Putting the Squeeze on Microsoft's Virtual PC

Tony Austin
Monday, 28 July 2008 15:50

Your IT - Home IT

Virtualization is all the rage these days. As well as the advantages, there are things to be watched and managed. Virtualized systems can grow and consume excessive system resources. Here are some test results about a way of reducing disk space (and other things) used by Microsoft Virtual PC running on a desktop system.

Virtualization has been around for a long time, in fact since the 1960s. I'd like to commence my first article on this topic with a little background history.

By the time I joined IBM Australia in 1970, they already were well into the research and development of virtual systems. The ground-breaking IBM System/360 range (or just S/360) was announced way back in 1964, with an architecture designed to encompass the "full 360 degrees" of the data processing spectrum (that is, both commercial and scientific computing, from smallest to largest organizations).

In 1965 IBM announced the System/360 Model 67 (S/360-67) and it shipped in July 1966. Back in those days, you had the luxury of a year or two between announcement of a new system and its delivery (FCS, or First Customer Shipment) -- in striking contrast to today's far shorter release cycles. The Model 67 was one of the earliest commercial systems that offered time sharing (which was very popular until the advent of the Personal Computer).

But more importantly, the Model 67 came out a little later with the CP-67/CMS operating system (an implementation of an early "full virtualization" research system, the IBM CP-40). In mid-1970 IBM announced the follow-on to the S/360, calling it the IBM System/370, which is when I first got involved. It wasn't until 1972 that IBM announced comprehensive virtualization support for the S/370, in the form of a new operating systems. With numerous virtualization hardware and operating systems enhancements over more than three decades it is essentially the same rock-solid, enterprise-level operating system that is available on today's IBM mainframes.

As well as the above Wikipedia links, here's another one: Timeline of virtualization development. This -- as quite rightly pointed out in the article by the Wikipedia content police -- misses out on information about several other early virtualized systems from other manufactures, such as the Burroughs B5000. (Burroughs was one of the so-called BUNCH of computer manufacturers, and there were also RCA and GE, and they're mostly not around any more.)

Another useful insight into the above appears in The History if the Mainframe Computer (skip down to the section titled "The 3rd Generation computers"). ... As the authors at Viking Waters say near the end: "Let's see a PC match that!" -- and I plan to say more about the purported death of the mainframe in future iTWire articles.

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