IBM Keyboard

Unique to IBM Keyboard =

Before the world moved to using PCs as the main interface to talk to the 400, we had IBM Keyboards with keys that are now largely disappeared from the keyboards of today.

ATTENTION KEY

Note that on PC keyboards the ESCAPE key usually does the same stuff as the Attention Key did on IBM keyboards.

This key by itself takes us to a menu that can be designated by our user profile.

Upper shift and this key gets you to the System Request Menu.

*DUP KEY

This meant DUPLICATION key. We have keyed in something on some screen, and we get to the same identical screen for another entry. Pressing the *DUP key on a field meant "Duplicate here an exact copy of what we keyed on this same field for our last entry."

ERASE INPUT KEY

This key erases 100% of the input on the current screen.

ERROR RESET KEY

There's various things that can go wrong when keying ... if you see a flashing # on screen and keyboard locked up, this is a safety mechanism to stop accepting input until after you do error reset.

If your keyboard is setup for keyahead, you might not want keystrokes acceepted after error detection.

Note that any time you see some error code on screen, you can cursor on it then F1 for more info.

HELP KEY

Now people need to remember to use the universal F1 help key.

HEX KEY

Hex here does not mean Witchcraft but Hexadecimal which is IBM name for Base 16 that Midrange computers used to run on (it might be a higher one now). This means that while humans count from 1 to 10, the 400 counts from 1 to 15 where the single character representing 10-15 is A-F.

Note that the world today now has two standards for how characters are represented.

• ASCII standard developed by IEEE and became standard in communications then was adopted by the micro computer industry.
• EBCDIC standard developed by IBM from Herman Hollerith inventioh.

Each byte is represented by a pair of hexadecimal characters, such as

• letter B upper case represented by blank then B
• letter b lower case represented by 8 then 2

Since 16 x 16 combinations comes to more than all the letters digits and special characters we are familiar with on most keyboards, there are a bunch more characters made available, which got used for such things as currency symbols around the world, and characters in some languages with a marking on top to give it an accent.

There were some intermediate keyboards where we had to use ALT then some key to get the HEX.

So to get at some character not on our keyboard, we would press the HEX key then the two characters in sequence that mapped that hexadecimal representation. One of the RPG manuals has a reference chart in an appendix showing all these characters.

Dual Availability

Several keys common to PC keyboards have special purposes or roles in the 400 world.