IBM seems to be pushing Linux under VM/390. This lets a single box run thousands of Linux virtual machines, each one independant from all the others with QOS guarantees on CPU availability and IO.

The only problem I see with this is reluctance to use mainframes for this stuff and a possible lack of availability of third party software thats runs on Linux/390. Yes, the open source stuff all runs but what if you need Sybase or Oracle on Linux or Peoplesoft/SAP etc. If you need to also have Suns or Intel Linux boxes for hosting these stuff then it detracts a lot from the 'vision' of better controlability and limiting costs versus traditional large Unix servers.

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Theoretically, IBM is supposed to port the vast majority of their software: DB/2, JVM, and middleware. Of course, whether or not they follow through and maintain these products is a whole 'nother issue. . .

I don't think so. Thousands of small Linux instances (even if it's one hardware box) doesn't make sense to me. If you compare them to some midsize (for example) Solaris machines, you have more adminstration overhead (struggeling to keep os, configuration and applications for much more instances up to date) and less flexibility.

While Linux is not as scaleable as Solaris or AIX, I don't see any advantage to throw away your old boxes and jump onto a totally new (at least for most companies) technology like IBM mainframes. And even if I don't know very much about mainframes, I can't imaginge that they are that much faster as Unix boxes, as the IBM/Telia announcement implies.

So Linux on S/390 my be an interesting migration path for companies, which already use those systems. But otherwise the jump to a totally different plattform looks too dangerous and uncertain to me. So the IBM effort is nothing more than marketing hype for their big irons in my eyes.

I can't believe how persistently stupid the business community is. The entire point of server farms is that they are NOT all on one box, ie you don't have all your eggs in one basket. Of course, implicit in that is the idea that a server farm ought to be geographically dispersed...

On a totally different matter, related to use of IBM mainframes, does anyone know the truth of a rumour I heard some time ago to the effect that a JVM for IBM mainframe was near release?

This seems to me an outstanding idea. Java is at disadvantage on most platforms because it runs on top of a VM when everything else sits directly on the OS. But on a mainframe, everything runs in a VM, so the playing field is level.

IBM mainframes are built to run VMs because IBM mainframe software is designed on top of these VMs for exactly the same reasons that Java is: portability across physical architecture changes, the ability to run differing versions of the same libraries in different VMs, and damage containment (if you do manage to toast the machine it is only a VM and the underlying OS has no trouble recovering resources).

It's an old strategy but it's still a bloody good idea.

Anyway, the performance of Java under such conditions would be on the same order of magnitude of any other compiled language. So I'm very interested. Can anyone comment on this?

we tried linux with WAS 3.5 and DB2 7.1. Cool Stuff. wE followed up the instrns straight from the manuals [we read a good number of those] and Red Hat sings on Intel 800Mhz...faster than NT on the same box. we even explored the option of LDAP...

regards IBM mainframe, I feel it will be faster. I know an appln written using MS C++ compiling to a DB2 on a MF on the Mainframe OS and they claim Linux is good - just do not whcih version - I have played with Red Hat a bit, on intel boxes. did not try caldera and SUSe or Dell-Va or even Turbo... Id o know larger machines are support intensive for the H/W....

guess that partially answers the Q..

Pam