--- Paul Raulerson <[EMAIL PROTECTED]> wrote: > I see two problems with this story - one is they > quoted Phil Payne, whose has some kind of vendetta > against IBM going. (I suspect he lost money in an > emulator solution) and two,
His input is pretty small and pretty accurate. Even for us Mainframe Software costs are hefty... I object more to the spin on that; Mr. Payne has a way of taking facts and presenting them in such as way as to lead people down the path he wants them to follow, even to the point where people will draw erroneous conclusions based on insufficient and/or incomplete facts. In specific, sure traditional mainframe software costs are high. zIIPs, zAAPs, and ILF's can be used to mitigate that cost, and the best part? IBM is producing those speciality engines in direct response to use complaints about cost. While I am not saying that a 10 person windows shop shoudl run out and but a mainframe as a file and print server, a 10 person shop with a high end software product just might find that a mainframe would host their product better than any other machine in the world. (Or not - it all depends doesn't it?) I simlpy don't know what Mr. Payne's agenda is, except I know he has an agenda, and that agenda is not compatible with getting lower cost high quality IBM products out on the market. Especially emulators. > Itanium hardware is > faster and more modern than a mainframe PC, but ... > it is not running Itanium software, it is emulationg > the zSeries arch. > How does this make it slower? The zArch is implemented largely with microcode (well, millicode perhaps) which servers to somewhat isolate the hardware of the machine from the processor instruction set it presents to software and programmers. An IBM processor (PC) is tuned to run that instruction set and does so very well indeed. There is also a lot of hardware stuff in a CP that helps too. Hint: the iSeries and pSeries (or whatever they are called these days) run POWER processors, which descend from and borrow from mainframe technology. NOT the zArch instruction set, but some of the underlying CP technology. An Itanium chip is not "tuned" to run that processor instruction set; it is by definition a General Purpose Digitial Processor. To emulate a MVI or LHI instruction on an emulator can require an order of magnitude more processing than on a CP (or IFL). For one thing, it has to emulate the GPRs, and may have to emulate the Access Registers and more. Then it has to reliable produce the correct results from exectution of the instruction. And those are two of the most simple instructions in the processor to emulate. The emulation may also be required to do things like run a 31bit OS under a 64bit OS - such as running OS390 under zVM or something. That is even before you beging to consider the subject of I/O. On a mainframe, I/O is usually handled by a SAP (System Assist Processor) which is nothing more of less than an entire CP. Also, each channel controller is smart, about the equivalent of a fast PC. Mainframes will usually loose out on raw processing power to the new generation of microchips - but they can move some I/O brother. There are not other GPDC machines around that move I/O like a mainframe. In short, additional overhead and a speed reduction is unavoidable when using emulation. Now, the Itanium processor is fast enough that slowdown may not be that much of a big deal. Again, it depends entirely upon the application set and the way the system will be used. Heck, anyone with a P4 running at a couple gig can build an emulated mainframe system that will clock in with a sustained 40 to 60 MIPS. It isn't legal to run anything other than Linux and some very old copies of VM and MVS on it, but it will run just about anything. That's on a X86 chip base. (BTW: Mentioning that to Mr. Payne will usually produce a strong reaction.) Anyway, point it, the article did not present the complexity and true situation very well, at least in my opinion. Your milage may vary. :) > I'm not sure the authors of this article really get > those ideas. :) > -Paul > > > > From: "Phil Smith III" <[EMAIL PROTECTED]> > To: IBMVM@LISTSERV.UARK.EDU > Date: Wed, 28 Feb 2007 13:17:00 +0000 > Subject: PSI story > > Interesting -- if not particularly accurate, at > least in some areas I know > about -- story about PSI and IBM: > http://www.theregister.co.uk/2007/02/16/psi_ibm_hp/print.html > > ...phsiii > > >
