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
  51 /etc/modprobe.conf.  If you are working on a VM virtual machine, you
  52 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 /etc/modprobe.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 /etc/modprobe.conf to automatically
  88         load the driver when it's needed.  With this line added,
  89         you will see login prompts appear on your 3270s as soon as
  90         boot is complete (or with emulated 3270s, as soon as you dial
  91         into your vm guest using the command "DIAL <vmguestname>").
  92         Since the line-mode major number is 227, the line to add to
  93         /etc/modprobe.conf should be:
  94                 alias char-major-227 tub3270
  95
  96         3. Define graphic devices to your vm guest machine, if you
  97         haven't already.  Define them before you reboot (reipl):
  98                 DEFINE GRAF 620
  99                 DEFINE GRAF 621
 100                 DEFINE GRAF 622
 101                 DEFINE GRAF 623
 102
 103         4. Reboot.  The reboot process scans hardware devices, including
 104         3270s, and this enables the tub3270 driver once loaded to respond
 105         correctly to the configuration requests of the next step.  If
 106         you have chosen 3270 console support, your console now behaves
 107         as a 3270, not a 3215.
 108
 109         5. Run the 3270 configuration script config3270.  It is
 110         distributed in this same directory, Documentation/s390, as
 111         config3270.sh.  Inspect the output script it produces,
 112         /tmp/mkdev3270, and then run that script.  This will create the
 113         necessary character special device files and make the necessary
 114         changes to /etc/inittab.
 115
 116         Then notify /sbin/init that /etc/inittab has changed, by issuing
 117         the telinit command with the q operand:
 118                 cd Documentation/s390
 119                 sh config3270.sh
 120                 sh /tmp/mkdev3270
 121                 telinit q
 122
 123         This should be sufficient for your first time.  If your 3270
 124         configuration has changed and you're reusing config3270, you
 125         should follow these steps:
 126                 Change 3270 configuration
 127                 Reboot
 128                 Run config3270 and /tmp/mkdev3270
 129                 Reboot
 130
 131 Here are the testing steps in detail:
 132
 133         1. Bring up an x3270 window, or use an actual hardware 3278 or
 134         3279, or use the 3270 emulator of your choice.  You would be
 135         running the emulator on your PC or workstation.  You would use
 136         the command, for example,
 137                 x3270 vm-esa-domain-name &
 138         if you wanted a 3278 Model 4 with 43 rows of 80 columns, the
 139         default model number.  The driver does not take advantage of
 140         extended attributes.
 141
 142         The screen you should now see contains a VM logo with input
 143         lines near the bottom.  Use TAB to move to the bottom line,
 144         probably labeled "COMMAND  ===>".
 145
 146         2. Use the DIAL command instead of the LOGIN command to connect
 147         to one of the virtual 3270s you defined with the DEF GRAF
 148         commands:
 149                 dial my-vm-guest-name
 150
 151         3. You should immediately see a login prompt from your
 152         Linux-390 operating system.  If that does not happen, you would
 153         see instead the line "DIALED TO my-vm-guest-name   0620".
 154
 155         To troubleshoot:  do these things.
 156
 157         A. Is the driver loaded?  Use the lsmod command (no operands)
 158         to find out.  Probably it isn't.  Try loading it manually, with
 159         the command "insmod tub3270".  Does that command give error
 160         messages?  Ha!  There's your problem.
 161
 162         B. Is the /etc/inittab file modified as in installation step 3
 163         above?  Use the grep command to find out; for instance, issue
 164         "grep 3270 /etc/inittab".  Nothing found?  There's your
 165         problem!
 166
 167         C. Are the device special files created, as in installation
 168         step 2 above?  Use the ls -l command to find out; for instance,
 169         issue "ls -l /dev/3270/tty620".  The output should start with the
 170         letter "c" meaning character device and should contain "227, 1"
 171         just to the left of the device name.  No such file?  no "c"?
 172         Wrong major number?  Wrong minor number?  There's your
 173         problem!
 174
 175         D. Do you get the message
 176                  "HCPDIA047E my-vm-guest-name 0620 does not exist"?
 177         If so, you must issue the command "DEF GRAF 620" from your VM
 178         3215 console and then reboot the system.
 179
 180
 181
 182 OPERATION.
 183
 184 The driver defines three areas on the 3270 screen:  the log area, the
 185 input area, and the status area.
 186
 187 The log area takes up all but the bottom two lines of the screen.  The
 188 driver writes terminal output to it, starting at the top line and going
 189 down.  When it fills, the status area changes from "Linux Running" to
 190 "Linux More...".  After a scrolling timeout of (default) 5 sec, the
 191 screen clears and more output is written, from the top down.
 192
 193 The input area extends from the beginning of the second-to-last screen
 194 line to the start of the status area.  You type commands in this area
 195 and hit ENTER to execute them.
 196
 197 The status area initializes to "Linux Running" to give you a warm
 198 fuzzy feeling.  When the log area fills up and output awaits, it
 199 changes to "Linux More...".  At this time you can do several things or
 200 nothing.  If you do nothing, the screen will clear in (default) 5 sec
 201 and more output will appear.  You may hit ENTER with nothing typed in
 202 the input area to toggle between "Linux More..." and "Linux Holding",
 203 which indicates no scrolling will occur.  (If you hit ENTER with "Linux
 204 Running" and nothing typed, the application receives a newline.)
 205
 206 You may change the scrolling timeout value.  For example, the following
 207 command line:
 208         echo scrolltime=60 > /proc/tty/driver/tty3270
 209 changes the scrolling timeout value to 60 sec.  Set scrolltime to 0 if
 210 you wish to prevent scrolling entirely.
 211
 212 Other things you may do when the log area fills up are:  hit PA2 to
 213 clear the log area and write more output to it, or hit CLEAR to clear
 214 the log area and the input area and write more output to the log area.
 215
 216 Some of the Program Function (PF) and Program Attention (PA) keys are
 217 preassigned special functions.  The ones that are not yield an alarm
 218 when pressed.
 219
 220 PA1 causes a SIGINT to the currently running application.  You may do
 221 the same thing from the input area, by typing "^C" and hitting ENTER.
 222
 223 PA2 causes the log area to be cleared.  If output awaits, it is then
 224 written to the log area.
 225
 226 PF3 causes an EOF to be received as input by the application.  You may
 227 cause an EOF also by typing "^D" and hitting ENTER.
 228
 229 No PF key is preassigned to cause a job suspension, but you may cause a
 230 job suspension by typing "^Z" and hitting ENTER.  You may wish to
 231 assign this function to a PF key.  To make PF7 cause job suspension,
 232 execute the command:
 233         echo pf7=^z > /proc/tty/driver/tty3270
 234
 235 If the input you type does not end with the two characters "^n", the
 236 driver appends a newline character and sends it to the tty driver;
 237 otherwise the driver strips the "^n" and does not append a newline.
 238 The IBM 3215 driver behaves similarly.
 239
 240 Pf10 causes the most recent command to be retrieved from the tube's
 241 command stack (default depth 20) and displayed in the input area.  You
 242 may hit PF10 again for the next-most-recent command, and so on.  A
 243 command is entered into the stack only when the input area is not made
 244 invisible (such as for password entry) and it is not identical to the
 245 current top entry.  PF10 rotates backward through the command stack;
 246 PF11 rotates forward.  You may assign the backward function to any PF
 247 key (or PA key, for that matter), say, PA3, with the command:
 248         echo -e pa3=\\033k > /proc/tty/driver/tty3270
 249 This assigns the string ESC-k to PA3.  Similarly, the string ESC-j
 250 performs the forward function.  (Rationale:  In bash with vi-mode line
 251 editing, ESC-k and ESC-j retrieve backward and forward history.
 252 Suggestions welcome.)
 253
 254 Is a stack size of twenty commands not to your liking?  Change it on
 255 the fly.  To change to saving the last 100 commands, execute the
 256 command:
 257         echo recallsize=100 > /proc/tty/driver/tty3270
 258
 259 Have a command you issue frequently?  Assign it to a PF or PA key!  Use
 260 the command
 261         echo pf24="mkdir foobar; cd foobar" > /proc/tty/driver/tty3270
 262 to execute the commands mkdir foobar and cd foobar immediately when you
 263 hit PF24.  Want to see the command line first, before you execute it?
 264 Use the -n option of the echo command:
 265         echo -n pf24="mkdir foo; cd foo" > /proc/tty/driver/tty3270
 266
 267
 268
 269 Happy testing!  I welcome any and all comments about this document, the
 270 driver, etc etc.
 271
 272 Dick Hitt <rbh00@utsglobal.com>