Software // Enterprise Applications
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Fred Langa
Fred Langa
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The Explorer: By the Bootstraps

In a recent issue of the LangaList ( I casually mentioned a few DOS commands that could cleanup some of the garbage files that Windows sometimes won't delete on its own, even if you use the "Cleanup Wizard" and such.

The reader response was very, very eye opening. A significant number of readers had never before booted their system directly to DOS or run their PCs without the graphical interface. I'm probably showing my age (ahem) but it simply hadn't occurred to me that DOS would be so alien to so many people.

It's mostly a good thing: a sign that Windows has matured. But all operating systems benefit from some knowledge of what's going on under the hood. And some systems (Linux, for example) demand reasonably extensive "command line" skills to use them much at all. In fact, much of the speed and power attributed to Linux stems from the fact that command-line operations give you direct access to the raw power of your PC. DOS commands can do the same sort of thing on a Windows PC.

Don't get me wrong: I'm glad DOS is essentially dead. But some command-line knowledge is a good thing and can help you get the most from a Windows PC. So, from time to time, I'll devote a column to some DOS-style tips and tricks. If you're an old hand at DOS, I invite your comments, suggestions, and amplifications in the discussion area; if you're new to DOS, I invite your questions. In this way, DOS experts can share their knowledge, and DOS newbies can learn. Done right, we'll all get something out of it!

We'll start with a look at Autoexec.bat and Config.sys. But to understand them, we need to step back and look at how your PC starts up:

All personal computers start in stages: There's just enough special, low-level code permanently stored in the system BIOS and inside the CPU itself to get the machine going to the point where the CPU can talk to the hard drive, monitor, etc. Once this tiny amount of initial code has run, the system then looks on a floppy or hard drive for the most basic components of an operating system. If it finds them, it loads and runs them. These core operating system components contain the instructions the system needs to load the rest of the operating system and to complete the start-up process. In this piece-by-piece way, your computer self-starts.

Computers didn't always start this way, and the idea of a computer that could "pull itself up by its own bootstraps" was once a novel idea. In fact, when this system of self-starting was first invented, it was called "bootstrapping," which later got shortened to "booting." (And that's where that familiar bit of computer jargon comes from.)

Some computers need special configuration files to boot properly - different operating systems call them different names, but the idea is the same: Once the core operating systems is running, but before the full-blown graphical OS starts, it looks for these special files to see what hardware drivers, software settings, and so on, are needed by the machine. These special files transform the generic, low-level operating system to transform itself into a version that's specific for the machine it's running on.

On PCs, two of these configuration files are called "Config.sys" and "Autoexec.bat." The former is a text file that can tell DOS what low-level memory managers, hardware drivers (etc.) to run. The latter is a series or "batch" of commands that run automatically at startup. Together, these two files create the software foundation for everything a PC can do, and in the Dark Old Days Of DOS, Power Users often would spend hours honing and perfecting these files to wring out every last iota of memory and performance from their PCs.

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