[HN Gopher] First new VAX in 30 years?
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First new VAX in 30 years?
Author : JoachimS
Score : 182 points
Date : 2021-07-07 09:03 UTC (13 hours ago)
(HTM) web link (mail-index.netbsd.org)
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| ChrisArchitect wrote:
| related / other thread from this netbsd list a few days ago
|
| _New Vax Implementation_
| https://news.ycombinator.com/item?id=27742540
| tpoacher wrote:
| Did anyone else misread the title as "First new _wax_ in 30 years
| " and imagine a _completely_ different article? xD
| hereforphone wrote:
| Only the young
| lc9er wrote:
| Interesting. I had an assembly course taught on a VAX system in
| 2001. At the time, I had the impression it was because the
| instructor had access to it and felt it was of historical
| significance. I wish I could remember more about the experience.
| bwanab wrote:
| I'd say it was because the VAX (and the PDP-11 family that
| preceded it) has one of the cleanest instruction sets of any
| processor family that was ever extensively used. It was almost
| as easy as C to program in its assembly language.
| GeorgeTirebiter wrote:
| Yes, and... each of the earlier processors had certain
| 'corner cases' in the way they handled setting (or not) flag
| bits; DEC s/w had to check these corner cases and execute a
| proper set of instructions for that specific machine. But
| yes, conceptually, the orthogonal addressing modes, and
| 'obvious' instruction names influenced probably 2 generations
| of students (for the better). The major lesson learned tho, I
| think, was: never be stingy with address bits! (16 is way too
| few; and even later 22-bit addresses weren't enough.)
| Torwald wrote:
| Anybody remember these?
|
| https://www.ebay.com/itm/174146521380?_trkparms=aid%3D111000...
| slumdev wrote:
| Wild. Apparently there are many different efforts to use FPGAs to
| simulate old hardware:
|
| "Using FPGAs to Simulate old Game Consoles":
| https://jakob.engbloms.se/archives/3026
|
| "AMSTRAD ON AN FPGA": https://hackaday.com/2017/01/06/amstrad-on-
| an-fpga/
|
| "MISTER FPGA: THE FUTURE OF RETRO GAME EMULATION AND
| PRESERVATION?": https://www.racketboy.com/retro/mister-fpga-the-
| future-of-re...
| tyingq wrote:
| I find it interesting when someone makes foundational
| improvements when using an FPGA to mimic an old CPU.
|
| The NextZ80 is a good example. It's designed to run 4x the
| amount of instructions at the same clock rate as a real Z80.
| And you can clock it to 40MHz, so it's effectively a 160Mhz
| Z80...compare to a typical 4/8Mhz real Z80.
|
| https://opencores.org/projects/nextz80
| mabbo wrote:
| This seems interesting, but I lack context. Can someone ELI5? Or
| maybe more like 'Explain Like I'm a CS Undergrad' (ELICSUG?).
| lproven wrote:
| Um. Now I feel like I'm 106 instead of "just" 53.
|
| OK, so, basically _all_ modern mass-market OSes of any
| significance derive in some way from 2 historical minicomputer
| families... from the same company.
|
| Minicomputers are what came after mainframes, before
| microcomputers. A microcomputer is a computer whose processor
| is a microchip: a single integrated circuit containing the
| whole processor. Before the first one was invented in 1974
| (IIRC), processors were made from discrete logic: lots of
| little silicon chips.
|
| The main distinguishing feature of minicomputers from micros is
| that the early micros were single-user: one computer, one
| terminal, one user. No multitasking or anything.
|
| Minicomputers appeared in the 1960s and peaked in the 1970s,
| and cost just tens to hundreds of thousands of dollars, while
| mainframes cost millions and were usually leased. So
| minicomputers could be afforded by a company department, not an
| entire corporation... meaning that they were shared, by dozens
| of people. So, unlike the early micros, minis had multiuser
| support, multitasking, basic security and so on.
|
| The most significant minicomputer vendor was a company called
| DEC: Digital Equipment Corporation. DEC made multiple
| incompatible lines of minis, many called PDP-something -- some
| with 9-bit logic, some with 12-bit, 18-bit, or 36-bit logic.
|
| One of its early big hits was the 12-bit PDP-8. It ran multiple
| incompatible OSes, but one was called OS-8. This OS is long
| gone but it was the origin of a command-line interface with
| commands such as DIR, TYPE, DEL, REN and so on. It also had a
| filesystem with 6-letter names (all in caps) with semi-
| standardised 3-letter extension, such as README.TXT.
|
| This OS and its shell later inspired Digital Research's CP/M
| OS, the first industry-standard OS for 8-bit micros. CP/M was
| going to be the OS for the IBM PC but IBM got a cheaper deal
| from Microsoft for what was essentially a clean-room re-
| implementation of CP/M, called MS-DOS.
|
| So DEC's PDP-8 and OS-8 _directly inspired_ the entire PC-
| compatible industry, the whole x86 computer industry.
|
| Another DEC mini was the 18-bit PDP-7. Like almost all DEC
| minis, this too ran multiple OSes, both from DEC and others.
|
| A 3rd-party OS hacked together as a skunkworks project on a
| disused spare PDP-7 at AT&T's research labs was UNIX.
|
| More or less at the same time as the computer industry
| gradually standardised on the 8-bit byte, DEC also made 16-bit
| and 32-bit machines.
|
| Among the 16-bit machines, the most commercially successful was
| the PDP-11. This is the machine that UNIX's creators first
| ported it to, and in the process, they rewrote it in a new
| language called C.
|
| The PDP-11 was a huge success so DEC was under commercial
| pressure to make an improved successor model. It did this by
| extending the 16-bit PDP-11 instruction set to 32 bits. For
| this machine, the engineer behind the most successful PDP-11
| OS, called RSX-11, led a small team that developed a new, pre-
| emptive multitasking, multiuser OS with virtual memory, called
| VMS.
|
| VMX is still around: it was ported to DEC's Alpha, the first
| 64-bit RISC chip, and later to the Intel Itanium. Now it has
| been spun out from HP and is being ported to x86-64.
|
| But the VMS project leader, Dave Cutler, and his team, were
| headhunted from DEC by Microsoft.
|
| At this time, IBM and Microsoft had very acrimoniously fallen
| out over the failed OS/2 project. IBM kept the x86-32 version
| OS/2 for the 386, which it completed and sold as OS/2 2 (and
| later 2.1, 3, 4 and 4.5. It is still on sale today under the
| name Blue Lion from Arca Noae.)
|
| At Microsoft, Cutler and his team got given the very incomplete
| OS/2 version 3, a planned CPU-independent portable version.
| Cutler _et al_ finished this, porting it to the new Intel RISC
| chip, the i860. This was codenamed the "N-Ten". The resultant
| OS was initially called OS/2 NT, later renamed - due to the
| success of Windows 3 - as Windows NT. Its design owes as much
| to DEC VMS as it does to OS/2.
|
| Today, Windows NT is the basis of Windows 10 and 11.
|
| So the PDP-7, PDP-8 and PDP-11 directly influenced the
| development of CP/M, MS-DOS, OS/2, & Windows 1 through to
| Windows ME.
|
| A different line of PDPs directly led to UNIX and C.
|
| Meanwhile, the PDP-11's 32-bit successor directly influenced
| the design of Windows NT.
|
| When micros grew up and got to be 32-bit computers themselves,
| and vendors needed multitasking OSes with multiuser security,
| they turned back to 1970s mini OSes.
|
| This project is a FOSS re-implementation of the VAX CPU on an
| FPGA. It is at least the 3rd such project but the earlier ones
| were not FOSS and have been lost.
| ableal wrote:
| In 1981 the VAX 11-780 was an object of lust for engineering
| undergrads, who'd be lured by faculty with promises of access
| to the "1 MIPS, 1 MB RAM beast" ...
|
| The author says he re-implemented the CPU (using Verilog) on an
| FPGA running at 50 MHz, well enough to run a test binary
| successfully.
| mabbo wrote:
| Thanks!
| rjsw wrote:
| Try this [1]
|
| [1] https://en.wikipedia.org/wiki/VAX
| tyingq wrote:
| There were apparently 2 prior working VAX FPGA implementations,
| but both were lost to time[1]. I tried the Wayback machine for
| both, but it doesn't seem to have the right time period cached.
|
| [1] http://www.avanthar.com/healyzh/decemulation/pdp_fpga.html
| (scroll to bottom)
| lproven wrote:
| RT Logic:
| https://web.archive.org/web/20061019161717/http://www.rtlogi...
|
| Not much info -- no more than is here:
| https://comp.os.vms.narkive.com/UKFNZj9v/fpga-vax
|
| Noboyuki Kondoh's PhD thesis on the university effort is here,
| but only the abstract is in English:
| http://labo.nshimizu.com/thesis/b2004/1adt2415.pdf
| phendrenad2 wrote:
| Oh that's sad. I remember when one of those was announced, I
| was going to grab the code, but now it's gone? Is internet
| decay accelerating?
| zinekeller wrote:
| Oh, wow, it's indeed nice (even though it's more like TransMeta's
| x86 implementation than a silicon-level design!) Reminds me of
| the efforts to implement the Japanese SuperH(2) RISC instruction
| set.
|
| (To you: you might want to clarify in the title that this is the
| VAX architecture they're talking about (since "vax" unfortunately
| might be confused here with the now-used shorthand for vaccine).)
| opless wrote:
| or more likely the brand of vacuum cleaners :)
| DonaldFisk wrote:
| Fun fact: the vacuum cleaner company (https://www.vax.co.uk)
| had "Nothing sucks like a VAX!" as its advertising slogan:
| http://foldoc.org/vax
| dhosek wrote:
| I have a vague recollection that "nothing sucks like a vax"
| was a parody and never the vacuum cleaner's slogan. A
| cursory google search doesn't pull up anything
| authoritative and it seems like most of the claims that the
| vacuum cleaner people used it are all worded nearly
| identically. The photocopied afi saw back in the 80s was
| too on the nose to be really believable, feeling an awful
| lot like the mouse balls memo.
| DonaldFisk wrote:
| In that case it may be an urban myth, with its origin in
| the (apparently real) Electrolux advert shown here: https
| ://web.archive.org/web/20180707150205/http://adland.tv/..
| .
| mprovost wrote:
| I felt quite old recently when someone at work recommended a
| Vax carpet cleaner and I mentioned that my first email
| account was on a Vax... and they had no idea what I was
| talking about. Had never heard of the platform, or of DEC.
| canadianfella wrote:
| You think more people associate "vax" with a relatively small
| vacuum cleaner company than vaccines?
| boondaburrah wrote:
| I've been meaning to check out J2 (the FPGA SH-2 core) for a
| while now. Mostly haven't because there doesn't seem to be as
| much support/howtos for the chip as there is for say
| arm/mips/m68k/whathaveyou. Most Super-H knowledge I can find
| online centers around programming the Dreamcast's SH-4 with
| GCC.
| p_l wrote:
| VAX was a heavily microcoded design, so there wasn't really
| "silicon level" implementation of VAX instructions themselves -
| the microcode decoded the instructions and set inputs to
| execution units, and unlike some modern microcoded designs,
| there was much less hardwired implementation AFAIK
| twoodfin wrote:
| At least some VAX models supported user-supplied microcode
| and thus a customizable ISA. This could be used, for example,
| to implement a Prolog abstract machine directly on the
| CPU[1].
|
| [1] http://hps.ece.utexas.edu/pub/gee_micro19.pdf
| baus wrote:
| I took my original programming classes on the VAX. I'm somewhat
| nostalgic for it. In many ways it was ahead of its time
| cbm-vic-20 wrote:
| The clustering technology was way ahead of its time. Stuff that
| everyone oozes about over Kubernetes was in VMS clusters back
| in the 1980s.
| mousepilot wrote:
| well does it boot vms or not?
| ok123456 wrote:
| Needs to add MMU.
| mrlonglong wrote:
| That would be awesome if that is possible some day. I still run
| OpenVMS in simh. And the new owners of OpenVMS are busy
| beavering away on an OpenVMS port to the amd64 platform and
| most software should compile cleanly so I've read. Can't wait
| !!!
| pickle-wizard wrote:
| VMS Software has released the x86_64 port of OpenVMS
| recently. However it is not currently available under the
| hobbyist program. They say that is coming soon.
| phendrenad2 wrote:
| Someone should tell them their website still says "VMS
| Software, Inc. is porting OpenVMS to x86", present
| continuous case.
| herio wrote:
| Really cool, but just to nitpick a bit not entirely correct in
| some ways.
|
| Logical systems still sell their NuVAX machines, see
| https://logical-co.com/product/nuvax-4400-system/
|
| They also do PDP/11 systems and hardware.
|
| I think they might be built using an emulator on PC hardware with
| some interfacing hardware, but still I would call it a "new" VAX
| for most purposes.
| minimaul wrote:
| Definitely at least some software emulation on x86. The manual
| for that system shows a board name "PEAK876VL2" in a picture -
| that's an x86 board - but LGA1156, so old!
| bencollier49 wrote:
| I suppose that means the author of the blog post potentially
| has a market for his FPGA implementation.
| rob74 wrote:
| I think getting VAX software to run on an FPGA board is the
| lesser problem - getting it to be 100% compatible so it can
| serve as a "slot-in" replacement for an existing VAX is
| probably a lot more difficult.
| jcurbo wrote:
| Are there really PDP-11s out there still doing stuff? That is
| wild
| spfzero wrote:
| Thanks, didn't know about NuVAX. How old is that product? It
| seems like you could do much better than 70 VUPs today. Or 5
| years ago, for that matter. I guess it is because everything is
| done in sw emulation?
| rob74 wrote:
| Fascinating... in the phrase "replaces the VAX chassis, CPU,
| memory, KWV11-C clock and mass storage", the clock being
| mentioned separately intrigued me, so i googled it. Turns out
| that _only the clock_ was a whole board full of good old TI 74x
| TTL chips - and a "used but working" board goes for 345$ on
| eBay (https://www.ebay.de/itm/M4002-KWV11-C-MODULE-USED-AND-
| WORKIN...)...
| TheOtherHobbes wrote:
| Compared to x nm VLSI, TTL and ECL are ridiculously low
| density. And soooo sloooow.
|
| DEC were very pleased with themselves when they got to
| ~40VUPs in the later ECL models, but a full modern VLSI - not
| FPGA - implementation wouldn't break a sweat at 1000VUPs.
| dfox wrote:
| What seems particularly interesting is that the board seems
| to really be just an RTC, yet does not have any obvious place
| for backup battery and has 10MHz oscillator on it.
| cbm-vic-20 wrote:
| The first-gen PDP-11's _CPU_ was just a couple of boards full
| of good old TTL chips.
| GeorgeTirebiter wrote:
| Yes, the pdp-11/20, released in 1969. Core memory only. In
| my opinion, it took the pdp-11/45 to firmly establish an
| impressive new line of machines, separate and more powerful
| than the pdp-8 line. But, in DEC's way of thinking, it's
| instructive to note that a pdp-11/40 was used as the
| console of the DECsystem-20. Separately, it's a shame we no
| longer have 36-bit machines; 36-bit ints would hold time_t
| just fine, and 72-bit doubles will work great for science.
| Oh well. What we're stuck with now bytes.
| noneeeed wrote:
| I remember reading an old paper on some funky experimentat
| user-interface that used a pair of PDP-11s (possibly, might
| have been event older) essentially wired together at the
| busses, with extra instructions added with new logic in TTL
| silicon, I think it was for doing the maths for the vector
| graphics. It was amazing the amount of hardware hackery
| that was necessary to build these experimental systems.
| p_l wrote:
| NuVAX is based around software reimplementation of VAX cpu with
| special-purpose I/O system to reuse existing interfaces
| (important when you need to deal with custom interface cards,
| for example).
|
| Funnily enough, it appears that real vaxen ended up being
| produced for shorter time than PDP-10, despite efforts going as
| far as encasing last high-end PDP-10 prototype in concrete and
| dumping it in mill pond (or so the story goes), as known
| single-chip PDP-10 were produced at least as late as 2004,
| after last VAX rolled off production line.
| DonHopkins wrote:
| "If you're not playing with 36 bits, you're not playing with
| a full DEC!" -DIGEX (Doug Humphrey)
| slowhand09 wrote:
| "Radix-50 Rulz!!!"
| jfengel wrote:
| I didn't realize anybody still remembered Digex.
| skissane wrote:
| > as known single-chip PDP-10 were produced at least as late
| as 2004
|
| Who was producing a PDP-10 in 2004? I'd love to know more
| about this.
| TheOtherHobbes wrote:
| XKL's TOAD-2 is/was based on a single chip PDP-10.
|
| The hardware is used as a router, but supposedly if you ask
| it very nicely you can get it to run TOPS-20.
| pinewurst wrote:
| https://commons.wikimedia.org/wiki/File:XKL_TOAD_2.jpg
| p_l wrote:
| Living Computer Museum had two XKL-2 running TOPS-20.
| lproven wrote:
| Yup, the XKL TOAD ("Ten On A Desk") and TOAD-2.
|
| https://en.wikipedia.org/wiki/XKL#TOAD-1
| p_l wrote:
| At the time of TOAD-1, there were also still machines
| built based on SC design, for effectively singular
| consumer - Compuserve.
| chx wrote:
| GE Canada has VAXen running their atomic plants and they are
| under contract to keep 'em running for a long time, 2035 or
| 2045. (Might be called BWXT today.)
| throw0101a wrote:
| * https://www.theregister.com/2013/06/19/nuke_plants_to_keep_
| p...
| mrweasel wrote:
| I would love to have some one write an article about how they
| even manages to do that.
|
| Are they real VAX servers or have they've been
| virtualized/emulated somewhere down the line.
| nickdothutton wrote:
| More than you would imagine.
| skissane wrote:
| Melbourne (Australia)'s train signals used to be controlled
| by PDP-11s running Ericsson JZA715 train control software.
| They were replaced by Ospreys. An Osprey is actually a
| hardware PDP-11 CPU on an expansion card which plugs into an
| x86 PC bus. It uses an actual CPU not emulation because
| realtime applications like train control need to be 100%
| cycle accurate. (Originally they used actual PDP-11 CPU chips
| manufactured by DEC, later they switched to using FPGAs). It
| also has Unibus cards to do Unibus-ISA/EISA/PCI translation
| so it can integrate with the original peripherals.
|
| http://web.archive.org/web/20210126085900/https://www.equico.
| ..
|
| http://www.strobedata.com/home/ospreyguide.html
| VectorLock wrote:
| Why does train control need to be 100% cycle accurate?
|
| PDP-11s ran at what, 1.25Mhz? I'd think that a modern CPU
| software emulating a PDP-11 CPU could get to below those
| cycle times.
| GeorgeTirebiter wrote:
| With bipolar memory option, the pdp-11/45 had a 300 ns
| memory cycle time.
| bluGill wrote:
| A few cache misses in a row, and some branches
| mispredicted and your modern CPU is slower than 1.25mhz.
| This almost never happens (CPUs are very good at this)
| but when it does things can get bad.
| VectorLock wrote:
| You could keep all of the PDP-11's RAM and probably most
| of its "external storage" in the L2 cache of most modern
| CPUs.
| jandrese wrote:
| Lets say the modern CPU gets itself really tied up in
| knots and is out of action for a staggering 10ms. During
| that time a speeding train doing 350kph travels not quite
| a meter. Do trains run such tight scheduling that this
| isn't sufficient time to cause delay on actuating a
| switching element and cause an accident?
| skissane wrote:
| You have a legacy safety-critical system, which
| incorporates legacy hardware peripherals. How sensitive
| is it to changes in timing? You may not actually know. Do
| you want to do the engineering analysis necessary to
| prove that replacing one part of that system with
| potentially different timing is not going to cause
| problems? Or do you just seek out a replacement whose
| timing is as close as possible to the original?
|
| The big issue may not be with the trains themselves but
| the signalling equipment and other peripherals. Changing
| the timing in the communication with them may lead to
| problems.
|
| And what if the original software has race condition bugs
| which have never been surfaced, and the occasional
| inaccuracy in timing starts to surface them? Good luck
| fixing bugs in some obscure piece of PDP-11 software that
| was written in the late 1970s.
| bluGill wrote:
| I have no idea. If this is real time control that could
| mean you keep running the motors in the switch long
| enough to damage something. Or maybe you go past the end
| of travel switch signal without reading it, the switch
| turns off and you never stop... There are a lot of ways
| real time systems can fail.
|
| You are correct that 10ms is well within the margin of
| error for safety stopping a train, but it may be out of
| the margin for some subsystem in the control.
| ChrisArchitect wrote:
| Thought this might be about getting "VAX-inated" with the
| vaccine..... ;)
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