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DEC units on ebay

Back in last century, we would take and leave off the front panel and carefully swap disks in and out of the RK05-F. The disks used all had to be formated in the same drive. Only 1 pack out of 20 gave us a problem. It was a dodgy pack to begin with. We did not have a second RK05-F, so we never tried to swap packs between different drives
 
Good question, but I wouldn't complain as the M837 gives you the option of adding more core (or Roland's SRAM based memory board). Of course at the current price it is "unobtainium" for many (most?) of us. Hopefully the current "glut" will bring the prices down to more reasonable levels. One can only hope. :)
 
ftcnet said:
How much memory is in these CNC 8M's? The G104-G227 modules would indicate 4K, so why would they have a KM8-E (M837) installed? What 'value-add' does a M837 bring to a 4K 8/E?
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The vendor selling just the one machine didn't include any details. The one with the 4 machines I emailed and got to add more photos. The comments below are about the machine shown from them.

Also missing is a console interface and some sort of access to any other peripheral. And without a front panel there must have been an M847 boot card which is not there. The M837 in addition to extending memory also gives you access to the time sharing protection mode.

If everything shown works correctly they should go for around $1000 each. About the same as if they are parted out. In my collection I have everything but the RTC card, the VC8E option boards and an 8/m case.

I am guessing they removed the card(s) attached to cables that were attached to the CNC machine. The CNC machine may still be in service using a more modern control computer. A custom program in an 8 wouldn't need more than 4k to hand commands off to a CNC mill at timed intervals. The guess for the M837 is the machines were bought as a standard package and it came with it that configuration or they were going to install non DEC memory if needed.

I am hoping to see if all the machines are equipped the same. I hope none of them sell for that asking price although if they do then I have an unexpected source of retirement income.
 
Too many people with too much money! Got out of the DEC game a couple years back and if anything it looks like things have gone up quite a bit in just a short time. Maybe I am stupid but can anyone tell me whats driving the high prices on eBay?
 
DougIngraham said:
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Also missing is a console interface and some sort of access to any other peripheral. And without a front panel there must have been an M847 boot card which is not there. T
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If everything shown works correctly they should go for around $1000 each. About the same as if they are parted out. In my collection I have everything but the RTC card, the VC8E option boards and an 8/m case.
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I hope none of them sell for that asking price although if they do then I have an unexpected source of retirement income.
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I wonder how these machines booted without an M847? Could the M848 be used to restart as long as core is not corrupted? So maybe you could have just one M847 and boot all 4 machines with it and then just keep the M847 in a safe place. No console board seems very strange though.

Yes we all have to think of a retirement income given how prices increase week by week. My once OK savings seem to be less OK as time goes by. Maybe I should start looking for a paid job rather than playing with old computers. :)
 
Oh it's $4,000 *each*? Ok. I was thinking "4k for 4 I guess one could build a pdp8 cluster or something...."
 
DougIngraham said:
I am guessing they removed the card(s) attached to cables that were attached to the CNC machine. The CNC machine may still be in service using a more modern control computer. A custom program in an 8 wouldn't need more than 4k to hand commands off to a CNC mill at timed intervals.
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CNC controllers were almost always more complicated than what amounted to a "spooler" for a set of pre-packaged signals to the CNC device servos. More commonly the controller accepted a compact description of the tool path (see: RS-273, RS-274, and Gcode) and was used to interpolate between control points in order to step the servos at a feed rate suitable to the tool and material. That included curves with given radii and so on. Cutting speeds could be interactively determined by the operator on a case-by-case basis, as well as the cutting head aligned WRT the stock and repositioned as necessary. An operator control panel was serviced by the (CPU) controller. Simple paths could be manually set up by the operator, perhaps then saved for reuse, in addition to feeding in a stock-part tool path description from a paper-tape library.

The missing cards may have provided some "computational support". For example, by including counter circuitry that indexed x/y servo positions by a fixed amount at a fixed time interval, thus offloading some housekeeping chores from the CPU once it had determined parameters for the next path-segment.
 
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