[The DOS Machine]

I am not sure whether this should be here, in Hardware, or in Networking, so I will let a mod help me out!

I have an IBM 755CD Laptop that has been having power problems recently. I have a lot on the HD that I would like to keep in case the HD fails, however, I have no easy means to back it up. All the laptop has is a floppy drive, but it also has parallel and serial ports.

I need to find a way to backup my HD!

I have built a gaming computer that has both DOS/Win 3.1 and Windows 98 SE partitions. I theorize that I could use the parallel or serial ports to transfer the entire contents of the HD to my new computer, however, I am not sure how to accomplish this. I know of a couple of drivers that came with DOS that would, supposedly, link the two computers(Interlink), but I have never used it before. I realize that a parallel or serial tranfer would be very slow, but it would be much faster than floppy(sneaker-net).

I do NOT have any parallel or IrDA tape backup devices. I just have an internal tape backup drive in my new computer. I would use that to transfer the data to a tape from the new computer's HD. I also have a shareware version of LapLink for DOS, but I have not been able to get it to work with any computer in the past. The laptop HD's total storage capacity is over 700MB, and it is almost totally full.

DAMN! I just remembered that I would need one of those special parallel or serial cables to connect directly between two computers. That is probably why my attempts to connect computers this way have failed in the past, but I would most certainly buy the necessary cable if I am confident that I could make such a transfer work!

SO: Advice, Suggestions, Comments?

Thank You!

-DOSMAN

[MacFromOK]

Hiya Dos Machine,

Interlnk and Intersrv will do the job if your IBM is a
DOS only system. You are correct, it does take a
null-modem cable. It is also pretty slow, so ya might
wanna start the transfer when ya go to bed some
night.

If you have Win95 (or later, I presume) you can
also connect with a null-modem cable using the
"Direct Cable Connection".

I have batch files to use Interlnk and Intersrv if
ya need them....

Cheers, Mac

[Lurker1]

Hi DOSMAN

Laplink is a pretty good program also. I have found that using a parallel transfer cable is faster than using the serial ports for moving files. You can usually pick up just the cable (without any software) pretty cheaply from a local computer dealer.

[The DOS Machine]

THANKS GUYS!

I will have to get a null-modem(forgot the name) cable for the backup, since I really DO need to save that data! Could you describe your batch files Mac? I have not used these drivers before, but it is surely not hard to figure out since I am the DOSMAN! I have both DOS and Windows 98 SE on my gaming computer, but only DOS on the Laptop. I can still use the Windows "Direct Cable Connection" if Interlink and LapLink does not work, right?.

BTW, could you guys refresh my memory regarding maximum safe cable lengths for parallel and serial cables? I know that serial is a slower transfer, but allows for longer cable length(less interference). I think that the maximum safe lengths are: 20 feet for parallel; 100 feet for serial. Is that right?

Surely, parallel and serial peripherals have their Tx, Rx, and other control lines assigned different pins for their respective DB25/DB9 connectors as compared to the ports on computers, thus the reason for null-modem cables to connect two computers. Isn't that right? I may invest in the breakout box that I had always wanted to purchase instead of a null-modem cable, so I can temporarily "assign" the null-modem qualities to a regular parallel or serial cable!

(It sure does not take much to excite this geek, huh! )

-DOSMAN

[MacFromOK]

OK DOSMAN, Here ya go.

I never used over a 10 ft cable myself, so I can't help ya on
max length.

Hopefully the REMarks will explain everything OK, if
you have any questions, just ask. I named this LINK.BAT
on my system, you can call it whatever you want. It
allows you to use the same batch file on both computers,
and pick either one as master or slave.

The stuff at the top must be in the config.sys file on both
computers. Copy the batch file to both computers, and
choose one as master and one as slave. You need to
choose the slave batch file first, so the master can find it.
Seems like you may have to reboot to swap master/slave,
been a while since I used this...

BTW, I'd blank my screen if you're doing long transfers.
You can check the HD light to see when it's finished.

rem -- THESE MUST BE IN CONFIG.SYS (remove REMs) --
rem -- This should reflect the last drive letter you'll assign.
REM LASTDRIVE = E
rem -- This should reflect your INTERLNK.EXE location and
rem -- the com port to use (Interlnk autoloads high if possible).
REM DEVICEHIGH=C:\DOS\INTERLNK.EXE /COM2


@ECHO OFF
cls
echo.
echo.
echo.
echo     NOTE: You must select on the SERVER computer first.         (X to Exit)
echo.
echo     PRESS 1 TO MAKE THIS COMPUTER THE CLIENT (MASTER).
echo.
echo     PRESS 2 TO MAKE THIS COMPUTER THE SERVER (SLAVE). 
CHOICE /c:12x /n > nul
if errorlevel 3 goto END
if errorlevel 2 goto 2 rem -- (client)
goto 1 rem -- (master/client)

:1 rem -- (master/client)
  cls
  rem -- Adjust these to meet your drive needs --
  rem -- This assigns D on the master to read A on the slave, etc. --
  rem -- Ignore CD-ROM letter, it can't be assigned. --
  INTERLNK D=A
  INTERLNK E=C
  goto END

:2 rem -- (slave/server)
  cls
  INTERSVR
  echo.
  echo.
  echo           THIS COMPUTER IS NO LONGER IN SERVER MODE
  echo.
  goto END

:END

Cheers, Mac

[MacFromOK]

BTW, I think Windows "Direct Cable Connection" only
works if both computers have Windows 95 or later...

Cheers, Mac

[The DOS Machine]

Very Good Mac!

BTW, why is it that you seem to have a batch file for everything?

-DOSMAN

[MacFromOK]

Well, my first comp (286-16) was a DOS only
machine, and I learned to program in DOS.

Also, while Windows and I get along now,
we've never really become friends...

[The DOS Machine]

^ I can easily relate to THAT!

[The DOS Machine]

Ok, I have not been able to find much info about parallel transfers. It is possible, right?? Also, I would need a special "null"-type parallel cable for the transfer, right?

As for the breakout box: It is still an option, but I can only find RS-232 breakout boxes. The one seen here and here is the most common. It says that it is only for the serial interface. How is that possible? Since it connects all 25 lines(24 are modifiable), shouldn't it work with parallel? I can understand that the LED labels and the pinout guide on the lid would be for serial only, but if I had an external reference for modifying the parallel interface, then I should be able to with this box, right?

Then again, a breakout box would not be needed for the parallel interface IF the cable does not need to be "special". I don't know since all of my technical material focuses on serial and not parallel.

At JDR Microdevices, they have two cables of interest along with their selection of null-modem serial cables. One is called the Universal Serial Cable, Item # CBL-MULTI-SER. It is a null-modem cable that has both DB25 and DB09 female connectors at BOTH ends for maximum flexibility. The second cable is the parallel LAPLINK cable, Item # CBL-LAPLINK. It has two DB25 male connectors. Now, as to what is the difference between this cable and their CBL-DB25MM-E, I could not tell you.

I would also not know the difference between their serial cables with two DB25 male connectors and the above parallel cables, but I figure that they might not connect all of the pins to each other to save money. I was under the assumption that ALL cables had ALL of their connectors connected, but that is probably not the case.

Anyway, feel free to help me out!

-DOSMAN

[MacFromOK]

Can't help you out much here Dosman, all I
ever used were null-modem cables. I think
LapLink is quite a bit faster for file transfer
than the DOS InterLink program.

All my null-modem cables have dual ends (9
and 25 pin). I originally bought em' to link 2
486s together to play DOOM. I have played
QUAKE2 with a null-modem cable in Win95,
but it was kinda pushing the limit.

BTW, I said earlier that I had only used 10 ft
cables, but I remember that I did make a 15 ft
or so extension cable that plugged into one of
the extra ends on a null modem cable. I had 3
computers, and just disconnected the one I
wasn't accessing at the time. It kept me from
dragging cables all over the place...

Hopefully someone else has more info.

Cheers, Mac

[Lurker1]

Hi DOSMAN

Most serial cables (even the ones with 25 pins) only actually have 9 pins connected. That is why you can use a nine pin to 25 pin adaptor and have it work.
http://www.rfcafe.com/references/ele...ort_pinout.htm

Parallel ports use more pins in the cable but still only have the used pins wired (to save on manufacturing costs)

http://www.rfcafe.com/references/ele...ort_pinout.htm

Most of the parallel to parallel cables I have used were only 6 feet long.

[The DOS Machine]

^ That helped a lot, Lurker1! I figured that they did not connect all of the pins to each other, and since serial and parallel standards differ as to what pins to use, a cable with pins made for just one of the interfaces would not work with the other interface.

As for the breakout box: The box I was looking at had the ground line for the serial interface directly connected and not modifiable. Parallel assigns different pins to the ground lines. Apparently, parallel breakout boxes have to have added hardware to make sure that the parallel signals are not interrupted. I found a couple of combined parallel and serial breakout boxes, but they are, of course, far too expensive. I guess I will get either a parallel or null-modem serial cable for my transfer.

However...

Wouldn't it be interesting if someone made a cable with both DB25 and DB09 connectors at BOTH ends of the cable, but still had all of the pins connected(!)? Then, you would be able to use it for both parallel(DB25) and serial(DB25,09) interfaces. It would not matter that the two interfaces use different pins since all of them would be connected. It would truly be the "all-purpose" cable, albeit expensive.

If no one makes such a cable, then maybe I should make my own!

-DOSMAN

[Lurker1]

Hi DOSMAN

Interresting thought about the cable except that a parallel cable would require male connectors and a serial cable needs female connectors. Have you thought about that?.

[The DOS Machine]

^-Good you caught that Lurker1!

I could still use gender changers though, but I would have to make sure that THEY connect all of the pins as well! This is getting complicated!

(Hmm, I wonder if I could put THREE connectors at each end of the cable! )

Of course, creating this cable myself would be a major and expensive undertaking. Consequently, there is little chance that I would actually build it. Also, I am not sure if this custom designed cable with so many parts and at least one open connector would interfere with the serial and parallel signals during use.

It is a good idea though, especially for PC sales/repair shops and professionals!

-DOSMAN