From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.33) id 1CeoTQ-0005pE-EB for qemu-devel@nongnu.org; Thu, 16 Dec 2004 00:46:48 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.33) id 1CeoTP-0005oy-Io for qemu-devel@nongnu.org; Thu, 16 Dec 2004 00:46:47 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.33) id 1CeoTP-0005ov-Fi for qemu-devel@nongnu.org; Thu, 16 Dec 2004 00:46:47 -0500 Received: from [64.233.184.197] (helo=wproxy.gmail.com) by monty-python.gnu.org with esmtp (Exim 4.34) id 1CemdX-0004rc-BJ for qemu-devel@nongnu.org; Wed, 15 Dec 2004 22:49:07 -0500 Received: by wproxy.gmail.com with SMTP id 71so164231wri for ; Wed, 15 Dec 2004 19:49:06 -0800 (PST) Message-ID: Date: Wed, 15 Dec 2004 22:49:05 -0500 From: Karl Magdsick Subject: Re: [Qemu-devel] QEMU WIN32 Porting Installing W2K In-Reply-To: <20041216001528.GA13017@jbrown.mylinuxbox.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit References: <20041215150334.81590.qmail@web14106.mail.yahoo.com> <20041216001528.GA13017@jbrown.mylinuxbox.org> Reply-To: Karl Magdsick , qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org > > 3. Is there a way to emulate an AS 400 System using > > QEMU or other software? > > what is AS 400? AS/400 is an IBM operating system for mid-range servers that runs on POWER chips. As I remember, all processes run in a single address space to eliminate TLB flushes in context switches, but page permissions get changed by the kernel when switching between processes. I believe I was reading about the history of POWER/PPC and learned that the POWER/PPC family encompases 3 overlapping instriction sets, one of which is required for AS/400. I believe the 604e and similar chips do not implement some of the functions required for AS/400. I'm not sure about G3s, but I doubt it. I believe QEMU emulates something G3-ish, so I don't think AS/400 will run on the QEMU-emulated PPC CPU. However, I could very well be wrong. I just did a quick search, and didn't find anything useful about AS/400. IBM has something called OS/400 (now called i5/OS), but that looks like something in the OS/370, OS/390 family. I don't think AS/400 is in the OS/370 family, but I could be wrong. AS/400 may have been phased out. It would be really cool if eventually QEMU could emulate IBM POWER based servers well enough to run IBM's hypervisor. The hypervisor virtualizes the hardware for the operating system(s) proper and provides resource partitioning. Imagine VMware slimmed down and ported to run on the bare hardware so it doesn't need a host operating system and you've got a hypervisor. Generally, the hypervisor logically partitions resources and runs a seperate operating system inside each partition. The Xen project is developing a hypervisor for x86 hardware, but it requires minor patching of the guest kernels to avoid certain instructions. (VMware works very similarly to Xen, but VMware scans and dynamically patches code at runtime.) Anyway, being able to play around with (emulated) high-end hardware that was designed for hypervisors would be cool. -Karl