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298 lines
11 KiB
298 lines
11 KiB
=============================== |
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IBM 3270 Display System support |
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=============================== |
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This file describes the driver that supports local channel attachment |
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of IBM 3270 devices. It consists of three sections: |
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* Introduction |
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* Installation |
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* Operation |
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Introduction |
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============ |
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This paper describes installing and operating 3270 devices under |
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Linux/390. A 3270 device is a block-mode rows-and-columns terminal of |
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which I'm sure hundreds of millions were sold by IBM and clonemakers |
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twenty and thirty years ago. |
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You may have 3270s in-house and not know it. If you're using the |
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VM-ESA operating system, define a 3270 to your virtual machine by using |
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the command "DEF GRAF <hex-address>" This paper presumes you will be |
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defining four 3270s with the CP/CMS commands: |
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- DEF GRAF 620 |
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- DEF GRAF 621 |
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- DEF GRAF 622 |
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- DEF GRAF 623 |
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Your network connection from VM-ESA allows you to use x3270, tn3270, or |
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another 3270 emulator, started from an xterm window on your PC or |
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workstation. With the DEF GRAF command, an application such as xterm, |
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and this Linux-390 3270 driver, you have another way of talking to your |
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Linux box. |
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This paper covers installation of the driver and operation of a |
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dialed-in x3270. |
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Installation |
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============ |
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You install the driver by installing a patch, doing a kernel build, and |
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running the configuration script (config3270.sh, in this directory). |
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WARNING: If you are using 3270 console support, you must rerun the |
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configuration script every time you change the console's address (perhaps |
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by using the condev= parameter in silo's /boot/parmfile). More precisely, |
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you should rerun the configuration script every time your set of 3270s, |
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including the console 3270, changes subchannel identifier relative to |
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one another. ReIPL as soon as possible after running the configuration |
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script and the resulting /tmp/mkdev3270. |
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If you have chosen to make tub3270 a module, you add a line to a |
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configuration file under /etc/modprobe.d/. If you are working on a VM |
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virtual machine, you can use DEF GRAF to define virtual 3270 devices. |
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You may generate both 3270 and 3215 console support, or one or the |
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other, or neither. If you generate both, the console type under VM is |
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not changed. Use #CP Q TERM to see what the current console type is. |
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Use #CP TERM CONMODE 3270 to change it to 3270. If you generate only |
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3270 console support, then the driver automatically converts your console |
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at boot time to a 3270 if it is a 3215. |
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In brief, these are the steps: |
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1. Install the tub3270 patch |
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2. (If a module) add a line to a file in `/etc/modprobe.d/*.conf` |
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3. (If VM) define devices with DEF GRAF |
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4. Reboot |
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5. Configure |
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To test that everything works, assuming VM and x3270, |
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1. Bring up an x3270 window. |
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2. Use the DIAL command in that window. |
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3. You should immediately see a Linux login screen. |
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Here are the installation steps in detail: |
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1. The 3270 driver is a part of the official Linux kernel |
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source. Build a tree with the kernel source and any necessary |
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patches. Then do:: |
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make oldconfig |
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(If you wish to disable 3215 console support, edit |
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.config; change CONFIG_TN3215's value to "n"; |
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and rerun "make oldconfig".) |
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make image |
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make modules |
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make modules_install |
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2. (Perform this step only if you have configured tub3270 as a |
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module.) Add a line to a file `/etc/modprobe.d/*.conf` to automatically |
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load the driver when it's needed. With this line added, you will see |
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login prompts appear on your 3270s as soon as boot is complete (or |
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with emulated 3270s, as soon as you dial into your vm guest using the |
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command "DIAL <vmguestname>"). Since the line-mode major number is |
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227, the line to add should be:: |
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alias char-major-227 tub3270 |
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3. Define graphic devices to your vm guest machine, if you |
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haven't already. Define them before you reboot (reipl): |
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- DEFINE GRAF 620 |
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- DEFINE GRAF 621 |
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- DEFINE GRAF 622 |
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- DEFINE GRAF 623 |
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4. Reboot. The reboot process scans hardware devices, including |
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3270s, and this enables the tub3270 driver once loaded to respond |
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correctly to the configuration requests of the next step. If |
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you have chosen 3270 console support, your console now behaves |
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as a 3270, not a 3215. |
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5. Run the 3270 configuration script config3270. It is |
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distributed in this same directory, Documentation/s390, as |
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config3270.sh. Inspect the output script it produces, |
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/tmp/mkdev3270, and then run that script. This will create the |
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necessary character special device files and make the necessary |
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changes to /etc/inittab. |
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Then notify /sbin/init that /etc/inittab has changed, by issuing |
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the telinit command with the q operand:: |
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cd Documentation/s390 |
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sh config3270.sh |
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sh /tmp/mkdev3270 |
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telinit q |
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This should be sufficient for your first time. If your 3270 |
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configuration has changed and you're reusing config3270, you |
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should follow these steps:: |
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Change 3270 configuration |
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Reboot |
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Run config3270 and /tmp/mkdev3270 |
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Reboot |
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Here are the testing steps in detail: |
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1. Bring up an x3270 window, or use an actual hardware 3278 or |
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3279, or use the 3270 emulator of your choice. You would be |
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running the emulator on your PC or workstation. You would use |
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the command, for example:: |
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x3270 vm-esa-domain-name & |
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if you wanted a 3278 Model 4 with 43 rows of 80 columns, the |
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default model number. The driver does not take advantage of |
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extended attributes. |
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The screen you should now see contains a VM logo with input |
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lines near the bottom. Use TAB to move to the bottom line, |
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probably labeled "COMMAND ===>". |
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2. Use the DIAL command instead of the LOGIN command to connect |
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to one of the virtual 3270s you defined with the DEF GRAF |
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commands:: |
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dial my-vm-guest-name |
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3. You should immediately see a login prompt from your |
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Linux-390 operating system. If that does not happen, you would |
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see instead the line "DIALED TO my-vm-guest-name 0620". |
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To troubleshoot: do these things. |
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A. Is the driver loaded? Use the lsmod command (no operands) |
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to find out. Probably it isn't. Try loading it manually, with |
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the command "insmod tub3270". Does that command give error |
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messages? Ha! There's your problem. |
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B. Is the /etc/inittab file modified as in installation step 3 |
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above? Use the grep command to find out; for instance, issue |
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"grep 3270 /etc/inittab". Nothing found? There's your |
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problem! |
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C. Are the device special files created, as in installation |
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step 2 above? Use the ls -l command to find out; for instance, |
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issue "ls -l /dev/3270/tty620". The output should start with the |
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letter "c" meaning character device and should contain "227, 1" |
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just to the left of the device name. No such file? no "c"? |
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Wrong major number? Wrong minor number? There's your |
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problem! |
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D. Do you get the message:: |
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"HCPDIA047E my-vm-guest-name 0620 does not exist"? |
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If so, you must issue the command "DEF GRAF 620" from your VM |
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3215 console and then reboot the system. |
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OPERATION. |
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========== |
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The driver defines three areas on the 3270 screen: the log area, the |
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input area, and the status area. |
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The log area takes up all but the bottom two lines of the screen. The |
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driver writes terminal output to it, starting at the top line and going |
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down. When it fills, the status area changes from "Linux Running" to |
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"Linux More...". After a scrolling timeout of (default) 5 sec, the |
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screen clears and more output is written, from the top down. |
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The input area extends from the beginning of the second-to-last screen |
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line to the start of the status area. You type commands in this area |
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and hit ENTER to execute them. |
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The status area initializes to "Linux Running" to give you a warm |
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fuzzy feeling. When the log area fills up and output awaits, it |
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changes to "Linux More...". At this time you can do several things or |
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nothing. If you do nothing, the screen will clear in (default) 5 sec |
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and more output will appear. You may hit ENTER with nothing typed in |
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the input area to toggle between "Linux More..." and "Linux Holding", |
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which indicates no scrolling will occur. (If you hit ENTER with "Linux |
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Running" and nothing typed, the application receives a newline.) |
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You may change the scrolling timeout value. For example, the following |
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command line:: |
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echo scrolltime=60 > /proc/tty/driver/tty3270 |
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changes the scrolling timeout value to 60 sec. Set scrolltime to 0 if |
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you wish to prevent scrolling entirely. |
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Other things you may do when the log area fills up are: hit PA2 to |
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clear the log area and write more output to it, or hit CLEAR to clear |
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the log area and the input area and write more output to the log area. |
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Some of the Program Function (PF) and Program Attention (PA) keys are |
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preassigned special functions. The ones that are not yield an alarm |
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when pressed. |
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PA1 causes a SIGINT to the currently running application. You may do |
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the same thing from the input area, by typing "^C" and hitting ENTER. |
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PA2 causes the log area to be cleared. If output awaits, it is then |
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written to the log area. |
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PF3 causes an EOF to be received as input by the application. You may |
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cause an EOF also by typing "^D" and hitting ENTER. |
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No PF key is preassigned to cause a job suspension, but you may cause a |
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job suspension by typing "^Z" and hitting ENTER. You may wish to |
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assign this function to a PF key. To make PF7 cause job suspension, |
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execute the command:: |
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echo pf7=^z > /proc/tty/driver/tty3270 |
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If the input you type does not end with the two characters "^n", the |
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driver appends a newline character and sends it to the tty driver; |
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otherwise the driver strips the "^n" and does not append a newline. |
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The IBM 3215 driver behaves similarly. |
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Pf10 causes the most recent command to be retrieved from the tube's |
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command stack (default depth 20) and displayed in the input area. You |
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may hit PF10 again for the next-most-recent command, and so on. A |
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command is entered into the stack only when the input area is not made |
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invisible (such as for password entry) and it is not identical to the |
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current top entry. PF10 rotates backward through the command stack; |
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PF11 rotates forward. You may assign the backward function to any PF |
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key (or PA key, for that matter), say, PA3, with the command:: |
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echo -e pa3=\\033k > /proc/tty/driver/tty3270 |
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This assigns the string ESC-k to PA3. Similarly, the string ESC-j |
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performs the forward function. (Rationale: In bash with vi-mode line |
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editing, ESC-k and ESC-j retrieve backward and forward history. |
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Suggestions welcome.) |
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Is a stack size of twenty commands not to your liking? Change it on |
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the fly. To change to saving the last 100 commands, execute the |
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command:: |
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echo recallsize=100 > /proc/tty/driver/tty3270 |
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Have a command you issue frequently? Assign it to a PF or PA key! Use |
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the command:: |
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echo pf24="mkdir foobar; cd foobar" > /proc/tty/driver/tty3270 |
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to execute the commands mkdir foobar and cd foobar immediately when you |
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hit PF24. Want to see the command line first, before you execute it? |
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Use the -n option of the echo command:: |
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echo -n pf24="mkdir foo; cd foo" > /proc/tty/driver/tty3270 |
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Happy testing! I welcome any and all comments about this document, the |
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driver, etc etc. |
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Dick Hitt <[email protected]>
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