2
I want to transfer 118 MiB data from an old Windows 95 PC to a laptop running Windows 95 and 2000 in dual boot.
The computers do not have an Ethernet card and I do not have a second computer where the IDE drives could be built into, to transfer the data.
I tried a null modem connection using directcc.exe . When I transfer using Total Commander the shown speed is 1 kbyte/s and 19 hours time needed.
I tried to speed up the process by increasing the baud rate from 9600bps to 115200bps on both computers' COM1 ports. Also I increased the receiving FIFO buffer and set flow control to "Hardware". (All using the device manager in the control panel). To be sure, I rebooted both computers.
The transfer is still 19 hours and 1 kbyte/s. Even when I decrease the baud rate to 110bps the time is still 19 hours and not more, so I think Windows ignores my settings. Why?
Daniel Marschall
Posted 2014-08-30T14:40:53.340
Reputation: 217
Where did you configure the com speed? E.g. Control Panel -> System -> Device Manager -> Ports -> com port -> port settings? Via system.ini (or was that win2.x/3.x only? It has been a while since I ran either). 2) Re flow control: What kind of cable do you use? 3 wire (2->3, 3->2, 7->7) or a 7 wire one ? – Hennes – 2014-08-30T14:53:51.010
I did it in the control panel via port settings. I did not edit any INI yet. I don't know what cable this is and how it is wired internally. I found it in the attic . Except for "null modem" there is nothing written on it. – Daniel Marschall – 2014-08-30T15:04:25.240
In that case some background information: There are several types of cables called 'nullmodem cable'. The simples on connects transmit from PC1 to receive on PC2 and vice versa (that is the crossing of wires 2 and 3) and has a straight connection on pin 7 (which is a common ground). These most simple ones do not support hardware handshake. That might prevent you from setting the flow control to hardware. That leaves one important question: Why can't the speed by set higher. Hopefully someone who still remembers win95 are stuff can answer that. My own knowledge is a tad rusty on this subject. – Hennes – 2014-08-30T15:09:02.043
I know that there are different cable types. I will check my cable to find out the wiring. But I also tried out Xon/Xoff and "none". Is it possible that invalid parameters (have I take attention to parity or stop bits etc? ) will reset the settings to default? – Daniel Marschall – 2014-08-30T15:17:19.507
1A LapLink cable (basically same as a null modem cable but uses the parallel port for higher transfer speeds) and INTERSVR (DOS 5.x command to redirect a drive letter over a serial or parallel link) is one option. – Brian – 2014-08-30T15:19:21.333
The system settings are generally used for
echo >com1 "My text goes here"and similar things from thecmd.exeprompt. The COMMS software you're using should have settings for bps/baud-rate - use these instead. Also: Z-modem, j-Modem, X-modem-1K or something similar should allow a vastly more successful transfer of files. – Hannu – 2014-08-30T16:15:48.593Note:
z-modemand the lot are file transfer protocols for upload/download and should be available in the com-software menus/settings. For most of these; launching a file transfer will initiate the transfer in the receiving software. Older versions require user action to initiate the transfer in both ends. – Hannu – 2014-08-30T16:26:02.130I looked in directcc.exe (the component delivered in windows 95, no third party software) and I didn't find any option that can change the speed. – Daniel Marschall – 2014-08-30T16:46:08.693
I just checked the cable with an Ohm meter. The pins (123456789) connect to (X3265487X) where X is nothing. – Daniel Marschall – 2014-08-30T16:59:29.890
According to the page http://www.lammertbies.nl/comm/info/RS-232_null_modem.html this cable has "full handshake" and can be high speed if using "special software". I wonder what software I need and if it is available in the Internet. ..
– Daniel Marschall – 2014-08-30T17:10:48.203@Brian using interlnk and intersvr, I could increase the speed from 1 kbyte/s to 4 kbyte/s. The connection speed is shown as "varying", but I do not think it is increased generally. I think the DCC in Windows was slow because of the overhead of the SMB protcol used for the network shares. – Daniel Marschall – 2014-08-31T11:46:36.323
@Brian I have found many male-male DB25 cables on the attic, which do not work with DCC (Microsoft Direct Cable Conncetion directcc.exe) resp. interlink . While checking the cables with an Ohm-meter I found out that they are not "crossed" (pins 1..25 connect to the pins 1..25 on the other side). Is this cable unuseable for this purpose, even with special software? – Daniel Marschall – 2014-08-31T11:55:03.260