Well, I have been told that some of the Intel servers are coming up to speed in the following areas, but in most other architectures, you get an outage if you have a memory error. On a zArch box, you might not even see this because the hardware will replace failing memory automagically. This is done strictly in the hardware by "sweeping" through memory doing testing during "off periods" to find these "soft" errors and fix them before they become a "hard" error.
And although it is not touted very much, the zArch implementations (and previous ones as well) are constantly doing internal cross-checking to verify correct results. That's one of the reasons that it is "slower" than other CPUs. On a zArch machine, you know you are getting the "correct" result (correct as in the hardware did not cause the problem. Not correct as in you program was doing what you thought it was doing <grin>). On some others, you are not sure because a "glitch" could cause an undetected error. Sort of like running without parity on your memory. BTW, did you know that the data path on an Intel process from the main memory to the CPU does not have parity or ECC? So, even with ECC memory, and errors can "creap in" if the error occurs during this movement of data. The zMachines do use ECC on these internal data paths. Likewise, every zArch box has at least one extra CP that cannot be assigned. If a CP fails, this extra CP can usually take over operation of the failing CP without the underlying software needing to do any kind of recovery at all. The software will get an indication of a hardware error and the box will "call home". Again, on most other boxes, this would result in a outage. Perhaps just a reIPL (uh, reboot), but you might be down until the server is fixed or replaced. (most likely replaced anymore). -- John McKown Senior Systems Programmer UICI Insurance Center Applications & Solutions Team +1.817.255.3225 This message (including any attachments) contains confidential information intended for a specific individual and purpose, and its' content is protected by law. If you are not the intended recipient, you should delete this message and are hereby notified that any disclosure, copying, or distribution of this transmission, or taking any action based on it, is strictly prohibited. > -----Original Message----- > From: Eric Sammons [mailto:[EMAIL PROTECTED] > Sent: Tuesday, October 28, 2003 12:27 PM > To: [EMAIL PROTECTED] > Subject: Re: Perpetuating Myths about the zSeries > > > I have heard the story line, "If you have high transaction > volume, then > you don't want Big Blue IRON." Well my question then is, what is a > transaction? Is this a computation, is this prime number > generation, is > this high volume websites, or is this is a large database > with a Tbyte of > data running 1000s of SQL statements in a brief moment of time, for > example a web application adding users to a secure way ldap > (back-end is > db2)? So what is a transaction? When is a instruction not a > transaction > and if everything is in some way a transaction what exactly > is Linux on > the MF good for, other than supporting a virtual environment > of previously > installed and largely under utilized distributed systems? > Would I want to > run 100 systems in a given z/VM each with some number of JVMs, yes > WebSphere? We are talking about putting 6 JVMs onto a single > Linux guest. > I am looking forward to this as during our POC (proof of Concept) we > never tested with more than 1 may be 2. > > On the topic of availability I am not sure I buy the whole MF > is better > than 80x86 or Intel / AMD 64 server hardware. Today, everything is > redundant and everything is hot swapable. What is different > is to get a > new stick or replacement stick of memory for the MF could cost you and > automobile and you won't find that stick of memory at the > local computer > store. > > Thoughts??? > > Eric Sammons > (804)697-3925 > FRIT - Infrastructure Engineering > > > > > > Phil Howard <[EMAIL PROTECTED]> > Sent by: Linux on 390 Port <[EMAIL PROTECTED]> > 10/28/2003 01:14 PM > Please respond to Linux on 390 Port > > To: [EMAIL PROTECTED] > cc: > Subject: Re: Perpetuating Myths about the zSeries > > On Tue, Oct 28, 2003 at 11:21:23AM -0600, Adam Thornton wrote: > > | On Tue, 2003-10-28 at 10:57, Jim Sibley wrote: > | > The speed of the top of the line zSeries has increased > | > at four fold in the last 3-4 years. > | > | I'd be amazed if Intel hasn't done at least this well too. > > It probably has. But CPU power isn't the whole story, > either. I'd ask > about how fast a machine built around an Intel/AMD CPU can deal with > multiple devices concurrently transferring data for read or write I/O > operations. If you need sheer computation power, zSeries is probably > not right for you (how about PPC?). But if you need a large, high > traffic, high uptime, database, you don't really want the kinds of > machines typically built around Intel CPUs. > > -- > -------------------------------------------------------------- > --------------- > | Phil Howard KA9WGN | http://linuxhomepage.com/ > http://ham.org/ | > | (first name) at ipal.net | http://phil.ipal.org/ > http://ka9wgn.ham.org/ | > -------------------------------------------------------------- > --------------- >
