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Modcomp Bailey 1055 on eBay

NF6X

NF6X

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Much like the newly-announced iWatch, I don't know what it is, I don't know what it does, but I could tell at first glance that I wanted it:

MODCOMP BAILEY 1055 VINTAGE COMPUTER (item 331314313755)

I'm neither close enough to flush enough with cash to buy this one myself right now, but it sure looks pretty to me! I hope that one of "us" will get it and then share lots of pictures and discussion here.

I'll ask the seller if it's OK for me to download the photos and post them here for posterity and discussion. I doubt they'll mind, but I won't do it without permission.
 
Thanks for sharing this auction.
Never seen that dense spacing TTL boards.
Frank
 
NF6X said:
...I don't know what it is, I don't know what it does, but I could tell at first glance that I wanted it...
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I've wondered why I haven't seen any ModComp computers before.

In college I worked at Johnson Controls SECD-Southwest in the engineering co-op program and worked with these things all the time. JCI did control centers for waste-water treatment plants and used ModComp very heavily. I had to build these up, test them and interconnect them in a mock-up area so the coders could start writing the system right away. The last job I did before graduating was "The Columbus Project" (i.e. Columbus Ohio) that used a ModComp distributive computing system instead. I think I had four or five of those things interconnected as they would be later on-site.

The worst part of that job though was running RS232 cables from the mock-up area to the programmers office up through the ceiling panels. Fiberglas itch was unavoidable.

I just figured ModComp vintage computers weren't around because they were put to controls systems use and industry carries those as far as humanly possible to avoid the cost of a new control system design.

Glad to see that Modcomp... they always did look great. IMSAI's big brother. :)

Frank S said:
...Thanks for sharing this auction. Never seen that dense spacing TTL boards....
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As unbelievable as this sounds, ModComp used wire-wrapped boards (automated obviously) on a lot of the system boards. It was a quality job... first rate sockets solder tapped to the board.

I remember having to rework some of the wirewrap on one set of boards to support Grinnell color display monitors.

The media of choice then was 14-inch platters usually installed in the base of the rack (less vibration, sway and motion being close to the floor pads.)
 
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There was a guy on Craigslist in Los Angeles not too long ago that was attempting to sell a brand new, unopened original 128k Macintosh for gold scrap (advertised as 68000 GOLD or something.) I emailed him to not scrap it, as it was worth more as a computer than the gold he was trying to get from it. He then went off the handle about nerds, virgins, driving Alfa Romeros, etc., then sent me pictures of him destroying the computer. Might still have the email somewhere. It was the weirdest thing I've ever read.

Pretty much sums up my impression of the gold scrapping industry.
 
The seller gave permission to share the pictures here, as well as a preview of coming attractions:

Yes, that would be fine with me, I have about 14 cabinets I will be putting up for auction, there are about 4 of these units, and the rest are disk drives, tape drives, etc. I also have a couple of the large keyboard units.
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Here are five pictures that I picked out from the listing:

Modcomp-1.jpg Modcomp-2.jpg Modcomp-3.jpg Modcomp-4.jpg Modcomp-5.jpg
 
I was literally just in Kennewick. :I

That's a very nice looking machine but 7K? Keep dreaming. Won't lie about the condition. It's almost pristine. I bet you it will start on the first try.
 
Al Kossow said:
It is a Modcomp Classic

https://www.flickr.com/photos/magnus_osterlund/238688862/

Bailey Controls is a process control company. I'm sure they OEMed it.
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In Sweden Modcomp machines were used by ASEA (ABB) at nuclear power stations. The ones depicted in Al's link above is from a test system for these control systems. The picture are a few years old. A couple of years ago the guy who took the photos asked if we were interested in a couple of incomplete Modcomp system that had been part of this test system. Incomplete since they had to save some spare parts for their other systems. We didn't take them.

There are very little information regarding Modcomp on bitsavers. I could ask Magnus if they saved the documentation if there are any interest.
 
Have to wonder why they were produced? They look like real big 16 bit systems that were something along the line of a PDP-11 but appear to have more internal room and maybe a later construction date although there is no sign of any LSI being used so almost looks like an early to mid-seventies design. Were they built as an alternative to the DEC and Data General Family? Looking at the construction would assume that they had to cost more than the stuff that was on the commercial market at the time and looking at the data center pictures also see that they had their own terminals and printers.
Would be great to own something like that but just imagine the problems with trying to find documentation and any useful software like an operating system or interpreter, maybe it’s just because I am stupid or whatever but the acid test for me in buying antique systems is will run Basic, being that’s the only language I can work in. Just try to imagine finding a Basic compiler for something like that.
 
Qbus said:
...wonder why they were produced?...big 16 bit systems...
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Probably produced because of their great selection of I/O; they seemed to be the choice for control systems.

Qbus said:
...no sign of any LSI being used...
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Actually one of the photos does show LSI chips. However most of the photos looked like memory boards with what were probably DRams of the day.

...the acid test for me in buying antique systems is will run Basic...Just try to imagine finding a Basic compiler for something like that.
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At Johnson Controls (SECD-SW) we used ModComp computers for process control systems and the programmers wrote in assembly language.
 
MattisLind said:
...those are Am2901 four bit bitslice ALU ICs...
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Sounds right. I remember reading up on those before I graduated. One of the Johnson Control engineers that worked with ModComps talked endlessly about doing his own bit-slice computer design. I kidded him that if a bit-slice design was in his future, he would have bought an S-100 computer for his home instead of an Apple II. :)

Another lesson learned on bit-slicing:
After graduation, I took a job with a company whose competitor went the Am2901 bit-slice route on a new product design. We looked into bit-slicing but my mentor there said that bit-slicing was a bad choice because it created too many choices that would only delay the design. I designed a state-machine solution (Signetics programmable part) to control all the bus DMA and winchester disk data flow and used a 8085 to do all the setup and I/O parameter block command support.

My mentor appeared to be correct because I had our new board done a year before the competitor got to market. A year later the competitor product appeared and it was a two-board Muliti-Bus set that offered no additional features, just bulk.

So not only did it take them twice as long to design their product, it was too big to sell.
 
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JDallas said:
I designed a state-machine solution (Signetics programmable part) to control all the bus DMA and winchester disk data flow and used a 8085 to do all the setup and I/O parameter block command support.
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Was this board OEMed? What sorts of disks? Sort of sounds like several different designs I can think of from the early 80's.
 
JDallas said:
Another lesson learned on bit-slicing:
After graduation, I took a job with a company whose competitor went the Am2901 bit-slice route on a new product design. We looked into bit-slicing but my mentor there said that bit-slicing was a bad choice because it created too many choices that would only delay the design. I designed a state-machine solution (Signetics programmable part) to control all the bus DMA and winchester disk data flow and used a 8085 to do all the setup and I/O parameter block command support.
Click to expand...

Sometimes one has other things to take into account: Companies like Emulex (who used Am2901 heavily) had a whole product line with different Unibus or Qbus controllers. Instead of tailor each controller to each interface using a state machine you simply modify the microcode and adapt the some interfacing logic. Then you can easily handle SMD, ESDi, MFM, PERTEC etc mostly using the same board. A sort of IP that you just put in.

But it will be a more complex and more expensive product. On the other hand a one off product certainly would have been more cost effective using the Signetics PLS chips.

Signetics, by the way had the 8X305 bipolar series which had some use in controllers. I have bunches of those if someone wants to waste time and play with ancient bipolar controllers...
 
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MattisLind said:
...Signetics, by the way had the 8X305 bipolar series...
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Yes, we were a 8x300 design shop mostly; the company had used it in video drivers, navy map protocol converters and winchester drives in the late 70s. The company had one of the few 8x300 emulators from company that originally made the processor, from whom later Signetics bought the rights.

The design I mentioned was for a faster version of winchesters for which an 8x300 in the data stream was no longer feasible so I had to design a new architecture. My mentor there, one of the owners, made the mistake of specifying that the board would be a two-sided board with no power and ground plane to improve margins as they had done that with all previous boards. However he had to make a second layout version of it with power and ground planes. At this time printed circuit board layouts were still done by tape and mylar. :)

The problem with the 8x300 for new designs at that time was that there was no support platforms from Signetics yet. Getting an emulator at that time was extremely difficult. To compile 8x300 code, we used an Intel ISIS development system's 8080 assembler, using macros for the 8x300 opcodes. The listings were a mess but its code was true.

I hopped to S.D.System to design their Versa-Floppy-Winchester III for the IEEE-696. I recommended using an 8x300 because would have been a better design and it was certainly fast enough for those drive interfaces. But S.D.Systems was locked into the WD1010 chip set and I think they had already invested a lot of time waiting for WD to stop changing their design of the 1010/1014/1015 chip set so the board could be started. The board was so tightly packed with chips that we had to use CAD layout from the same firm in Atlanta that did D.C.Hayes boards to get it to fit on an S-100 board.

When Western Digital later started using 8x300 on the WD100x series, I assumed that was due to one of the following: (1) the same company designed them for WD, (2) an employee from the company hopped to WD and designed it for them or (3) that Signetics had fielded a new emulator and assembler for WD to use.
 
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