275 lines
11 KiB
Plaintext
275 lines
11 KiB
Plaintext
IBM 3270 Display System support
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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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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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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
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/etc/modprobe.conf. If you are working on a VM virtual machine, you
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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 /etc/modprobe.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 /etc/modprobe.conf to automatically
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load the driver when it's needed. With this line added,
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you will see login prompts appear on your 3270s as soon as
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boot is complete (or with emulated 3270s, as soon as you dial
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into your vm guest using the command "DIAL <vmguestname>").
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Since the line-mode major number is 227, the line to add to
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/etc/modprobe.conf 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. If you have selected DEVFS, the driver
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itself creates the device files, and /tmp/mkdev3270 only changes
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/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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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 <rbh00@utsglobal.com>
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