The Windows 95 Registry continues to be a fascinating subject for readers far and wide. I often hear tales of weird registry changes. Now I have an example that seems to have been diagnosed by a reader and even has a fairly easy solution.
Mark Ottaway sent me his description of this behaviour. Because he's done such a good job of describing it, I'll let him tell you about it in his own words:
"Windows 95B appears to be slightly more vulnerable than its predecessor to slight damage to Registry settings when crashes occur during programs that require frequent CD-ROM access.
I know of a number of Win95B users who have suffered system damage due to a crash in the middle of using a CD-ROM program. The most common complaint is that the AutoRun facility of Win95 suddenly stops. CDs still work well, but will no longer run themselves using the Autorun.inf information on the CD - they need to be manually started each time.
Although this is a minor irritation, it's an irritation nonetheless - especially for frequent CD users. Users have been forced to either completely reinstall Win95, or restore an old Registry backup and try to remake all the changes that may have occurred since that backup. Neither prospect is particularly appealing to most users.
After an analysis of the problem, I've hit upon a simple solution. The damage has been done to an important Registry key - NoDriveTypeAutoRun in HKEY_USERS\.Default\Software\Microsoft\ Windows\CurrentVersion\Policies\Explorer. This key controls the action taken by Explorer upon notification from the CD-ROM drive that a CD has been inserted (as long as Auto Insert Notification is turned on for the hardware in System Settings for the CD-ROM).
To correctly autorun any inserted CD-ROM (and coincidentally to display the AutoPlay menu option when right-clicking on a CD-ROM icon), the value of NoDriveTypeAutoRun should be hex: 95 00 00 00.
I've found that all errors of this type have been caused by corruption of this key's value. Editing the key and inserting the correct hex value, followed by a reboot, consistently fixes the problem."
To change this key to the proper value, run RegEdit.exe. In the window that appears, click the plus sign to the left of HKEY_USERS. Then keep clicking plus signs until you drill down to the Explorer folder at the end of the list of Registry keys mentioned by Ottaway. (Notice the period at the beginning of the .Default key.)Select the Explorer folder, then right-click the NoDriveTypeAutoRun key in the right pane. On the context menu that appears, click Modify. Change the value to hex: 95 00 00 00.
This work-around for CD AutoRun problems may yet shed light on some other hidden workings of the Win95 Registry.
A Cool Tool
Much has been written about the current commercial build of Windows, known as Windows 95B, OSR2, or OEM Service Release 2. But OSR2 continues to unearth new gems, so I'll keep revealing them to you.
One new goodie is a virtually unknown hardware diagnostic tool called Hwdiag.exe. This program resides in a non-compressed, executable form on the Windows 95B CD-ROM. You can run it from your CD, or simply copy it to your hard drive and run it from there. Its location on the CD is D:\Other\Misc\Hwtrack, where D: is the letter of your CD-ROM drive. It works on Win95, 95A, or 95B.
Windows 95B, as you may know, is a version of Windows that Microsoft hasn't made available as a commercial upgrade from Windows 95 or 95A. Under Microsoft's licensing terms, you can only get it from an OEM dealer with the purchase of a new computer system, a new motherboard, or a hard drive.
For details on OSR2, a good source is a Web site maintained at www.users.cts.com/king/s/serwin/osr2.html.
Once you have OSR2 and you can access Hwdiag.exe, there are many ways this little tool can be useful to you.
Hwdiag.exe lists every key in the Windows Registry that refers to hardware in your system. The entries are colour-coded to make the display easier to decipher. Registry entries are displayed in green, and file attributes (path and date information for drivers, for example) are in magenta. Error messages and warnings are displayed in red and blue, respectively.
The information in Hwdiag.exe isn't intended for beginners, but if you know a little about interrupts and drivers this tool can be very helpful. For example, when my CD-ROM drive and Zip drive had mysteriously vanished from the components listed in My Computer and the Explorer, Hwdiag.exe reported that my SCSI adapter (to which both devices are attached) wasn't working properly, providing a specific error code. This suggests a hardware problem, and the code may help me get my components talking to one another again.
For those who find Hwdiag.exe's information about hardware useful, there are a variety of ways to look at the output. You can cut and paste selected sections or the whole listing into your word processor. You also can save the output as a plain text file (losing formatting such as colour-coding) or as a rich text file, which is compatible with most word processors and suitable for e-mailing if you want to share the data.
Hwdiag.exe also supports menu options to filter the data to show only certain classes of devices (storage devices, for instance) or devices with problems. But in version 1.0, which I used, these options didn't seem to change the output much. Typically for a Microsoft utility, there is no README file or Help file to guide the user, so you'll have to try it out for yourself to judge its usefulness for you.
Another cool utility
Iomega Zip drives are an increasingly popular removable storage medium. Using disks that are only slightly larger and thicker than a 1.44Mb floppy disk, Zip drives store about 100Mb in a convenient package.
I use Zip drives for large data files, but I also install on them whole programs that are bulky and infrequently used. A Zip drive installed on an IDE or SCSI controller is comparable to a hard drive in terms of access time. People who can't spare an IDE or SCSI connection can use a version of the Zip drive that operates off a parallel port (although it operates quite a bit more slowly).
For all of its similarities to a floppy drive, however, a Zip drive (which bears no relation to PKZip compression software) doesn't work well as an A: or B: floppy drive.
That's too bad, because many people have vacant B: drives and could use a removable disk drive there.
And, if a Zip drive could be configured as drive A:, you could boot from a 100Mb removable drive, which would make it easy to switch between different configurations or entire operating systems. (For example, your data files could reside on a hard drive and continue to be accessible from whichever configuration you were currently using.)Now there is a shareware utility that allows you to boot from a Zip disk in the same way many people boot from different floppy diskettes. Programmer Benedict Chong has developed two related programs: Z-pA works with IDE/ATA Zip drives, and ZppA works with parallel-port Zip drives.
There isn't a version available now for SCSI Zip drives. (Some SCSI adapters already allow Devices 5 and 6 to be configured as bootable devices - check your documentation.)To determine if you have an IDE/ATA Zip drive, check to see if the drive is mounted internally, like a floppy drive, and has a 40-pin connector at the back of it.
Zip it all up
A Zip drive that requires an external AC adapter is not an IDE/ATA drive. A SCSI Zip drive has a cable that plugs into an SCSI controller.
Both versions of Chong's program reside in the master boot record of your C:drive. They run before the operating system is loaded and they detect IDE/ATA Zip drives whether or not a disk is present in the drive. When Z-pA detects a Zip drive, it configures it as drive A: or B:.Also, computers can start up from a Zip drive configured as the A:drive just as they can from any floppy A:drive.
Having a Zip drive with an A:drive configuration also means that you can right-click files in the Windows Explorer and use the Send To menu to copy files to removable storage. The menu command Send To A: appears automatically when you install Windows 95.
Windows 95B, also known as OEM Service Release 2 (OSR2), is a particularly hospitable environment for Zip drives. OSR2 supports floppy drives larger than 100Mb; previous versions of DOS and Windows supported floppies as large as 32Mb. (OSR2 is available only from OEMs with the purchase of compatible hardware.)Z-pA 0.99e and ZppA 0.91 are 30-day trial versions that are available for download from a Web site that is maintained by Chong. Z-pA is at pw1.netcom.com/bluesky6/zpa.html; ZppA is at pw1.netcom.com/bluesky6/zppa.html.
You should also read FAQs at pw1.netcom. com/bluesky6/zpafaq.html.
You can contact Benedict Chong at bluesky firstname.lastname@example.org.