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Unauthorized Windows 95 by Andrew Schulman Recommended

ISBN: 1-56884-169-8       Publisher: IDG       Pages: 593pp       Price: £28-99

Categories:   internals and hardware     MS Windows

Reviewed by Steve Davies in C Vu 8-1 (Nov 1995)

Schulman has clearly spent a lot of time investigating how Windows works and he tells the story in 550 pp. I use the word story because Schulman's style is informal and the facts are presented in the form that they were acquired - the results of a series of explorations. I use the general term Windows because the book is not just about the 95 version; one of Schulman's main points is that Windows 95 merely extends technology that Microsoft first introduced in Windows/386 (in 1987).

The book investigates and describes how Windows functions as an operating system (i.e. the layer provided, for Win95, by VMM32.VXD and the support VxDs), including the extent to which it relies on 16-bit DOS code. There is little here about the more familiar, KERNEL, USER and GDI DLLs. There is a lot of detail; you get listings (in C or assembler) of the key parts of his exploration tools and some sometimes complex outputs. Schulman does not worry too much about whether you know and understand the terms, e.g. VxD, PSP. There is also rueful reflection on how Microsoft's expanding operating system is squeezing the small software vendors and whether there will be much future for developers beyond customisation of the Office suite with Visual Basic.

The book comes in two versions. The copy I reviewed is sub-titled 'A Developer's Guide ...'. The other one, sub-titled 'Developer's Resource Kit', seems identical except that it includes a disc containing utilities and a try before you buy programmer's CD and costs £10 extra. The utilities are hacker tools that enable you to do things like walk the VxD chain and are the tools that Schulman used for his investigations.

I'm a Schulman fan. I'm pleased that people are exploring software like this and I'm pleased that they are getting published. Undocumented DOS though, included an annotated bibliography and it's disappointing that there are no comments in the bibliography of this book.