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Linux Possibly Ported to IBM Mainframes 147

Jah-Wren Ryel writes " Vnunet is reporting that IBM has a version of Linux ported to their S/390 mainframe architecture waiting in the wings. Apparently there are two versions, one that runs under VM (a kind of meta-os, sort of like VMware) and one that runs on the bare hardware." An "anonymous source" and "speculation from analysts" story. Nothing official from IBM. Please read and judge accordingly.
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Linux Possibly Ported to IBM Mainframes

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  • by Greyfox ( 87712 ) on Saturday November 20, 1999 @09:51AM (#1516439) Homepage Journal
    They'd probably set it up to run in a VM -- have VM/CMS or MVS dealing with most of the machine and have a bunch of smaller Linux virtual machines running within it. Someone mutters something like this from time to time in IBM; I get the impression it'd be more of an academic exercise than management sanctioned.

    Still, 5 years ago they were talking about how great it would be to have one OS across the board so that you wouldn't have to retrain employees as you scaled systems up from PC's. At the time, they were talking about doing that with OS/2 and we all know where that went, but Linux is out of their control so will continue to gain popularity no matter what they do with it.

    It'd be cool to be able to telnet to bldvmb and get a Linux session when I log in, I hope they do this :-)

  • by RISCy Business ( 27981 ) on Saturday November 20, 1999 @09:51AM (#1516440) Homepage
    ...take it from someone who's discussed it with the guy who actually started it. Linux/390 isn't very special, really. When I last spoke with him (I'm sorry, I've forgotten his name.. I forget names easily. :P) it just ran on the bare hardware, and didn't support much at all. If anything.

    Now, some info on the S/390 from someone who's not gotten to play with one, really, but has seen one.

    The S/390 is a 'massively parallel' computer. Meaning that everything is parallel. The S/390 is capable of running just about any OS you throw at it, from Linux on an x86 host controller to Windows NT on that same host controller. You can run AIX on an RS/6000 host controller. Or OS/400 on the AS/400 host controller. It's designed to do massive processing while serving up literally thousands of hosts. Usually 'dumb' terminals over twinax (twin-prong coaxial), triax (three-prong coaxial), or RS232/RS242.

    No, it's not meant to run Linux instead of OS/390. I wouldn't dare to say that it should, because in truth, it shouldn't. The S/390 is not a 'convenience' machine or a 'play' machine. It is a mainframe, and it needs a mainframe OS.

    However, I see absolutely no reason why Linux shouldn't run on the S/390. Bear in mind; running on the S/390 does not mean replacing OS/390. It means SUPPLEMENTING OS/390. Say you have an S/390 handling most of your financial transactions, but accounting wants a website to keep track of it. Running Linux on an x86 host controller on an S/390 is the perfect solution. But say accounting wants to cut some major expenditures out of the budget; eliminating OS/390 isn't a good idea. Plain and simple.

    OS/390 is a *VERY* mature OS, pretty much dating back to OS/360 (the similarities between OS/390 and OS/370 are very obvious) and as a direct result, is rock solid stable, extremely secure, and inherently reliable. Add that in to hardware that is designed to have decades of uptime. Add in the power to get the job done and then some. That's what the S/390 is about. It's a big-bucks big-iron machine meant to be your network-edge solution for ERP and transactions and whatever else you want to throw at it. It's not your webserver, it's not your fileserver. It's a mainframe.

    However, I've noticed quite a few people are moving away from S/390 to the actually more powerful RS/6000's, which lack some of the features of the S/390. Okay, MOST of the features people look for in the S/390. Some RS/6000 models border on the commodity machine definition. Linux doesn't belong there, either. Yes, that's right, you're hearing it from someone who spends about 99% of his spare time working on porting Linux more thoroughly to the RS/6000. Linux doesn't replace AIX. Period. AIX is a mature OS, probably 7 or 8 years Linux's elder. AIX has a very stable and regular release and development cycle, and is built on principles that have been proven a million times over. It's inherently reliable, stable, and very fast. Unlike Linux, AIX does not just have 'general' releases for all RS/6000's with all architecture support. There is AIX for the RS/6000 F40 (Dual PowerPC 604e) and there is AIX for the RS/6000 Power260 (single POWER3). You can't mix and match those two or components from them. AIX is optimized at the hardware level extensively. Unlike my work, it's built on native platform, optimized on that platform, and meant for that platform.

    Yes, every piece of AIX has a common code base. The compilers do the work. That's why it's built on the native platform. You can get AIX C/C++ compilers for PowerPC 604e, POWER2, POWER3, and so on. And they're designed to optimize and compile reliably. ANd they do it well. Better than gcc or egcs could ever hope to.

    Linux/390 is a great project. Like I said; there's no reason whatsoever that Linux should NOT be able to run on the S/390. There's no reason Linux should not be able to run on ANY system. The question is, though, do you want to replace what that system is MEANT to run with Linux?

    Not yet. Linux is still a long way off from being ready to do that. But maybe someday it will be ready.

    -RISCy Business
  • It is conceivable to purchase a mainframe class machine for hobbyist use. Grant it, it would be a pretty expensive hobby. Used machines are very plentiful on the market, but hardly practical for use in your basement or den. IBM has the P/390, which is a Mainframe class processor in a server. They probably start at around $10000-$20000, not including M/F software. There is a company that sell emulation software that will turn your Intel box into a mainframe. These products get very respectable performance, even compared to todays mainframe class machines. This obviously depends upon how many Mhz you throw at it. The product is called Flex/ES.
  • When I was at the University of Toronto [utoronto.ca] in the early 80's, they had this system that ran Unix under VM. It was called BICS [Basic Interactive Camel System], and it was awful. There was a test-input line that was always on the bottom of the screen, and text would be drawn on the rest of the screen, until it got ful,, at which point the scree cleared and would start drawing from the top. It was kind of like running every single command through 'more', or 'less'.

    I hope this new effort doesn't have any of these limitations. I remember how creepy it was to have a Unix command called "vmpunch", which submitted JCL files to the VM system. Ug.

  • To put it bluntly: I'll believe it when I see it.

    Then go and download a precompiled kernel and bootloader from http://www.linas.org/linux/i370.html [linas.org]. Note that this is a port that Linas Vepstas and others have been working on for some time now -- it's different to the rumoured "official" Linux port by IBM to which this story refers.

  • The purpose won't fall within the realm of most users, but it would be to run Linux along with other legacy apps on the same machine. Lest anyone think this is an entirely stupid idea, the place I used to work had an S/390 mainframe running legacy apps that are unlikely to be changed anytime soon, and we wanted to make use of some of the OMVS features on the machine. OMVS is supposed to be a UNIX-compatible OS running on the S/390. The machine was perfectly capable, if incredibly overpowered and overpriced for the simple purpose of getting at the unused disk storage we had for it via UNIX-type software. But OMVS was a real pain. The reason? It just wasn't convenient to compile for. We could download software all day, but if we wanted to run something of our own design or just compile the latest version of some kind of freeware for it we were out of luck without an army of IBM technicians to help us out. I personally wasn't a real supporter of keeping the mainframe around, but Linux as a VM partition would have at least been infinitely preferable to the proprietary system they were using, in openness and plain convenience. There are lots of possibilities for a system like this running on the existing mainframes out there. It allows integration of UNIX software into a mainframe shop's army of old-school applications, and increased use of underutilized hardware.
  • Not only that, but you could run multiple copies of the SAME OS, just like one of those Russian nesting doll sets. So you could debug mods to your own OS in a virtual environment before deploying them to the real machine.
  • More than six years ago -- more like 12. I remember playing with it before there *were* RS/6000s -- AIX ran on some other early IBM workstation hardware at that time.
  • Reminds me of a joke press release from Borland Int'l a while back: "Announcing Turbo Cobol for your mainframe! BI really stands for Big Iron..."

    Come to think of it, though this may be real, it could still be a trial balloon... Though IBM occasionally develops insanely alright technologies, it's known also for internecine warfare that kills said tech in the cradle... mainframe group killing multitasking o/s initiative (rumor from the middle 80's).

    As legend has it, IBM's makes most profit from sales of hardware... so, so what if Linux is given free with a gigabuck machine, when the markup on the iron is prolly 200%!!?

    And if you consider the version running under VM (VM/Linux? Linux/VM? ye gods..) it's just another application on a large timeshare appliance.

    I don't see a conflict. This'll probably stimulate mainframe sales and free software dev. The word "Linux" has strong buzz and cachet, and even if the CIO doesn't "get" oss/gnu/etc, he's further increased his career trajectory by getting into the "latest" tech in a safe (and very expensive -think IBM tech support acolytes) way -but, hey, that's okay. Win-win.

    Get ready ... think device drivers ... "XFree3270 has just announced support for the latest IBM BluHat(r) Linux kernel build (3.0.3) for S/390 processors."

    Ugh. Even if it does become a reality, the "synergy's" gonna be upward, not so much downward, doncha think? I mean, what does IBM mainframe world, albeit running Linux, have to offer the single-user Linux world? Gotta think about that...

  • Not sure why you said IBM ran away from java on the mainframes. They have Websphere ported to all platforms from linux to AIX to the S/390. They are completely embracing java on the S/390; just released jdk 1.1.8, have JDBC driver right into DB/2, ECS calls right into CICS, java RACF interface classes. Where have you been?
  • IBM already has created "Unix System Services" on 390's running OS390. You have to have it installed and configured in order to use TCP/IP on new versions of OS390. If they replaced it with Linux it would make it a whole lot easier and enjoyable. "Unix System Services" is a pretty lame shell if you ask me. -I drink, therefore I am.
  • by Mong0 ( 105116 )
    Well I work for Bank Of America on the mainframe side of the shop and IBM already has Unix(AIX) running on S/390. It is called Unix System Services. You are right about it running in a virtual environment. As a matter of fact they(IBM) have already got Apache running in this environment. Their goal is to eventually get the Lotus Domino servers running in this environment also. We are in the process of setting up a all java based reporting system that will have live real time acess and update capability to DB2. The reasoning behind the use of a machine like the mainframe is the fact we will have up to 100,000 people acessing dynamically created reports all delivered through the corporate intranet to the banking centers. Especially with the new JDBC drivers that DB2 is now supporting it really runs smoothly. I even talked to some of the IBM reps who said to most software it looks just like they are running on AIX and then the Unix System Services make the apropriate calls to S/390. I guess my real question would be why would IBM want to port Linux for the mainframe when they already have AIX running smoothly there?? Can anyone tell me what you gain from running Linux instead of Unix???? Just my two cents on the subject.
  • by Wakko Warner ( 324 ) on Saturday November 20, 1999 @08:48AM (#1516466) Homepage Journal
    The only customers for mainframes have historically been banks, insurance companies, and large fortune 500 companies and colleges who need to manage enormous databases. It's not like your average Joe has big iron in his basement, and banks/insurance companies/colleges aren't about to switch their operating system over, especially when even a minutes' worth of downtime would probably cost a bank several million dollars.

    Not to mention the specialized hardware IBM mainframes use. It's not just a CPU and a few busses you have to be worried about. Literally *everything* has its own controller. Code would need to be written for so many things besides simply the CPU that, when all is said and done, what you'd have would be a far cry from the Linux we all know and love.

    To put it bluntly: I'll believe it when I see it.

    - A.P.


    "One World, one Web, one Program" - Microsoft promotional ad

  • Ummnn.. OS/390 *isn't* VM...

    OS/390 is IBM's new name for MVS, which is a huge (dare I say bloated) OS for System/390 hardware.

    VM (which is what the article mentions) is a relatively lean (posix!) OS used for decades Universities and smart companies.

    VM is the only OS (that I know of) that can virtualize itself completely (you can run VM in a virtual machine under VM (and in that VM you can run a third-level copy of VM (and...))).

  • i think this would be a excellent step for IBM, i do a lot of work regarding SAP, ORACLE, BAAN, etc. and IBM is probably the least represented hardware Ive seen, this should open the doors of the market for them by providing a somewhat standard API for developers to work against, instead of their proprietary architecture.
  • by velkro ( 11 )
    TCP/IP has been available on the S/390s for quite awhile. In fact, there was even a recent Bugtraq posting about it...

    Cisco makes the ESCON channel adapter cards for hte 7000 series routers for exactly this purpose.

  • Your comment about IBM shying away from Java on their mainframes is just not true. When I worked at Hursley they were spending a lot of time and effort on Java, particularly on CICS. Java is seen
    as a good replacement for COBOL in the CICS environment. With multi-heap JVM's and some innovative garbage collection techniques they were
    expecting Java performance to be on a par with COBOL within 12 months.

  • The NetBSD [netbsd.org] project already has a port to the VAX desktops and some mainframes. See NetBSD/Vax [netbsd.org] It's not stable though...

    It's interesting that IBM would do their own port of Linux.. I wonder what's wrong with their current mainframe OS?

  • Its not about the market that they already have, their doing this to become competetive with some of the smaller hardware stuff that has dominated the mid range, HP9000's, etc...
  • Your point, which I generally understand as

    "if there is tuned software available for a platform, this is typically a better choise than 'agnostic' software such as linux".,

    is valid, but I would counter that in many cases, the increased performance of hardware is making the cost of maintaining tuned software prohibitive.

    Look at web serving, for example. Perhaps its simply the timliness of the web that is forcing IBM to market AIX boxes as webservers, but nonetheless its out there in print. In such a case I would argue that simply having two FreeBSD boxes instead of one AIX box is going to give you the equivalent aggregate performance.

    Stock hardware and software are slowly closing in on the tuned, expensive alternative. AIX and Solaris are in genuine danger of being made obselete by Linux and FreeBSD, if hardware continues to get cheaper and faster simultaneously. As the number of applications for which Solaris or AIX is preferred continues to shrink, the cost of maintaining them will outpace their profitability.

  • There is this assummption that mainframes are ancient technology and are just dinosaurs waiting to die. I work for a company that is a large mainframe shop, and after checking out one of our 4 data centers, I was quite impressed with the technology involved in a modern mainframe system.

    We have several processing boxes which are linked by fiber optics. They provide many different logical partitions (i.e. systems) which are dynamically allocated across the available CPU's. Kind of a cross between redundancy clusters and Beowolf clusters with dedicated I/O processors to handle the I/O requests of several hundred users.

    While these systems might not beat out the raw horsepower of modern CPU's, the supporting communication and I/O bandwith cannot be beat.

    Now let's have Mindcraft have a benchmark against a mainframe running Linux and the best NT system (I know...it's an oxymoron) out there, and let see what results they get...
  • I work in one of the indutries that you mention, and things like this fuel fantasies of overturning the Microsoft bought-out world where I work and installing Linux. Those people on production support, network admins, etc. would love me!

    Please don't kill my dream!
  • And we're putting gigabit Ethernet interfaces on ours...
  • VM supported TCP/IP daemons as virtual machines in the late 1980's. I know, I installed it then to support a network which included RS/6000 machines running AIX, IBM's version of UNIX, connecting to the mainframe via an 8232. On MVS, in the early 1990's, you had a choice of running TCP/IP in outboard controllers, or (somewhat later in the 1990's) running TCP/IP in address spaces on the mainframe itself. In the early 1990's, IBM's proprietary System Network Architecture evolved to support flowing TCP/IP over VTAM (Virtual Terminal Access Method, or something like that), and VTAM itself became a marketing item called "AnyNet" ...charming, no? AIX continues to have an SNA-compatible networking product, but the die has long been cast, TCP/IP is now and has been for a long time, the lingua franca of networking. I also worked with the Amdahl UTS product mentioned in these posts and it worked with 3270 controllers, in the same late 1980's timeframe. AIX/370 ran on IBM 370 mainframes in the late 1980's. AIX/ESA ran on 380 or 390 mainframes in the late 1980's. The MVS operating system, since MVS/ESA 5.3, now known as Open Edition/390 or whatever the current marketeering name for it is, since the mid 1990's has included the "omvs" command, which, issued from a TSO session, will bring up a POSIX shell. You can use the standard command line interface; your directories and files are stored in an MVS dataset called a PDS/E; even though you can store NFS-mountable ASCII data in these essentially EBCDIC operating system datasets, they can be backed up and managed via standard MVS/ESA job control language batch jobs. In other words, with the exception of specialized super computers like Asia Pacific - Blue (which is a large cluster of RS/6000 boxes, by the way), the largest UNIX file server you ever saw is probably an IBM mainframe. Of course, you may never have seen a mainframe. They are still kept inside the raised-flooring area, minded by systems programmer gurus who dwell in closed offices. No one talks to the gurus, we just shove food under their doors with our paltry requests for guidance. Or so the story goes. Although new mainframes are expensive to purchase or lease, the vast number of users they can support actually make the total cost of ownership lower than our favorite mini-computer boxes running proprietary operating systems. That's been documented, you could look it up. You could get an older, water-cooled mainframe for the cost of hauling it away. The maintenance costs on water-cooled mainframes, and the proprietary software charges, will kill you though. Maintenance costs on air-cooled mainframes are much lower, but the software is still expensive... not just the operating system, but the extremely high cost of products sold by vendors. I know an organization that got a freebie mainframe, set it up, and found to their amazement that they were spending almost a million dollars a year on software charges (most of it going to application vendors) and maintenance contracts (oops, it was a water-cooled unit). Enter Linux/390, and the opportunity to replace some proprietary software applications with Linux based solutions. Hey, you can run these in a virtual machine with your regular mix of second-level virtual machines on top of the VM/ESA Control Program, or if you are Open Edition/390 based already, you can partition off part of your RAM and run Linux/390 on the bare metal. That's a pretty attractive proposition.
  • IBM has not sold AIX for the Big Iron for a long time. The current UNIX for the IBM mainframe is OS/390.
  • OS/390 is NOT UNIX
  • by drw ( 4614 )
    Yes...it's not that hardware costs that are so prohibitive...it's the service and software contracts are. While mainframe harware is modern, not all software and service contracts are.

    Many companies believe they can still sell their their software for an outragious price. So much so, it would make an open source advocate to keel over in his tracks.
  • I went to the website. All I found out is that these machines have a bunch of processors, and they run at 637 MHz.

    What the hell are they? PowerPC's? If not, won't IBM have a hell of a time porting glibc, gcc, binutils, XFree86, the kernel, etc. etc. etc. to the new CPU and architecture. Are they going to get SMP running? Methinks that's a hard task.

    By the time they get done porting Linux, it'll basically be a new operating system.

    I'd like to see it, but it seems like a lot of work for very little profit.

  • Why is this post moderated to 1? This post points to EXACTLY what the article is talking about! Get over yourselves, you stupid moderators.

    All through? Click on the comment id link and you will discover that the post has not been moderated at all. It's right where it started. Get over yourself! :-)

    "Rex unto my cleeb, and thou shalt have everlasting blort." - Zorp 3:16

  • They're mainframes. These are not normal computers. They may not even have conventional CPUs at all. That's why most mainframe programs are written for the VM which hides the actual hardware from the programmer.

    As for your list of problems:

    • glibc: this is mostly written in C already. The platform specific parts can't be that hard to port, especially since IBM already has (at least one) C library for 390s.
    • gcc: again, mostly written in C, and it's already been ported [cozx.com] to the 390
    • binutils: ditto
    • Xfree86: you're kidding, right? Mainframes don't usually have graphics consoles, and even if they did, what do you think the 86 stands for?
    • SMP: this is really an Intel thing, but I assume you mean multi-processors. I've never heard of a mainframe with less than 4 processors, so they'll probably want to get this going. Alternatively, you could just run multiple instances of the kernel, each in its own VM.


  • The Big Iorn is back! MVS will still be there as it is THE most robust and secure operating system in existance. Liux on s/390 will seriosly rock.

  • And if you consider the version running under VM (VM/Linux? Linux/VM? ye gods..)...

    rms will probably ask you to call it VM/Gnu/Linux or Gnu/Linux/VM

  • No, I'm not talking out of my ass. I worked at a shop that was an ideal IBM shop (running OS/390, CICS, etc.) and were trying to implement Java (E-commerce and EJBs). IBM kept giving us the run around on Java support and OS/390. Our feeling was that they don't want to support it. If they open the door to Java-land, then why use IBM servers? Unless of course, they beat the crap out of everyone else's Java implementation.

    We eventually went with Sun's E10k servers. We tried, but IBM basically just said that Java was not meant for their high-end machines. In personal computing and maybe RS/6000 land, Java is not deemed as a threat, but as far as enterprise level computing goes, they are SCARED or clueless (your pick).

    I also said that chances are that it will not replace OS/390. See the post from the guy who has talked to the Linux/390 developer. It'd be nice if they ported CICS and VTAM (and everything else) to Linux. But, it ain't going to happen. They have too much invested in them to let them walk to another OS. IBM may release Linux/390 so that in our case where we want to use our IBM hardware we can use *different* software that is not part of the OS/390 fold, but is supported by Linux (et al).

  • one minor niggle. XFree86 is overdue for a rename. In fact, I think the developers have taken to calling the forthcoming version XFree 4.0.

    The XFree codebase is used on x86, m68k, PowerPC, Arm, Alpha, MIPS and Sparc (with whatever grphics hardware is relevant).

    eg. XFree was ported to the Amiga m68k platform when linux was pre 1.0 , AFAIK
  • I guess my real question would be why would IBM want to port Linux for the mainframe when they already have AIX running smoothly there?? Can anyone tell me what you gain from running Linux instead of Unix????

    IBM is a big company. A very big company. A very big company in the computer business. Very big companies tend to have quite a lot of smart people working for them (just being big enough makes that happen - they also have lots of dumb people working for them). And because they are in the computer business, they have smart people with all kinds of computer related interests working for them.

    I wouldn't be surprised this started off by some IBM engineers trying to port Linux to the mainframe, just for the heck of it. And from there, it trickled upwards.

    And what IBM gets out of it. Publicity. The ability to run applications without needing to port it - not even to AIX. An extra sales point. The investment in porting Linux might have been low, so IBM doesn't need gain much to make it worthwhile. And perhaps they are just thinking We offer Linux for the mainframe, just because we can.

    -- Abigail

  • The danish mag Computer world had an article about a month ago, that mentioned that a lot of the "old" style I/O processors in the big iron machines are being released in new "quick/lite" versions attached directly to the system bus of the S/390. Making the "adapter" interface look more like the ones found in a "normal" *NIX box (PCI/MCA/PCx/...). Making drivers should be a lot easier with these new adapters. The artcile mentioned a Gigabit LAN controller that has already been released.

    The article also mentioned that IBM has discussed the Linux port project with Linus.
  • The question is, though, do you want to replace what that system is MEANT to run with Linux?

    I dunno. Why don't you ask Mac users running Linux PPC? (Macs are MEANT to run MacOS, I don't think ANYONE will argue that point...) One might even say that x86-based PCs were meant to run MS-DOS (the original IBM PC architecture, which ALL modern x86 desktops are derived from was very much designed around PC-DOS.)

  • Actually, VM is a complete OS, with tools, editor, compilers and applications deisgned specifically for it.

    Is that for the component that actually implements the virtual machines, or for the OSes that run on the virtual machines, e.g. CMS (was CMS ever capable of booting as a single-user OS on a "raw" S/3x0?), or the regular IBM OSes (or non-IBM OSes, as per the topic of this thread...) that can also run as guests in a virtual machine?

    Actually, what do you think, would it be possible to port VM to anything non-mainframe? (a PC, for example?)

    As VM implements a virtual, err, umm, S/3x0, complete with channel controllers, simulated mainframe-flavored disks, etc., and, I think, depends on features of S/3x0 to provide that emulation, it probably couldn't be ported at all easily.

    However, VMware [vmware.com] implements a similar type of "virtual machine" on NT or Linux on a PC. (The posts asking whether VM was like VMware were somewhat amusing, given that VM/3x0 and CP/360 antedated the 8086, much less VMware, by many years, as in "probably around 15 years, if not more".)

  • cute ain't it... I've seen that little trick too. They claim it's cheaper to use the same MCM in variety of boxes and control the performance by software then it is to develop custom MCM for each configuration. I beleive them; and besides... "MIPS on Demand" is a damn cool concept.

    and to really diverge... remember that in X the client-server division is backwards... that "regular old X-client" is really a server (ala XFree) providing GUI services to the window manager and other X clients you're running on the mainframe. But, again... why? :)
  • Look here http://www.chips.ibm.com/news/1999/s390/s390.html

    The processor instruction set is a super-set of the ones found in PowerPC (I think).

    - Extract from link above

    IBM returns with the enhanced, copper-based S/390 G6 that can run at more than 1600 MIPS. By incorporating copper wiring, IBM's chip designers increased system performance, nearly doubled the number of transistors and added two additional processors to the G6's multichip module (MCM) -- without increasing its size. The MCM for the S/390 G6 Turbo server features 31 chips, including 14 microprocessors, representing nearly 1.4 billion transistors wired onto a five-inch-square ceramic substrate.

    - Linux/390 Hmmm
  • Let me suggest that some of the confusion about the nature of "mainframes" can be cleared up by thinking of mainframes as giant servers designed for i/o intensive operations like, for instance, printing a whole month's telephone bills for several states.

    Linux in a VM/390 environment is very promising, and would be even more promising if someone did a variant of XML designed to control 3270-family terminals which, if one squints a little, are not all that different from character-only browsers. As a native OS on the S/390 family, I've got my doubts; Linux doesn't currently support multi-processors well, and I don't know how it cope with the extremely fast parallel network that connects the 390 mass storage system. Still, IBM has people who've been working with those technologies for decades, so perhaps they know how to make it work.

  • SGI and Sun have both made workstations based upon x86 that have no PC heritage, thank God.. anyone remember the Sun 386i?
  • The processor instruction set is a super-set of the ones found in PowerPC (I think).

    Nope. It's a 16-general-register CISC instruction set (dating back to the early 1960's). The Linux on the IBM ESA/390 Mainframe Architecture [linas.org] page has a link to the the ESA/390 Principles of Operation manual [ibm.com], which describes the instruction set.

  • Quickly to answer: I have not worked with the S/390 series, but I have still seen a lot of old IBM iron. Never seen CMS running without VM. I have seen, however, VSE running without VM. And it seems to be quite a common setup, even though VSE on VM seems more common.
    Not a scientific answer, but that's what I can give right now.
    Hey, would you believe, I have a friend who had a 360 in the yard! I got some of those discrete (non-integrated) technology flip-flop boards as a souvenir!
    I really appreciated this thread, made me remember the good-ol days...

  • by Jerenk ( 10262 ) on Saturday November 20, 1999 @03:21PM (#1516510) Homepage
    Okay, while I was not the person who talked to IBM directly (gee, you went to my website, good for you!), my understanding was that he talked to every person under the sky about getting our system to work with Java. He talked to their marketing people who assured them that Java would be entirely supported by IBM. He then asked for an example (Alan Cox's "show me the code"). Their technical people failed to produce one line of code that would run under OS/390. Eventually after dragging several VPs on both ends into it, we finally got something running on the system (this was mid-summer). Mind you this was on their beta OS running on a test proc. slice - we needed this on our production environment by the end of the summer (a company that dependent on it is not going to run their production m/f on an beta OS - even IBM's). However, by now, I believe that IBM has officially released the OS version that supports Java natively (but I may be wrong - I am no longer at IM).

    However, since we used CICS (as do most IBM shops), we wanted CICS/Java connectivity on OS/390. And, that was what ultimately killed it. While Java was technically supported by the OS, their killer app did not support it. What they said is that all of the COBOL would have to be rewritten to conform to Obj. COBOL standards, then the Obj. COBOL could call C++ wrappers which could then call Java (and that was only if we installed every beta they had). In something so performance driven, this was not an option (never mind beta code). We were trying to make this faster NOT slower. At the same time, we had to support the legacy COBOL code. Ingram has so much COBOL code that forcing a rewrite of any subset of the code becomes a logistical nightmare. We eventually settled upon having a J/Gate (Java->CICS) architecture. Far from our ideal, but at the time, it was our only option. IBM failed to deliver what their customer needed when they needed it. Now, in six or seven months, IBM may finally get their heads out of the sand and support Java in CICS in a reasonable manner. But, Ingram is now a lost cause in that respect.

    So, to clarify my position a bit, yeah, OS/390 supports it. CICS doesn't. If you aren't using CICS, then why use OS/390? Yeah, DB2 and all of that is supported in OS/390, but IMNSHO CICS is still the lifeblood of the OS/390 series...

    BTW, you are indeed correct, IBM's machines kick Sun's ass clear across the room. And, in a place where IBM has so much clout, they should never have let Sun in the door. Now that Sun has their foot in the door, some are seriously considering dumping all IBM products and turning into a strictly Sun shop.

    Sun delivered, IBM did not. That is what matters in the end...

  • I can't possibly believe that USS would be replaced. It is an integral part of OS/390, whereas Linux/390 would be a standalone operating system.
  • I also worked in a fortune 500 data center for 2 years. I did happen to monitor the consoles and am still provide training for that area though I have moved on to messing with RS/6000 and various unix boxen. Our production systems (6 lpars across 3 cmos machines) have been down six times (One of them 3 times, the others were individual faults) in those two years. Four of those times were the fault of the operator (once was my fault) and two were unscheduled faults. The development and y2k systems did come down more often, but that is what they were there for. We do have a monthly maintenance period of about 8 hours when they are all scheduled down. All in all they were the most stable machines I ever worked on

  • That is not entirely true. Banks and Insurance Companies are certainly the largest customers, but far from the only ones. There are plenty of large and medium size companies that are mainframe based and are also not banks nor insurance companies.

    Mainframe hardware is not so specialized anymore. There are a number of companies that sell emulation software that will run mainframe operating systems and ancillary software off the shelf on a PC or large server of YOUR choice. The line dividing mainframe and file server is blurring rapidly.

    The benefit to mainframe hardware is the dizzying speed of the I/O bus. Where your typical PC server has one bus, a mainframe can have dozens or hundreds. I/O rates are now measured in tens of thousands per second. Not to mention 32GB of central memory in the largest models.
  • I must be thinking of another hi-end IBM system then. Yes you are right, the Power2 is found in high end RS/6000 systems.
  • and the moderation of this thread is another trend that's developing... the moderators that marked the original comment "insightful" obviously didn't read the article either. of course then someone marked the second response as falimbait ... which is true, but the comment was also 100% correct and thus hardly deserved to be a -1; and beign under that of course means that most of this conversation won't see the light of day.....
  • Um, I hate to point this out, but:

    o Xfree86. It's just a name. You can run Xfree86 on anything if you *compile* it on it...

    o "...written for the VM which hides the actual hardware from the programmer"... Not really a true statement: the virtual machine that it presents is a REPRESENTATION of the ACTUAL underlying hardware, i.e. you program it EXACTLY the same way you program the underlying hardware.

    While mainframes may not have "conventional" (i.e. one chip) CPUs, architecturally they are virtually identical, as are most commercial machines (e.g. memory, registers, PSW, etc)
  • They're mainframes. These are not normal computers.

    Err, umm, once upon a time, mainframes were one of the few sorts of "normal computers" around. They don't look like PC's, but PC's are the only type of "normal" computers if you take "normal" literally, as in "average", as in "the average computer, by sheer numbers, is probably a PC" (I neglect embedded systems here, which I suspect may well outnumber even "IBM-compatible PC's").

    They may not even have conventional CPUs at all.

    The S/3x0 instruction set is pretty conventional - 32-bit, 16 general registers, register-register/register-memory/memory-memory instructions, most of which are boring old load, store, add, subtract, multiply, divide, etc., with various more exotic add-ons. Just because something's a mainframe, that doesn't mean its instruction set and CPU are immensely exotic.... (The Burroughs mainframes, and their Unisys A-series successors, have a fairly exotic instruction set, but IBM mainframes don't.) The ESA/390 Principles of Operation manual [ibm.com] documents the S/390 instruction set.

    That's why most mainframe programs are written for the VM which hides the actual hardware from the programmer.

    If by "the VM" you mean "VM/390" or whatever it's called these days:

    1. it doesn't hide the underlying user-mode instruction set from the programmer, it just provides a simulated "bare hardware" machine letting you run various S/390 OSes at the same time on the same machine;
    2. I doubt that "most mainframe programs" are written for it - the programs that run atop VM are largely OSes, and the applications are presumably written for those OSes (OS/390, ESA/VM or whatever DOS/360 turned into, etc.).

    Perhaps you're thinking of System/38 and AS/400, where the compilers used by application programmers don't generate native machine code, they generate code for a virtual machine, and the low-level OS code ("system licensed internal code") translates that code into the native machine code for the particular machine, if it hasn't already been done, in order to run it (that native machine code being a System/3x0-like instruction set on older machines, and an extended flavor of PowerPC on newer machines).


    A port is in progress, according to the Linux on the IBM ESA/390 Mainframe Architecture page [linas.org]. ("A port of glibc has been started. System calls work. Signals don't.")

    Xfree86: you're kidding, right?

    Perhaps porting the X server code would make no sense (although there do exist graphical terminals for mainframes - I think they're still used for engineering and scientific work), but the X client code might be useful.

    SMP: this is really an Intel thing

    As far as I know, "SMP", meaning "symmetrical multi-processing", as in "multiple processors, without particular processors being devoted to particular tasks such as 'one processor runs OS kernel code and another runs user-mode code' or 'only one of the processors is allowed to ever run kernel code' (as opposed to, say, a single kernel lock allowing only one processor at a time to run kernel code), has, as a term, been around longer than have SMP systems with Intel processors. SMP systems, whatever they've been called, have definitely been around longer than have SMP systems with Intel processors....

  • IBM's newer mainframes are all pretty standardised, consisting of multiple Power or PowerPC cores linked together.

    Indeed? If so, then those "Power or PowerPC cores" are presumably interpretively executing the System/3x0 instruction set, which is not, and has never been, a derivative of POWER. (POWER and its descendants are load/store 32-general-register RISC architectures; S/3x0 is a 16-general-register CISC architecture with register/memory arithmetic instructions.)

  • by delmoi ( 26744 )
    double-precision shift instructions,

    Dude, what the f**k is a double-precision shift instruction??

    I mean, do you just mean that you can shift up to 64bits? (that's what I would guess from the conetext).
    "Subtle mind control? Why do all these HTML buttons say 'Submit' ?"
  • Little anecdote on S/390 processors. We run a 2003-205 S/390 box. Came with 1 processor, running 13 MIPS. We found it to be too slow, so we ordered an upgrade to a model 207 (24 mips). Cost 60K. The tech came in one night, put a floppy in the hardware console (it is an IBM pc, P-II/300), fiddled a bit, and viola! It was now a 207!

    I queried this guy a bit on this black (blue?) magic. Seems the 200x series processors come with 6 CPU's in them. The clock oscillation rate of each, and the number that actively process are controlled by SOFTWARE! These things can be 6-way SMP, and over 140 MIPS by doing the same procedure... oh, yea, and forking over mega-bucks to big blue.

    What an incredible business model! My (red) hat is off to the guys who came up with *that*.

    That aside... I agree with another poster that Linux would be a damn sight better than the OE shell and Unix system Services. And yes, you can run the X server on the mainframe, and use your regular old X-client. But, again.,.. why?


  • Wakko Warner wrote:
    The only customers for mainframes have historically been banks, insurance companies, and large fortune 500 companies and colleges who need to manage enormous databases. It's not like your average Joe has big iron in his basement, and banks/insurance companies/colleges aren't about to switch their operating system over, especially when even a minutes' worth of downtime would probably cost a bank several million dollars.
    Actually, there's kind of a fallacy operating here. Mainframes date from the era when there were only mainframes. They were expensive and big because computers were expensive and big. I remember the end of that era clearly; I was there. :)

    Minicomputers followed. They were somewhat less expensive and newer technology. In theory, a very complete set of applications could have developed for minicomputers, and in fact quite a few applications did, but it became a marketing war, and the pitch was that somehow minicomputers were less capable than mainframes. It was an effective pitch but really there was a lot of marketing hype there.

    Finally, as "mainframe" manufacturers began to develop a lot of the same newer technology to keep up with "minicomputer" manufacturers in terms of cost and size, the "personal computer" came along and threw the whole equation into a cocked hat. PC hardware certainly was initially less capable than mainframe hardware; the processor architecture featured such ancient constructs as an accumulator. Missing were things like orthogonal register sets; clean, simple instruction formats; end-to-end error correction.

    But nothing said that PC hardware had to be less capable than mainframe hardware; it just didn't matter that it was, since it was inexpensive enough to be bought by multiple users in multiple departments. This allowed departmental users in the corporate world to bypass the huge project backlogs that most IS departments had developed and gave control of much more computing to those departments.

    By the present day, it's clear that most computation is done on platforms that are considerably more powerful than the first PC's, but are descended from those platforms. It's also the case that more and more features originally found on mainframes are making their way to PC's, and this trend is likely to continue.

    PC variants (not necessarily on Intel architectures) represent "where it's at" because anybody can buy them and stage them for particular applications. They're cheap and easy to operate. So they are certainly likely to accumulate a very rich feature set as time goes on.

    The "mainframe versus personal computer" war has never been about hardware capabilities, per se. It's always been about who has control of computing, and clearly the PC won that war. At this point we can regard mainframes such as the S/390 as being relatives of PC's, in that they have to compete in the market to perform the same tasks that PC's routinely perform.

  • SMP is NOT an intel thing. IBM's been doing SMP on Mainframes in various forms long before Windows was a twinkle in Bill Gates' eye. You think clustering is new, OS/390 can cluster up to 32 machines, each with up to 1600 MIPS each. Now that's POWER.
  • but the real question is does it support EBCDIC?
  • Rather, this is probably closer to how FreeBSD "emulates" Linux: It provides a compatible Application Binary Interface

    Given that the only "emulator" I saw mentioned in the article was for AIX, and that by AIX they probably mean AIX for RS/6000, and that most if not all current RS/6000's use the PowerPC member of the POWER family of architectures, and that Linux also supports PowerPC, that's possible.

    However, what the article said was:

    In September IBM announced software it described as a Linux emulator. This provides an application program interface which allows Linux applications to be
    recompiled to run on IBM's own AIX variant of Unix.

    (emphasis mine). That suggests that there's no ABI compatibility involved, just API - Application Programming Interface - compatibility.

    In any case, the only ways to provide the ability for IBM mainframes running OS/390 to run Linux binaries would be

    1. include code to "emulate one machine on another", e.g. emulating an x86 on an S/390;
    2. run binaries intended to run on, say, a Linux port to an S/390.

    IBM already have "a POSIX to OS/390 translation layer", in a sense - they have a UNIX-compatible environment, in the sense that it passed the UNIX 95 test suite [opengroup.org], so at least some programs can presumably be recompiled to run in that environment...

    ...as long as they, say, don't assume that the characters "A" through "Z" or "a" through "z" are encoded as a contiguous set of values; their UNIX environment uses EBCDIC, not ASCII, as its character set [ibm.com]. (Here's the home page for the OS/390 UNIX System Services [ibm.com].)

    I infer from the article that part of the rationale for a Linux/390 port is to make it easier to port applications from UNIX environments - OS/390's UNIX environment may not be enough like "Real UNIX", implemented, as it is, atop a different OS, and using a different native character set, and so on, to allow quick porting, whereas Linux systems look enough like "Real UNIX" to me, at least, for me to consider them to be "Real UNIX", even though the Open Group don't yet have any Official Certification Results for any Linux system but do have one for OS/390.

  • I'm a VM and VSE systems programmer, VSE is not necessarily unintuitive, it just takes a little getting used to. It is certainly no more unintuitive than *NIX.
  • My office mate at Team One was one of Amdahl's kernal hacks, circa 1991. Amdahl got Sys V going under VM. Very cool thing, since he could have multiple instances of UNIX running under VM, and diff them to see the results of his code mods.

    Today, running Linux under EROS would be the best of *all* worlds, if only Linux had a decent GUI.

  • VM beats *every* UNIX all to hell when it comes to reliability.

    Running Linux under VM, is like running NT under VMWare. It lets the unreliable code run in a safe, isolated compartment.

  • I don't think they have. AIX is for RS/6000 and the like.

  • This is just the kind of thing Linus was talking about during his keynote, the ability of Linux to scale not only to small systems but also large ones. Quite impressive having such an adaptable OS. Emulating it, not quite shure if that is as impressive. Wouldn't it take away from the power of a direct port?I wonder what uses this could bring if it has been ported... hmmm

  • Not too many years ago, IBM was considered the great Satan of the computer industry. My, how perceptions change.

    I personaly am pleased that a Linux port can be used on the S/390... mighty impressive and a feather in the cap to all that made this possible.

  • by Jerenk ( 10262 ) on Saturday November 20, 1999 @08:55AM (#1516537) Homepage
    If this is true (highly doubtful), this would definitely send shockwaves throughout the enterprise class server industry. If IBM believes Linux is ready to run on their heavy metal boxes, then some serious (re)consideration of Linux is going to occur in the next few months.

    However, after personally seeing IBM run away from Java on the mainframes (running OS/390-MVS), I have to doubt this is true. IBM looked scared to death of Java on the mainframes. For the personal computers (i.e. with Jikes), they really seem to embrace Java, but on their enterprise class servers, they seem to be frightened to death of it. After all, if they support Java, then why not just use Sun boxes? Of course if they do such a thing, they'd have to do it better than anyone else (including Sun) - not to say that they aren't capable of this, but they'd have to try really hard. =)

    This could also mean the beginning of the end of OS/390 (MVS) - maybe IBM finally decided that they no longer want to mess with having to recompile or support weird programs on their OS. Just give them a little VM (or actually processor slices most likely) and let them run their own little OS that will allow them to run their weird apps. Keep all of the VTAM and CICS stuff under OS/390 though. I'd be pleasantly shocked if they came out with full-blown support for Linux though... Oh, man, CICS Server on Linux/390 - oooh, wow - there would be a lot of people jumping into to learn Linux really quickly if that happened.

    But, rumours are rumours for a reason. I'd be curious to know whether Linus knows about stuff like this - would a company tell him that they were porting Linux to XYZ hardware platform?

  • I must say that it is infinately amusing to see IBM's VM described as being "like VMware". I was just describing VMware to a mainframer that I work with as "like IBM VM".

    It's amusing to me, anyway.

  • Err, umm, once upon a time, mainframes were one of the few sorts of "normal computers" around.

    Of course you're right. By 'normal' I really meant 'commodity'. Mainframes are quite dissimilar from the desktops or workstations that most of us are used to.

    Perhaps porting the X server code would make no sense (although there do exist graphical terminals for mainframes - I think they're still used for engineering and scientific work), but the X client code might be useful.

    Indeed. But the only really interesting part about porting X would be the server side. The server side has to interface with graphics devices. I haven't looked at the XFree codebase, but I presume that there's very little platform specific code in the client.

    As far as I know, "SMP", meaning "symmetrical multi-processing"

    I believe that this was a term introduced by Intel, and I don't think that other multi-CPU architectures are described with this acronym, but I could very well be wrong. I also believe that the 390 architecture is massively parallel but not really symmetrical. As another poster mentioned that the 390 can have various CPU modules which might not even run the same instruction sets.


  • IBM already has Unix(AIX) running on S/390. It is called Unix System Services

    It is "UNIX" in the sense that it passed the UNIX 95 test suite, but it's not an AIX port - it's part of OS/390 and, as noted in another post, it's different from what you might think of as "real UNIX" in some ways; for example, it does not use ASCII as its character set.


    I guess my real question would be why would IBM want to port Linux for the mainframe when they already have AIX running smoothly there?? Can anyone tell me what you gain from running Linux instead of Unix????

    ...that question might better be phrased as "Can anyone tell me what you gain from running a native UNIX-compatible operating system instead of Unix System Services?", in which case the answer may be (as per the VNUNET article) that a native UNIX-compatible operating system such as Linux may look "more like real UNIX" than even the it-passed-the-UNIX-95-suite Unix System Services in some ways - ways that might make it easier to port to Linux than to Unix System Services.

    One might ask why they'd want to port Linux rather than, say, revive the old "real UNIX" port of native AIX they once had (I don't know whether they still offer it or not); I don't know whether it's because

    1. AIX/370 looked less like other current UNIXes than does Linux;
    2. AIX/370 is a bit out of date now and they decided that a Linux port would be less work than modernizing AIX/370;
    3. AIX/370 isn't "AIX/390", and would take a fair bit of work to get it to make full use of the capabilities of System/390;
    4. some of the above;
    5. all of the above;
    6. none of the above.
  • are you sure you aren't thinking about the AS/400? (hint: it isn't a mainframe.)

    the S/390 uses the G5 or G6 chips [ibm.com] (be sure to check out the images link on the upper right... intel bunny suits eat your hearts out :)

    the AS/400 uses a cousin of the PowerPC chip; and was in fact the first IBM product to use PowerPC based technology over five years ago [ibm.com].

    the RS/6000s use PowerPC as well as PowerRS chips such as the Power4.
  • S/390 hardware hasn't been 32 bit for quite awhile... there are some dedicated chuncks that do 1Kbit (yes, 1024 bit processors), but I think most is 64 bit.

    Define "32 bit" and "64 bit". S/390's general-purpose registers are still 32 bits wide [ibm.com] (it says "For some operations, two adjacent general registers are coupled, providing a 64-bit format", but, as I remember, that's been true since System/360, back in the early '60's, in that it had, I think, double-precision shift instructions, at least) and, whilst I think ESA/390 has some segmentation-like scheme to boost the address space size above 2^31, the instruction set still looks more 32-bit than 64-bit or whatever. The internal data paths of the implementation may be wider, but, if you go by internal data path widths or processor-to-storage data path widths, there are few if any 32-bit processors left....

  • 2.I doubt that "most mainframe programs" are written for it - the programs that run atop VM are largely OSes, and the applications are
    presumably written for those OSes (OS/390, ESA/VM or whatever DOS/360 turned into, etc.).

    Actually, VM is a complete OS, with tools, editor, compilers and applications deisgned specifically for it. I have done some little developement on VM. It's true that the company where I worked used VSE/ESA over VM for their production mainframes, but that doesn't have to be necessarily so. And actually, I personally hated VSE/ESA. It has a lot of features, but it's so friggin unintuitive. I have never seen anything so incompatible with human brain as VSE. VM, on the other hand, is was much clearer and simpler for me. I would accept a job of VM software developement anytime (if it payed better than the current one).

    Actually, what do you think, would it be possible to port VM to anything non-mainframe? (a PC, for example?)

    (I have 5 or 6 VSE/ESA student manuals. Anyone interested? I would gladly trade them for an old AHA 1540 or other ISA SCSI adapter)

  • IBM lost their ability to force anyone to use their products. That's why notbody hates them today.

    Now, back in the day, IBM would happily rat you out to your boss if you bought DEC, or if you did anything else that wasn't toeing the party line, but even at their worst, they were never as arrogant as Micro~1.

  • by wik ( 10258 )
    TCP/IP has been on Unisys mainframes for a while (in addition to the proprietary BNA connections). There's a decent webserver named Atlas for these machines and I'm somewhat surprised that they don't market the machines as ultra-powerful webservers, since they can switch between multiple tasks (e.g. web browser requests) like a breeze.

    Aside from the fact that BNA is a pain to interface to a cheap wintel box, TCP/IP makes it much easier to have a terminal emulator running on your windows box.

    On a different note, many great GNU programs have been ported to these machines to make porting Java easier. Granted, getting any (what you might think of as normal) C program to run correctly on a Unisys A-series is a challenge. 48-bit words with signed-magnitude representations are entirely unexpected by a normal C programmer. Don't use shifts!

  • I mean, do you just mean that you can shift up to 64bits?

    Yes [ibm.com].

  • I believe that [SMP] was a term introduced by Intel,

    Possibly, but I seem to remember hearing the term before x86 MP systems were common (although they date back at least as far as the Sequent Symmetry, so they do go back a while).

    and I don't think that other multi-CPU architectures are described with this acronym, but I could very well be wrong.

    Perhaps Digital^H^H^H^H^H^H^HCompaq don't say "SMP", but they sure say "symmetric multiprocessing" (admittedly, not "symmetrical", if one wants to be fussy) on the Digital^H^H^H^H^H^H^HTru64 UNIX home page [digital.com].

    I also believe that the 390 architecture is massively parallel but not really symmetrical.

    There exist S/390 machines that have a lot of processors, but the Multiprise 3000 "enterprise servers" [ibm.com] (every time I hear some marketoon say "enterprise", I wonder whether they intend to install the "enterprise" product in question on the bridge of NCC-1701) start out as uniprocessors and go up to big honking two-way systems.

    I also have the impression that the MP S/390's are "really symmetrical", in the sense that there aren't particular S/390 processors dedicated to specific functions.

    As another poster mentioned that the 390 can have various CPU modules which might not even run the same instruction sets.

    I suspect he's thinking of I/O processors, e.g. the processors that run the channel controllers (which I wouldn't be surprised to hear were PowerPCs these days), the communication controllers, etc. - the processors that run the applications, and the bulk of the OS, are S/390s, as far as I know.

  • actually they're up to the Power3 now... expect the Power4 [ibm.com] to replace that sometime next year with it's awesome technology [ibm.com].
  • Mainframes aren't dead for three important reasons:

    • Maximum ("take no prisoners") single-thread performance;
    • Maximum I/O bandwidth; and
    • Maximum I/O connectivity.

    There are some large jobs (like the merge phase of a sort) that MUST be performed as a single-thread operation.

    Dealing with databases (and, especially, key/index management) that requires serious I/O bandwidth along with that single-thread performance.

    Somehow I doubt that Linux will ever be a primary OS for an S/390 sysplex- but it could happen.

    I'd figure that the VM version would be most likely (though VM tries to mimic bare metal anyway) but, AFAIK, there are folks inside IBM that want VM to evaporate (like it's gonna happen).

    I could see Linux living within a VM allowing a system to handle MVS, VM/CMS and Unix applications all at the same time...

    Of course, this kind of facility makes time-to-market for WebSphere App Server and brethren that much shorter...

  • 20 years ago I'd never have anything to do with IBM- Yes, there was arrogance, but...

    The key difference between IBM then and M$ now is that IBM put more effort into making things work.

    With many of the shifts that have occurred, IBM's leadership has been humbled...

    ...which is why it's easier to deal with 'em nowadays. Just remember that IBM is opportunistic- but then, they had to learn how (something that AT&T always failed at when it came to computers) which is what competition is about.

  • by soup ( 6299 )
    Consider the stories of how IBM came to embrace Apache as the core technology of WebSphere- rather than having Domino Go as core...

    I've heard that some folks w/i IBM didn't like the Domino Go webserver they were using, so they (sneakily?) replaced it w/ Apache. Executives noticed the improvements in performance and wanted to know how they got Domino Go to run so fast...

    Beats me if it's true but it makes a cool story.

  • I reported this story to Slashdot over 6 months ago. I was on a high profile team at IBM and the project leaders for this porting effort asked us if anyone wished to join the development team for porting Linux to S/390. It's no bull people, IBM is adopting Linux in a corporate sweeping manner.

  • Tain't nothin' new.

    The old UNIVAC 1108 sold a *lot* of copies before UNIVAC's mgmt (Rand? Remington?) realized there actually was a demand for computers.

    So, they rolled out the 1106 computer for less than the cost of the 1108 (the development costs for which had already been amortized) which only had a clock-card (and badges) different between the two machines (some time later the 1106's were their own machines, but the first cut was a downgraded 1108).

    If you look at IBM's licensing issues for ADSM (on AIX/NT, maybe MVS) it seems that you can license it w/o paying for it- which is, in it's own way, true. If you've exceeded the nominal license, however, you may have problems getting serviced...

    I don't think companies with their businesses dependant on these machines will be in a hurry to exceed their service contracts...

    Ya gets what ya pays for- but you also pay for whatcha get...

  • This has been done on the IBM ESA/390. See the Linux on the IBM ESA/390 Mainframe Architecture [linas.org] project. Unfortunatly it's still in devlopment. So no banks will be using it. :-)

    And there is a project looking at the possibility of a AS/400 [snip.net] port. It's not even in development though.

  • About 6 years ago I saw a version of AIX Unix running on a IBM mainframe under VM. It was interesting, emulated a powerpc based RS/6000, as I recall.

    I could believe that they might have a version of Linux running under VM, using some of the same tech they developed for that port of AIX.

    But I don't see too many people with spare 3090s sitting around wanting to run Linux.
  • by MrCynical ( 63634 ) on Saturday November 20, 1999 @09:02AM (#1516562)
    I work in the mainframe world and although we run MVS, I have seen references to IBM running Unix on their S/390 line (maybe others). So, it shouldn't be too hard for them to get Linux to run too. Someone posted something about TCP/IP and seemed suprised it might be on a MF. Well even on our MVS box we use TCP/IP for everything. We even have SMTP and FTP servers running on it and it works great. I think it would be wonderful to have Linux as the base OS.
  • As the article states, the issue is that the mainframe OS/390 API porting target gets addressed late, if even at all, by the developers. So what's wrong with the mainframe OS is probably two things. One, there isn't as big a market share as UNIX has. Two, just because it's different, the cost of porting applications becomes much higher. Linux/390 is basically the low cost route to putting a POSIX/UNIX API on the mainframe hardware, which still has advantages in performing massively parallel I/O to hundreds of devices. Have you ever worked on a computer that had over 800 disk drives attached through over 30 I/O channels?

    While we may have no real interest in it for home and small/startup business purposes, IBM has a real business interest in positioning their mainframe hardware investment to large corporations and banks who are moving to the newer software systems like Notes (IBM owns Lotus) and SAP.

    I see it as proof that Linux is a mature OS. So it happens to save a legacy 32-bit architecture for a few more years.
  • It's true that IBM mainframe hardware is ungodly complex, but this wouldn't be the first version of UNIX to run on it. Amdahl created UTX for the S/370 architecture many years ago. I taught a course on UNIX (back when that wasn't a laughable notion) to some folks who'd bought one of these. Amdahl had a full-screen half-duplex editor that ran on 3270s. Pretty amazing. Typing 'ls' on a 3720 and having file listings come up was even more amazing.

    Then on other mainframes there's UNICOS and whatever they call the flavor of UNIX that runs on Crays.

    It's a big piece of work but it certainly isn't out of the question. IBM ignored the Next Big Thing once and it cost them big-time: they're no longer king of the hill. If (as many /.ers take as an article of religious faith) Linux is the Next Big Thing, it's not out of the question that IBM would have one or two projects on the back burner, just in case.
  • Code would need to be written for so many things besides simply the CPU that, when all is said and done, what you'd have would be a far cry from the Linux we all know and love.

    As the article said, this effort isn't really about porting the linux kernel to big iron, it's about porting linux software to big iron.

    Want some real performance? Look at how fast Apache and all your perl cgi scripts run on this machine! Imagine serving slashdot off an S/390. Suddenly, IBM has the latest versions of samba, mars_nwe, domino, SAP, gnuplot, and that numerically intensive simulation your poor grad student has been writing. AND LOOK HOW FAST IT RUNS!

    IBM will sell some boxes with that sales pitch. I want one in my basement.

  • I am still laughing. I remember using VM/370 at a company I worked at. We ran CMS (Conversational Monitoring System) as the "OS". The beauty of VM was you could run multiple OS's on the same system, which was rather amazing for the late 70's/early 80's. Had a crash, just reboot your OS and restart, the real hardware seldom hiccupped. You could even suspend the OS you were running, load and run another one, and then return to the first. It would have been even better if we had had graphics terminals in place of the 3270's but hey, it was a long time ago. I guess it just took a long time for someone to reinvent it.
  • by starling ( 26204 ) <strayling20@gmail.com> on Saturday November 20, 1999 @09:17AM (#1516567)
    ..they're minicomputers. That's not just a nit-pick - programming for a mainframe, at least at the lower levels, is much nastier than on the relatively uniform minicomputer architecture. A mainframe feels closer to a tightly integrated network of special purpose devices than a single CPU system.

    From a programming perspective, a VAX is much more like a souped up microcomputer than a mainframe. One reason why virtual machines are popular on mainframes is that they hide the really ugly parts of the system; not just from application programmers but from kernel programmers.

    I can believe a Linux port to VM, but I'm much more skeptical about a port to the bare metal.

    Caveat - my mainframe penance was on Unisys machines, so correct me if I'm off base about IBM's big iron. No such doubts about the minicomputers though.

  • by DragonHawk ( 21256 ) on Saturday November 20, 1999 @09:23AM (#1516568) Homepage Journal
    This is Old News, in computer terms.

    LinuxToday [linuxtoday.com] ran a story on this [linuxtoday.com] back in mid-October. In it, they referenced an article [computerworld.dk] in the Danish version of ComputerWorld [computerworld.dk]. The feedback comments to LinuxToday are interesting, and several of them pointed out one project's home page. [linas.org]
  • I am a Systems Programmer for a community college. My supervisor (the Lead Systems Programmer) just recently told me that an IBM systems engineer told him that a port of Linux for the 390 was in the works to be officially released the end of 2000. This would be a SUPPORTED product, apparently.

    Things to remember about mainframes. There are a myriad of OS's that run on one box at a time. Big banks and big corporate outfits traditionally run
    MVS, which is a beefier (more expensive) OS. Colleges (or other institutions that need mainframes but are a little short on cash) usually
    run VM. There is a Unix OS available that goes along with MVS, but according to my boss, the Linux for 390 will be targeted more towards those running VM.
  • Yes. At first it was called AIX/370. It evolved into AIX/ESA to support more real storage and provide some of the benefits that ESA mode allows.
    It was discontinued a number of years ago, Perhaps to free up development dollars for USS.
  • That's interesting. The marketing hype is that OS/390 is the most stable operating system that IBM develops. I run a VM/VSE shop and our system is very very stable, so stable that we have even cut out the typical therapeutic IPL. We can be up for weeks at a time.
  • Linux on IBM big iron?! Well, I'll BDAM...

    You're right, it is/will be a LOT of work. I for one would love to see the device drivers, and how they manage to move the beast from the 80-column world view to the Unix notion of files.

  • This would be cool! I've ben working on IBM mainframes for five and a half years now - under VM, MVS, and OS390 operating systems.

    It would be interesting if IBM took a spare mainframe, loaded Linux up on it, and connected it to the web for the OSS community to play with, experiment with, and tweak. I wonder what kind of performance scores Linux would get as compared to OS390 or IBM's other mainframe OSs.
  • were true why in the world would IBM replace AIX on their Big Iron? Linux is a nice OS that is finally getting some attention but maybe it's getting a little too much. It's at the point now where everyone has a Linux .plan so they can tout it for PR and then not really go anywhere with it. Porting Linux fully to their mainframes would require a huge rewrite of the kernel which would make it look alot like AIX. Whats the point of calling it Linux if you have to take out most of the kernel code to port it to the mainframe? PR dude.
  • What would the purpose of this be?

    As the article says (you did read the article, right? *grin*), the main point would be to run Linux in parallel with other S/390 OSes like MVS. As everyone seems to be pointing out, Virtual Machines are very popular in the mainframe world, and it is quite common to run more then one OS at a time. Thus, Linux would be just one more OS.

    The suggested application was Lotus Domino. I can also see web servers, application servers, general Internet servers, that sort of thing, being useful. Perhaps a company running a big back-end mainframe database would want to use Linux for the front-end interface, with (for example) Cold Fusion. I can see quite a few uses for it.

    Is a big bank going to dump MVS and move to Linux on the S/390? No, of course not. That isn't the point.

    Plus, there is hack value. We can now say with a fair amount of confidence that Linux is the most scalable OS on the planet. It runs on everything from large IBM mainframes to hand-held Palm Pilot devices.

    I'll believe it when I see it.

    It is already partly done, from what I understand. My comment here [slashdot.org] has links with details.

I've got a bad feeling about this.