Documentation/s390/3270.txt

   1 IBM 3270 Display System support
   2
   3 This file describes the driver that supports local channel attachment
   4 of IBM 3270 devices.  It consists of three sections:
   5         * Introduction
   6         * Installation
   7         * Operation
   8
   9
  10 INTRODUCTION.
  11
  12 This paper describes installing and operating 3270 devices under
  13 Linux/390.  A 3270 device is a block-mode rows-and-columns terminal of
  14 which I'm sure hundreds of millions were sold by IBM and clonemakers
  15 twenty and thirty years ago.
  16
  17 You may have 3270s in-house and not know it.  If you're using the
  18 VM-ESA operating system, define a 3270 to your virtual machine by using
  19 the command "DEF GRAF <hex-address>"  This paper presumes you will be
  20 defining four 3270s with the CP/CMS commands
  21
  22         DEF GRAF 620
  23         DEF GRAF 621
  24         DEF GRAF 622
  25         DEF GRAF 623
  26
  27 Your network connection from VM-ESA allows you to use x3270, tn3270, or
  28 another 3270 emulator, started from an xterm window on your PC or
  29 workstation.  With the DEF GRAF command, an application such as xterm,
  30 and this Linux-390 3270 driver, you have another way of talking to your
  31 Linux box.
  32
  33 This paper covers installation of the driver and operation of a
  34 dialed-in x3270.
  35
  36
  37 INSTALLATION.
  38
  39 You install the driver by installing a patch, doing a kernel build, and
  40 running the configuration script (config3270.sh, in this directory).
  41
  42 WARNING:  If you are using 3270 console support, you must rerun the
  43 configuration script every time you change the console's address (perhaps
  44 by using the condev= parameter in silo's /boot/parmfile).  More precisely,
  45 you should rerun the configuration script every time your set of 3270s,
  46 including the console 3270, changes subchannel identifier relative to
  47 one another.  ReIPL as soon as possible after running the configuration
  48 script and the resulting /tmp/mkdev3270.
  49
  50 If you have chosen to make tub3270 a module, you add a line to a
  51 configuration file under /etc/modprobe.d/.  If you are working on a VM
  52 virtual machine, you can use DEF GRAF to define virtual 3270 devices.
  53
  54 You may generate both 3270 and 3215 console support, or one or the
  55 other, or neither.  If you generate both, the console type under VM is
  56 not changed.  Use #CP Q TERM to see what the current console type is.
  57 Use #CP TERM CONMODE 3270 to change it to 3270.  If you generate only
  58 3270 console support, then the driver automatically converts your console
  59 at boot time to a 3270 if it is a 3215.
  60
  61 In brief, these are the steps:
  62         1. Install the tub3270 patch
  63         2. (If a module) add a line to a file in /etc/modprobe.d/*.conf
  64         3. (If VM) define devices with DEF GRAF
  65         4. Reboot
  66         5. Configure
  67
  68 To test that everything works, assuming VM and x3270,
  69         1. Bring up an x3270 window.
  70         2. Use the DIAL command in that window.
  71         3. You should immediately see a Linux login screen.
  72
  73 Here are the installation steps in detail:
  74
  75         1.  The 3270 driver is a part of the official Linux kernel
  76         source.  Build a tree with the kernel source and any necessary
  77         patches.  Then do
  78                 make oldconfig
  79                 (If you wish to disable 3215 console support, edit
  80                 .config; change CONFIG_TN3215's value to "n";
  81                 and rerun "make oldconfig".)
  82                 make image
  83                 make modules
  84                 make modules_install
  85
  86         2. (Perform this step only if you have configured tub3270 as a
  87         module.)  Add a line to a file /etc/modprobe.d/*.conf to automatically
  88         load the driver when it's needed.  With this line added, you will see
  89         login prompts appear on your 3270s as soon as boot is complete (or
  90         with emulated 3270s, as soon as you dial into your vm guest using the
  91         command "DIAL <vmguestname>").  Since the line-mode major number is
  92         227, the line to add should be:
  93                 alias char-major-227 tub3270
  94
  95         3. Define graphic devices to your vm guest machine, if you
  96         haven't already.  Define them before you reboot (reipl):
  97                 DEFINE GRAF 620
  98                 DEFINE GRAF 621
  99                 DEFINE GRAF 622
 100                 DEFINE GRAF 623
 101
 102         4. Reboot.  The reboot process scans hardware devices, including
 103         3270s, and this enables the tub3270 driver once loaded to respond
 104         correctly to the configuration requests of the next step.  If
 105         you have chosen 3270 console support, your console now behaves
 106         as a 3270, not a 3215.
 107
 108         5. Run the 3270 configuration script config3270.  It is
 109         distributed in this same directory, Documentation/s390, as
 110         config3270.sh.  Inspect the output script it produces,
 111         /tmp/mkdev3270, and then run that script.  This will create the
 112         necessary character special device files and make the necessary
 113         changes to /etc/inittab.
 114
 115         Then notify /sbin/init that /etc/inittab has changed, by issuing
 116         the telinit command with the q operand:
 117                 cd Documentation/s390
 118                 sh config3270.sh
 119                 sh /tmp/mkdev3270
 120                 telinit q
 121
 122         This should be sufficient for your first time.  If your 3270
 123         configuration has changed and you're reusing config3270, you
 124         should follow these steps:
 125                 Change 3270 configuration
 126                 Reboot
 127                 Run config3270 and /tmp/mkdev3270
 128                 Reboot
 129
 130 Here are the testing steps in detail:
 131
 132         1. Bring up an x3270 window, or use an actual hardware 3278 or
 133         3279, or use the 3270 emulator of your choice.  You would be
 134         running the emulator on your PC or workstation.  You would use
 135         the command, for example,
 136                 x3270 vm-esa-domain-name &
 137         if you wanted a 3278 Model 4 with 43 rows of 80 columns, the
 138         default model number.  The driver does not take advantage of
 139         extended attributes.
 140
 141         The screen you should now see contains a VM logo with input
 142         lines near the bottom.  Use TAB to move to the bottom line,
 143         probably labeled "COMMAND  ===>".
 144
 145         2. Use the DIAL command instead of the LOGIN command to connect
 146         to one of the virtual 3270s you defined with the DEF GRAF
 147         commands:
 148                 dial my-vm-guest-name
 149
 150         3. You should immediately see a login prompt from your
 151         Linux-390 operating system.  If that does not happen, you would
 152         see instead the line "DIALED TO my-vm-guest-name   0620".
 153
 154         To troubleshoot:  do these things.
 155
 156         A. Is the driver loaded?  Use the lsmod command (no operands)
 157         to find out.  Probably it isn't.  Try loading it manually, with
 158         the command "insmod tub3270".  Does that command give error
 159         messages?  Ha!  There's your problem.
 160
 161         B. Is the /etc/inittab file modified as in installation step 3
 162         above?  Use the grep command to find out; for instance, issue
 163         "grep 3270 /etc/inittab".  Nothing found?  There's your
 164         problem!
 165
 166         C. Are the device special files created, as in installation
 167         step 2 above?  Use the ls -l command to find out; for instance,
 168         issue "ls -l /dev/3270/tty620".  The output should start with the
 169         letter "c" meaning character device and should contain "227, 1"
 170         just to the left of the device name.  No such file?  no "c"?
 171         Wrong major number?  Wrong minor number?  There's your
 172         problem!
 173
 174         D. Do you get the message
 175                  "HCPDIA047E my-vm-guest-name 0620 does not exist"?
 176         If so, you must issue the command "DEF GRAF 620" from your VM
 177         3215 console and then reboot the system.
 178
 179
 180
 181 OPERATION.
 182
 183 The driver defines three areas on the 3270 screen:  the log area, the
 184 input area, and the status area.
 185
 186 The log area takes up all but the bottom two lines of the screen.  The
 187 driver writes terminal output to it, starting at the top line and going
 188 down.  When it fills, the status area changes from "Linux Running" to
 189 "Linux More...".  After a scrolling timeout of (default) 5 sec, the
 190 screen clears and more output is written, from the top down.
 191
 192 The input area extends from the beginning of the second-to-last screen
 193 line to the start of the status area.  You type commands in this area
 194 and hit ENTER to execute them.
 195
 196 The status area initializes to "Linux Running" to give you a warm
 197 fuzzy feeling.  When the log area fills up and output awaits, it
 198 changes to "Linux More...".  At this time you can do several things or
 199 nothing.  If you do nothing, the screen will clear in (default) 5 sec
 200 and more output will appear.  You may hit ENTER with nothing typed in
 201 the input area to toggle between "Linux More..." and "Linux Holding",
 202 which indicates no scrolling will occur.  (If you hit ENTER with "Linux
 203 Running" and nothing typed, the application receives a newline.)
 204
 205 You may change the scrolling timeout value.  For example, the following
 206 command line:
 207         echo scrolltime=60 > /proc/tty/driver/tty3270
 208 changes the scrolling timeout value to 60 sec.  Set scrolltime to 0 if
 209 you wish to prevent scrolling entirely.
 210
 211 Other things you may do when the log area fills up are:  hit PA2 to
 212 clear the log area and write more output to it, or hit CLEAR to clear
 213 the log area and the input area and write more output to the log area.
 214
 215 Some of the Program Function (PF) and Program Attention (PA) keys are
 216 preassigned special functions.  The ones that are not yield an alarm
 217 when pressed.
 218
 219 PA1 causes a SIGINT to the currently running application.  You may do
 220 the same thing from the input area, by typing "^C" and hitting ENTER.
 221
 222 PA2 causes the log area to be cleared.  If output awaits, it is then
 223 written to the log area.
 224
 225 PF3 causes an EOF to be received as input by the application.  You may
 226 cause an EOF also by typing "^D" and hitting ENTER.
 227
 228 No PF key is preassigned to cause a job suspension, but you may cause a
 229 job suspension by typing "^Z" and hitting ENTER.  You may wish to
 230 assign this function to a PF key.  To make PF7 cause job suspension,
 231 execute the command:
 232         echo pf7=^z > /proc/tty/driver/tty3270
 233
 234 If the input you type does not end with the two characters "^n", the
 235 driver appends a newline character and sends it to the tty driver;
 236 otherwise the driver strips the "^n" and does not append a newline.
 237 The IBM 3215 driver behaves similarly.
 238
 239 Pf10 causes the most recent command to be retrieved from the tube's
 240 command stack (default depth 20) and displayed in the input area.  You
 241 may hit PF10 again for the next-most-recent command, and so on.  A
 242 command is entered into the stack only when the input area is not made
 243 invisible (such as for password entry) and it is not identical to the
 244 current top entry.  PF10 rotates backward through the command stack;
 245 PF11 rotates forward.  You may assign the backward function to any PF
 246 key (or PA key, for that matter), say, PA3, with the command:
 247         echo -e pa3=\\033k > /proc/tty/driver/tty3270
 248 This assigns the string ESC-k to PA3.  Similarly, the string ESC-j
 249 performs the forward function.  (Rationale:  In bash with vi-mode line
 250 editing, ESC-k and ESC-j retrieve backward and forward history.
 251 Suggestions welcome.)
 252
 253 Is a stack size of twenty commands not to your liking?  Change it on
 254 the fly.  To change to saving the last 100 commands, execute the
 255 command:
 256         echo recallsize=100 > /proc/tty/driver/tty3270
 257
 258 Have a command you issue frequently?  Assign it to a PF or PA key!  Use
 259 the command
 260         echo pf24="mkdir foobar; cd foobar" > /proc/tty/driver/tty3270
 261 to execute the commands mkdir foobar and cd foobar immediately when you
 262 hit PF24.  Want to see the command line first, before you execute it?
 263 Use the -n option of the echo command:
 264         echo -n pf24="mkdir foo; cd foo" > /proc/tty/driver/tty3270
 265
 266
 267
 268 Happy testing!  I welcome any and all comments about this document, the
 269 driver, etc etc.
 270
 271 Dick Hitt <rbh00@utsglobal.com>