What will we need?  - A computer running linux OS (Red Hat 7.0 in our case).  - An old 8088 or 8086 computer (will also work for any kind of PC like 286, 386, 486,Pentium, K6-II,K7 or higher).  - A Serial cable to connect both computers (called null-modem cable).  - A Boot disk for the 8086 and a clean disk for software we will need.

Let's put our hands on.

Go to  your linux box and look for the file /etc/inittab

Add this line at the bottom using your favorite text editor: (if you don't know how try: emacs /etc/inittab ,pico /etc/inittab or vi /etc/inittab
S1:23456:respawn:/sbin/getty ttyS1 DT9600 vt320
Save the file (Ctrl-x s) if you use emacs and exit (Ctrl-x c)
This will allow serial connections on this computer using ttyS1 wich is COM2 in dos eviroments(change it ot ttyS0 if you want to use COM1)

Details:

S1 is the name we choose for this line.
23456 are the run levels.
respawn means that if the process gets killed turn it on again (do you remember -respawn option in Doom2?).
/sbin/getty is the command we are going to use.
DT9600 is the serial port speed we'll use 9600 is the highest speed for old PC XT computers.
vt320 is the kind of terminal emulation.

now we must be sure that we getty command is available in our linux box, lets search it:
whereis getty
or a more deeper search:
find / -name 'getty'
If the file is not on our system as it's in our case (Red Hat 7.0), we must install it.
For RH 7.0 mount your cd-rom (mount /dev/cdrom)get the second CD and look at /RedHat/RPMS/getty_ps-2.0.7j-12.i386.rpm
We need to install it, type: rpm -i /mnt/cdrom/RedHat/RPMS/getty_ps-2.0.7j-12.i386.rpm
It'll be installed on /sbin/getty, if you don't have the 2 CD or you're using other linux distribution you can donwload getty from:
http://www.zbottech.com/d/wd/112.htm
Now once is getty on the system we need to make system read /etc/inittab again, type: init q or if you want reboot the system(but it's not necessary).
 

Now is time to connect the cable between the computers and turn on our old XT PC.
It's not necessary that the old computer have a hard disk, you'll only need a ms-dos boot disk (ms-dos 6.2 in our case) boot the system pressing SHIFT to not load any devices nor any memory managers. Then download this file: Kermit 3.12 and unzip it on another disk (or if you have enougth disk space on the same boot disk). Kermit is a MS-DOS terminal emulator utility the 3.12 version is an ancient one, but it's small in size. For running Kermit in a modern computer you will need a newer version due to "division by 0" error, you can download it from:
http://www.columbia.edu/kermit/
Edit the mskermit.ini bottom lines to set it to your XT com port (it's set to port1 that's COM1), edit only if you use COM2 (set port 2)
Then it's time to run Kermit on your 8086, put the floppy disk on the disk drive and type: kermit
wait and press 'c' and press a few enters, you will see the login screen.

You are now using your XT PC as a dumb terminal for you linux box.