I was involved in one of the first PLC installations at GM back in 1977 and the Allen Bradley 1774 PLC Black Box used large core memory cards that often failed in the summer heat (90 degrees or so), so the Allen Bradley sales guy would come back every week and pickup a batch of failed cards and drop off a batch of repaired cards.
Each card was over $5-7,000. And we oftentimes swapped out 3-4 cards in a week. I think a PLC CPU box was about $40-50K. At the time I was making about $6-7 per hour and that was really good pay for a coop student. :-) Needless to say, the cards where handled very gently. The $35 Raspberry Pi has a lot more CPU horsepower and memory and the software is a lot nicer! :-) Years earlier, in the plant next door, Dick Morly invented the PLC using a DEC PDP computer. http://en.wikipedia.org/wiki/Dick_Morley Unfortunately both plants have been shutdown at least once and re-purposed a couple of times. Dave On 12/18/2012 11:07 AM, dave wrote: > On Tue, 2012-12-18 at 09:49 -0500, Mark Wendt wrote: > >> On Tue, Dec 18, 2012 at 9:39 AM, Kent A. Reed<[email protected]> >> wrote: >> >>> On 12/18/2012 5:16 AM, Mark Wendt wrote: >>> >>>> What's so amazing to me about that - $11 for 2 GB of memory. Remember >>>> when RAM was measured by MB and cost hundreds of dollars? Oy... >>>> >>> MB? as in megabytes? I remember when RAM was hand-wired core memory and >>> 4KW (e.g., 8 KB) cost nearly as much as the minicomputer I put it in. >>> The first-cost of the machine with memory was more than US$10000. >>> >>> That PDP-11* was the hottest thing on the block but I recently looked up >>> the specs and it weighed in at approximately 0.019 MegaWheatstones, a >>> fraction of what a RaspberryPi can do. >>> >>> I reconciled myself to the prices we were paying because the computers >>> let us do experiments and experimental analyses that we weren't getting >>> done any other way. I could probably git-er-done with an Android or >>> iPhone today. >>> >>> The price/performance ratios of today's electronics are breathtaking. >>> >>> Regards, >>> Kent >>> >>> *the model line was so new they didn't call it a PDP-11/20 yet. >>> >> Kent, >> >> Yeah, I was speaking mainly of the PC type memory. The Vax servers we >> had running here at the Lab, and even the later Alpha's had memory >> that cost into the multiple thousands of dollars. >> >> Mark >> > It hurts to think about the $$$ we spent for early computing. Even our > minimal /03 using a 8514(?) HP calc for a systems device was spendy. > However, that system ran on 16 Kb of memory; half core and half dynamic. > It used a Analog Devices A/D to acquire data and the printer off the HP > to make a paper copy of the results off the AA. (PE-303). > > I still have core memory off a 11/40. :-) > > Dave > > >> ------------------------------------------------------------------------------ >> LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial >> Remotely access PCs and mobile devices and provide instant support >> Improve your efficiency, and focus on delivering more value-add services >> Discover what IT Professionals Know. Rescue delivers >> http://p.sf.net/sfu/logmein_12329d2d >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > > > ------------------------------------------------------------------------------ > LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial > Remotely access PCs and mobile devices and provide instant support > Improve your efficiency, and focus on delivering more value-add services > Discover what IT Professionals Know. Rescue delivers > http://p.sf.net/sfu/logmein_12329d2d > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
