IBM Corp is serious about Unix on the mainframe – and with the Messianic zeal of the convert, the company is today trotting out many of the arguments for its position that Amdahl Corp first expressed a dozen years ago when it went public with its plans to create a guested Unix under VM in 1980. Amdahl has of course been delivering native Unix on its mainframes for about five years now, but with AIX/ESA, IBM has just about caught it up. Amdahl’s over-riding justification for supporting Unix all those years ago was that there were so many people coming out of universities with a familiarity with and a love of the operating system that it seemed a little short-sighted not to harness some of that enthusiasm. To be fair, back in 1980, it was by no means concerted company policy to push Unix: indeed there was then only a minority of people within Amdahl that really believed in it, while sceptics were legion. Since then, Unix on the mainframe has built up to a relatively healthy $300m-a-year business for the $2,000m-a-year company, and IBM can see glimmerings of a rather bigger business than that for itself with mainframe Unix. After all, European governments increasingly insist on it, the US government is leaning that way, and as Mike Frevert from the Data Systems Division in Kingston, New York observes, Unix is where the growth in applications is to be found these days. And in a decidedly open-minded decision – everyone is expected to be open in every sense at IBM these days – before embarking on the effort to develop AIX/ESA, IBM went out and hired enough university graduates that knew and loved Unix that they made up a third of the development team.
Disparagement
Who is going to want Unix on the mainframe? According to Frevert, IBM’s target markets are compute-intensive technical applications, activities that require a large consolidated file server, and environments – such as university and research campuses – requiring a centralised interactive computing resource. As usual, IBM has come so late to a market that for years it derided that it is running the risk to which it exposes itself so often, that of people that wanted the thing but were put off by IBM’s disparagement reacting by thinking well if it is all right after all, even in IBM’s book, we’ll certainly go that way, but we’ll go with the people that believed in it all along. And that is a more serious danger than IBM anticipated, because Frevert comments candidly that the company is finding more interest from large commercial customers that it expected. Moreover, IBM isn’t quite there yet: the current plan is to start shipping the product next June, and to have everything promised for the first release available by the end of next year. But once again, IBM is doing all it can to get the message over that it really has changed: Frevert says that with Unix, there can be no question of adding support for new standards only in releases that come out six, 12 or 18 months apart as has been the case with MVS – new functions will have to be bolted on as addenda to the current release as soon as they are implementable, he says.
Vector Facility
So what do you get with AIX/ESA? To start with, a kernel that has been designed to support up to 64-way multiprocessing, which will run single-image on the current biggest machine, the six-processor ES/9000 Model 900. There is this nasty little problem that all IBM’s Unixes are different, so that at minimum you need to recompile to move applications between AIX PS/2, AIX 3 and AIX/ESA – but IBM recognises the problem and the fact that users want the same environment right through the product line. The base AIX/ESA 1.0 will include the base OSF/1 from the Open Software Foundation, and compliance with Posix 1003.1, the X/Open Portability Guide release 3, Unix System V.3.2, BSD 4.3, X Window 11.4, Motif 1.1, and the Network Computing System 1.5.1. It runs on all 370 ESA machines as well as ESA 390s, can be run in a PR/SM partition or under VM as well as native, supports the Vector Facility with equivalent performance to MVS or b
etter – that is a promising market because Unix is probably a better host environment for vector processing than MVS. It also supports Extended Storage, the fibre optic serial channel, Escon, the HIPPI High Performance Parallel Interface, and 3088 channel-to-channel connection. Other communications include TCP/IP (of course), the SNMP Agent for netwrok management, which means that it can be controlled in an SNMP network, but cannot be a control point; and the 3172 device that directly connects local area networks to the mainframe channel. IBM long ago stopped being dogmatic about local area network, and the 3172 connects Ethernet and Fibre Distributed Data Inteface as well as Token Ring. So how do you attach ASCII terminals to the EBCDIC host? The 3172 is probably the cheapest way: the ASCII terminals, and X terminals can be interfaced via the local area network. What about the 3174, which comes in versions that now support some ASCII terminals as well as 3270s? Well, yes, that is being looked at, and it may well be a means of getting at Unix through 3270s one day, but there remains the ASCII-to-EBCDIC conversion problem. What about SNA support? Do you know any Unix programs that use LU 6.2? asks Mike Frevert rhetorically. Another way to hook up terminals is to use the new channel-attach feature on the RS/6000. It works out kind of expensive if the RS/6000 does nothing else, but it does provide access for terminals directly attached to the RS/6000, to terminals on a local area or a wide area network, provides full SNMP support, and access to X25 networks. If a large number of terminals is to be connected, the RS/6000 route may be the best, since up to 256 can be directly attached using the Outboard Communications System, with buffering code in both the RS/6000 and the mainframe. AIX/ESA supports the Berkeley Fast File System with multi-volume support and mirroring, data spaces greater than 2Gb, 2Gb process size, and data striping and memory mapping. Needless to say, AIX/ESA already brings some baggage with it: there are 200 AIX/370 licensees out there to be taken care of, so AIX/370 binaries and the AIX/370 file system are supported – along with about 100 applications aviailable for the old VM guest.
System V.4
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Languages: VS/Fortran, ANSI C and Cobol. That’s more or less what to expect in 1.0, but in the works are the Distributed Computing Environment – a toolkit by late next year or early 1993, the full product by mid-1993. OSF 1.1 will include Unix System V.4 compatibility; the Open Systems Interconnection Gosip specifications are to be supported; there will be page printer support and security will go up to B1 from the present C2, achieved via Secureware. X Window 11.5, Motif 1.2 and network management on the mainframe are coming as well as asynchronous input-output, capacity planning and performance tools, Distributed Management Environment, Parallel Fortran, Vector C, C++, Ada and transaction processing monitors, with a tie between the Transarc Corp product and CICS. How about database? Ah, that is a tangled tale for another day.
