Al's Review of Virtual PC for Amazon

modified: 19 Apr 2005

The free 45-day trial period expired on the copy of Virtual PC that I had downloaded for testing with Minix. Having concluded that I probably needed to buy a copy, I went to Amazon.com to look at prices, and I noticed there were several user reviews of Virtual PC. Since none of the reviews already present came anywhere close to my own reasons for being interested in the product I decide to post a review myself. Here it is:

Using Minix on Virtual PC for Windows free demo version, April 14, 2005

Reviewer: A. Woodhull (Amherst, MA USA)

My interest in Virtual PC is for experimenting with the Minix operating system without repartitioning the hard disk. Minix is meant for educational use, and university lab PCs are not always available for dedicated use. I downloaded the free VPC for Windows demo. I found VPC easy to install on a Windows 2000 system. However, the link to Microsoft support on the startup page did not work for me.

Installing Minix on a VPC virtual disk was another matter. The standard Minix installation method, which is to boot a Minix floppy disk into a RAM disk, fails. Others have reported similar failures with VPC for Mac as well as VPC for Windows.

Minix can be started in "DOSMinix" mode, which uses a FAT file system as a simulated disk, and another Minix user has provided a ready-to-run DOSMinix-on-FreeDOS VPC image file, which I found works OK. Minix worked well as far as I tested it. I found that I could set rootdev=ram in the boot monitor and run with the root on a RAMdisk, even though people who have tried to do a conventional installation of Minix onto a Virtual PC virtual disk have seen messages about inability to open the RAMdisk. I created a second virtual hard disk and was unable to format it with FreeDOS, but Minix was able to partition it and create file systems on the partitions, so this may be a route to making a true native Minix installation on Virtual PC. I recompiled the Minix system in a time that seemed normal for the PII-266 system I was using. I haven't checked out the floppy disk or CD-ROM interfaces yet, and I don't expect networking will work, since there is no Minix driver for the emulated DEC 21140 ethernet interface that Virtual PC presents to guest systems.

Problems: I had some problems with the keyboard interface while using Minix on FreeDOS on Virtual PC. Occasionally there would be long periods when Minix would not respond to keypresses, alternating with periods in which Minix acted as if the keys were bouncing, with multiple characters echoed for a single keypress. Caveat: my test system for the above installation was a 266 Mhz Pentium II, and Microsoft specifies a 400 Mhz system as a requirement for Virtual PC, so the problems I observed may not be seen on a faster system.

Comparison with alternatives: Minix does not have a graphical user interface, it's a command line system, and it works well even on old slow PCs with limited resources. So even though the Bochs emulator is much slower than either Virtual PC or VMWare, Minix on Bochs works well enough on any Pentium-class system, and of course Bochs is free and available for multiple platforms. Minix on FreeDOS on Virtual PC is about as fast as Minix on VMWare, and is definitely a less expensive alternative than VMWare. Also, my sense is that VMWare's target market is not the home or educational user, it is the business or ISP that wants to run heavy-duty servers as virtual machines. So I would expect support for the kind of use that interests me might be better from Microsoft than from VMWare. Of course this is conjecture, I haven't asked for support from either Microsoft or VMWare.

Additional support for Minix in any virtual or emulated environment is likely to come from users, so a web search for Minix + Virtual PC may yield useful hints. The same would, of course, apply with VMWare or Bochs.

Bottom line: VPC looks useful enough for my somewhat specialized purpose that I will probably buy a copy when the free trial expires.

Additional note:

Amazon does not allow URLs in a review, which is why I suggested a web search for Minix + Virtual PC. Hopefully one of sites one would find by such a search would be the Minix Hints/FAQ page here, on which there is a section on Hints on Minix 2.0 for emulated and virtual platforms. There are links there to other articles about Minix and Virtual PC, as well as links to articles about VMWare, Bochs, and QEMU, all of which are potentially useful as platforms for running Minix. You can also get the VPC FreeDOS/DOSMinix image mentioned here from my sites.