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NeXT
March 14th, 2009, 10:45 PM
I got an email from a friend in Vancouver tonight who said that through his many strings he has managed to locate a DECsystem-20 which is scheduled to be decommissioned pretty soon and there is a chance that instead of hauling it off to be recycled and cut up they might be willing to give the whole system (cabinets, washing machine drives and all) away to whoever wants it. It's obviously way too big for my garage (as well as it would cost too much to drive down to Vancouver and get it) but if me and my friend can find someone who wants it, we'll try and see to it that it's yours.
I still have very little info on this myself but if someone is interested we could look into getting it for you. I only wanted a PDP-8 or a 12 at the largest and this is overkill, even for me.

Again, this is what might be soon up for grabs (though not the one pictured below):
http://www.columbia.edu/acis/history/dec20_2.jpg

Lallander
March 15th, 2009, 03:01 AM
I really hope someone picks it up, would be a shame to see it go for scrap.

cosam
March 15th, 2009, 05:14 AM
Given that a PDP-10 went for (IIRC) $25,000 on ePay last year, I'm sure there are plenty of folk who'd be willing to shell out a reasonable fraction of that sum getting that beast shipped to them.

NeXT
March 15th, 2009, 12:57 PM
Bit more information.
Turns out that my friend used his leads to get it from NavCanada so it probably came from one of the airports around Vancouver. It's also apparently completely maxed out. Memory, networking....everything. He's going to try and see if he can cram all of it into his garage and then (eep!) get three phase power working. The system itself is not expected to be free of red tape (some of those disk packs have sensitive data and we want those packs as we won't be finding more any time soon so they need to be blanked and then certified that the data can't be recovered) until some time in May.
I'm still wondering how the hell this will all fit into the garage.

Chuck(G)
March 15th, 2009, 01:43 PM
Post it to the cctalk list--there's a whole horde of extremely hard-core DEC-heads who hang out there who would likely travel to the other side of the world to get it.

cosam
March 15th, 2009, 02:32 PM
Post it to the cctalk list
I posted a link there earlier today, but I'm not sure it's gone through. I've not had any mail from cctalk since - looks like it may be broken again :-\

That said, it would of course be good if OP could post there too so that potential picker-uppers could make contact directly (i.e. not via the forums).

NeXT
March 15th, 2009, 03:14 PM
I posted a link there earlier today, but I'm not sure it's gone through. I've not had any mail from cctalk since - looks like it may be broken again :-\

That said, it would of course be good if OP could post there too so that potential picker-uppers could make contact directly (i.e. not via the forums).

I'm just making this aware should the whole setup not fit into the garage. ;)
If it does then I'll be driving down there to start photographing everything and help him safely try and get the system up and running again. I know you can run some older rack SGIs that were set for three phase and the same with a few older IBM mainframes on single phase if you know what the hell you are doing and the last thing I want to do is see the PSU go poof in this system.

Chuck(G)
March 15th, 2009, 07:36 PM
I posted a link there earlier today, but I'm not sure it's gone through. I've not had any mail from cctalk since - looks like it may be broken again :-\

That said, it would of course be good if OP could post there too so that potential picker-uppers could make contact directly (i.e. not via the forums).

Uh-huh--it's been quiet this weekend, which usually means that something's plugged up. I'm pretty sure that the post will make it through when the sewer auger finds the clog. :)

Unknown_K
March 15th, 2009, 07:45 PM
Could just be the moderators are busy and have not ok'd the post?
That list is kind of weird lately.

Going by that picture I think you could fit it all in a garage, just not in a usable configuration. Unless you have other vintage machines in the garage already.

How would you ship that stuff without popping a board out or breaking something? I bet the interconnects are a pain to replace if you lose one.

NeXT
March 15th, 2009, 08:59 PM
Could just be the moderators are busy and have not ok'd the post?
That list is kind of weird lately.

Going by that picture I think you could fit it all in a garage, just not in a usable configuration. Unless you have other vintage machines in the garage already.

How would you ship that stuff without popping a board out or breaking something? I bet the interconnects are a pain to replace if you lose one.

Well I won't be the owner of the system but I doubt too much will happen to it as the trip from Vancouver Airport to the garage is almost 15Km. I think he's going to be renting a cube van and backing it up to the loading bay behind one of the terminal buildings. I'm not exactly sure as it's his find (not mine) and I'm way the hell up here in Kamloops.
I think it's a double car garage and the parents only have one car so I guess they will let it get setup in the empty side of the garage.

pontus
March 15th, 2009, 10:43 PM
Wow!

This I did not expect!! A DECsystem-20 is probably as rare as it gets :)

I'll send an email to the guy at pdpplanet (http://www.pdpplanet.com) who bought the one on ebay last year. This machine just _have_ to be saved.

As for running it on a single phase... well, the front end CPU is an PDP-11/70 which in itself uses quite a bit of juice. The PDP-10 cpu will _not_, at least not with its original linear power supply. A few were modified to use switched PSU:s which use considerably less power.

alderson
March 16th, 2009, 10:26 AM
Hi. I'm "the guy who bought the one last year on eBay." We are building a living computer museum (that is, one in which the systems are running or runnable 24x7), starting with the mainframe systems in Paul Allen's personal collection. Pontus, whom I know from the cctalk list, pointed this thread out to me.

I have a couple of things to note. First, a correction to Pontus' posting: The front-end processor on a DEC-20 (if we're talking about a KL-10 system) is a PDP-11/40, not a -70. It is not a major portion of the power budget of the overall system.

Next, the power requirements: An unmodified KL-10 uses 60A 3-phase 208VAC power, and has an in-rush power rating of 12.4KVA. This settles to about 6KVA during normal operation. Because the circuitry is ECL, it really hates being power-cycled, so it is best to plan on running the system 24x7.

It is very likely that the large aluminum electrolytic filter capacitors throughout the power system are shot. Manufacturers' data on these beasts indicates that they are reduced to ~10% of their nominal rating after 10 years, whether in use or not. Unless there was a rigorous program of changing out the caps in this machine, they are likely to be more than 25 years old (if it's one of the newest machines built, in 1983). Do not kid yourself that you can "re-form" these caps--they're dead as history.

Yes, people have replaced the original regulators with modern switching power supplies. We've done that on one of our systems, and will do it to more, because rebuilding old power supplies is a painful and expensive experience. Plan on spending about $5K on power supplies, and a lot of time running new power harnesses--and that's if you have an electrical engineer on your team.

The new owner's parents are going to need to move their car out of the two-car garage. The system unit of a KL-10 consists of three cabinets that must be connected together for RF shielding (and the cabinets mandated by Canadian law are huge: The systems in our collection are only 30in deep; the Canadian cabs are about 12in deeper). These cabinets are 43in wide and 60in high; overall system footprint is 130inx60inx30in (or x43in).

Tape drives are 30x60x30 and require single-phase 20A 220VAC; RP06 disk drives are 34x36x30, and require 3-phase 30A 208VAC, though there is a hack to convert them to single-phase posted on the Resources section at http://www.pdpplanet.org/ if you think you want to do that; and RP07 Winchester-technology disk drives are 30x36x30, and take 30A power as well.

If there are terminal servers (PDP-11/40 or PDP-11/34), these will be in cabinets similar in size to the system unit, and bolted in-line with it.

Before you begin the project, I suggest that you read the story of the restoration of our running 2065 ("DEC-20") on the PDPplanet site.


On the other hand, if you have a DECSYSTEM-2020, It should fit in the garage. It is only 30x60x30, and runs on single-phase 25A 220VAC. The peripherals are the same as on its bigger sibling, and the caps in the main power supply are about as old. AND BE CAREFUL! THE 200V MAIN CAP CAN KILL YOU IF YOU DISCHARGE IT WITH YOUR BODY.

Feel free to write if you have questions. Since this is a forum page rather than a mailing list, I've used a personal account to register. If you write to me there and ask, I'll send you my work e-mail address which I've removed from the signature below.


Rich Alderson
Vintage Computing Server Engineer
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104

Terry Yager
March 16th, 2009, 12:22 PM
It is very likely that the large aluminum electrolytic filter capacitors throughout the power system are shot. Manufacturers' data on these beasts indicates that they are reduced to ~10% of their nominal rating after 10 years, whether in use or not. Unless there was a rigorous program of changing out the caps in this machine, they are likely to be more than 25 years old (if it's one of the newest machines built, in 1983). Do not kid yourself that you can "re-form" these caps--they're dead as history.

When the poster indicates that it is "soon to be decommissioned" the implication is that it is on the job right now, and hopefully properly maintained over the years.
Seattle is just a stone's throw from Vancouver, so hopefully, you'll be interested in picking up this beast if possible, since the possible damage from movement will be minimal.

--T

nige the hippy
March 16th, 2009, 12:38 PM
Don't make my (sort of) mistake.
If at all possible get the disks with any sensitive data re-formatted on the machine by it's present sysops before it leaves it's current location.

That way it can be signed off as clean, and you won't have to go grovelling or pay a fortune to a company who will degauss them and leave them without a servo track & therefore useless. Disk packs are consumable, and therefore getting rarer, you need as many as you can.

Also if the heads don't automatically lock, remember to lock them before moving, and make a note of which packs were in which drives, (just in case of any alignment issues) common sense, but easy to overlook in the excitement.

And.... someones going to have a garage a bit like mine ;)

XXDP
March 16th, 2009, 09:33 PM
I posted a link there earlier today, but I'm not sure it's gone through. I've not had any mail from cctalk since - looks like it may be broken
I tried to subscribe to cctalk last night, and the relevant script returned a "disk full" error page.

pontus
March 17th, 2009, 12:43 AM
I tried to subscribe to cctalk last night, and the relevant script returned a "disk full" error page.

Ouch. Lets hope they get it going again, that list is really nice. Maybe I should send them a new hard drive or two :)

I like your nick by the way :D Welcome to the forums :)

NeXT
March 17th, 2009, 07:05 PM
I just got an email back from my friend and it looks like he'll be taking the whole system in and I shotgun dibs on it should he ever need to part with it.
Also, he said this:

My dad has an electrical engineering degree and he is trained in operating and maintaining PDPs. He was starting out when they were the most common minis. These machines were maintained and had their caps and power supplies RIGGOROUSLY maintained, as they were responsible for such things as radar, and if they were to suffer a serious failure, planes would have been flying into each other :P. From my understanding there were 2 systems, and every few months one was switched out to be maintained, while the other took the workload. That is why I;m so excited about this, its not going to be so difficult to get them up and running. My dad will be getting the place set up for 3 Phase power some time after he gets back from his trip. The power bill is going to be expensive but whatever I'm not paying it ;).
It answers your questions regarding the PSUs and the power system itself but to install three phase power in the house?! Good lord.

XXDP
March 17th, 2009, 07:38 PM
I like your nick by the way :D Welcome to the forums :)
Many thanks, Pontus!

...

Now, here's another thing to think about. What are the thermal requirements of a DECsystem-20? I thought I read somewhere that these systems require some serious cooling capacity in addition to the three-phase power.

NeXT
March 17th, 2009, 09:14 PM
Many thanks, Pontus!

...

Now, here's another thing to think about. What are the thermal requirements of a DECsystem-20? I thought I read somewhere that these systems require some serious cooling capacity in addition to the three-phase power.

Cooling won't be much of a Problem in Vancouver however dehumidification will be necessary as it's right next to the ocean and it's always raining there (one joke is that if you stand in place for too long you start to grow moss).

patscc
March 17th, 2009, 09:51 PM
NeXT's pal said...My dad will be getting the place set up for 3 Phase power some time
If this works out, can you guys post the arguments used with your power company to make it happen ? I've yet to convince them out here to wire 3-phase & more than two phone lines.
It's been mentioned earlier, but are you guys, just to keep the power bill sane, going to try to switch to switching power supplies ? The ones that operate in the 500kHz ~ 1Mhz range in particular are quite efficient and compact. Might be better to use several cheaper ones in parallel, sort of like RAID with power supplies.
patscc

pontus
March 18th, 2009, 12:12 AM
I just got an email back from my friend and it looks like he'll be taking the whole system in and I shotgun dibs on it should he ever need to part with it.
Also, he said this:

It answers your questions regarding the PSUs and the power system itself but to install three phase power in the house?! Good lord.

WOW! Some dad :) Could you convince your friend to take some pictures?

Regarding the cooling and humidity, among the documentation kept for the DECsystem-20 we have , there are binder upon binder with logs from humidity readings :)

alderson
March 18th, 2009, 12:11 PM
Don't make my (sort of) mistake.
If at all possible get the disks with any sensitive data re-formatted on the machine by it's present sysops before it leaves it's current location.

That way it can be signed off as clean, and you won't have to go grovelling or pay a fortune to a company who will degauss them and leave them without a servo track & therefore useless. Disk packs are consumable, and therefore getting rarer, you need as many as you can.

Also if the heads don't automatically lock, remember to lock them before moving, and make a note of which packs were in which drives, (just in case of any alignment issues) common sense, but easy to overlook in the excitement.

And.... someones going to have a garage a bit like mine ;)

If these are RP06 drives, the heads lock in place unless and until power is applied, a pack is inserted, a LAP plug is inserted (to assign a unit number to the drive), the START rocker is depressed, and the disk pack is spinning at speed.

Also, addressing the highlighted portion above: RP06 packs do not have a servo track. They are low-level formatted with the utility DDRPI, which is usually run from the KLAD pack (a Field Service diagnostics pack) but which can be run from floppies as well. We can supply info on how to do that if the new owners do not know how. (For that matter, the new owners and their friends might want to think about coming to Seattle for a day for some lessons.)

If the new disk drives are RP07s, YES! BE SURE TO USE THE HEAD-LOCKING MECHANISM PRIOR TO MOVING THEM AT ALL! These are Winchester technology, NOT field-formattable, and a PITA to maintain, so if you're getting any of these, good luck, and write if you need help.


Rich Alderson
Vintage Computing Server Engineer
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104

alderson
March 18th, 2009, 12:20 PM
When the poster indicates that it it "soon to be decommissioned" the implication is that it is on the job right now, and hopefully properly maintained over the years.

Let me just say for the record that I have been managing DECSYSTEM-20s since 1982.

When these systems were in their prime, Field Service would replace an entire PSU from spares, and send the failing unit off to the factory for refurb. These days, spares are few and far between, and internal repairs are necessary.

It very well may be that the filter caps in the power supplies are (relatively) up to date, but we urge that they be checked, rather than that assumptions about "properly maintained" systems be allowed to override caution.

(Note to those who might have seen the previous version of this response: I was using 2009 thinking about a 1980s issue. Sorry if anyone might have been offended.)


Rich Alderson
Vintage Computing Server Engineer
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104

alderson
March 18th, 2009, 12:48 PM
I just got an email back from my friend and it looks like he'll be taking the whole system in and I shotgun dibs on it should he ever need to part with it.
Also, he said this:

My dad has an electrical engineering degree and he is trained in operating and maintaining PDPs. He was starting out when they were the most common minis. These machines were maintained and had their caps and power supplies RIGGOROUSLY maintained, as they were responsible for such things as radar, and if they were to suffer a serious failure, planes would have been flying into each other :P. From my understanding there were 2 systems, and every few months one was switched out to be maintained, while the other took the workload. That is why I;m so excited about this, its not going to be so difficult to get them up and running. My dad will be getting the place set up for 3 Phase power some time after he gets back from his trip. The power bill is going to be expensive but whatever I'm not paying it .
It answers your questions regarding the PSUs and the power system itself but to install three phase power in the house?! Good lord.

OK, first off, there is no such thing as "PDPs". DEC built 4 different product lines with "PDP" in the name, on different factory floors, using different design teams and different technologies, over a period of 35 years, and these even competed with each other in the marketplace. Experience with a PDP-11 or PDP-8 minicomputer does not necessarily translate to a PDP-10 mainframe like a DEC-20.

It may very well be that there was rigorous maintenance on these particular machines. However, my experience of the last 15 years (that is, since Digital stopped providing any maintenance contracts at all on this hardware) is that people do the least possible to keep things running so as not to break things they need to keep working.


PLEASE NOTE: I am not trying to discourage anyone from doing this, even if it sounds as though I am. I simply want anyone who tries to put a large system like a DEC-20 into running condition to be aware of the kinds of things they will most likely face.

Please, let your friends know that should they wish to come to Seattle to visit our facility and see a DEC-20 running, that is easily arranged and we would be very happy to have them (and you, if you like).


Rich Alderson
Vintage Computing Server Engineer
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104

NeXT
March 18th, 2009, 02:19 PM
Hey, not a problem however coming to visit would be a days drive alone.

pontus
March 18th, 2009, 10:23 PM
Hey, not a problem however coming to visit would be a days drive alone.

On the other hand, It's not every day you get to see a live DECsystem :D

Terry Yager
March 19th, 2009, 02:18 AM
(one joke is that if you stand in place for too long you start to grow moss).

Even Mick Jagger?

--T

NeXT
March 19th, 2009, 08:27 AM
Even Mick Jagger?

--T

I have seen cars parked in backyards that were growing moss. :eek: