7 ms·

Melbourne Train Control System is running on a hardware emulated PDP11

129 points by SerCe 2y ago

retrac 2y ago
The largest nuclear power plant in North America, Darlington Nuclear Generating Station in Ontario, a bit east of Toronto, uses robots for handling the fuel rods. The plant was designed in the late 70s and the control software is apparently written in PDP-11 assembler. And they will keep using it for the remaining lifespan of the plant. So probably long after I retire and I'm not old. Now that's an idea for any young coders looking for a language that'll still be in use when they retire; they were hiring maintenance engineers to help keep it running a few years back. Maybe a bit of a dead end skills wise but some of it'll transfer to the embedded VAXen that still run half the assembly lines in the same region. (That career advice is sarcastic - probably.)
- rbanffy 2y ago
  > That career advice is sarcastic - probably If you are into retrocomputing, they’ll pay you to have fun doing archeology and necromancy. It’s heaven.
  - binary132 2y ago
    Point me to the hiring board!
madaxe_again 2y ago
And so do several U.K. high street banks, written in COBOL for the PDP-11, run via an emulation layer of an AS/400, last I stuck my head into that particular hell, and I doubt much has changed.
- lbourdages 2y ago
  At least those who started on a System 360 can run some applications essentially unmodified on modern hardware... The bus factor on that PDP-11 software must be uncomfortably low.
- mastazi 2y ago
  > last I stuck my head into that particular hell I don't think it's hell if you like retrocomputing. Personally I find it fascinating. In the past I sometimes had to work on legacy systems and I liked playing the archeologist role. Maybe you are not referring to the platform, but rather to code quality. But I have found some a lot of jumbled messy React code in early stage startups, and some decent code in legacy systems I have worked on, so I guess code quality is not always directly related to age of the system...
  - madaxe_again 2y ago
    I like retro computing - and this ain’t it. This is consultants gouging their clients, and a cultish “we don’t touch that” inherited through generations of management. To be clear, parts of it are in COBOL. Other bits are in RPG, others yet in PL/1, and then a generous application of java, c++, windows shell scripts, unix shell scripts, and it’s all held together with TSVs. It’s more like hoarding than anything else - “don’t touch that, it might be useful, I don’t know, just leave it as it is, we’ll get eleven new servers for whatever it is that it does” In the end we gave them a pile of python that ingested malformatted EDIs that another system made and spat out TSVs so that same system could then not trip over its own shoelaces.
    - mastazi 2y ago
      Ah, makes sense, yeah that's not what I had pictured, and it seems like it's not fun at all!
- jen729w 2y ago
  I got an insight in to why this is the case in 2012, when I had the misfortune to be part of the worst project I've ever worked on. I was at one of Australia's 'big four' banks. My $100m project was charged with replacing a tiny part of their mortgage system: the onboarding of a new customer. That was it: just getting a new customer in to the existing legacy system. Oracle were the prime. They were a disgrace. Accenture had their grubby little fingers in the pie and were theoretically, laughably, going to run the thing. They used to charge us $2m to copy and paste documents. The thieves. It was an utter shambles. The 'plan on a page' was diamond shapes on a PowerPoint slide. There was no link to any sort of reality. I lasted 9 months before the blessed gods let me go. Shortly thereafter the whole thing was cancelled.
  - skissane 2y ago
    > Oracle were the prime. They were a disgrace I think I may have actually been working on the project you are talking about from the Oracle side. I think many of us tried our very best as individuals. I was never on it full-time, I worked for Oracle engineering but they'd sometimes send us on-site at big customers to fix problems when they blew up. It can be a lot easier to debug a customer's problem when you have the source code right in front of you.
- nxobject 2y ago
  Christ, why would you go from (relatively) commodity PDP-11 hardware to a more restrictive IBM platform? If you want reliability, any industrial/rugged x86 at that time would have been cheaper and easier to maintain in-house.
  - madaxe_again 2y ago
    Couldn’t tell you, but probably some variant of “that’s what the CTO’s last gig used”
- tonyedgecombe 2y ago
  All the UK high street banks I worked with were running on IBM mainframes (or UNIX in one case) rather than AS400. The only bank I have come across running on an AS400 was a small one in Luxembourg that serviced the mafia.
  - nxobject 2y ago
    Why keep the mafia computing at the bank when your crime cartel could have the AS/400 in org? Apparently the Cali cartel had sophisticated “business analytics and intelligence” back in the day. https://www.vice.com/en/article/the-cartel-supercomputer-of-1994/ https://www.vice.com/en/article/the-cartel-supercomputer-of-...
avipars 2y ago
Archive link: https://web.archive.org/web/20221225231302/https://webinfo.uk/webdocssl/irse-kbase/ref-viewer.aspx?refno=1559669757&document=2.10%20strangaric%20-%20legacy%20train%20control%20system%20stabilisation.pdf https://web.archive.org/web/20221225231302/https://webinfo.u...
chasil 2y ago
We still run VAX VMS in production. Sometimes I run it on SimH. https://en.m.wikipedia.org/wiki/SIMH https://en.m.wikipedia.org/wiki/SIMH You can run it too. https://gunkies.org/wiki/Installing_VMS_V1.0_on_SIMH https://gunkies.org/wiki/Installing_VMS_V1.0_on_SIMH
- cowboylowrez 2y ago
  where would you get help running that simh? it builds and produces binaries on linux but chokes on things like 'set quiet' says non-existant device, much less do much in the vax780.ini. should I try again on a 32 bit installation, as I'm using a 64 bit linux right now?
  - cowboylowrez 2y ago
    I found the problem, when I followed the links I ended up installing the "classic" version of simh but it didn't like the vax780.ini, biggest clue was "set quiet" everything else was very confusing to me haha Installing simh from "open-simh" and everything works according to instructions, I tried using the version V3.12-5 mentioned on the page https://simh.trailing-edge.com/ https://simh.trailing-edge.com/ and this (and all 3.x?) is the "classic" simh and didn't support the referenced vax780.ini, but the version from github (4.x?) worked. Very cool to see vms boot!
aryonoco 2y ago
The emulated PDP-11 was replaced sometime around 2015 by a system from Invensys.
locusm 2y ago
Whilst not a train guy, I found this talk at Laracon AU to be pretty entertaining... https://www.youtube.com/watch?v=bbPzSdyroRM https://www.youtube.com/watch?v=bbPzSdyroRM
tw1984 2y ago
Ironically, because of the unbelievably bad infrastructures and general policies, Melbourne because a relatively affordable place to live in Australia. When other capital cities saw double digits property price growth, Melbourne prices actually went down.
notorandit 2y ago
Maybe the PDP-11 is the one running the linked website.
abrookewood 2y ago
FYI: "The PDP–11 is a series of 16-bit minicomputers originally sold by Digital Equipment Corporation (DEC) from 1970 into the late 1990s, one of a set of products in the Programmed Data Processor (PDP) series." https://en.wikipedia.org/wiki/PDP-11 https://en.wikipedia.org/wiki/PDP-11
FireBeyond 2y ago
Almost 20 years ago I worked for a company that was bidding on replacing the CRTs that had been rendering platform train information, which was spat out as a stream from said PDP11. I even went to Flinders St and got to see it. It was everything you imagine a 70s era data stream to look like. 1200bps, weird control sequences, etc., etc. And no-one could really tell us much about it, but there was some poorly photocopied incomplete documentation.
- SulphurCrested 2y ago
  I worked on this system during its development in the 1980s. There were actually two PDP-11s, the one to run the platform displays running locally-written software. The “weird control sequences” sent between the PDP-11 and the plaform displays were HDLC, a synchronous protocol then common in IBM token ring networks as SDLC. This was actually a decent technical solution because they only had to run one coax cable down each train line and the PIDS could sit there watching for their token slot. The hardware for HDLC would have been commodity, whereas fibre optic or carrier sense for long-run packet was not. The other PDP-11 that ran the signals (the “train describer”) could plot the position of trains on glass TTY terminals using escape sequences (VT100, same as in xterm today) so our PDP-11 pretended to be one of those and screen-scraped. So I was told, when I asked the guy who wrote it. All of that was done before I got there. I was called in with 6 weeks to go before commissioning to fix the bit in the middle that recalculated train positions and arrival times.
  - aryonoco 2y ago
    As a Melburnian and a PDP-11 bits collector, this is just fantastic information! Do you have a blog or somewhere else where you share tidbits of information like this? Cause I sure would love to read that.
skissane 2y ago
Apparently, this is no longer the case, and the old emulated PDP-11 system was replaced with a new system in 2014–2016: https://news.ycombinator.com/item?id=29157259 https://news.ycombinator.com/item?id=29157259 The old system we are talking about here was Ericsson JZA 715, mostly written in Pascal with some parts in PDP-11 assembly, running under RSX-11M. Melbourne was the first site in the Southern Hemisphere for Ericsson's JZA series train control software, going live in 1982. JZA 715 first went live in Oslo in 1979. Earlier iterations of Ericsson's JZA software (JZA 410) went live in Stockholm in 1971 and Copenhagen in 1972.
- bobthepanda 2y ago
  There is also an even newer CBTC system going into use for the new metro tunnel.
  - rbanffy 2y ago
    I wonder how much of that code is the old code compiled for the new platform.
    - bobthepanda 2y ago
      As part of the new system, I don't think very much at all, since the two technologies are fundamentally different; CBTC is trains talking directly to each other, and cab/wayside signalling is the tracks telling the trains what to do. That being said, it's pretty common in retrofits for the older system to still be around as a fallback if the CBTC fails.
      - skissane 2y ago
        The Melbourne Metro is just a new tunnel on existing lines, so I would guess they are going to have to support some kind of interoperation between CBTC and non-CBTC? I mean, the ability to run CBTC trains on non-CBTC track or vice versa? This is different from Sydney, where the Metro lines are physically disconnected from the traditional rail lines. (Apparently there is still some track linking the Northwest metro line to the Main Northern line underneath Epping station, legacy of the old Epping-Chatswood Rail Link, but it is blocked with off with stops; there is no plan for any rail connection between the new Metro West line and the traditional rail network, despite the fact that remnants of the old Carlingford line are directly adjacent to the site of the new Metro West maintenance facility, meaning they could create such a connection if they wanted to.)
mrngm 2y ago
The toot itself is from 2021, and links to a 2012 PDF* from the "ASPECT 2012 Conference (UK)", specifically 2.10 strangaric - legacy train control system stabilisation.pdf [*] Due to the website's interface, navigating directly to https://webinfo.uk/webdocssl/irse-kbase/ref-viewer.aspx?refno=1559669757&document=2.10%20strangaric%20-%20legacy%20train%20control%20system%20stabilisation.pdf https://webinfo.uk/webdocssl/irse-kbase/ref-viewer.aspx?refn... seems to serve a web page that requires clicking through to request the PDF.
- avipars 2y ago
  Wayback machine solved the problem for me https://web.archive.org/web/20221225231302/https://webinfo.uk/webdocssl/irse-kbase/ref-viewer.aspx?refno=1559669757&document=2.10%20strangaric%20-%20legacy%20train%20control%20system%20stabilisation.pdf https://web.archive.org/web/20221225231302/https://webinfo.u...

129 points by SerCe 2y ago

The largest nuclear power plant in North America, Darlington Nuclear Generating Station in Ontario, a bit east of Toronto, uses robots for handling the fuel rods. The plant was designed in the late 70s and the control software is apparently written in PDP-11 assembler. And they will keep using it for the remaining lifespan of the plant. So probably long after I retire and I'm not old. Now that's an idea for any young coders looking for a language that'll still be in use when they retire; they were hiring maintenance engineers to help keep it running a few years back. Maybe a bit of a dead end skills wise but some of it'll transfer to the embedded VAXen that still run half the assembly lines in the same region. (That career advice is sarcastic - probably.)

rbanffy 2y ago
> That career advice is sarcastic - probably If you are into retrocomputing, they’ll pay you to have fun doing archeology and necromancy. It’s heaven.
- binary132 2y ago
  Point me to the hiring board!

madaxe_again 2y ago

And so do several U.K. high street banks, written in COBOL for the PDP-11, run via an emulation layer of an AS/400, last I stuck my head into that particular hell, and I doubt much has changed.

lbourdages 2y ago
At least those who started on a System 360 can run some applications essentially unmodified on modern hardware... The bus factor on that PDP-11 software must be uncomfortably low.
mastazi 2y ago
> last I stuck my head into that particular hell I don't think it's hell if you like retrocomputing. Personally I find it fascinating. In the past I sometimes had to work on legacy systems and I liked playing the archeologist role. Maybe you are not referring to the platform, but rather to code quality. But I have found some a lot of jumbled messy React code in early stage startups, and some decent code in legacy systems I have worked on, so I guess code quality is not always directly related to age of the system...
- madaxe_again 2y ago
  I like retro computing - and this ain’t it. This is consultants gouging their clients, and a cultish “we don’t touch that” inherited through generations of management. To be clear, parts of it are in COBOL. Other bits are in RPG, others yet in PL/1, and then a generous application of java, c++, windows shell scripts, unix shell scripts, and it’s all held together with TSVs. It’s more like hoarding than anything else - “don’t touch that, it might be useful, I don’t know, just leave it as it is, we’ll get eleven new servers for whatever it is that it does” In the end we gave them a pile of python that ingested malformatted EDIs that another system made and spat out TSVs so that same system could then not trip over its own shoelaces.
  - mastazi 2y ago
    Ah, makes sense, yeah that's not what I had pictured, and it seems like it's not fun at all!
jen729w 2y ago
I got an insight in to why this is the case in 2012, when I had the misfortune to be part of the worst project I've ever worked on. I was at one of Australia's 'big four' banks. My $100m project was charged with replacing a tiny part of their mortgage system: the onboarding of a new customer. That was it: just getting a new customer in to the existing legacy system. Oracle were the prime. They were a disgrace. Accenture had their grubby little fingers in the pie and were theoretically, laughably, going to run the thing. They used to charge us $2m to copy and paste documents. The thieves. It was an utter shambles. The 'plan on a page' was diamond shapes on a PowerPoint slide. There was no link to any sort of reality. I lasted 9 months before the blessed gods let me go. Shortly thereafter the whole thing was cancelled.
- skissane 2y ago
  > Oracle were the prime. They were a disgrace I think I may have actually been working on the project you are talking about from the Oracle side. I think many of us tried our very best as individuals. I was never on it full-time, I worked for Oracle engineering but they'd sometimes send us on-site at big customers to fix problems when they blew up. It can be a lot easier to debug a customer's problem when you have the source code right in front of you.
nxobject 2y ago
Christ, why would you go from (relatively) commodity PDP-11 hardware to a more restrictive IBM platform? If you want reliability, any industrial/rugged x86 at that time would have been cheaper and easier to maintain in-house.
- madaxe_again 2y ago
  Couldn’t tell you, but probably some variant of “that’s what the CTO’s last gig used”
tonyedgecombe 2y ago
All the UK high street banks I worked with were running on IBM mainframes (or UNIX in one case) rather than AS400. The only bank I have come across running on an AS400 was a small one in Luxembourg that serviced the mafia.
- nxobject 2y ago
  Why keep the mafia computing at the bank when your crime cartel could have the AS/400 in org? Apparently the Cali cartel had sophisticated “business analytics and intelligence” back in the day. https://www.vice.com/en/article/the-cartel-supercomputer-of-1994/ https://www.vice.com/en/article/the-cartel-supercomputer-of-...

avipars 2y ago

Archive link: https://web.archive.org/web/20221225231302/https://webinfo.uk/webdocssl/irse-kbase/ref-viewer.aspx?refno=1559669757&document=2.10%20strangaric%20-%20legacy%20train%20control%20system%20stabilisation.pdf https://web.archive.org/web/20221225231302/https://webinfo.u...

chasil 2y ago

We still run VAX VMS in production. Sometimes I run it on SimH. https://en.m.wikipedia.org/wiki/SIMH https://en.m.wikipedia.org/wiki/SIMH You can run it too. https://gunkies.org/wiki/Installing_VMS_V1.0_on_SIMH https://gunkies.org/wiki/Installing_VMS_V1.0_on_SIMH

cowboylowrez 2y ago
where would you get help running that simh? it builds and produces binaries on linux but chokes on things like 'set quiet' says non-existant device, much less do much in the vax780.ini. should I try again on a 32 bit installation, as I'm using a 64 bit linux right now?
- cowboylowrez 2y ago
  I found the problem, when I followed the links I ended up installing the "classic" version of simh but it didn't like the vax780.ini, biggest clue was "set quiet" everything else was very confusing to me haha Installing simh from "open-simh" and everything works according to instructions, I tried using the version V3.12-5 mentioned on the page https://simh.trailing-edge.com/ https://simh.trailing-edge.com/ and this (and all 3.x?) is the "classic" simh and didn't support the referenced vax780.ini, but the version from github (4.x?) worked. Very cool to see vms boot!

aryonoco 2y ago

The emulated PDP-11 was replaced sometime around 2015 by a system from Invensys.

locusm 2y ago

Whilst not a train guy, I found this talk at Laracon AU to be pretty entertaining... https://www.youtube.com/watch?v=bbPzSdyroRM https://www.youtube.com/watch?v=bbPzSdyroRM

tw1984 2y ago

Ironically, because of the unbelievably bad infrastructures and general policies, Melbourne because a relatively affordable place to live in Australia. When other capital cities saw double digits property price growth, Melbourne prices actually went down.

notorandit 2y ago

Maybe the PDP-11 is the one running the linked website.

abrookewood 2y ago

FYI: "The PDP–11 is a series of 16-bit minicomputers originally sold by Digital Equipment Corporation (DEC) from 1970 into the late 1990s, one of a set of products in the Programmed Data Processor (PDP) series." https://en.wikipedia.org/wiki/PDP-11 https://en.wikipedia.org/wiki/PDP-11

FireBeyond 2y ago

Almost 20 years ago I worked for a company that was bidding on replacing the CRTs that had been rendering platform train information, which was spat out as a stream from said PDP11. I even went to Flinders St and got to see it. It was everything you imagine a 70s era data stream to look like. 1200bps, weird control sequences, etc., etc. And no-one could really tell us much about it, but there was some poorly photocopied incomplete documentation.

SulphurCrested 2y ago
I worked on this system during its development in the 1980s. There were actually two PDP-11s, the one to run the platform displays running locally-written software. The “weird control sequences” sent between the PDP-11 and the plaform displays were HDLC, a synchronous protocol then common in IBM token ring networks as SDLC. This was actually a decent technical solution because they only had to run one coax cable down each train line and the PIDS could sit there watching for their token slot. The hardware for HDLC would have been commodity, whereas fibre optic or carrier sense for long-run packet was not. The other PDP-11 that ran the signals (the “train describer”) could plot the position of trains on glass TTY terminals using escape sequences (VT100, same as in xterm today) so our PDP-11 pretended to be one of those and screen-scraped. So I was told, when I asked the guy who wrote it. All of that was done before I got there. I was called in with 6 weeks to go before commissioning to fix the bit in the middle that recalculated train positions and arrival times.
- aryonoco 2y ago
  As a Melburnian and a PDP-11 bits collector, this is just fantastic information! Do you have a blog or somewhere else where you share tidbits of information like this? Cause I sure would love to read that.

skissane 2y ago

Apparently, this is no longer the case, and the old emulated PDP-11 system was replaced with a new system in 2014–2016: https://news.ycombinator.com/item?id=29157259 https://news.ycombinator.com/item?id=29157259 The old system we are talking about here was Ericsson JZA 715, mostly written in Pascal with some parts in PDP-11 assembly, running under RSX-11M. Melbourne was the first site in the Southern Hemisphere for Ericsson's JZA series train control software, going live in 1982. JZA 715 first went live in Oslo in 1979. Earlier iterations of Ericsson's JZA software (JZA 410) went live in Stockholm in 1971 and Copenhagen in 1972.

bobthepanda 2y ago
There is also an even newer CBTC system going into use for the new metro tunnel.
- rbanffy 2y ago
  I wonder how much of that code is the old code compiled for the new platform.
  - bobthepanda 2y ago
    As part of the new system, I don't think very much at all, since the two technologies are fundamentally different; CBTC is trains talking directly to each other, and cab/wayside signalling is the tracks telling the trains what to do. That being said, it's pretty common in retrofits for the older system to still be around as a fallback if the CBTC fails.
    - skissane 2y ago
      The Melbourne Metro is just a new tunnel on existing lines, so I would guess they are going to have to support some kind of interoperation between CBTC and non-CBTC? I mean, the ability to run CBTC trains on non-CBTC track or vice versa? This is different from Sydney, where the Metro lines are physically disconnected from the traditional rail lines. (Apparently there is still some track linking the Northwest metro line to the Main Northern line underneath Epping station, legacy of the old Epping-Chatswood Rail Link, but it is blocked with off with stops; there is no plan for any rail connection between the new Metro West line and the traditional rail network, despite the fact that remnants of the old Carlingford line are directly adjacent to the site of the new Metro West maintenance facility, meaning they could create such a connection if they wanted to.)

mrngm 2y ago

The toot itself is from 2021, and links to a 2012 PDF* from the "ASPECT 2012 Conference (UK)", specifically 2.10 strangaric - legacy train control system stabilisation.pdf [*] Due to the website's interface, navigating directly to https://webinfo.uk/webdocssl/irse-kbase/ref-viewer.aspx?refno=1559669757&document=2.10%20strangaric%20-%20legacy%20train%20control%20system%20stabilisation.pdf https://webinfo.uk/webdocssl/irse-kbase/ref-viewer.aspx?refn... seems to serve a web page that requires clicking through to request the PDF.

avipars 2y ago
Wayback machine solved the problem for me https://web.archive.org/web/20221225231302/https://webinfo.uk/webdocssl/irse-kbase/ref-viewer.aspx?refno=1559669757&document=2.10%20strangaric%20-%20legacy%20train%20control%20system%20stabilisation.pdf https://web.archive.org/web/20221225231302/https://webinfo.u...