TechNotes		June 16, 1995  Vol 1 No 6
Copyright (c) 1995 Dynamic Learning Systems.  All rights reserved worldwide.

Table of Contents
-------------------------
A.	Disclaimer and Cautions
B.	About TechNotes
C.	About Dynamic Learning Systems

1.	DOS and Windows
		Incorrect DOS Version With CD-ROM
		Turning Power Off Under Windows

2.	Drives
		An Uncooperative Floppy Drive
		EIDE Performance Discrepancy

3.	Manufacturers and Parts
		HP on the Net
		Boca Research Drivers

4.	Memory
		Dealing With Memory Parity Errors

5.	Monitors
		Trident Video Memory Problems

6.	Motherboards, Ports, and Busses
		New Life For an i386 System
		Lockups and Drive Lights
		Cooling the Hot Connections
		MIDI Problems With a New Video Board


Disclaimer and Cautions
------------------------------------
	This document is COPYRIGHTED under international law.  This document is provided as an educational service by Dynamic Learning Systems, and is intended to benefit all readers.  Although this document is copyrighted, you may print and re-transmit this document freely, so long as the document is used in its entirety, and credit is given to Dynamic Learning Systems.

	THIS DOCUMENT IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.  The reader assumes the entire risk as to the accuracy and the use of this document.  All PC service and maintenance involves some element of personal risk, as well as risk to the equipment involved.  If you are not comfortable following the information contained herein, refer the work to more qualified personnel.  ALWAYS BACKUP VITAL INFORMATION IF POSSIBLE BEFORE ATTEMPTING ANY TYPE OF SERVICE.


About TechNotes
------------------------
	TechNotes is a compilation of symptoms and solutions for various PC problems.  A new release of TechNotes is released every two weeks.  We welcome your contributions of symptoms, as well as solutions that you have found to your own PC problems.  We also encourage you to contribute enhanced or alternative solutions.  It is our hope to make TechNotes a first-rate tipsheet for PC and peripheral service.  The file name of each TechNote includes its release date.  For example, a file name TN040795 indicates a TechNote (TN) date of April (04) 7th (07), 1995 (95).

About Dynamic Learning Systems
----------------------------------------------
	Dynamic Learning Systems specializes in PC upgrade, maintenance, and troubleshooting topics for electronics/computer enthusiasts and technicians.  We publish The PC Toolbox newsletter.  If you have any questions or contributions for TechNotes, or wish to obtain subscription information for The PC Toolbox, feel free to contact us:

	Dynamic Learning Systems
	P.O. Box 805
	Marlboro, MA  01752  USA
	Fax: 508-898-9995
	CompuServe: 73652,3205
	Internet: sbigelow@cerfnet.com


SECTION 1.	DOS and Windows
============================

INCORRECT DOS VERSION WITH CD-ROM

Q. When I connect my external NEC CD-ROM drive (model CDR-38) to my PC using the Parallel-to-SCSI interface kit, I get the message 'Incorrect DOS version' when the drivers load.  I am running DOS 6.22. I basically stuck and could do with some suggestions.  This is an "almost new" older model - a single speed drive - so I am not sure what sort of response I can expect.

A. First, make it a point to check the version of MSCDEX in use (the latest version is 2.23).  Chances are that you are using an older version that may have been shipped with the CD-ROM software rather than the new version of MSCDEX that is included in DOS.  Open a text editor and take a look at your AUTOEXEC.BAT file.  If the entry for MSCDEX is using a path other than DOS, check your DOS directory to be sure a copy of MSCDEX is available there, then compare the file dates of both copies.  I bet you'll find that the version of MSCDEX under DOS is newer.  Try changing the path in AUTOEXEC.BAT so that you use the version in DOS (i.e. device=c:\dos\mscdex.exe...and so on).
	If the version of MSCDEX is not causing your problem, suspect a driver conflict between the low-level CD-ROM driver and other drivers in the system.  Contact the drive manufacturer and see if there are any newer drivers available - old drivers are often the cause of system conflicts.  If the problem persists, try disabling other drivers in CONFIG.SYS and AUTOEXEC.BAT one at a time to see if the problem will disappear.  The last driver disabled before the problem disappears is likely to be the culprit.
	Finally, try including the SETVER utility.  This is often employed to fool applications into working with otherwise-incompatible DOS versions.  For a complete explanation of SETVER and how to use it, type help setver from the DOS command line.

TURNING POWER OFF UNDER WINDOWS

Q. I've been told that it's bad to turn a PC off while Windows is running.  Is this true?  If so, why?

A. During normal operation, Windows uses disk caching, temporary files, swap files, and so on.  These resources remain in use as long as Windows and its applications are running.  It is only when you leave Windows that the disk cache is flushed, and temporary files are erased.  Simply turning the power off allows those temporary files to remain on the disk - this results in disk clutter (and can cross-link files on occasion).  So powering down Windows prevents normal "housekeeping" operations.  An even greater danger is that vital data in the disk cache that must be written to files is lost when power is removed - this will almost certainly corrupt some files.  In some cases, Windows may not start again once vital files are corrupted.  While consequences are rarely this severe, it IS a possibility that must be considered.


SECTION 2.	Drives
==================

AN UNCOOPERATIVE FLOPPY DRIVE

Q. I tried to add a 1.44MB floppy disk drive to my PC as the A: drive.  But when I restart the PC, it fails while booting from the new diskette.  I see an error message that says "Boot File Failure".  I tried the same floppy and the same diskette with another PC and they worked.  What's the problem?

A. Start by taking a close look at your floppy drive cable - make sure that it connected properly and securely to the drive.  Since the drive works on other PCs, you might try a new drive cable outright.  Also see that the power connector is inserted completely into the drive.  If problems persist, start the CMOS Setup routine and check that the reference for drive A: has been changed to reflect the new drive.  If problems persist, try a new drive controller board.

EIDE PERFORMANCE DISCREPANCY

Q. I've been following the introduction of EIDE lately, but I don't understand the speed claims.  After talking to some techie friends, they tell me that it's unlikely you'll get over 2MB/sec off the drive.  I'm lost with this.

A. I suspect that your friends were discussing the data transfer rates off the media - and they're right - given the current rotational speeds, seek times, latencies, and so on, it would be difficult to get over 2MB/sec off the media.  However, that is not what SCSI, IDE, and EIDE transfer rates describe, and frankly, it's not what you care about.  The transfer rates you see in literature are typically quoted from the drive interface (but not from the media).  You see, all newer drives include some amount of cache within the drive itself.  This allows the drive to "stage" data from the media and achieve better performance.  In addition, the newer drives support multi-block transfers which is a way to "clump" I/O together and transfer more data during a transfer.  Multi-block transfers are most effective for sequential access.
	Also, EIDE is not necessarily faster than IDE, but EIDE provides for PIO modes 3 and 4 (11.1 and 16.6MB/sec), and multi-word DMA transfers too.  The controller has to support these modes in order to maximize  drive performance.  Non-EIDE drives support PIO mode 0 (3.33 MB/sec), mode 1 (5.22 MB/sec), or mode 2 (8.33 MB/sec) transfer rates.
	As an experiment, we recently tried a VLB IDE controller in place of my old ISA paddle card.  We have an ancient Quantum drive and a new WD drive.  Using the latest version of CORETEST, the WD drive tested slightly faster than the Quantum using the ISA IDE card.  On the VLB card, performance (throughput) of the WD drive increased about 7 times and the Quantum about 2 times.  Now, the increase for the Quantum was strictly due to moving to VLB.  The WD drive "took off" because the controller implemented multi-block transfers which this
drive supports (and the Quantum doesn't).  Ultimately, EIDE drives and controllers will typically provide a much higher rate of data to the controller than classic IDE architectures even though the actual rate of data being read from the drive is limited by physical constraints.


SECTION 3.	Manufacturers & Parts
=============================

HP ON THE NET

Q. I've been looking everywhere for Hewlett-Packard contact information for the Internet.  Don't they have a Web page for software service and support?

A. They sure do.  You can reach HP on the WorldWide Web by connecting to their home page at: http://www.hp.com./Misc/Peripherals.html
On the other hand, you can also access HP drivers and utilities through their anonymous FTP site at: ftp-boi.external.hp.com

BOCA RESEARCH DRIVERS

Q. I need to get my hands on the latest Windows video drivers for my Boca Research video board.  Can you tell me if they have any resources on the Internet?

A. While Boca is not yet wired to the Internet, you can obtain drivers for many Boca boards through Cirrus Logic (whose chipsets are used extensively in Boca video products).  You can obtain a utility IDCHIP.EXE from the Cirrus FTP site at: ftp.cirruc.com/pub/support/util
When you execute the utility, it will tell you which Cirrus chipset is in use.  You can then download the proper drivers for that chipset from: ftp.cirrus.com/pub/support/desktop where you will find DOS, Windows, WFW, and OS/2 drivers.  For a master index of Cirrus Logic drivers, download the CONTENTS.DOC file from: ftp.cirrus.com/pub/support


SECTION 4.	Memory
====================

DEALING WITH MEMORY PARITY ERRORS

Q. While working in DOS (especially while playing games), I am encountering memory errors which are being displayed as "PARITY ERROR".  What's going on here, and what should I do?

A. First, don't panic - parity errors can be caused by a variety of problems.  Before you do anything, run an up-to-date anti-virus program on your system.  A virus known as "Parity B" (which hides in the hard drive boot sector) has been known to be responsible for such errors.  However, that is hardly the only possibility.  If the system is new (or has had this type of problem for a measurable period of time), check your CMOS Setup routine and systematically try the following: (1) try slowing down your bus speed, and (2) try adding a DRAM wait state.  Note that your CMOS Setup routine may not support these options.
	If the problem is recent (and there are no viruses detected), then the PC configuration is likely good, and the fault lies in your memory itself.  Try a serious diagnostic such as PC Technician by Windsor Technologies at 415-456-2200.  The diagnostic can excersize system memory much more thoroughly than the BIOS POST or HIMEM.SYS and report the exact location of the failure.  You can then identify and replace the appropriate SIMM (or replace the motherboard if necessary).


SECTION 5.	Monitors
====================

TRIDENT VIDEO MEMORY PROBLEMS

Q. I'm having problems with my monitor on a cold boot (usually first time it's turned on after sitting for a while).  I get a scrambled screen with $ signs.  If I wait about 2 minutes and reboot while the computer is running, it straightens itself out.  I have a 486DX4-100 with 8MB of RAM and a Trident 9440 AGI VLB.  I installed the card about 2 weeks ago and the problems have started happening this past week.  Is it the card, or is my monitor starting to go?

A. Always start by inspecting the video card to see that it is seated properly and securely.  If it is, I would seriously suspect the card.  We have had reports about memory problems with Trident video boards in the 9400 and 9420 series.  Take the card back and replace it for another video board (preferably one from a different manufacturer).  The problem should disappear.


SECTION 6.	Motherboards and Busses
===================================

NEW LIFE FOR AN i386 SYSTEM

Q. I've got a motherboard fitted with an AMD 386DX40 (128K cache) with a Cyrix 387DX40.  Rather than buy a new PC, I would like to upgrade the CPU.  Do you know if there is an upgrade for this configuration?  Is it possible to change for a 486DX/2 80 or 486DX40?  I don't really need a faster motherboard - just a faster processor.

A. The i386 CPU was never designed to be upgraded, so there are no direct i486-class CPUs that will fit your older motherboard.  However, Cyrix has developed an upgrade module that allows you to place an i486 into an i386 socket.  You can find these Cyrix upgrades off-the-shell at just about any computer/software store, or you can contact Cyrix directly at: 2703 N Central Expressway, Richardson, TX  75080, Tel: 800-848-2979

LOCKUPS AND DRIVE LIGHTS

Q. I recently purchased two used i386DX-40 motherboards and promptly installed one of them in my dinosaur i286 case.  When powering up the system, the LED in both the floppy drives as well as the hard drive remain lit.  The system immediately locks up, and I receive no video display at all.  Any ideas?

A. It is not unusual for motherboard upgrades to encounter such problems.  The first thing you should check is the installation of your drive cables.  Make sure that the HDD cable is not flipped at one end.  While this is a common oversight (and will not damage the drive or adapter), the system will often freeze the way you describe.  Remember that the faint red stripe on a ribbon cable represents pin 1.  Also review the installation of your floppy drive cable for any accidental reversals.
	Double-check the installation of the drive adapter board, and see that it is seated properly and completely into its expansion slot - you may also try the controller in another expansion slot.  If problems persist, take a good close look at the motherboard's physical installation, and make certain that there are no metal brackets or standoffs touching (and shorting out) the motherboard or power supply.  Finally, take a look at the power supply itself.  Use a multimeter and measure each power supply output (+5, -5, +12, and -12 Vdc) while the system is running.  If any one of thise voltages is low (especially the +5 Vdc output), you may have a defective or overloaded supply.

COOLING THE HOT CONNECTIONS

Q. I have a Compaq subnotbook which does not have a floppy drive.  Instead, it uses WinLink to transfer files between the subnotebook and my desktop PC.  My question is, can I connect the serial (null modem) cable between the computers while either is turned on?  Also, is it proper to connect a printer and computer while either is turned on?

A. Ideally, the safest technique when connecting two pieces of electronic equipment is to keep everything off until the connection is established, then power up the master device, then power up the peripheral device.  The reason for this is largely due to traditional connectors which keep all pins exactly the same size.  There is always a possibility that the ground wire may not be in full contact when the "hot" wires are - this can easily cause unpredictable paths of current which (in some cases) results in damage to the interface.  If the ground pin was always longer (as they are in PCMCIA cards which are designed for hot insertion and removal), the device would always be grounded before hot signals were applied, and the risk of damage would be significantly reduced.
	However, I - like many readers - don't always practice this technique.  Just consider the AB printer switch.  I often find myself switching printers which may or may not be turned on.  So far, I - like many readers - have escaped damage, but the potential for damage is there.  If you can not turn off both of the devices, at least turn off the peripheral device.  Make it a point to inspect your cables regularly, and replace any whose pins seem worn or damaged.

MIDI PROBLEMS WITH A NEW VIDEO BOARD

Q. I just inherited a used video card and installed it on my system.  It seems to work pretty well except when I try to run MIDI programs.  I only have an i386SX/20, but it always used to run MIDI properly until I got the new card.  Now when I load up my MIDI sequencer, my mouse starts to act as though it's gliding on ice.  Not only that, but if I move the mouse around while playing a MIDI sequence, the sequence slows down to a crawl and screws up the timing.  If I wiggle the mouse around a lot, it practically makes the song I'm playing stand still.  As soon as I leave the mouse in one place, the sequence returns to normal.

A. This sounds like either the MIDI card or the mouse are using the same system resources as your new (used) video board - in other words, you have a hardware conflict.  Probably the easiest thing to do is to replace the original video board and use a diagnostic such as MSD to review the IRQ, DMA, and I/O port assignments in use, then compare those assignments to the new video board settings.  Chances are that the base I/O is overlapping the resources used by the mouse, and causing a conflict which is interrupting the system processing (which in turn is slowing the MIDI system.  Check the video board documentation to see if any additional memory must be excluded in the EMM386 command line (not uncommon for advanced video boards).  This oversight allows the video board to "step" on memory that might ordinarily be used by other devices.

