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Re: [edlug] VM : more details

Nice to hear from other mainframers on this list !

I worked as a VM sysprog, and later as an MVS>>OS/390>>z/OS sysprog>>team 
leader, on several generations of IBM hardware up to and including their 
recent zSeries platform. I started to find out about Linux after hearing what 
IBM had to say about their interest (and investment) in running it on their 

VM started life as CP/67 (Control Program 1967) which provided the "virtual 
machine" environment that allowed the user to run an operating system in each 
virtual machine (vm), unaffected by the activities of other vm's. Later along 
came CMS (Conversational Monitor System) which was a single user OS that 
could run only in a vm and provided facilities for editing, compiling, 
running and debugging programs. 

A neat feature was being able to run a new release of VM in a virtual machine 
so you could test it while other users worked on uninterrupted in their own 
vm's. So in one VM system, you could have different vm's running CMS, VM, MVS 
and any other suitable OS's.

This is the capability that is now being exploited to allow customers to run 
many vm's each running Linux. I would expect that, if desired, you could run 
different releases of Linux in the same way as I describe above.

I've heard a number of IBMers explaining that IBM were concerned that new 
generations of computer users coming out of universities didn't know anything 
about IBM's mainframe systems, but they did know about other systems like 
Windows, Unix and Linux. Hence IBM's interest in running Linux on their "big 
iron". They see an opportunity for companies to consolidate large numbers of 
smaller servers on to a single large IBM machine and simplify the management 
of the services they provide.

IBM has a lot of documentation about VM and Linux available online. If you're 
interested in looking at it, a good place to start is : 

Denis Leslie
SuSE Linux 9.0 Prof

On Friday 12 March 2004 21:17, Philip Nelson wrote:
> Here you have another mainframer, and proud of it !!!
> VM does indeed stand for Virtual Machine.  The latest incarnation of this
> IBM technology, called z/VM (all "mainframe" things from IBM are zSomething
> these days) is the recommended method of running Linux on the zSeries. 
> It's possible to hosts hundreds (even thousands) or virtual Linux servers
> on one zSeries box.  It's also possible to install one Linux instance
> natively on zSeries, or to install it natively into one LPAR (Logical
> PARtition).
> The other "mainframe" operating system is (was) MVS, renamed to OS/390 and-- 
> now known as z/OS.   I work with this every day and still think there is no
> text editor in the world to match the ISPF editor found on this platform
> !!!
> I'm principally a DBA working with DB2 (all flavours).  There are four
> "flavours" of DB2 : DB2 for z/OS (sometimes called "DB2 Classic"), DB2 for
> VM (previously known as SQL/DS), DB2 for iSeries (the former AS/400 and
> S/36 minis) and DB2 for Linux, UNIX and Windows.   DB2 on Linux is
> supported on a whole range of hardware architectures (zSeries, IA-32,
> IA-64, AMD64, iSeries, pSeries at least).
> If anyone is interested in a good description of VM and how it works with
> Linux then I'd suggest the book "Linux on the Mainframe" -
> http://www.amazon.co.uk/exec/obidos/ASIN/0131014153/qid=1079126201/sr=1-2/
> ref=sr_1_0_2/026-6702578-9086019#product-details
> Phil Nelson-- 
> On Friday 12 March 2004 11:12, Catriona & Anand wrote:
> > On Friday 12 March 2004 10:20, Gordon Guthrie, BTP, BT, SE wrote:
> > -----------------8<-------------------------------
> >
> > > So back in the day when I was a mainframe programme my target
> > > architecture was VM/MVS. However the support machines were a big
> > > Honeywell Multics and the confusingly named VMS on the Vax platform...
> > >
> > > Gordon
> >
> > -----------------8<--------------------------------
> > "When you were a mainframe programme"? Does that mean you have now been
> > ported to Linux on a PC. Up to now I had thought that all list
> > subscribers were human. Equal rights for AIs!
> >
> > Anand
> > -

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