A quick demonstration

To help demonstrate this feature, consider the write control that instructs a Comet workstation to operate in "single key transmit" mode. Prior to Comet 504, this feature was accomplished via the following hex write control:

     "@040002@"

However, here is how the feature is implemented via a DDL:

First, we need to choose a mnemonic name for this feature. Signature Systems has created the following mnemonic name for this purpose:
```
          (SINGLEKEYTRANSMIT)
```
Note: When this mnemonic is coded in MTB, it can be written in upper or lower case or a combination, and can include imbedded blanks. Thus, the following mnemonic will create the same result:
```
          (Single Key Transmit)
```
Next, this mnemonic must be registered on the master list (the MTB50 file). The registration includes the mnemonic name and the number and type of arguments. In this case, there are no arguments, so the definition includes only the mnemonic name.
Note: Once a mnemonic is registered in the MTB50 file, it will be recognized by the MTB compiler. However, the actual definition of the mnemonic occurs at the next step.
Now we must create the exact definition for the new mnemonic. This is done by creating a dynamic driver library.
1. First, we must create an editor file and enter the mnemonic definition(s) using the mnemonic code generator "language." For this example, the source lines are:
```
               [Single Key Transmit]
               Print "@040002@"
```
  The first line contains the mnemonic name within square brackets, and the second line contains the action to be taken (in this case, the printing of the hex sequence for single key transmit mode).
2. Once the source file definitions are written, we must use the new utility program named MNEMGEN to process the mnemonic definitions. This program reads the source file and creates the DDL (an output file with tokenized representations of the mnemonics). In this regard, MNEMGEN functions like a compiler program, albeit a very simple one.
3. In the case of printer drivers, you can use the new version of QCFIG to configure a driver for each type and brand of printer you have. This means that you can register one mnemonic (e.g., LANDSCAPE), but create multiple printer drivers for your system by creating and "compiling" multiple DDLs.

Dynamic Driver Libraries