[HN Gopher] Ask HN: What is the oldest, still supported OS?
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       Ask HN: What is the oldest, still supported OS?
        
       I recently discovered that TSOS, an old Univac OS that I used (and
       loved!) in the mid 1970's and first released in 1968 by RCA, is
       still supported (although the name has changed) as Fujitsu's BS2000
       OS. Unix was released a year after that (1969). Is there something
       that beats these?
        
       Author : abrax3141
       Score  : 92 points
       Date   : 2022-02-28 21:13 UTC (1 hours ago)
        
       | Animats wrote:
       | UNIVAC 1108 EXEC-8, now OS-2200. Still in use, 55 years later,
       | with mostly the same API and commands.
       | 
       | [1] https://en.wikipedia.org/wiki/OS_2200
        
       | kragen wrote:
       | Burroughs MCP was released in 01961 and seems to still be
       | supported. The latest release was 20.0 in May. That's probably
       | the oldest.
       | 
       | z/OS was released in 01966. BOS/360 made it out the door earlier,
       | in 01965, thanks to the disastrous delays in z/OS, but it's no
       | longer supported; DOS/360 (z/VSE) also beat z/OS out, is still
       | supported, and is arguably the continuation of BOS.
       | https://en.wikipedia.org/wiki/DOS/360_and_successors
       | 
       | Unix wasn't released in 01969. I think it wasn't released until
       | Fifth Edition in 01974, though Thompson and Ritchie described the
       | Fourth Edition in CACM in 01973. Fourth Edition had "over 20"
       | installations, but I think all within AT&T.
       | https://en.wikipedia.org/wiki/Research_Unix
        
         | mattl wrote:
         | Long Now promoting NFTs, lost my respect.
         | 
         | https://twitter.com/longnow/status/1436364868131586054
        
         | alexvoda wrote:
         | I find it interesting that you write years using 5 digits with
         | leading zeroes. Can you tell me more about that choice?
        
           | gumby wrote:
           | 01961 is not a valid year as '9' is not a valid octal digit.
        
             | kragen wrote:
             | It is in K&R!
        
           | matthoiland wrote:
           | Probably a time traveling technology historian?
        
           | WorldMaker wrote:
           | It's often used to encourage long-term thinking. I most
           | directly associate it with the Long Now Foundation [1], which
           | encourages that format for dates as many of their initiatives
           | strive to consider the Y10K view and beyond.
           | 
           | [1] https://longnow.org/
        
             | imoverclocked wrote:
             | Since we are adding insignificant digits, I think there
             | aren't enough zeros after the most significant digits; We
             | need to focus on solving todays problems too.
             | 
             | For an extreme version of this, 1961 might be written in
             | scientific notation: 0.196100e4
             | 
             | This is also future-proof as we will always have a built-in
             | 0 at the beginning of the number implying that we never get
             | to "1" and there will always be more time to solve the
             | problems we can't even begin to understand that may exist
             | 10k years from now.
             | 
             | Sorry for the sarcasm, it was the easiest way to make my
             | point.
        
               | kragen wrote:
               | This is a great idea! I'll try it next week if I
               | remember.
        
               | mattkrause wrote:
               | Next 0.1923e-1, you mean?
        
           | compressedgas wrote:
           | https://longnow.org/ideas/02013/12/31/long-now-years-five-
           | di...
        
             | oxguy3 wrote:
             | Lol, that's completely silly. Who even knows if we'll still
             | be using the same calendar in 8,000 years? Y10K is not
             | worth dealing with until the 100th century.
        
               | kragen wrote:
               | Yes, it is!
        
               | _jal wrote:
               | So then why not Y100K?
               | 
               | Does preparation become pointless sometime after 8,000
               | years from now, but before 92,000 have elapsed?
        
               | kragen wrote:
               | Go wild!
        
               | mod50ack wrote:
               | Even if we do, the year 900 is not written "0900".
        
             | radford-neal wrote:
             | "It's an idiosyncrasy to which we are dedicated."
             | 
             | Sounds like a good thing to me.
             | 
             | It quickly identifies you as someone who prioritizes
             | personal idiosyncrasies over communicating whatever it is
             | you want to communicate - since pretty much every reader
             | will do a double-take on the date (or is it a date?) and be
             | distracted from reading the content.
             | 
             | That's helpful, since one can generally assume that anyone
             | with that attitude isn't communicating anything useful.
        
           | oh_sigh wrote:
           | I thought it was interesting that I've noticed someone doing
           | that twice today, and never before in my life, but it turns
           | out it was just another one of kragen's comments from earlier
           | today on a different thread.
        
             | kragen wrote:
             | I think this means I've spent _far too much time_ on HN
             | today.
        
               | Shared404 wrote:
               | And there's my cue to turn on noprocrast for the day.
        
           | [deleted]
        
           | tenebrisalietum wrote:
           | Y10K problem: https://simple.wikipedia.org/wiki/Year_10,000_p
           | roblem#:~:tex....
        
             | [deleted]
        
             | drewzero1 wrote:
             | See also, the Long Now Foundation:
             | https://en.wikipedia.org/wiki/Long_Now_Foundation
        
             | umanwizard wrote:
             | Writing with four digits doesn't induce any Y10k problem.
             | We write dates with as many digits as they need; for
             | example, we write the year 327 with three digits.
        
               | rbanffy wrote:
               | In the best interest of future generations, we should
               | specify that this count is in the Christian Era. Our
               | descendants may want to reset the count (and change the
               | duration of a standard year) at some point.
        
           | sgt wrote:
           | On HN you find all kinds, that's why.
        
         | djbusby wrote:
         | I'd like to see these long-now dates with a Y included - to
         | clearly identify a year, like y01960 - so it's not confused
         | with things like hex/octal or post-codes.
        
       | aluminum96 wrote:
       | This is slightly off topic -- it's about an old supported
       | _microarchitecture_ -- but Linux still supports DEC Alpha,
       | despite no chip with that architecture having been developed
       | since 2004.
       | 
       | DEC Alpha has extremely weak memory ordering. [1] In fact, it's
       | the weakest ordering of any arch supported by linux, which
       | includes extra fence instructions to support it. The memory model
       | is crazy weak, but it apparently allows for extra speculative
       | execution parallelism.
       | 
       | [1] Awesome Raymond Chen post, totally worth a read:
       | https://devblogs.microsoft.com/oldnewthing/20170817-00/?p=96...
        
         | Klonoar wrote:
         | One question: _why?_
         | 
         | Is this still used en masse somewhere and needs updates?
         | Consider me 100% ignorant.
        
       | ElevenLathe wrote:
       | OS/360 dates to 1966. I believe z/OS in theory still provides
       | compatibility back to applications of that vintage, though AFAIK
       | it is a separate codebase.
        
         | retrac wrote:
         | Z/OS is directly descended from OS/360. It's just a renaming.
         | And yes, it continues to have almost complete binary
         | compatibility back to 1966. I know for a fact that the IBM
         | Fortran compiler from 1972 runs unmodified on z/OS today. Just
         | pipe the 80 column EBCDIC data representing punch card images
         | into the virtual punch card reader and off you go.
        
           | chefkoch wrote:
           | > into the virtual punch card reader
           | 
           | as someone to young to have seen punch cards live this sounds
           | really strange.
        
             | anonymousiam wrote:
             | You can still create (virtual) punched cards on Linux. Just
             | install the bsdgames package and run bcd. I guess punched
             | cards are such a novelty that the bcd program belongs in
             | "games".
             | 
             | Note that bcd, ppt, and morse are all in the same binary.
             | ppt simulates punched paper tape and morse will
             | encode/decode International Morse Code.
             | 
             | I actually ran these yesterday when I was explaining some
             | computer history to my 19 year old son.
        
             | retrac wrote:
             | If you think about it, it is no weirder than Linux users
             | talking about TTYs when no one has connected an actual
             | teletype to a Linux machine other than for a laugh. The
             | basic IO device becomes an abstraction that hangs around.
             | Fun fact: you also boot Linux on zSeries by feeding a
             | kernel image into a virtual punch card reader!
        
           | p_l wrote:
           | There was a big rewrite around MVS, but z/OS to this day
           | executes a lot of code in 24bit address mode of S/360[1], and
           | well, OS/360 code should mostly just run
           | 
           | [1] Easy to observe when running z/OS under Hercules, as one
           | of the console modes shows the CPU address size mode. A lot
           | of the time during bootup of basic ADCD you'll see 24, a bit
           | less 31, and rarely 64
        
             | rbanffy wrote:
             | 31 bits ought to be enough for anyone.
        
             | monocasa wrote:
             | If it ain't broke, don't fix it. And if it's broke just a
             | little, someone probably depends on it for compat.
        
               | gjvc wrote:
               | https://www.hyrumslaw.com/
        
       | p_l wrote:
       | Master Control Program of Burroughs Large Systems fame was first
       | released in 1961 - latest release is from May 2021
        
         | bombcar wrote:
         | https://en.wikipedia.org/wiki/Burroughs_MCP and there's even a
         | link to the latest release notes:
         | https://public.support.unisys.com/aseries/docs/ClearPath-MCP...
        
         | abrax3141 wrote:
         | Okay, seems like that's the one to beat!
        
       | Jerry2 wrote:
       | The oldest one I know is PDP-11. It's still being used in nuclear
       | power plants and many plants will continue using it until at
       | least 2050 (maybe even longer if they remain working). [1] PDP-11
       | was released in 1970 so your TSOS find is even older. I'm sure
       | there's something even older than these two that's being used by
       | various gov orgs and industrial systems. There's plenty of small
       | consulting firms that support ancient systems. These contracts
       | provide them with steady and stable income.
       | 
       | [1]
       | https://www.theregister.co.uk/2013/06/19/nuke_plants_to_keep...
        
         | ghaff wrote:
         | Used != supported especially for systems that are not network-
         | connected. Also the PDP-11 is a minicomputer series. There were
         | a bunch of operating systems from DEC and others that ran on
         | it. Certainly there are consultants who support ancient system
         | but they probably have limited (if any) access to the OS source
         | code--though they can probably patch to a limited degree.
        
           | cptnapalm wrote:
           | BSD 2.11 is still getting patched by Steve Schultz, last I
           | saw.
        
           | SilasX wrote:
           | Sufficiently advanced long-term maintenance via patches
           | _seems_ indistinguishable from providing support.
        
         | kragen wrote:
         | PDP-11 isn't an OS.
        
           | egberts1 wrote:
           | a ginormous scripting OS, PDP/11 is.
        
           | p_l wrote:
           | What's more, when it comes to computer architectures, even
           | among Digital it's not the oldest nor still supported.
           | 
           | Because you can still buy a _new_ PDP-10 (well, PDP-10
           | compatible, iirc a lot of I /O is different, but it can run
           | TOPS-20 V7 with patches)
           | 
           | Of course S/360 has longer continuity of hw/sw combination.
        
             | kragen wrote:
             | You can't buy it from Digital, and TOPS-20 isn't still
             | supported.
        
         | drewzero1 wrote:
         | This is a good answer to another question: what is the oldest
         | computer family/architecture still in use? I'm sure there are
         | other contenders out there, especially with modern descendants
         | of old architectures and different interpretations of the
         | question. I'd be interested in hearing about others as well.
         | 
         | I believe my employer's PDP-11 ran RSTS/E or some variant, and
         | the software was written in BASIC by my current boss. There
         | were a lot of operating systems available for the PDP-11 for a
         | lot of different contexts (including UNIX).
        
         | retrac wrote:
         | I seriously considered applying for that job! I'm probably 30
         | years younger than anyone with real PDP-11 experience but I got
         | a background in programming tiny embedded systems, with some
         | robotics. And I love computer history with a particular soft
         | spot for the PDP-11. (I've got an LSI-11 in the basement
         | somewhere.) But then I thought about it. Tracing race
         | conditions in PDP-11 code all day seems like the surest way to
         | kill all love for my hobby.
         | 
         | Anyway, the PDP-11 wasn't really an OS but an architecture
         | (like ARM or x86). The robotics software in question probably
         | runs bare metal. It was very, very popular and will indeed
         | remain around in pockets (in emulation) probably until the 22nd
         | century. Ain't broke? Don't fix.
        
       | nix0n wrote:
       | Possibly Burroughs MCP[0] from 1961, currently Unisys ClearPath
       | MCP.
       | 
       | Not to be confused with Encom MCP[1], which was defeated by Flynn
       | and Tron in 1982.
       | 
       | [0]https://en.wikipedia.org/wiki/Burroughs_MCP
       | [1]https://www.imdb.com/title/tt0084827/
        
         | rbanffy wrote:
         | > Not to be confused with Encom MCP
         | 
         | MCP is the most user hostile OS I've ever seen. It may be less
         | intelligent, but shows the same contempt for users as its
         | fictional counterpart.
        
           | oh_sigh wrote:
           | Not surprising, considering the "guardian" process is called
           | J_EDGAR_HOOVER. Rumor has it it will even drop fake emails in
           | your inbox urging you to kill yourself if your username
           | starts with MLK_
        
           | pjmlp wrote:
           | Safety first has a price.
        
             | rbanffy wrote:
             | You can't hack an OS you can't use.
        
               | annoyingnoob wrote:
               | I worked on an HP3000 in the early 90s. It had a software
               | package that changed all of the error messages to
               | resemble IBM360 error messages, just to throw would be
               | attackers off.
        
         | jounker wrote:
         | Wasn't Encom MCP. just a rebranded vmunix.el?
        
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       (page generated 2022-02-28 23:00 UTC)