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R.I.Feigenblatt - August 2005 (minor subsequent edits)


In Lesson One we introduced the basic concepts underlying digital computers, explained how and why they are rapidly changing the world today, and offered some guidelines on their wise use. This lesson might be seen as a more detailed look at the last element of that instruction. But we do exploit some of the material covered in Lessons Two through Five to motivate our content and make explanation economical.

1. The promise and hazards of customizing your PC

Today, the financial downside of making an inferior choice about which PC brand and model you should buy is so very small, that it is better to make some choice now, rather than delay the benefits of use if you don't already own. Rest assured that whatever you do, a machine of dramatically superior capability at the same cost or less will emerge within a year or so. While things will become obsolete long before they wear out, that doesn't mean you have to "change horses" all the time either. The biggest cost you will incur in starting to use a PC will be the cost of learning to use it and the particular tasks to which you will put it. As long as your PC serves those ends efficiently and you can discover no new needs it cannot address, there is no reason to "keep up with the Joneses". Migrating your old work to a new machine can prove problematic and expensive, too. That's why even if you buy a new machine you may land up not immediately tossing the old one anyway.

An alternative to replacing a PC is upgrading one you already own. Sometimes this is achieved via one-for-one swaps, and sometimes it involves the addition of entirely new devices. Today, PCs include welcome standard means of attaching powerful new devices via fast external interfaces like network adapters and USB ports. Even the task of swapping out nominally internal hardware like magnetic hard disk or optical drives can be eased by the one-time installation of aftermarket hardware like dock-and-drawer systems.

And if you are skittish about opening up your PC to do things like adding more primary memory chips, you can usually hire someone to do that for you. (You might make it cheaper to do this if you can provide your help with any manual bundled with the machine.) Compared to something like an automobile or even a toaster, the inside of your PC is a rather benign place. It would be rather odd to be exposed to the potentially deadly mains power voltage, for example. (A hot heat-sink sounds like a more likely hazard if you have a new high-power microprocessor.) But the hazard you present to your PC, for example, by electrostatic discharge resulting from walking on a carpet on a dry day, advises you should show proper respect for its well-being if you open its case and you have never done any electronics work previously.

An excellent (but overmodestly-named) in-depth technical reference for today's PC hardware is the Third Edition of the book PC Hardware in a Nutshell (2003), published by O'Reilly Media Inc., loved by techies everywhere. (Consider O'Reilly when the time comes you need a serious and well-written book about computing and related topics, rather than beginner stuff.)

If you have never used a PC before, let me suggest that the sorts of problems you might encounter upgrading and using one these days infinitely more resemble redressing the heartaches arising from a badly-written legal contract after the fact, rather than the mystery of figuring out the rain ingress path of a roof-leak whose consequences are sadly evidenced by a stain on your ceiling.

A general purpose computer, such a PC you buy at an electronics store or over the Internet, is very unlike nearly every other consumer good you might purchase. While the accelerator and braking pedals of you automobile will never reverse functions with one another, your PC is not so inflexible. The PC began as a hobbyist toy that inched its way first into the office and then into the home. The commercial culture it spawned has been very resistant to standardization and lock-down.

Why is this so? Well, in part it is because the PC fulfills the dream of a machine that can be infinitely customized with little effort. And in part it is because endlessly collapsing component prices keep making it ever more powerful and so ever more able to perform new functions. But it is hard to eat your cake and have it too: Military fighter aircraft are extremely manuverable; but that comes at the cost of making them highly unstable.

Happily, dramatically falling prices have not just ironically instigated problems, but have facilitated solutions as well. Many functions born on the PC can now be provided via affordable, parochial fixed-function appliances, often rather smaller in size as well. Their selling point is that they take rather little time to learn and don't require a lot of effort to maintain. (We will meet some of them later on in this lesson - and some others in the following lesson.)

2. Fleeing the customization and upkeep rat-race: going vanilla

Even the stubborn multifunction PC itself is starting to learn this lesson. Devices like MSN TV (originally developed outside Microsoft and called WebTV) are basically simplified, fixed-function, (almost) locked-down PCs. You cannot personally add new capabilities to it by installing new hardware or programs, but you don't have to fret how to undo some customization you didn't intend, or figure out why the installation of something new has somehow managed to break something old. In principle, something like MSN TV, which is not quite locked-down, but is professionally managed offsite through its networking connection, should be a very reliable platform. Sadly, even it has sometimes managed to get the ocassional black eye.

An important reason not to favor MSN TV per se is that you can ONLY use a conventional (NTSC) television set as your display screen. While television is just fine for showing conventional video programming, it cannot do a good enough job displaying a page of text clearly. That's one reason you might consider the alternative represented by things like the Linspire Webstation, which can use a conventional PC monitor. Instead of a hard disk, this very inexpensive product employs a CD-ROM as its secondary storage, which means that its Linux-based software behaves the same way every time you start it up: the CD-ROM cannot be altered. (Unless, of course, you elect to replace it whole with an updated version of the CD-ROM.)

The Linspire Webstation uses what is called "Live CD" technology. When *any* PC starts up ("bootstraps"), it first runs software in its chip-based BIOS memory and then looks for a secondary memory drive to load and run the operating system (whether Windows, UNIX, Linux, DOS, etc.) Recent PCs have the ability to use a CD or DVD drive in this manner. (Which of multiple drives is used in the boot process is designated by setting a parameter in the - today typically misnamed - writable "CMOS RAM" section of the BIOS.)

You can download and burn a copy of many different types of CD-ROM "disk images" based on the Linux operating system, to create your own free Live CD. The chances are good that you will be able to boot your PC from it and see what using Linux is like - without disturbing another operating system, like Microsoft Windows, which is installed on your hard disk. Some of the live CD images are quite small, like that of Damn Small Linux, which can even fit on, and maybe boot from, a thumbnail-sized flash memory card as well. A LiveCD "distribution" (flavor) like this is capable of running respectably on quite antiquated hardware and provides a way to breathe life back into ancient PCs headed for use as a door stop or landfill.

Downloading large files with a slow dial-up modem connection over an ordinary telephone line can prove problematic. Slow speed per se is not the main issue - by leaving your computer on and downloading while you sleep 8 hours, it could transfer 140 megabytes of data with a bandwidth of only 5 kilobytes per second, a rate easily possible these days. The real issue is that your PC may "crash" ("spontaneously" stop working) or the telephone line disconnect (perhaps as a telephone company surge protector saves your modem by acuating during a lightning strike) part of the way through the transfer of a huge file like a disk image. The way to deal with this is to use a utility program called a "download manager", which is almost always able to resume a file download after interruptions occur without starting from scratch. One acceptable free choice is Download Accelerator.

A mobile professional who has never before used a PC might be tempted to get a (general purpose) laptop computer - which is not necessarily a bad idea. But some computer-like capabilities are also now offered by "smart" cell phones. Since the easy-to-carry cell phone has become for many people as permanent a companion as only our watches once were, this sounds promising for the future.

Nokia 770 wireless Internet pad The Nokia 770
A third alternative is offered by handheld computers, the more appliance-like of which are called Personal Digital Assistants, or PDAs. One example is the charming Nokia 770, (product of a cellphone manufacturing giant) which should be shipping around the time this is being written. No heavier than a cellphone, but with a compact and yet highly detailed screen, this $350+ device resembles the Linspire WebStation in upkeep ease and the MSN TV somewhat in functionality. It is intended as a portable means of accessing the Internet via one of the many (multiple tens of thousands) of public WiFi hotspots multiplying throughout the developed world. Internet access is also possible with help from any nearby Bluetooth(-radio)-enabled cellphone.

But consider also a skeptical opinion on the Nokia 770 offered here, which takes note of the failure of many similar wireless Dynaboook-like products about 5 to 10 years ago (in the pre-WiFi-frenzy era). It also turns out yours truly helped develop a gadget which worked similarly in the late 1980s, too. Has its time now come at long last?

WiFi digital radio provides a means of attaching wireless users to the Internet via a high-speed ("broadband") connection. It is easy and cheap to add a WiFi "hotspot" that will likely serve your entire home, and cities like Philadelphia are moving forward with plans to turn their entire area into a contiguous zone of them. It should be noted the wireless carriers are presently also spending billions to roll out so-called third-generation or 3G cellular radio service, such as now available throughout cities like Washington, DC. Such 3G provides an alternative to WiFi as an avenue for broadband Internet access.

Parties who are serious PC users - like businesses - should remember that the vast majority of PC problems can be diagnosed and addressed remotely. A broadband Internet connection makes this especially easy. "Truck rolls" are expensive, but electricity is cheap, ever more so in a long-travel rural area as fuel prices rises. Firms providing remote management services include CenterBeam and everdream. (As far as I know, there are no firms named "centerdream" or "everbeam", haha.) The Chief Technology Officer of one Information Technology (IT) industry journal writes:

Iíve run the numbers many times and one of the great mysteries in IT management for me is why every company isnít a customer of one of these two companies.

3. Maintaining and upgrading your conventional PC

But many people want to run some version of Microsoft Windows on a conventional general-purpose computer like a PC. What are the sorts of things one has to do to manage such a PC?

When you get a new PC, make sure that you have a backup hard disk "image" (e.g. stored on a CD or DVD) that will let you restore your PC to the exact condition it was in when brand new, via "disk cloning". If something other than hardware goes bad in the future, this will let you get a fresh start within a very few minutes any time you want - but make sure you first backup (make copies) of precious data: like documents, e-mail archives, chat logs, photos, music files and such which you added to your PC in the course of using it. One way to make this easy is to put your "My Documents" folder onto its own disk drive or partition - one that is different than the one on which your programs are stored. Even if you have a single physical hard drive, it can be divided into two mythical "logical" drives (typically called C: and D:) to follow this regimen. By placing all your data into the "My Documents" tree branch you will make backing up your data (e.g. onto a DVD disk you burn) easy. This is something you should do regularly anyway, against the chance your PC is damaged or stolen: it is very cheap insurance.

If your PC does not have a disk backup image for your operating system and application programs, contact a computer professional to have one made for you - and at lousy 25 cents per blank disk, make at least two copies (which are kept in different places) against the chance one is manhandled, lost or has decayed when you have vital need to use it. Also see if your help can assist with segregating programs and data in the manner we explained.

Incremental methods to reliably "roll back" changes to the software installed on a PC's magnetic hard disk are also possible. (This approach avoids the need to generate an entire backup disk image, but is not as robust against the machinations of malevolent software which is clandestinely installed and discovered too late.) I started calling for this capability about a decade ago as I write this, as documented in the brief history here.

Microsoft Windows versions released in this century include a tool called System Restore to perform this type of function.

A good backup regimen is all the more important in light of contemporary "digital hygiene" problems. Today, an Internet connection is the primary way by which malicious software, or malware, is introduced into the average person's Microsoft Windows-based PC. This withering assault has proved so bad that Wall Street Journal technology columnist Walter S. Mossberg has recently (Dec. 9, 2004) written:

For the vast part of the public whose computers aren't bought and deployed by corporate computer departments... the burden of using personal computers has grown dramatically heavier in the past couple of years because of the plague of viruses, spyware and other security problems that now afflict the dominant Windows platform... A big reason for this slide backward is the failure of Microsoft to cope adequately with the security crisis...

Meanwhile, the company's historic rival, Apple Computer, has been making giant strides in ease of use. The Macintosh, with its [BSD UNIX-based] OS X operating system, is rock solid... Best of all, the current Mac operating system has never been attacked by a successful virus, and almost no spyware can run on it. This is largely because the Mac's small market share presents an unattractive target for digital criminals. But it's partly because the Mac operating system is harder to penetrate. I'm sure there will eventually be viruses that afflict Mac users, but nowhere near the 5,000 new Windows viruses that appeared in just the first six months of this year.

An interesting recent development is Apple's announcement that it will shift to the same brand of microprocessor (Intel) that Microsoft Windows PCs widely use. This raises the intriguing possibility that Apple may at one point try to leverage the vast amount of Intel PC hardware that now exists, laying the stage for software "crossgrades" away from Microsoft Windows, as Linux now pursues.

Until a more fundamental solution to the hard disk-based Windows PC malware epidemic emerges, using a back-up is a quick, cheap and easy way to remove problems once they have been detected. You can use a personal firewall program to help detect the presence of clandestine software running on your PC that uses the Internet to communicate with external computers (e.g. to copy sensitive data out from your PC or act as a proxy for harassing or even subverting yet other computers.)

With the security provided by a good backup strategy, you need not fear experimenting with your PC, whether you want to add new hardware, or just new software. If something goes wrong, or you are spending too much time to make it work, just give up and go back to the configuration with which you were happy. The ease and parsimony with which digital photos can be taken suggests that you consider snapping photos of hardware before, after - and maybe even while - making hardware changes.

You also have the choice of paying someone to upgrade or maybe just customize your PC. Whichever route you take, when you are happy with the new configuration, make sure the first thing you do is create a new disk backup image for the disk or partition on which sits your operating system and all your programs. When things go wrong from now on, you probably want to get back to the new plateau you have just achieved, and not the condition in which your PC was received. (But don't toss those very thin older disk images just yet - it is not impossible you may need to lose your latest changes and go back further to make something else new work in the future.)

Generally speaking, you will probably replace your PC - or all of its parts one-by-one - before nearly anything wears out, on account of how affordably cheap and improved new technologies will be. A common exception may be a dial-up modem which gets fried by lightning. It is not a bad idea to disconnect your PC from the mains power and the telephone line in advance of a known lightning storm. But I have never disconnected my satellite TV set-top box from its small-dish antenna or mains power, and it has yet to be clobbered by lightning in almost a decade of continuous use.

Unless you are very poor, don't bother with a ball-based mouse: who wants to clean mouse balls on a regular basis?! You can get a (camera-based) optical mouse for little more than $10 these days.

Most people who use PCs have a printer as well. Ink-jet printers are very cheap up front, but supplies are rather costly. Unless you really need to make color prints at home, invest in a laser printer instead. You might find a limited-refurbs-style model that runs only about $100 these days. Save on toner by avoiding the use of large black areas, and print throw-away drafts in a draft mode which spares the toner even more. Use the duplexing ability of your printer to mark both sides of a page to save yet more money - as well as paper storage space. Best of all, consider doing without paper, and publishing to the Internet, or maybe to an optical disk if you have a lot of material to justify burning a disk. Remember, you have to carry paper to the place you will need it, but electronic records like Web pages are always available from countless millions of Web terminals - and can be searched and copied at super-fast electronic speeds as well.

4. Installing and running programs in the old days

In the early days of PCs, the operating system in wide use was a modest program called MS-DOS, a near-acronym for "Microsoft Disk Operating System". (Aside: Today a free clone of MS-DOS called FreeDOS is available.) To run an application program under MS-DOS, you typically licensed a copy of the single disk file which embodied it. This you stored on your disk (which may have just been a humble removable floppy disk before hard disk drives were available.)

When a PC was booted up under MS-DOS, it finished by running a text-based program called COMMAND.COM. You would control the PC by typing commands on the keyboard to this program, which listened for keystrokes, echoed them to the text-only screen, and then carried out the instructions they comprised. We say that COMMAND.COM was the program by which MS-DOS provided a "command-line interface" to control your PC.

Originally, MS-DOS didn't even support the idea of file subdirectories; all the files on a given disk sat within a common directory. To run a program embodied as a file called DOAPP.EXE, sitting on your B: disk drive, you just typed B:DOAPP.EXE and hit the ENTER key. COMMAND.COM would copy this program into primary memory and transfer control of the PC to it. Thereafter, you interacted with the DOAPP program (using little more than your keyboard before other gadgets like joysticks and mice was available), until it was finished and handed control back to COMMAND.COM. Basically, only one program ran at once - unlike in modern operating systems like Mircosoft Windows and Linux, where many programs can operate virtually at the same time through multitasking.

As the notion of file subdirectories was imported from other operating systems into MS-DOS, things got a bit more involved through adoption of the idea of a file "path". MS-DOS acquired the notion there was an implicit "working (or current) directory" for each of the letter-designated disk drives it could access.

A legacy of COMMAND.COM remains in Microsoft Windows. Named the same thing in earlier versions like Windows 98, and CMD.EXE in later versions like Windows XP, it can be invoked by using Windows Explorer in the manner described in our third lesson - by double-clicking on its representation within the file system tree. Another method of activation is to use our old friend, the "three-step dance": Hit the "Windows" key, hit the "R" key and then enter the name of the program, either "COMMAND.COM" or "CMD.COM" as is appropriate.

Application programs are not the only software we install on computers. An important operating system extension called a device driver needs to be installed when we add a new piece of hardware. A device driver might be bundled with the purchased hardware, or the operating system might be able to install a suitable device driver from the physical media used to install the operating system itself. Modern versions of Microsoft Windows include a capability called "Plug-and-play", by which one can stick a USB device into the USB port or (expansion) USB hub of a PC which is already operating and have Windows assist in completing the software interfacing process to make it operable. (Traditionally, it is generally a bad idea to wire up electronics to which power is applied!) Disappointments with the perfection of this regimen led critics to coin the term "Plug-and-pray".

5. Installing programs today

Installing programs under complicated operating systems like Microsoft Windows or Linux is much more involved. The installation may involve the addition of dozens - or even hundreds - of different disk files to various subdirectories on one's disk drive - as well as the modification of existing (configuration) disk files. Because copying so many files by hand would prove onerous, typically one uses a single file, called an "installation" file to do all the work. Under earlier versions of Microsoft Windows, like Windows 98, this file was program which you ran but once; other operating systems may use a non-executable configuration file which is presented to a standard installer utility. Indeed, recent versions of Microsoft Windows also include such a utility, called Windows Installer.

The installation file for an application program might come from a removable storage medium like an optical disk or flash memory card. It might alternately come through a computer network, such as via a network share or a Web page in which a link points to the installation file. Wherever it comes from, be sure that you trust the source of the file and are legally licensed to do the installation.

Licensing is different from purchase - and may involve no transfer of money at all. You can find much excellent free software by using the resources you find listed here.

Software for which you pay no money still requires that the people who create and distribute it enjoy a means to live all the same. Sometimes people do simply donate their labor - an amazing amount of the time, as it turns out. But sometimes they use alternate financing schemes which include "adware" - among the least objectionable of many methods, some of which (i.e. "spyware") might be used without your knowledge, because it would never get your consent!

It is not possible to put something like a physical sticker on a file to guarantee its authenticity - after all, a binary digital file is just an ordered sequence of 0's and 1's. But it is possible to perform a (complicated) mathematical operation (e.g. using a program) on the file to produce an alternate, much smaller (lossy) representation of the file called a message digest. (Here "lossy" means it is not possible to reproduce the original file from the computed respresentation, as one can from a "losslessly" compressed version of the file.)

A file which is alleged to be identical to an original file should produce the same message digest with a particular algorithm that it did when the algorithm was used on that original file. This is why people will sometimes publish the message digest of a file they are promoting, even if they don't have a copy of the original file to give you: when you find a file which is alleged to be a copy, you can apply the algorithm to verify you get the identical message digest, and thereby have evidence of its authenticity. Of course, agreement of a computed message digest with a published message digest is only useful if you can trust the published one is authentic itself!

Acceptable algorithms for generating a method digest have the property that they detect the change of a single bit anywhere in a file (a way to detect non-malicious errors due to marginally defective computing hardware) as well as the property that it is exceptionally hard for a forger to adjust the bits of a counterfeit file so that a particular message digest is produced. (A famous, simple algorithm with the first property - but not the second - is parity bit computation.)

The PCs in the main reading room at the Buchanan-Haralson Public Library include a copy of a program to compute the famous MD5 message digest function for a file, to help users authenticate that file.

6. Running programs today

Today, the most common way for users to start up programs is to employ a menu system, which lists many (if not all) of the programs installed on the computer. The menu is often cascaded, meaning it consists of a tree-like structure so popular in the world of computing. This structure helps people place similar programs near to one another in the hierarchy so that the tree is easier to navigate, including ease to distinguish programs which are similar enough that they might otherwise be confused. But in general, this tree structure is independent of the file tree hierarchy used to organize the files on the computer.

It turns out we sort of used the program menu system designed into Microsoft Windows (called the "Start Menu") as early as our second lesson, because one way to elicit it is to tap the "Windows" key! (Another equally good way is to click the "Start" button on the screen with the mouse cursor - hence the rationale for its name.) After such alternate activation, you can use either the cursor keys or move the mouse to navigate the hierarchy of icons, each of which represents one program you can start up; you move horizontally to move "up/down" (sic.) a tree level, and vertically to move within a level. When you have highlighted the icon for the program you want to activate, you can either hit the ENTER key, or single-click the left mouse button.

Most of the icons for the programs you want to activate sit within the "Programs" branch of the Start Menu hierarchy; but they can also be placed at the root of that hierarchy. In Microsoft Windows, these icons are actually what are called "shortcuts", which are tiny configuration files which point at an executable file and specify some details about how it will be activated.

It is also possible to put "shortcuts" on the "desktop", which is to say overlayed on the "wallpaper" used to decorate the screen when no programs are running. By default, you need to double-click such a desktop shortcut to activate the program.

Shortcuts can point to things other than executable program files. They can point to file system hierarchy subdirectories/folders or non-executable data files as well. Clicking on a nonexecutable data file shortcut as if it was a program often activates a program which will examine or otherwise process that data file. (We saw this same behaviour in our second lesson, when entering a data file name after hitting the "Windows" and "R" keys in order.) Choosing how to associate particular file types with particular programs is something the user can specifiy, but is not covered in this lesson.

It turns out that the Start Menu items are actually a branch of the file system hierarchy rooted at: "C:\WINDOWS\Start Menu" and the collection of shortcuts on the desktop are actually a branch rooted at: "C:\WINDOWS\Desktop". Use Windows Explorer to examine these branches when you find some spare time, as a lesson in alternate manifestations of a common thing - the patterns of 1's and 0's on the hard disk which embodies the Windows Desktop and Start Menu.

7. Getting help when you need it

We can't teach you everything - not even everything generic - about configuring and using a PC. It just takes too long. That's why it is important to study more, especially learning how to learn more on your own.

Your Microsoft Windows computer contains some "documentation" - if perhaps not as much as you would like. You can always hit the F1 key near the top left of your keyboard to bring up what is called the "Help" system for the program associated with the window which has "keyboard focus". (Microsoft Windows indicates focus by highlighting of the bar at the top of that window differently from all other windows; it is this window which is told of the keys on the keyboard which you strike.) If the Windows desktop has keyboard focus, hitting the F1 key brings up "Windows Help". The interface for this facility uses menus, tabs, a cascading hierarchy of icons and many other features typical of Microsoft Windows programs. Use your mouse to click on things to explore them - this facility is read-only and you cannot do it any harm. Effort here is well spent, even in the absence of some specific and passing need - you will learn important things for which we have no time here.

Almost any program includes an item called "Help" at the root of its menu hierarchy, drawn at the top of some window it shows. Click on it for additional help with that program, typically including the thing you can call up by hitting the F1 key.

Letting your mouse "hover" (dwell) over a particular feature within a window will often popup a small label called a "ToolTip" for the feature in question. It is as if Windows guesses you are "stuck" and offers a hint to help get you on your way.

Many programs also draw windows which include a small icon with a question mark within it. If you click on this icon and then click on something else within the window in question, a short explanation is offered about that second thing you click.

If you are stumped despite your use of the aforementioned built-in help aids, you need not despair merely because there is no one around to help you - as long as you can use your Web browser to access the Internet! Try our old friend the Google search engine to pose a phrase that may appear in a Web page explaining the thing about which you seek more information. It could be a tutorial article from the online version of a trade serial, some school course notes, or maybe just the FAQ ("Frequently Asked Questions") list a software vendor posted on its Website about the software product in question.

Don't forget more focused things like topic-specific online bulletin boards, such as Google Groups, which includes the UseNet archives, many of whose groups address technical questions about particular computing topics. Also consider using a "live" tool like text-based chat to immediately interact with other people on the Internet. The Search IRC engine can help you locate a chatroom on IRC that may be full of people who would love to answer your questions. Find a small collection of online resources for reaching other people, either synchronously or asynchronously, here.

If your PC is attached (e.g. via the Internet) to another PC attended by a human being, that person might be able to help you reconfigure your machine remotely. For example, if both PCs run a version of Microsoft Windows XP, you can use XP's Remote Assistance tool. In earlier versions of Windows, you could instead use the free NetMeeting utility program, which we will mention again when discussing teleconferencing in our next lesson. We will also discuss a similar tool capable of operating between computers running dissimilar operating systems, called VNC.

Now that we know more about how to upgrade and operate our PC, our next lesson will focus on some of the exciting and amazing applications to which it and specialized devices inspired by it can be put.