[HN Gopher] On the strange joys of mainframe OSes that have surv...
       ___________________________________________________________________
        
       On the strange joys of mainframe OSes that have survived into
       modern times
        
       Author : todsacerdoti
       Score  : 102 points
       Date   : 2022-09-25 07:57 UTC (15 hours ago)
        
 (HTM) web link (liam-on-linux.dreamwidth.org)
 (TXT) w3m dump (liam-on-linux.dreamwidth.org)
        
       | rahen wrote:
       | > All modern computers are microcomputers
       | 
       | I'm not sure if an IBM i system would really qualify this way,
       | it's mini software running on downscaled mainframe hardware.
       | 
       | IBM i is probably the last mini out there, it will feel
       | completely alien to someone coming from the microcomputer world
       | (say, *nix and Windows, x86 and ARM).
        
         | trasz wrote:
         | "Mini" is just a marketing name at this point. The "i" is just
         | a POWER machine - a micro - running a weird operating system.
        
           | rahen wrote:
           | It's not even marketing since IBM doesn't use this
           | terminology.
           | 
           | But i is still quite removed from the micro standards: POWER,
           | EBCDIC, COBOL, RPG, 5250 terminals, and the SLIC/TIMI/LPAR
           | abstractions.
           | 
           | The typical "micro" app would use x86, UTF-8,
           | Java/C++/Rust/Go on top of a general public system like
           | Linux.
           | 
           | Well at least both use 8 bits words, it hasn't always been
           | the case.
        
         | lproven wrote:
         | [Article author here]
         | 
         | It's not really, you know.
         | 
         | IBM i is very interesting: the last mainstream single-level
         | store system. This is a concept I've both talked and written
         | about in recent years -- examples here on HN:
         | 
         | https://news.ycombinator.com/item?id=26066762
         | https://news.ycombinator.com/item?id=32314814
         | 
         | Saying that, I've done very very little work on the system. One
         | job ever, really, 20Y ago.
         | 
         | But IBM i is OS/400, yes, a minicomputer OS, yes -- but running
         | on IBM P series, i.e. a POWER server, i.e. a modern RS/6000.
         | It's a RISC workstation. Not even slightly mainframe-like.
         | 
         | Other minicomputer _OSes_ survive, notably VMS, now on x86-64.
         | 
         | https://www.theregister.com/2022/05/10/openvms_92/ <- Another
         | of my stories, just so you know where I stand.
         | 
         | So, yes, mini _OSes_ survive, sure, but not really any mini
         | _hardware_. Arguably as minicomputers died out they evolved
         | into workstations, and those have now died out, too. 99.99% of
         | the workstation market is basically high-end PCs now, if we
         | count modern Macs as sort of honourary PCs. (Arm Macs are in
         | some ways more like desktop /laptop-shaped iPads, really.)
        
           | phoehne wrote:
           | In order to disagree or agree with your statement I would
           | need some working definition of mini, micro, and mainframe.
        
             | lproven wrote:
             | Mainframes: the first style of computer. Primarily designed
             | as a batch-oriented system, meaning that they are not
             | directly interactive. Jobs are queued up, run without
             | interaction, results stored, and then the next job
             | processed. Later models added interactivity as a secondary
             | feature, usually like most mainframe I/O handled by
             | intelligent peripherals which in effect are networked to
             | the main processors. So, the terminal, on its own, shows a
             | form and then handles all user input as the user completes
             | the form, without communicating with the host at all. Then,
             | when the user signals that the form is complete, the entire
             | contents, maybe many pages, are sent as a single message to
             | the host.
             | 
             | Separate processors in storage, in terminals, in networking
             | controllers, in printers, in everything. Typically the
             | machine cannot actually drive any output or input directly
             | (e.g. mouse movements, or keystrokes, or anything):
             | peripherals do that, collect and encode the results, and
             | send them over a network. So as someone else commented, a
             | mainframe isn't really _a_ computer, it 's a whole cluster
             | of closely-coupled computers, many with dedicated
             | functionality. Quite possibly all implemented with
             | different architectures, instruction sets, programming
             | languages, bit widths, everything.
             | 
             | Here's an article I wrote about a decade back about how IBM
             | added the new facility of "time sharing" -- i.e. multiple
             | users on terminals, all interacting with the host at the
             | same time -- by developing the first hypervisor and running
             | 1 OS per user in VMs, because the IBM OSes of the time
             | simply could not handle concepts like "terminal sessions".
             | 
             | https://www.theregister.com/Print/2011/07/14/brief_history_
             | o...
             | 
             | Minicomputer: the 2nd main style of computer. Smaller,
             | cheaper, so affordable for a company department to own one,
             | while mainframes were and are mostly leased to whole
             | corporations. Typically 1 CPU in early ones, implemented as
             | a whole card cage full of multiple boards: maybe a few
             | boards with registers, one with an adder, etc. The "CPU" is
             | a cabinet with thousands of chips in it.
             | 
             | Hallmarks: large size; inherently multitasking, so that
             | multiple users can share the machine, accessing it via dumb
             | terminals on serial lines. User presses a key, the
             | keystroke is sent over the wire, the host displays it.
             | Little to no networking. One processor, maybe several disk
             | or tape drives, also dumb and controlled by the CPU. No
             | display on the host. No keyboard or other user input on the
             | host. All interaction is via terminals. But because they
             | were multiuser, even the early primitive ones had fairly
             | smart OSes which could handle multiple user accounts and so
             | on.
             | 
             | Gradually acquired networking and so on, but later.
             | 
             | In some classic designs, like some DEC PDPs, adding new
             | hardware actually adds new instructions to the processor's
             | instruction set.
             | 
             | Wildly variable and diverse architectures. Word lengths of
             | 8 bit, 9 bit, 12 bit, 18 bit, 24 bit, 32 bit, 36 bit and
             | others. Manufacturers often had multiple incompatible
             | ranges and maybe several different OSes per model range,
             | depending on the task wanted, so offering dozens of totally
             | different and incompatible OSes across half a dozen models.
             | 
             | Microcomputer: the simplest category. The entire processor
             | is implemented on a single silicon chip, a microprocessor.
             | Early machines very small and simple, driven by 1 terminal
             | with 1 user. No multitasking, no file or other resource
             | sharing, no networking, no communications except typically
             | 1 terminal and maybe a printer. Instead of 1 computer per
             | department, 1 computer per person. Facilities added by
             | standardised expansion cards.
             | 
             | This is the era of standardisation and commoditisation. Due
             | largely to microcomputers, things like the size of bytes,
             | their encoding and so on were fixed. 8 bits to a byte,
             | ASCII coding, etc.
             | 
             | Gradually grew larger: 16-bit, then 32-bit, etc. In the
             | early '80s gained onboard ROM typically with a BASIC
             | interpreter, on-board graphics and later sound. Mid-'80s,
             | went to 16-bit with multicolour graphics (256+ colours),
             | stereo sound. Lots of incompatible designs, but usually 1
             | OS per company, used for everything. All single-user boxes.
             | 
             | These outperformed most minis and minis died out. Some
             | minis gained a hi-res graphical display and turned into
             | single-user deskside "workstations", keeping their
             | multitasking OS, usually a UNIX by this point. Prices
             | remained at an order of magnitude more than PCs, and
             | processors were proprietary, closely-guarded secrets, and
             | sometimes still implemented across multiple discrete chips.
             | Gradually these got integrated into single chip devices but
             | they usually weren't very performance competitive and got
             | displaced by RISC processors, built to run compiled C
             | quickly.
             | 
             | In the '90s, generalising wildly, networking became common,
             | and 32-bit designs became affordable. Most of the 16-bit
             | machines died out and the industry standardised on MS
             | Windows and classic MacOS. As internet connections became
             | common in the late '90s, multitasking and a GUI were
             | expected along with multimedia support.
             | 
             | Apple bought NeXT, abandoned its proprietary OS and
             | switched to a UNIX.
             | 
             | Microsoft headhunted DEC's team from the cancelled MICA
             | project, merged it with the Portable OS/2 project, and got
             | them to finish OS/2 NT, later Windows NT, on the N-Ten CPU,
             | the Intel i860, a RISC chip, then on MIPS, and later on
             | x86-32 and other CPUs. This was the first credible
             | commercial microcomputer OS that could be both a client and
             | a server, and ultimately killed off all the proprietary
             | dedicated-server OSes, of which the biggest was Novell
             | Netware.
             | 
             | That is a vastly overlong answer but it's late and I'm just
             | braindumping.
             | 
             | Mainframe: big tightly-clustered bunch of smart devices,
             | flying in close formation. Primary role, batch driven
             | computing, non-interactive; interactivity bolted on later.
             | 
             | Mini: departmental shared computer with dumb terminals and
             | dumb peripherals, interactive and multitasking from the
             | start. Most text-only, with interactive command-line
             | interfaces -- "shells" -- and multiprogramming or
             | multitasking OSes. Few had batch capabilities; no graphics,
             | no direct I/O, maybe rare graphical terminals for niche
             | uses. Origins of the systems that inspired CP/M, MS-DOS,
             | VMS, UNIX, and NT.
             | 
             | Micro: single-chip CPU, single-user machines, often with
             | graphics and sound early on. Later gained GUIs, then later
             | than that networking, and evolved to be servers as well.
             | 
             | If the machine can control and be controlled by a screen
             | and keyboard plugged into the CPU, it's a micro. If its CPU
             | family has always been a single chip from the start, it's a
             | micro. If it boots into some kind of firmware OS loader,
             | it's probably a micro. The lines between micros and UNIX
             | workstations are a bit blurred.
             | 
             | I'm not sure this is helping any more. I'll shut up.
        
               | phoehne wrote:
               | That helps. I don't necessarily agree, but it's
               | definitely interesting!
        
               | __d wrote:
               | If you squint a bit, you can view Web-1.0-era UIs as
               | being a bit like a 3270: the terminal downloads the
               | template, the user fills out the fields, and hits the
               | submit button. That creates a HTTP POST, which is kinda
               | like a CICS transaction.
               | 
               | This enables the central CPU running the application
               | server to ignore all the terminal I/O issues, and just
               | deal with a set of transactions implementing the
               | application logic. If the load-balancer and HTTP server
               | are separate machines, then at a high-level boxes-and-
               | lines level, it's not a long way from a mainframe
               | application architecture (at the front end, anyway).
               | 
               | But this isn't really accurate, and it's become less
               | superficially similar with more recent web trends where
               | the REST layer isn't a hard boundary, and pre-rendering
               | and so on have muddied the model again.
        
             | __d wrote:
             | I think those definitions are somewhat complicated, because
             | micro-computer architectures have gradually adopted
             | features (perhaps in reduced form) from their mini-computer
             | and mainframe counterparts.
             | 
             | So, mainframes have channel controllers, and micro-
             | computers don't. But a modern micro-computer Ethernet
             | driver might run some software on the NIC. It's not really
             | a channel and yet the architectural distinction is blurred.
             | 
             | The distinctions made more sense in the 80's, when the
             | lines were clearer.
             | 
             | But I think the point is valid: the micro-computer
             | architecture has taken over the industry, and _some_ things
             | of value have been lost.
        
               | __d wrote:
               | Similarly, the "bus" of a micro-computer started out as a
               | pretty simple thing: parallel, 8 bits of data, 16 bits of
               | address, with memory-mapped or I/O-mapped fixed-function
               | peripherals managed by the (single) CPU. Memory and I/O
               | devices on the same bus.
               | 
               | But the modern PCIe "bus" is really more of a packet-
               | switched network. Memory is now separate (although, see
               | CXL). Devices on that network can talk directly to each
               | other, or to the CPU. In some ways, this is closer to a
               | mainframe architecture.
        
               | rahen wrote:
               | It absolutely is. IBM started to bring mainframe features
               | to the PC architecture with its PS2 line. The PS2
               | microchannel architecture (MCA), in particular, was
               | inspired by the 360 and became itself the inspiration for
               | the PCI bus.
        
             | rahen wrote:
             | - You lose a screw inside: microcomputer
             | 
             | - You lose a screwdriver inside: minicomputer
             | 
             | - You lose a technician inside: mainframe
             | 
             | When you bring a new addition to your personal collection:
             | 
             | - your wife complains: microcomputer
             | 
             | - Your wife yells at you: minicomputer
             | 
             | - Your wife leaves you: mainframe
        
       | hatsuseno wrote:
       | In jest I'll also assume the author could write a similar article
       | lamenting what storage tech could have been, but instead everyone
       | with data that mattered took the maintenance hit with RAID and
       | called it a day.
       | 
       | Commoditization is, to me, just a natural effect of product
       | development in a free market, capitalist(-ish) society. It feels
       | to me that as long as much of the population is chasing
       | financially optimal outcomes this will continue to happen, and
       | that may be okay.
        
       | thriftwy wrote:
       | I'm pretty sure nothing serious runs in mainframes outside of US
       | and maybe EU.
       | 
       | They have all that infrastructure like banks and planes and it
       | looks quite modern and resilient.
        
         | __d wrote:
         | Japan? NEC, Hitachi, and Fujitsu all used to make mainframes.
         | 
         | Hitachi has merged their line with IBM z-Series, but I think
         | it's still for sale? Fujitsu still sells several lines, and NEC
         | still sells in Japan.
         | 
         | I suspect their customers are pretty similar though: banks and
         | airlines.
        
         | wokkel wrote:
         | Unless understand your comment wrong: most older EU banks run
         | their core on mainframe. Sure the webapp to see your account is
         | running on some websphere/j2ee or nowadays maybe even angular
         | server. But that's just a gateway to the real accounting system
         | on the mainframe.
        
           | thriftwy wrote:
           | What about banks outside US/EU?
        
             | rbanffy wrote:
             | Brazilian banks and parts of the government were pretty big
             | mainframe clients. I'm most familiar with the IBM ones, but
             | Unisys also had quite a footprint with their A series
             | (which evolved into the Clearpath Libra family).
        
       | jasode wrote:
       | _> I read this wonderful article on mainframe OSes._
       | 
       | As irony, the url link points to an article mentioning the Unisys
       | mainframe. Unisys later switched to running on commodity x86
       | servers with a Unisys emulation on top:
       | https://www.google.com/search?q=unisys+clearpath+shift+xeon
       | 
       |  _> , and that you don't need all the fancy scaling
       | infrastructure because one modern box [mainframe] can support a
       | million concurrent users no problem, and a few such boxes can
       | support tens of hundreds of millions of them, all in something in
       | the corner of one room, with an uptime of decades and no need for
       | any cloud. But it's hard to do it that way, _
       | 
       | The author proposes that "mainframes-are-superior" by vague
       | generalizations and no performance data.
       | 
       | As a case study, consider that the Sabre travel reservations was
       | the _first IBM mainframe commercial customer_ since 1960. With 6
       | decades of experience with IBM 360 and Z upgrades, they 'd know
       | more about running mission-critical performance workloads on
       | mainframes than just about anyone.
       | 
       | And yet, they've been _migrating off of mainframes_ to AWS +
       | Azure + Google cloud :
       | https://www.google.com/search?q=sabre+migration+multi-cloud+...
       | 
       | To think of the opposite case from Sabre, let's consider a new YC
       | startup today with no legacy IT systems. Thinking from first
       | principles (i.e. raw math of cpu & io performance & costs on an
       | Excel spreadsheet), what situation makes sense to build the
       | solution on an a new IBM z16 mainframe instead of cloud?
       | 
       | If one is an old bank already running an older IBM z14 or z15
       | mainframe and wants the next iteration of performance
       | improvements, a z16 upgrade is the simplest so probably makes the
       | most financial sense. But without a "legacy IT" constraint,
       | what's the compelling spreadsheet model for a YC company to
       | choose a mainframe?
        
         | neverartful wrote:
         | "But without a "legacy IT" constraint, what's the compelling
         | spreadsheet model for a YC company to choose a mainframe?"
         | 
         | The most compelling reasons for the mainframe, based on its
         | intrinsic values, are 'RAS' (reliability, availability,
         | serviceability). However, those virtues come with a very high
         | price tag. So far the most part, I cannot imagine any startup
         | business choosing one (UNLESS system downtime will kill the
         | business).
        
           | derefr wrote:
           | Plus, you can squeeze out those same RAS factors from a
           | cluster of commodity x86 boxen, at the software level, if
           | your devs are willing to learn a little Erlang.
        
         | rbanffy wrote:
         | > Unisys later switched to running on commodity x86 servers
         | 
         | It runs the same OS on an emulation layer. Not sure they do it,
         | but you can get zero downtime out of multiple x86 boxes with a
         | number of interesting tricks while pretending you are on a
         | single CPU
        
         | derefr wrote:
         | > raw math of cpu & io performance & costs on an Excel
         | spreadsheet
         | 
         | But that's not the raw math; the raw math is "total OpEx", and
         | OpEx for these large systems is increasingly dominated not by
         | the systems themselves, but rather by development-talent
         | acquisition costs, and operational-maintenance talent labor
         | costs.
         | 
         | Even Sabre's choice wasn't "upgrade to z16 vs. move to IaaS";
         | it was "hire people to replace churned devs+ops to write the
         | next feature of the system: people with z/OS experience, or
         | people with IaaS experience?"
        
         | dangus wrote:
         | Also, supporting a lot of concurrent users is easier when the
         | capabilities of the services being offered are very basic.
         | 
         | Banks weren't doing things like providing millions of customers
         | instant OCR processing of checks in the mainframe days.
        
         | mhh__ wrote:
         | Migrating away from mainframes can also be just because of
         | talent availability but also lock in.
         | 
         | Where I work we have processes that would make perfect sense
         | chucking jobs at a mainframe (if we implement our language on
         | it...), but IBM have no competition so it's super risky.
        
       | reaperducer wrote:
       | I'd like to see an article about the joys of mainframe operating
       | systems that _didn 't_ survive.
       | 
       | I cut my teeth on a PR1MEOS machine at SUNY New Paltz. Great
       | system. But there is no modern emulator and almost zero
       | information about it on the internet.
        
       | trasz wrote:
       | There is a reason why there are no proper benchmark results for
       | mainframes available, and why the EULA prohibits publishing them.
        
         | neverartful wrote:
         | Back when IBM changed the branding on their hardware lines, it
         | was done to help people identify WHY you would pick one
         | platform versus another.                   z (mainframe) =
         | "Zero downtime"         i (as/400) = "integrated" (e.g., DB2
         | and stuff like processing queues is baked into the OS)
         | p (rs/6000) = "performance"         x (x86) = was sold off to
         | Lenovo after a few years
         | 
         | See the "p"? If you need maximum performance, you go with POWER
         | and run AIX or Linux.
        
       | 13of40 wrote:
       | "minimum viable product"
       | 
       | I've heard a few folks use this term disparagingly lately, and I
       | just want to point out that the spirit of an MVP isn't that you
       | do the bare minimum required to huck your product to an
       | unsuspecting customer. The point of an MVP is that every
       | milestone you deliver something that's actually useful and
       | functional in some way, end-to-end. The alternative to an MVP is
       | a junk mock-up with all of the technical debt swept under the rug
       | and the devs whistling and looking the other way when questions
       | start coming out.
       | 
       | Also, I loved the article.
        
       | NonNefarious wrote:
       | Into "mo?"
       | 
       | Whatever that is.
       | 
       | Buried.
        
         | KolmogorovComp wrote:
         | Modern times
        
       | bhauer wrote:
       | > _A handful of grumpy old gits know that if you pick the right
       | languages, and the right tools, you can build something to
       | replace this 2nd level system in the same types of tools as the
       | first level system, and that you don't need all the fancy scaling
       | infrastructure because one modern box can support a million
       | concurrent users no problem, and a few such boxes can support
       | tens of hundreds of millions of them, all in something in the
       | corner of one room, with an uptime of decades and no need for any
       | cloud._
       | 
       | I suppose I am a grumpy old git, then, although I did not think
       | of myself that way until recently. In the past decade or two,
       | I've seen computer science lose its collective appreciation of
       | the staggering potential of hardware. This has steadily resulted
       | in software being built with tremendously over-engineered, hyper-
       | complicated, cloud-first architectures that barely match the
       | throughput of a single box running a high-performance platform
       | (and for the record, "high performance" can still be relatively
       | ergonomic via Java, C#, Rust, and so on).
       | 
       | The scale of hardware, clock cycles, bits per second of
       | bandwidth, etc., being squandered on modern cloud-first highly
       | complicated architectures boggles the mind.
       | 
       | I fear there is no strength behind any pendulum swing back to
       | architectural simplicity, appreciation of the available capacity
       | of hardware and how to use it, and local-first.
        
         | phoehne wrote:
         | I think that's changing. You're seeing more companies investing
         | more in custom silicon. Like Microsoft, Amazon, and Google all
         | make custom silicon to support their cloud efforts. That's
         | expected to increase over time. Apple has shown that if you
         | don't settle for BOG standard hardware you get better than BOG
         | standard performance.
        
         | fock wrote:
         | > I fear there is no strength behind any pendulum swing back to
         | architectural simplicity, appreciation of the available
         | capacity of hardware and how to use it, and local-first.
         | 
         | I'm pretty sure, the ecological devastation we are living will
         | raze these things. If we are lucky we can salvage a bit. And
         | the whole industry of the last 20years isn't worth saving.
        
       | Eleison23 wrote:
       | Cloud services and hyperscale data centers are arguably modern
       | mainframe-class systems. If you look at them from the perspective
       | of the provider, they have a lot of mainframe type features that
       | distinguish them from micros or supercomputers.
       | 
       | In the 70s, VM/CMS dominated the time-sharing landscape, and
       | everything old is new again.
        
         | qaq wrote:
         | Reliability is nowhere near mainframe
        
           | froh wrote:
           | yup. error detection in the CPU (Alu, Decoder, etc) traps
           | into the hypervisor which fires up a spare core, transfers
           | the registers over to it and calls the technician.
           | 
           | technician calls you to tell you "your machine needs
           | maintenance"
           | 
           | and at application level there was a short "mouse hang"
           | latency for this hardware failure.
           | 
           | and of course that works cross-site, too, hot moving running
           | software across data centres at the hypervisor level, because
           | you want one data centre downtown, one at the airport.
           | 
           | but it's not just for finance. some mainframe customers have
           | virtualized thousands of "your personal domain and web server
           | running php/perl/nodejs" on a single physical machine which
           | shares a r/o mounted /usr, in ram, transparently.
           | 
           | customer X needs more ram? click click life assign more ram.
           | needs more cpu? activate another core. the Linux
           | virtualization Features to support hit cpu and ram swap were
           | driven by the mainframe guys from IBM, years ago.
        
             | delusional wrote:
             | It sounds very impressive until the entire mainframe wont
             | boot up after a simple routine upgrade as happened recently
             | at my place of work.
        
               | yourapostasy wrote:
               | That's more of a training / staffing issue than a tech
               | stack issue. I've seen similar outages at my clients in
               | distributed systems. A lot of mainframe staff has been
               | outsourced / offshored and those providers suffer
               | constant turnover because the money and job prospects in
               | distributed systems is generally better.
               | 
               | Mainframe jobs pay well at the very apex of skills, but
               | if you're coming up through the ranks in an outsource
               | provider you're a cost not profit center. The
               | compensation package and work life balance are good if
               | you are with a company that keeps everyone in house,
               | trains in house, have a deep bench of expertise who
               | maintain the systems in an orderly fashion, and have a
               | continuous succession plan for staff. Super low drama,
               | and they keep the financial lights on in the house by
               | processing the bulk of profit-generators' needs. These
               | tend to be in places like stodgy COBOL shops the Cool
               | Kids would rather gnaw their feet off to avoid, though.
               | 
               | The part many people miss when comparing mainframes and
               | distributed is you get all that mainframe magic with the
               | application programmers accommodating the architecture
               | little if at all. But your system programmers (system
               | admins in Linux) have to be top tier.
               | 
               | You can accomplish most if not all of that same magic in
               | distributed architectures with parallelizable workloads.
               | But your application and devops staff have to be top
               | tier.
        
               | delusional wrote:
               | > That's more of a training / staffing issue than a tech
               | stack issue.
               | 
               | I mean sure, but the same could be said for distributed
               | systems. What breeds reliability is qualified personnel
               | working on a system that they understand. Slapping an IBM
               | logo on the front doesn't make something more reliable,
               | and stacking proprietary technology that "transparently"
               | moves subsystems between datacenters only increases the
               | training burden.
               | 
               | Mainframes became a victim of their own moat. While
               | proprietary _._ magic _._ can hold people in, those very
               | same technologies also keep new people out.
        
               | qaq wrote:
               | It sounds impressive until a whole region or whole cloud
               | goes down because of bug in the control plane.
        
             | lmz wrote:
             | > some mainframe customers have virtualized thousands of
             | "your personal domain and web server running
             | php/perl/nodejs" on a single physical machine which shares
             | a r/o mounted /usr, in ram, transparently.
             | 
             | For general public use? Can you name one?
        
               | froh wrote:
               | yes for general public use
               | 
               | page 15 in this white paper from 2012 is the closest I
               | can go in terms of naming. there were more , in
               | continental Europe.
               | 
               | https://www.slideshare.net/hcl/effective-web-
               | hostingonzlinux...
        
               | Spooky23 wrote:
               | IBM was paying them to do it. The problem is you're
               | running in a separate set of processors... it's almost
               | like a blade chassis at this point. The cost structure
               | didn't work as if you're doing anything significant
               | you're going to end up licensing more CPU time (yes, you
               | need to buy access to the stuff you bought), and it
               | cheaper to buy x86 and run Linux OR just rent VMs from
               | Amazon.
               | 
               | I had to do a POC of this for an IBM app in 2008-9, as it
               | was seen as a way to save on IBM software licensing. I
               | killed the notion after spending 6 months getting stuff
               | to work (ie the IBM boys and inwere the first idiots to
               | try) when i borrowed from surplus PCs awaiting shredding
               | and replicated the entire environment on 6 circa 2005
               | pentium whatever desktops (which I did during the week
               | between Christmas and New Years). My little lab
               | outperformed the mainframe by a factor of 5 for the task.
               | 
               | If these solutions were sold commercially, there must
               | have been some German compliance requirement that led
               | people to do it. Nobody would ever do this without
               | getting directly compensated for "choosing" to do so.
        
               | froh wrote:
               | what works financially is providing a fleet of simple
               | similar independent machines.
               | 
               | think "your personal wordpress instance w/ own email and
               | ftp server", centrally maintained, identical baseline but
               | individual content.
               | 
               | to this day Linux KVM does not enable multi tenancy. with
               | z/VM you can provide that, and you still have the shared
               | /usr in physically shared ram in z/vm.
               | 
               | the physical CPUs are also virtualized and shared, each
               | "full own wordpress server" only needs slivers of that
               | cpu pool.
               | 
               | it was done and it qorkwd. and it was profitable for both
               | the hosters and IBM.
        
             | greggsy wrote:
             | > some mainframe customers have virtualized thousands of
             | "your personal domain and web server running
             | php/perl/nodejs"
             | 
             | Are there hosting providers offering this type of service?
        
               | rwmj wrote:
               | IBM Cloud offers Z systems:
               | https://www.ibm.com/community/z-and-cloud/ I imagine
               | they're absurdly expensive like the real hardware.
        
               | retcore wrote:
               | Only available for existing Z/OS sites via your
               | organization rep.
        
               | froh wrote:
               | that was around 2010/2012, eg page 15 here
               | 
               | https://www.slideshare.net/hcl/effective-web-
               | hostingonzlinux...
               | 
               | however virtualization on arm and Intel has meanwhile
               | matured enough to replace that business model.
        
             | bionsystem wrote:
             | What would prevent, in your opinion, to make some changes
             | to current commodity hardware architectures (say, x64,
             | arm...) to allow for mainframe-like scalability and
             | reliability ?
             | 
             | As per the article, how is the jitted/interpreted world of
             | languages so bad ?
        
               | bayindirh wrote:
               | I'd say cost (of research, implementation and resulting
               | product ).
               | 
               | The additional hardware both in silicon and on PCB is
               | massive to enable these kinds of reliability numbers. I
               | played with some higher end HP servers back in the day,
               | which allowed hot-swapping RAM carriers to maximize
               | uptime. The construction on mechanical, electrical and
               | software was much more sophisticated to enable these
               | features. Which made the systems bigger, somewhat noisier
               | and harder to maintain in a sense.
               | 
               | When everybody is moving towards more cattle-like
               | systems, and the behemoths like HPC doesn't care about
               | reliability in the worker nodes (we just re-schedule the
               | job, no biggie), that kind of reliability is not wanted
               | by the people, in most sectors, and this low demand
               | doesn't make the capabilities worthy to pursue.
               | 
               | Also, there are system dynamics which affect operations
               | profoundly. Your normal server boots in 5 minutes tops
               | from power to "all services are ready to serve". Your run
               | off the mill SMP server needs 15 minutes. A mainframe is
               | never expected to be shut down, and if it's ever turned
               | off, it's at least an hour required to spin that thing
               | back up.
               | 
               | We're talking about machines which have small "guns"
               | inside to physically sever power lines in an emergency
               | (sorry I can't find the story I've read about moving a
               | datacenter hence turning of the IBM mainframes, however a
               | related reference can be found at [0]).
               | 
               | The JIT/Interpreted languages of the day were really bad.
               | Java was heavy, other languages were slow. Today's
               | JIT/Interpreted languages are fast enough, because the
               | VMs running these have been optimized heavily, and the
               | processors allows these VMs to run at much faster speeds
               | because of available instructions, available memory and
               | system interconnect speed at every level and interface.
               | So the evolution of JIT and interpreted languages is a
               | matter of chicken and egg. Hardware enabled both faster
               | speeds and technology to write better VMs and optimize
               | them further.
               | 
               | [0]: http://www.catb.org/jargon/html/B/Big-Red-
               | Switch.html
        
               | ianai wrote:
               | ECC bring the norm and better error handling all around.
               | OSes that better handle memory and uptime. Possibly
               | something like a user session being accessible from
               | allowed terminals and applications that call for that.
               | Think hotel front desk staff or anyone public facing who
               | move from desk to desk.
        
               | neverartful wrote:
               | There's far more to reliability than ECC. What if a
               | processor/CPU goes bad in an x86 server while running?
               | You have to take the server down, replace it, and bring
               | it back up. IBM mainframes allow for processor
               | replacements while it's running. I think it's the same
               | with memory. IIRC, in the mainframe world IBM has
               | processor and RAM packaged together as a 'book' and it
               | may be the book that can be hot swapped. Hopefully
               | someone more knowledgable can clarify.
        
               | rbanffy wrote:
               | A mainframe reminds me more of a cluster of specialised
               | machines networked over ridiculously fast interconnects
               | and purpose-specific networks that host those specialised
               | machines.
               | 
               | Some functionality of those specialised machines is
               | exposed to user programs that can delegate some
               | processing to these smart peripherals, offloading things
               | like allocating blocks in the filesystem and letting the
               | boxes that run your used code focus on running it without
               | ever being disturbed with servicing network or disk
               | interrupts.
        
               | User23 wrote:
               | That ECC isn't entirely standard is shameful.
        
               | froh wrote:
               | patents, tongue in cheek...
               | 
               | on a more serious note yagni: for most workloads you
               | simply don't need the dependability and Xeon has caught
               | up sufficiently for most workloads.
               | 
               | however if your business depends on less than 5 minutes
               | of unplanned downtime per year you need stacks designed
               | for faul operational subsystems, i.e. subsystems which
               | don't just detect faults and halt, but which gracefully
               | handle many faults with a short degradation but no
               | failure.
               | 
               | and that's not only hard to master it's also plastered
               | with IBM patents.
               | 
               | wrt the jit/interpreted world my personal take is that
               | silicon vendors are very happy about it. very few
               | organisations feel the pain to an extent they innovate
               | things like golang... and once they are in the business
               | of selling compute power (as cloud service provider),
               | there goes their motivation to create a sexy cobol.
        
             | Macha wrote:
             | > but it's not just for finance. some mainframe customers
             | have virtualized thousands of "your personal domain and web
             | server running php/perl/nodejs
             | 
             | To be fair, shared hosting providers did this on x86 server
             | machines on a scale of 100s of customers in the 90s, and
             | I'm sure a modern revival on 2022 could do 1000s also
        
               | marcus0x62 wrote:
               | Sure, but they way we did that back in the 90's was very
               | different, and carried a much lower overhead than LPARs
               | in the IBM mainframe world or any hypervisor or container
               | used today -- shared hosting "virtualization" in the 90's
               | was little more than chroot jails, and frequently not
               | even that.
        
               | neverartful wrote:
               | I think you're confusing LPARS with guests under z/VM. A
               | mainframe LPAR is a coarse-grained (relatively speaking)
               | partitioning of the system. LPARS are created and managed
               | by a Hardware Management Console (HMC), and run on PR/SM
               | [0]. No one creates mainframe LPARS to run a VPS. Those
               | would simply be a guest under z/VM. Realistically
               | speaking, z/VM would be running in an LPAR (less than the
               | whole of the mainframe resources) and then within z/VM's
               | LPAR, z/VM hypervisor allows all of its guests to run
               | concurrently.
               | 
               | [0] https://wiki.alquds.edu/?query=PR/SM
        
               | marcus0x62 wrote:
               | >> ... or any hypervisor or container used today ...
               | 
               | > I think you're confusing LPARS with guests under z/VM.
               | 
               | I am not, but thanks.
        
               | rbanffy wrote:
               | KVM is also available now in addition to z/VM. The IBM
               | cloud "trusted environments" run on it.
        
               | bayindirh wrote:
               | We have a 10 machine Proxmox cluster at the office, and
               | no. It doesn't lend itself to such capacities.
               | 
               | Maybe we over-provision systems, and can fit that number
               | of VMs, but what will be the performance?
               | 
               | You can use a proper SMP machine with 16 sockets, but you
               | are already at half mainframe price and journey-wise, and
               | you'll be wasting the machine's capabilities.
        
         | bayindirh wrote:
         | Just no. They are very large herds of cattle systems, which act
         | like as a big pet system, because it tolerates small blows.
         | 
         | A mainframe is a single pet, which can live undisturbed even
         | with moderate size blows, and can host a sizable herd of cattle
         | systems without even noticing on the load monitor.
        
       | jimkoen wrote:
       | Every time I hear someone advocating for mainframes, they always
       | praise them and make them appear as something like a computing
       | behemoth, that, while expensive outperforms any commoditiy
       | hardware at the tasks it's good at, wether it's in performance or
       | reliability.
       | 
       | But there's never any real world use case. It's always just "If
       | you're running a mainframe, you don't care about money". No
       | performance benchmarks, no architecture comparisons. You get
       | shown an architecture diagram of a mainframe, next to one of say,
       | a cloud system and you get asked "See??", like the conclusion is
       | obvious.
       | 
       | > Instead, we got lowest-common-denominator systems. Not what was
       | best, merely what was cheapest, easiest, and just barely good
       | enough - the "minimum viable product" that an industry of
       | shysters and con-men think is a good thing.
       | 
       | How is this _not_ a good thing??
       | 
       | >But mainframes aren't. They cost a lot, and rental and licensing
       | costs a lot, and running them costs a lot... everything costs a
       | lot. Meaning you don't use them if you care about costs that
       | much. You have other reasons. What those are doesn't matter so
       | much.
       | 
       | ...which is exactly my point! Yeah it makes sense that there is a
       | separate ecosystem for mainframes! Because from the outside and
       | these kind of arguments it looks like IBM has been siphoning off
       | some great marketing in the 80s and 90s and _really_ ignorant
       | managers in charge of purchasing at large banks and the US gov.
       | 
       | On an unrelated note, I kinda made the experience that people
       | that like mainframes usually have some weird obsession with high
       | level computing architectures. Is there maybe a correlation?
        
         | mhh__ wrote:
         | Mainframes are supposed to be good at the type of jobs that you
         | can't really do an apples to apples comparison of - they're not
         | supposed to be running linear algebra benchmarks, however
         | equally a lot of quasi-distributed systems (some cloud infra or
         | whatever) performance will completely collapse when you try to
         | scale them beyond little benchmarks.
         | 
         | I've read IBMs docs on their processor architectures, I'm sure
         | they're fast _enough_ but no more than that.
         | 
         | Wouldn't choose one for infrastructure but would love to have a
         | play with a mainframe.
        
           | rbanffy wrote:
           | > I've read IBMs docs on their processor architectures, I'm
           | sure they're fast enough but no more than that.
           | 
           | I've played with the LinuxONE community cloud for a while and
           | one thing that quickly become obvious is how ridiculously
           | fast the machines are. Not only the 5+ GHz CPUs but all that
           | very smart IO that seems to magically predict what the CPU
           | will want, and have it on hand.
           | 
           | And the cache architecture of the z16 CPU is awesome.
        
         | HyperSane wrote:
         | IBM actually forbids customers from sharing the performance of
         | its z/OS mainframe performance benchmarks, which should tell
         | you that they must be terrible for the money.
        
           | neverartful wrote:
           | The value proposition (if I may use that terminology) of
           | mainframes is not performance -- it's 'RAS' (reliability,
           | availability, serviceability). Of course, if you've got a
           | huge legacy codebase of COBOL and CICS, it might be more a
           | matter of 'keeping the lights on' for the business.
        
             | rbanffy wrote:
             | Also, benchmarks would have to be carefully set up. Sure
             | you can do more MIPS on a cluster of generic underpowered
             | x86 boxes, but what happens if you remove a RAM stick,
             | shoot a bullet through an SSD or are hit by an earthquake?
             | The numbers alone are hard to compare if the guarantees are
             | totally different.
             | 
             | A second thing to count is that it's vastly cheaper to run
             | thousands of services out of a small group of very large
             | machines than to run the same workload on a large number of
             | cheap machines.
        
         | lproven wrote:
         | Hi. I wrote the blog post here.
         | 
         | > Every time I hear someone advocating for mainframes, they
         | always praise them
         | 
         | [1] I wasn't "advocating" anything. I was talking about how
         | they've survived. They _have_ survived. Whether it 's under
         | emulation doesn't matter: still being sold, still driving the
         | same peripherals from the same software.
         | 
         | Their survival, thus far, is a fact. So the question I was
         | trying to address was _why_.
         | 
         | That's not advocacy.
         | 
         | [2] If I were, which I wasn't -- It is pretty hard to advocate
         | for anything without praising it. :-)
         | 
         | The points about performance others have answered very well.
         | 
         | > How is this _not_ a good thing??
         | 
         | "You can have good, fast, or cheap. Pick any two."
         | 
         | We have fast and cheap.
         | 
         | The end.
         | 
         | > people that like mainframes usually have some weird obsession
         | with high level computing architectures
         | 
         | Um. Define what you mean by "high level architectures" here?
        
         | zppln wrote:
         | > No performance benchmarks, no architecture comparisons.
         | 
         | Yeah, I remember dipping my toes into this world when I was
         | trying out COBOL a few years ago. IIRC they market these things
         | with "transactions per second", which doesn't exactly lend it
         | self to direct comparison with other systems...
        
       | retrocryptid wrote:
       | What does this have to do with mainframes other than the word
       | "mainframe" is in the title and it links to a blog post where
       | someone mentions Unisys. BeOS and OS/2 were operating systems
       | that predominantly ran on PC class systems.
        
       | abrax3141 wrote:
       | Relevant previous discussion:
       | https://news.ycombinator.com/item?id=30505219
        
       | magic_hamster wrote:
       | This actually got me fairly curious as to what the big difference
       | is between mainframes and regular ol' micros. I don't think I
       | ever used a proper mainframe, and I honestly wanted to know more.
       | The author keeps building up to this massively different,
       | otherworldly system, and then just finishes without ever
       | answering.
       | 
       | I did feel some contempt towards certain developers (who dare
       | call themselves software engineers) and there was definitely an
       | "old man yelling at cloud" undercurrent. If only I could learn
       | something of merit, that would have been worth it.
       | 
       | So I guess it's up to us plebs to go and see what makes
       | mainframes so different. How the "weird" custom architectures
       | work. What's it like to work on one and write code for it.
        
         | Tor3 wrote:
         | The maybe most distinguishing feature of a "mainframe" is
         | intelligent I/O channels, which offloads a lot of what would
         | otherwise be CPU work. And those I/O channels is why the PDP-10
         | was called a "mainframe" while the rest of the PDP series
         | (without I/O channels) were called "minicomputers". There's
         | more, but it depends on the system - some can do maintenance on
         | parts of the system while still operating.
        
           | HyperSane wrote:
           | The x86 world is getting I/O channels in the form of
           | "SmartNICs" which are NICs with substantial processing power.
        
             | rbanffy wrote:
             | They also have it with disks local and remote. The idea is
             | that the CPU is running user code 100% of the time and that
             | it doesn't need to wait for anything.
        
               | neverartful wrote:
               | With the mainframe all disks are external. This diagram
               | [0] does a good job of showing that.
               | 
               | [0] https://en.wikipedia.org/wiki/Count_key_data#/media/F
               | ile:IBM...
        
               | trasz wrote:
               | In the PC world this has been done couple of times, eg
               | https://en.m.wikipedia.org/wiki/I2O from the late 90's.
               | 
               | I think the real reason why it works for mainframes is
               | that their operating system is so primitive, so it's easy
               | to cross layers - because there are so few of them. z/OS
               | is closer to MS-DOS than to Unix in that regard.
        
           | Sebb767 wrote:
           | > some can do maintenance on parts of the system while still
           | operating.
           | 
           | That's not that rare these days. Basically any server will
           | allow hot-plugging hard drives, with some configurations
           | network cards and by now a lot of laptops can even hot-plug
           | GPUs via Thunderbolt.
        
             | [deleted]
        
             | neverartful wrote:
             | Hot-plugging hard drives is a bare minimum. There are many
             | other points of failure and a failure of any of the
             | following WILL result in downtime while the component is
             | replaced: disk controller, CPU, memory, NIC. Having dual
             | NICs and dual processors helps, but it's still a far cry
             | from 100% availability.
        
             | rbanffy wrote:
             | I remember some big iron could do it with processors and
             | memory as well. IIRC, you can no longer remove CPUs with
             | IBMs, but replacing memory is relatively simple.
        
         | lproven wrote:
         | Hi. I wrote the piece. Thanks for taking the time to read it.
         | 
         | I wasn't aiming or trying to give a worked example of the
         | differences, though.
         | 
         | That's in the link that inspired the comment. Didn't you look
         | at that? It's exactly what you ask, with discussions of
         | filesystems, CLI, even C code examples. It would have been
         | redundant to try to duplicate that. It's why I recommended it.
         | I still do. You should read it, because it sounds like what you
         | want to me.
         | 
         | https://arcanesciences.com/os2200/
         | 
         | As for sounding like a grumpy old man -- well:
         | 
         | "I don't mean to sound bitter, cold, or cruel, but I am, so
         | that's how it comes out."
         | 
         | -- Bill Hicks
         | 
         | :-D
         | 
         | It's only a comment from Lobste.rs, copied-and-pasted. It might
         | grow into something more significant at some time. Might not.
         | Can't promise.
        
         | Animats wrote:
         | > The author keeps building up to this massively different,
         | otherworldly system, and then just finishes without ever
         | answering.
         | 
         | Yes, it's a weak article.
         | 
         | So, what do mainframes have that microcomputers don't?
         | 
         | - Much more internal checking.
         | 
         | Everything has parity or ECC. CPUs have internal checking.
         | There are interrupts for "CPU made a mistake", and OSs which
         | can take corrective action.
         | 
         | - Channels.
         | 
         | Mainframes have channel controllers. These connect to devices
         | on one end, and the main CPUs and memory on the other. They
         | work in a standardized way, independent of the device. The
         | channel controllers control what data goes to and from the
         | devices. Sometimes they even control what a program can say to
         | a device, so that an application can be given direct device
         | access with access restrictions. This would, for example, let a
         | database talk to a disk partition without going through the OS,
         | but limit it to that partition. The channel controllers
         | determine where peripherals put data in memory. Mainframes have
         | specific I/O instructions for talking to the channel
         | controllers. Drivers in user space have been around since the
         | 1960s.
         | 
         | Minicomputers and microcomputers, on the other hand, once had
         | peripherals directly connected to the memory bus. Programs
         | talked to peripherals by storing and loading values into
         | "device registers". There were no specific I/O instructions
         | built into the CPU. Some devices accessed memory themselves,
         | called "direct memory access", or DMA. They could write
         | anywhere in memory, a security and reliability problem.
         | 
         | Microcomputer CPUs haven't worked that way for decades. Not
         | since the era of ISA peripherals. _But they still pretend to._
         | Programs use store instructions to store into what appears to
         | the CPU is a memory block. But that 's really going to what's
         | called the "southbridge", which is logic that sends commands to
         | devices. Those devices offer an interface which appears like
         | memory, but is really piping a command to logic in the device.
         | On the memory access side, the program stores into "device
         | registers" which tell the "northbridge" to set up data access
         | between devices and memory. Sometimes today there's a memory
         | management unit between peripherals and main memory, to control
         | where they can store.
         | 
         | The end result is something more complicated than a mainframe
         | channel, but without the architectural advantages of isolating
         | the devices from the CPU. Attempts have been made to fix this.
         | Intel has tried various types of I/O controllers. But the
         | architecture of Unix/Linux isn't channel-oriented, so it just
         | adds a layer of indirection that makes drivers more difficult.
         | 
         | (Then came GPUs, which started as peripheral devices and
         | gradually took over, but that's a whole other subject.)
         | 
         | - Virtual machine architecture
         | 
         | The first computer that could virtualize itself was the IBM
         | System 360/67, in the 1960s. This worked well enough that all
         | the System/370 machines had virtual machine capability. Unlike
         | the mess in x86 world, the virtual machine and the real machine
         | look very similar. Similar enough that you can load an OS
         | intended for raw hardware into a virtual machine. This even
         | stacks; you can load another copy of the OS inside a VM of the
         | first OS. I've heard of someone layering this 10 deep. The way
         | x86 machines do virtualization required adding a special layer
         | in hardware underneath the main layer, although, over time,
         | it's become more general in x86 land. Arm AArch64 considered
         | virtualization from the start, and may be saner.
        
         | neverartful wrote:
         | If you want to quickly get a feel for traditional IBM mainframe
         | software, you can do that easily enough. Download Hercules
         | mainframe emulator [0] and then you can fire up MVS 3.8 [1] or
         | VM/370 [2]. Be aware that the community has made significant
         | improvements on these old open source software systems.
         | [0] http://www.hercules-390.org         [1]
         | https://www.jaymoseley.com/hercules/installMVS/iPREREQv7.htm
         | [2] http://gunkies.org/wiki/Installing_VM/370_on_Hercules
        
       | tristor wrote:
       | As someone who's worked deeply on mainframe and minicomputer
       | systems and then worked even more deeply in the cloud, there is
       | really no point to mainframes anymore unless you are doing a
       | realtime application, which in most cases is unnecessary.
       | 
       | The only value proposition I see is realtime redundancies, which
       | are physically impossible with geographically distributed
       | systems, but par for the course on mainframes. For most non-
       | realtime applications, though, you can achieve same or better
       | uptime for cheaper and with better flexibility building in the
       | cloud.
        
         | badrabbit wrote:
         | Whay is a mainframe's redundancy/uptime? > 5 9s?
        
           | Tsiklon wrote:
           | A mainframe has 100% uptime. Redundancies are baked in by
           | design, hardware maintenance can be performed while the
           | system is live
        
             | _-david-_ wrote:
             | Can they update firmware without rebooting?
        
               | rbanffy wrote:
               | You rarely reboot the whole computer. You can take parts
               | of it offline for repairs and the software will route
               | around it. There is a PC inside it running Linux whose
               | job is managing the various subsystems up from powering
               | up the PSU, making sure UPS batteries are charged, that
               | cooling is working even before the CPUs are powered up
               | and microcode is loaded.
        
             | badrabbit wrote:
             | If that is true then that is enough of a selling point.
             | Cloud providers with 5 9's have one or two outages a year.
             | If you need the uptime for systems that can't have one
             | outage in a decade, is there a competing solution?
        
               | __d wrote:
               | NonStop?
               | 
               | Originally from Tandem, then bought by .. Compaq? And
               | then HP, now HPE.
               | 
               | Not a mainframe, but designed and built for 100% uptime.
               | They used to do demos where you could open the cabinet
               | and pull out boards at random, and it'd just keep going.
               | 
               | It migrated from custom hardware, to Itanium, to x86-64.
               | It's a custom OS, but has a Unix-like layer on top for
               | ease of porting stuff.
        
       | captainmuon wrote:
       | I don't really share the reverence for mainframes. While they
       | have certain cool unique features, like extreme resiliance, that
       | doesn't matter very much because all the low-level details can be
       | abstracted away. We have learned to build reliable systems on
       | "commodity" hardware.
       | 
       | In all the other places where mainframes are different, they are
       | not only utterly alien, but I would also argue inferior. Focus on
       | 60s languages, weird menu-based OSes, no proper Unicode support
       | (judging from plane tickets and payrolls with missing symbols),
       | and so on.
       | 
       | That they hold out in "important" areas like banking and
       | insurances is especially damning. This is the "allocation" layer
       | of our society and is also hopelessly obsolete. The way we
       | allocate resources has not caught up with our technological
       | development. My personal belief is, one day, when we make the
       | step to "capitalism++" - I don't know what it will look like, but
       | it will compare to our current society like that compared to
       | feudalism - then all that legacy infrastructure will become
       | unneccessary.
        
         | tyingq wrote:
         | A lot of the holdouts are specifically z/OS mainframes running
         | TPF. It's a distinctly different OS than z/OS (what MVS is now
         | called). Used by VISA and the Airline industry.
         | 
         | They've both had multiple attempts over the years to replace
         | TPF, with varying degrees of success. Amadeus/Altea just barely
         | finished getting rid of their mainframes. The other big GDS
         | systems are still working on it.
         | 
         | I don't think it was lack of desire or commitment of resources.
         | ITA spent quite a lot trying to replace it, with an unusual
         | collection of the best/brightest, and was able to replace the
         | shopping piece successfully, but stalled on commercial success
         | of the booking part.
         | 
         | It's just a hard problem to solve. TPF is incredibly good at
         | extremely high transaction rates in a distributed fashion with
         | high reliability.
        
         | rahen wrote:
         | > We have learned to build reliable systems on "commodity"
         | hardware.
         | 
         | It is still cobbled together, and it still doesn't compare with
         | what a mainframe can offer in reliability, security, resource
         | efficiency and technical debt.
         | 
         | Mainframes are the original computers, if anything the
         | microcomputers are more alien. They had virtual machines from
         | the early 70s, Z/OS can still run code from the 360 and maybe
         | even the 1401, and it still has far fewer vulnerabilities, part
         | from obscurity, part from a smaller attack surface compared to
         | general public systems like Linux. Nothing wrong with CICS and
         | 3270 either, which you seem to call "menu based OS". These are
         | extremely resource efficient presentation layers.
         | 
         | Also, i and Z basically are turnkey systems. They require close
         | to no sysadmin, you don't have to run after the latest update
         | to fix the latest issue. How many vulnerabilities had to be
         | patched in the 51 years of existence of the 3270 protocol?
         | 
         | I would trust a mainframe a lot more than a cloud based, or
         | worse, anything based on Linux or Kubernetes when it comes to
         | reliability and security - in fact, I bet an app running on
         | such a solution will be considered obsolete in a mere 15 years
         | (if not 10).
         | 
         | I've seen companies running their own internal mainframe
         | classes just because there's no suitable alternative to replace
         | them.
        
           | neverartful wrote:
           | "Also, i and Z basically are turnkey systems. They require
           | close to no sysadmin ..."
           | 
           | I think this is true and fitting for i, but not for Z.
        
             | __d wrote:
             | The MVS systems I worked with had a small priesthood of
             | sysops and sysprogs keeping them ticking. They certainly
             | weren't set and forget.
        
           | dangus wrote:
           | You might as well say that battle tanks are better than
           | Toyota Corollas. I'm sure a battle tank is safer in an
           | accident but that doesn't mean it's the best choice for a
           | daily driver.
           | 
           | The goal of a business is to produce as many outputs as
           | possible with as few inputs as possible.
           | 
           | If mainframes are so much better, why don't you own one? Why
           | doesn't your company own one? I see a Z 2828 on eBay for
           | $9,995, sounds like a pretty good deal! I know the Raspberry
           | Pis that run my self-hosted services only cost me $200, but,
           | like you said, you get what you pay for! Where the heck is my
           | credit card!?
           | 
           | Mainframes are a dying breed because they aren't a solution
           | for 99.9% of businesses (yes, that's right, literally 99.9%
           | of businesses have fewer than 500 employees). [1]
           | 
           | By the time a new business has grown large enough to
           | potentially benefit from a mainframe architecture, it has
           | been using x86/ARM commodity computing for years/decades.
           | 
           | The only way a business would ever choose mainframes would be
           | if they were already gigantic businesses before
           | microcomputers were invented and their business has a high
           | amount of clerical overhead. This is why banks and airlines
           | ended up with mainframes.
           | 
           | Having the best, most resilient technology possible isn't the
           | end goal of most businesses. The goal of a business is to
           | sell things and make money. Computing is essentially a cost
           | center where the lowest bidder wins, where the cheapest
           | possible solution is always the best one as long as the level
           | of risk is acceptable.
           | 
           | [1] https://www.chamberofcommerce.org/small-business-
           | statistics/
        
             | rbanffy wrote:
             | > By the time a new business has grown large enough to
             | potentially benefit from a mainframe architecture, it has
             | been using x86/ARM commodity computing for years/decades.
             | 
             | And this is why I say IBM is failing terribly in providing
             | a simple onboarding ramp to these platforms. Almost nothing
             | will scale as far up as a Z, but almost no company will
             | need that and spending the money required by the entry
             | level mainframe is a capital expense most companies won't
             | consider appealing.
        
               | neverartful wrote:
               | In my opinion, the marketing and legal group at IBM (for
               | decades) must have this for their mission statement:
               | "Let's see how quickly we can sink this business!".
               | They're completely inept.
               | 
               | Examples? - Customers: "Can we license z/OS, z/VM, and
               | other IBM mainframe software to run on Hercules
               | (mainframe emulator) for DR purposes?" IBM: "we'll sue
               | your ass out of existence!"
               | 
               | - POWER5 brought some pretty amazing virtualization
               | technology allowing for 'micro LPARS' down to 1/10 of a
               | CPU [0]. It's gotten even better since then. When and
               | where have you ever heard about these capabilities?
               | They're part of what used to be called APV (now branded
               | as PowerVM) [1].
               | 
               | - At one time you could buy a used RS/6000 off of eBay
               | (or from a reseller) and get a legal license (and media)
               | for AIX. To do this today with modern Power systems, you
               | have to first put the hardware under maintenance
               | agreement. Oh, and if the server wasn't already under a
               | maintenance agreement ('SWMA') (or there's been a lapse
               | since it was under maintenance), you have to pay an
               | additional fee ('ALF'). How much are these fees? SWMA
               | estimate is $1800 PER YEAR. ALF estimate is $3200 (one
               | time, unless you have a lapse in SWMA and need to do ALF
               | again). Since Power8, you have to buy a separate HMC
               | (nearly $2000) to configure LPARS. Net result is that it
               | has become cost prohibitive for individuals to buy a
               | second-hand POWER system and run latest AIX or i.
               | 
               | - Want to get IBM's C or C++ compiler for AIX? There are
               | 3 pricing options [2] available: $5780 per user, $17500
               | per concurrent user, or $88.60 per VPC per month.
               | [0] https://en.wikipedia.org/wiki/Micro-Partitioning
               | [1] https://en.wikipedia.org/wiki/PowerVM         [2]
               | https://www.ibm.com/products/open-xl-cpp-aix-compiler-
               | power/pricing
        
               | rbanffy wrote:
               | It must indeed be very frustrating to work for IBM and
               | want to cover different markets and being unable to do
               | it.
               | 
               | I see, however, IBM can migrate a lot of those products
               | from item sales to cloud subscriptions and, in that case,
               | there would be little space for entry level hardware.
        
           | [deleted]
        
         | adwn wrote:
         | That was a wild ride - from a reasonable start of "mainframes
         | are a sub-optimal compromise" via "important foundations of our
         | society rely on obsolete systems" all the way to "we'll replace
         | capitalism with something completely different and better, but
         | I don't know what".
        
           | 2fast4you wrote:
           | They said we'd replace capitalism with another version of
           | capitalism, he didn't say it would be better
        
             | adwn wrote:
             | It was implied:
             | 
             | >> _it will compare to our current society like that
             | compared to feudalism_
             | 
             | Unless you disagree that our current society is better than
             | feudalism?
        
               | rbanffy wrote:
               | Speak for yourself. My family was faring really well
               | under feudalism ;-)
        
               | 2fast4you wrote:
               | I think he was saying capitalism is an evolution of
               | feudalism
        
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