Based on kernel version 4.2. Page generated on 2015-09-09 12:14 EST.
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 <email@example.com>