM blinking lights were trivially replaceable -- simply grasp one between your thumb and index finger and the incandescent bulb would pop out, and you could then push back a new one into place. There was also a "lamp test" button on the console which you could press to light up *all* of the lights, to see if any were burned out. If I recall correctly, I think that the real-time clock was one of the registers always displayed in the console lights. One day, we noticed that one of the bits of this clock had its light burned out. After a couple of seconds of contemplation, one of my associates swapped the light from the highest order bit of the real-time clock with the light that failed. He correctly computed that we would never see that high order bit turn on (except via the lamp test button) during the lifetime of this computer. He was correct! At 09:17 AM 4/8/2018, Victor Miller wrote:
In the summer of 1966 I was working at the Rome (NY) Air Development Center, on a Univac 1218 computer (a militarized verson of the 418). It was an 18 bit ones-complement machine. On the console were two banks of lights each in a 6 x 3 format. The machine had a primitive time sharing system, and the lights on the console normally displayed a pattern which was I L (for idle loop). I found out where the pattern was stored and one day I changed it to read FU. The Univac engineer came in, saw it, and said "things aren't that bad, arey they?". I just stared at him, and he said, well, I guess they are.
On Sun, Apr 8, 2018 at 10:11 AM, Henry Baker <hbaker1@pipeline.com> wrote:
Robert Baruch is building a 32-bit RISC-V processor out of 3.3v MSI logic chips.
This cool video describes his circuit board for a single 32-bit register (out of 32 such registers) of this modern RISC architecture. He uses two standard PCIE-style busses & connectors for his sink + 2 source busses.
In 1950's/1960's style, the register comes with its own set of LED blinking lights! (BTW, the LED's cost more and take substantially more power than the register itself.)
For the cognescenti: I find it curious that he built a full 32-bit register board instead of a *bit slice* of the entire register-cum-ALU a la the PDP-8 or the old AMD bit-slice chips.
This guy built everything big enough so people could see exactly how everything works, including LEDs for each bit of RAM: https://www.youtube.com/watch?v=z71h9XZbAWY Here's the megaprocessor channel: https://www.youtube.com/channel/UCB_Zl-VNSH5DLAtG40riCCg On Sun, Apr 8, 2018 at 10:43 AM, Henry Baker <hbaker1@pipeline.com> wrote:
Unlike the DEC blinking lights, the IBM blinking lights were trivially replaceable -- simply grasp one between your thumb and index finger and the incandescent bulb would pop out, and you could then push back a new one into place.
There was also a "lamp test" button on the console which you could press to light up *all* of the lights, to see if any were burned out.
If I recall correctly, I think that the real-time clock was one of the registers always displayed in the console lights. One day, we noticed that one of the bits of this clock had its light burned out. After a couple of seconds of contemplation, one of my associates swapped the light from the highest order bit of the real-time clock with the light that failed. He correctly computed that we would never see that high order bit turn on (except via the lamp test button) during the lifetime of this computer. He was correct!
At 09:17 AM 4/8/2018, Victor Miller wrote:
In the summer of 1966 I was working at the Rome (NY) Air Development Center, on a Univac 1218 computer (a militarized verson of the 418). It was an 18 bit ones-complement machine. On the console were two banks of lights each in a 6 x 3 format. The machine had a primitive time sharing system, and the lights on the console normally displayed a pattern which was I L (for idle loop). I found out where the pattern was stored and one day I changed it to read FU. The Univac engineer came in, saw it, and said "things aren't that bad, arey they?". I just stared at him, and he said, well, I guess they are.
On Sun, Apr 8, 2018 at 10:11 AM, Henry Baker <hbaker1@pipeline.com> wrote:
Robert Baruch is building a 32-bit RISC-V processor out of 3.3v MSI logic chips.
This cool video describes his circuit board for a single 32-bit register (out of 32 such registers) of this modern RISC architecture. He uses two standard PCIE-style busses & connectors for his sink + 2 source busses.
In 1950's/1960's style, the register comes with its own set of LED blinking lights! (BTW, the LED's cost more and take substantially more power than the register itself.)
For the cognescenti: I find it curious that he built a full 32-bit register board instead of a *bit slice* of the entire register-cum-ALU a la the PDP-8 or the old AMD bit-slice chips.
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