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Win98 on P4 systems: COM ports not working

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Twospruces

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I'm looking for some help to debug an issue I have seen twice now on 2 separate hardware.

I am trying to run Laplink from a windows 98 machine to an old 8088 laptop, using serial transfer.

I have two different Pentium 4 class systems, both with windows 98 installed and working.

I see two problems on each of the 2 P4 systems.

1. When running Laplink in a window in Windows98 the serial port is unreliable for transfers.

2. When I restart the machine in dos mode, the COM ports are reported as unavailable. They are just inaccessible. I observe this behavior when I run the applications in MSDOS mode from Windows also.

Does anyone have any suggestions as to where the problem may lie?

Thanks for any help.
 
I made some progress. Learned a bit.

* to run Laplink under Windows 98, I needed to (1) configure the application to run in MS-DOS mode, and furthermore (2) I had to use a "different than Windows 98" autoexec and config.sys
* this means a reboot everytime I want to run Laplink. AND, since it is running in MSDOS mode, the Windows98 network share is not available.
* also, performance was limited. 8088 <---> P4 could run at 38400baud only; whereas 8088 <---> 8088 can run 115kbaud (* when using 16550 UARTs)

So, this isn't great, but better than totally broken. I wonder if there is a way to boot up windows 98 in such a way that Laplink3 can work correctly?
And, why is the COM1 port working more slowly than it is capable of?
 
modem7 said:
You may be interested in the 'DOS version of Laplink running in DOSBox on a modern computer' section of [here].
Click to expand...
Hi, thanks for this. Yes, I have read and have a somewhat workable DOSbox implementation. That's a Ubuntu based system and while it's ok, I am trying to assemble a single Win98 "Tweener" that can make disk images on real 3.5 and 5.25 media, access the network, and transfer files with DOS laptops.

The Ubuntu system doesn't really lend itself to the floppies too well.

The only hardware I have that can still host a 5.25 inch floppy is this P4 system I have. I have got W98 installed and working well, and this is the last hurdle.
 
I may just bite the bullet and purchase Fastlynx 3.3 as you reference. Seems like it avoids a lot of hassle!
 
I am still curious though.
Why, if I take a Pentium 4 system, can't MS-DOS 3.3 (or 6.22?) and Laplink, operate the serial port properly?

In other words, take a known good software implementation, and swap the hardware from "old school" to "new-ish".... this does not work. Why?
I thought things like serial ports would have seen basically no change over the years....

Anyone have some color here? thanks
 
Huh, I actually have an original set of Laplink cables, and the program is archived... somewhere.

But for file transfers I use ethernet (shared drives), or USB sticks (even in DOS), or floppy disks - whatever is most convenient.
 
Twospruces said:
I am still curious though.
Why, if I take a Pentium 4 system, can't MS-DOS 3.3 (or 6.22?) and Laplink, operate the serial port properly?
In other words, take a known good software implementation, and swap the hardware from "old school" to "new-ish".... this does not work. Why?
I thought things like serial ports would have seen basically no change over the years....
Click to expand...
But you are swapping more than hardware. The other 'variable in the equation' is that you have introduced Windows 98.
Microsoft never promised that all DOS programs would work flawlessly in Windows. Even in Windows 3.1, I remember having to sometimes create supporting PIF files.
LapLink is timing sensitive, and the DOS version of LapLink was written for DOS, not a multitasking OS that will 'pause' it frequently.

And even if Windows is removed from the equation, there is still the possibility of problems such as 'Problem #1' at [here].
 
On my systems with Win98SE, I edit the MSDOS.SYS file to "BootGUI=0", which causes Windows by default to boot into MSDOS Real mode. If I want to get into the GUI, I just enter the "WIN" command.

www.computerhope.com

Msdos.sys Help and Information

Msdos.sys command and file information for MS-DOS and the Windows command line. Page includes msdos.sys command and file availability, syntax, and examples.
www.computerhope.com www.computerhope.com
 
I don't know how to help with Laplink and Windows 98 on your P4. I do use Laplink but only with my systems up to 486. On my P4 and more modern systems I use the Ethernet LAN and FTP. Brutmans mFTP on my DOS machines and WinFTP on Windows 95 and Filezilla on Windows 7.

For my systems without an Ethernet card I use my Windows95 tweener and move by FTP to the Win95 machine and then LapLink for DOS by either Serial or Parallel to the DOS machine. I've not had success going directly from a P4 to an old PC/XT system except by FTP.

Seaken
 
You can use Laplink on a P4 running DOS, but really, networking is the fastest and most straightforward approach. See Mike Brutman's very nice MTCP suite on the XT side.
 
There are lots of options other than Laplink for sending files over a serial port. I can't recall if Laplink might be much nicer than the others though.

Recently I sent some files from a Core 2 Duo laptop running Linux to a Pentium 100 machine running Windows for Workgroups 3.11. On the Linux side I used SyncTERM and on the Windows side I ran the Terminal application that came with Windows because it was the only thing I had on there that would talk to a serial port (other than CTTY or whatever it's called), and I had to send the files using the XMODEM protocol which sucks because you have to type the filename on the remote end and it's particularly slow.

SyncTERM doesn't support batch uploads using ZMODEM (which does send filenames) but some software does. ZMODEM was a very widely implemented protocol so there should be plenty of options for whatever platforms you want to run on.
 
If I recall, LapLink for Windows has some compatibility with the DOS versions, although it might need to be newer then LapLink 3.x. If the P4 box has a parallel port, a properly wired LapLink parallel cable might actually be a more reliable connection, maybe even faster. Personally I always used INTERLNK/INTERSVR since it gave me a nice drive letter on the Windows 98 side. Run INTERSVR on the XT, and setup INTERLNK in the config.sys of the 98 box.

See also: https://forum.vcfed.org/index.php?threads/laplink-cable-with-ms-dos-interlnk-intersvr.71432/
 
Thanks for all the discussion.

I for one have been unable to get any form of serial link to work reliably regardless of what combination of hardware,dos, windows, Linux, laplink, Norton commander fastlynx etc.

The other end is always the constant.. an 8086 T1000 or equivalent.

But I did land on a solution as others have suggested. Parallel transfer.

Getting laplink 3 to work on windows 98 for parallel transfers seemed OK. I had to fiddle a bit with the startup configuration of the dos program in win98, but I have laplink now working well in a window. No need to drop into msdos.

The win98 P4 box now sits as a pure middle man providing the network share as dos Z: accessible by laplink 3.

I don't want to say how many hours I have dumped into getting a solution that works.
 
Twospruces said:
Thanks for all the discussion.

I for one have been unable to get any form of serial link to work reliably regardless of what combination of hardware,dos, windows, Linux, laplink, Norton commander fastlynx etc.

The other end is always the constant.. an 8086 T1000 or equivalent.

But I did land on a solution as others have suggested. Parallel transfer.

Getting laplink 3 to work on windows 98 for parallel transfers seemed OK. I had to fiddle a bit with the startup configuration of the dos program in win98, but I have laplink now working well in a window. No need to drop into msdos.

The win98 P4 box now sits as a pure middle man providing the network share as dos Z: accessible by laplink 3.

I don't want to say how many hours I have dumped into getting a solution that works.
Click to expand...
I'm sure we have all spent a significant amount of time learning new stuff over the years ;)
 
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