I am trying to configure a computer (yet to be purchased) to use virtual (pc
or server) and can't figure out how to plan for memory. If Vista is used as
the host and it can only use a little more than 3gb of memory and if I
understand my reading the sum of all memory for virtual machines could not
exceed the physical memory available or is that the memory available to the
host OS?

If I have a 4gb machine can a VM use the part of that 4gb that my host Vista
cannot use? What about on a 6gb machine?

I need to support Vista, XP, Server2003 and Server2008 when available. The
servers will have SQL2000, SQL2005 and SQL2008 (when available) and at times
Oracle and PostgreSQL. The machine is for application development and will
not be used in a "production" mode. It is not clear to me what is the best
choice for my host OS. It seems that if I host with Server2003 I might be
able to better utilize more memory, is that true?

I am inclined to use Virtual Server, but don't really know if that provides
any advantage over Virtual PC, any suggestions?

Thanks

The memory requirement is the sum of the memory the hosts needs plus what
you allocated for all vm's running concurrently plus a little overhead that
goes with running each vm. If Vista needs 1GB to run and you have 4GB
installed then allocating 256MB to an XP vm or 1GB to a Vista vm still
leaves you lots of memory to work with on the host. You allocate how much
memory a vm can use at the time you create the vm or change in the vm's
settings later. A vm does not use any memory when it is not running, of
course. VPC's New Virtual Machine wizard displays how much is available to
allocate at the time you are creating the vm. You would not be able to have
a vm use any memory that is not available to you as a user. A vm cannot use
memory that the BIOS has reserved for things like memory-mapped IO for your
devices, for example.

You allocate memory to a virtual machine just like you would select the ram
to install on a physical computer at the time you buy it.

It is appropriate to use VPC for running client operating systems and VS for
running server operating systems. And of course you can simply run both.

<newscorrespondent@charter.net> wrote in message
news:Gjjwj.23$xE3.9@newsfe02.lga...
>I am trying to configure a computer (yet to be purchased) to use virtual
>(pc
> or server) and can't figure out how to plan for memory. If Vista is used
> as
> the host and it can only use a little more than 3gb of memory and if I
> understand my reading the sum of all memory for virtual machines could not
> exceed the physical memory available or is that the memory available to
> the
> host OS?
>
> If I have a 4gb machine can a VM use the part of that 4gb that my host
> Vista
> cannot use? What about on a 6gb machine?
>
> I need to support Vista, XP, Server2003 and Server2008 when available. The
> servers will have SQL2000, SQL2005 and SQL2008 (when available) and at
> times
> Oracle and PostgreSQL. The machine is for application development and will
> not be used in a "production" mode. It is not clear to me what is the best
> choice for my host OS. It seems that if I host with Server2003 I might be
> able to better utilize more memory, is that true?
>
> I am inclined to use Virtual Server, but don't really know if that
> provides
> any advantage over Virtual PC, any suggestions?
>
> Thanks

On Sun, 24 Feb 2008 19:11:47 GMT, newscorrespondent@charter.net wrote:

>I am trying to configure a computer (yet to be purchased) to use virtual (pc
>or server) and can't figure out how to plan for memory. If Vista is used as
>the host and it can only use a little more than 3gb of memory and if I
>understand my reading the sum of all memory for virtual machines could not
>exceed the physical memory available or is that the memory available to the
>host OS?

Go with an x64 host os, and you lose this restriction.

>
>If I have a 4gb machine can a VM use the part of that 4gb that my host Vista
>cannot use? What about on a 6gb machine?

No, if the host OS can't access, no app can, and VPC and Virtual
Server are just apps runningon the host OS.

>
>I need to support Vista, XP, Server2003 and Server2008 when available. The
>servers will have SQL2000, SQL2005 and SQL2008 (when available) and at times
>Oracle and PostgreSQL. The machine is for application development and will
>not be used in a "production" mode. It is not clear to me what is the best
>choice for my host OS. It seems that if I host with Server2003 I might be
>able to better utilize more memory, is that true?

Yes, 32bit server OSes have less restrictions on memory, depending on
the version. Vista x64, XPx64 don't have the 4GB limit either.

>
>I am inclined to use Virtual Server, but don't really know if that provides
>any advantage over Virtual PC, any suggestions?

It really depends on what you want to do. Virtual PC is designed for
working with VMs a lot and directly. Virtual Server is designed for
running servers in the background. MS has docs on the differences and
the diffrences between the two have been covered in the newsgroups
extensively many times before.

--
Cheers,
Steve Jain, Virtual Machine MVP
http://vpc.essjae.com/
I do not work for Microsoft.

newscorrespondent@charter.net wrote:

>I am trying to configure a computer (yet to be purchased) to use
>virtual (pc or server) and can't figure out how to plan for memory.
>If Vista is used as the host and it can only use a little more than
>3gb of memory and if I understand my reading the sum of all memory
>for virtual machines could not exceed the physical memory available
>or is that the memory available to the host OS?
>
>If I have a 4gb machine can a VM use the part of that 4gb that my
>host Vista cannot use? What about on a 6gb machine?
>
>I need to support Vista, XP, Server2003 and Server2008 when
>available. The servers will have SQL2000, SQL2005 and SQL2008 (when
>available) and at times Oracle and PostgreSQL. The machine is for
>application development and will not be used in a "production" mode.
>It is not clear to me what is the best choice for my host OS. It
>seems that if I host with Server2003 I might be able to better
>utilize more memory, is that true?
>
>I am inclined to use Virtual Server, but don't really know if that
>provides any advantage over Virtual PC, any suggestions?
>
>Thanks

If you use a 64bit version of Vista, you are not restricted to 3.2GB of
accesible memory.

In one of the news groups I go to, one of the Users there is using
Vista Ultimate and has 8GB of memory so that he can have multiple VMs
running. He is using VMPlayer, but if MS VPC2007 can run on a 64bit
Vista than you need not worry about memory confinements . . . (other
than hardware <LOL>).

--
Sincerely,
C.Joseph Drayton, Ph.D. AS&T

CSD Computer Services
Web site: http://csdcs.tlerma.com/
E-mail: csdcs@tlerma.com

Thanks to all of you who ed me with this.