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- Why Diagnostic Software Runs in DOS
- -----------------------------------
- We get a lot of questions about "When will you have a version for
- Windows?" (or Windows 95, Windows NT or OS/2). There is a good
- reason why our software (as well as most true diagnostic software
- runs in DOS or from a self-booting diskette.
-
- For the purposes of this note, we will define two types of system
- testing programs: "diagnostic tools" and "system scanners".
-
- A "diagnostic tool" is a software program to assist in the
- troubleshooting of a hardware failure or hardware and/or software
- configuration problem. These tools actually take control of and
- test the hardware to determine if it is working, and, if so, what
- port address and IRQ it is using. This is the way the shareware
- (trial) version of PortInfo operates. An additional feature of
- some diagnostics is to verify that the software is set up
- properly to use the hardware. The complete version of PortInfo
- will also do this by verifying that the Windows SYSTEM.INI file
- is correctly set up to use the serial ports.
-
- A "system scanner" is a generic "it's working" or "it's broke" type
- of program. They often run in Windows (or Windows 95) and have
- real cool user interfaces, but they don't actually test the
- hardware. Instead, a system scanner is reporting what the
- operating system driver reports. The drivers typically provide
- little diagnostic information other than they found (or didn't
- find) the device. But at the end, you don't really know a whole
- lot more than you did before.
-
- Why do Hardware Testing Programs Run in DOS?
- --------------------------------------------
- PortInfo (and most other diagnostic tools) run in DOS because
- most operating systems (Windows, Windows 95, Windows NT and OS/2)
- prevent software from using the hardware directly. This is done
- intentionally for a number of reasons, but primarily to make the
- system easier to use and to reduce the risk of system lockups
- caused by software using the hardware incorrectly.
-
- The operating system uses "device drivers" to control the
- different hardware devices. The driver provides a defined
- interface for use by applications written for the operating
- system and also provides an interface for DOS compatibility. This
- causes problems for diagnostic software because the diagnostic
- has to work with the driver and cannot access the hardware
- directly. This limits the diagnostic to reporting information
- that is available from the driver.
-
- Hardware diagnostic programs (like PortInfo) require direct
- access to devices for reliable testing. Since DOS is the only
- operating system that allows software to access the hardware
- directly, you should plan on using DOS for many of the most
- useful diagnostics.
-
- How to Test From a Windows Environment
- --------------------------------------
- You can obtain some useful information about what ports are
- detected and which ports have modems when you run a DOS
- diagnostic such as PortInfo from within Windows. However, since
- PortInfo is not working directly with the hardware, PortInfo (and
- your applications) may not detect a serial port (or modem) if
- Windows has not been set up properly. For best results, start by
- running in DOS to determine what hardware exists and then run
- again from within Windows to verify that all of the hardware
- detected by the DOS test is available to your Windows
- applications.
-
- Windows 95 Considerations
- -------------------------
- Windows 95 and Plug-and-Play has made troubleshooting
- communications problems more difficult than in the past as there
- are a number of new issues to consider. While we are working to
- on a good solution for Windows 95 communication setup problems,
- we suggest that you continue using PortInfo as before. First, run
- PortInfo after you have rebooted into DOS mode (select "reboot to
- DOS" from the Windows 95 shutdown menu). Run PortInfo and note
- which ports are installed and which port addresses and IRQs are
- being used.
-
- Next, restart Windows 95. Temporarily turn off any communication
- applications (especially fax reception programs as these will
- allocate and hide the serial port from other applications). Then
- run PortInfo from within Windows 95. All of the ports detected in
- the first PortInfo run should be listed at the same address and
- IRQ. It is also possible that an additional port will appear if
- there is a plug-and-play modem installed that was not configured
- to operate during the DOS test. If one of the ports is missing,
- make certain that another application is not using the port.
-
- Finally, compare the results from PortInfo with the Windows 95
- Device Manager. From the "My Computer" icon, select "Control
- Panel" and then "System". The second tab is the "Device Manager".
- Under the entry "Ports" there should be a listing for each Com
- port in the computer. Select "Properties" and then "Resources" to
- see what I/O address and IRQ Windows 95 is using for each port.
- If a port is showing different resources than PortInfo indicated,
- then try to change the port setting in the device manager by
- disabling "Use Automatic Settings" and selecting a configuration
- that matches the actual port use. If this does not work, select
- Cancel, then Remove the port from the device manager. Restart
- Windows 95 and re-install the port by selecting "My Computer",
- "Control Panel" and "Add New Hardware".
-
- Last Update: 8/6/96
-