A base device driver performs I/O during the OS/2 kernel initial load sequence. There are a number of operational differences between base device drivers and installable device drivers. See Adapter Device Driver Development Considerations for a description of how this affects adapter device driver development.

The BASEDEV keyword new with the OS/2 2.0 operating system, loads a base device driver into the operating system. Its syntax is as follows:

    BASEDEV= ÄÄÄÄ filename ÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄ´
                             ÀÄÄ arguments ÄÄÙ

Unlike the DEVICE= statement, the BASEDEV= statement must not contain either drive or path information. The root directory of the startup partition is searched first for the specified file name, followed by the \OS2 directory of the startup partition. (In the startup sequence, the OS/2 operating system cannot process drive or path information at the point where BASEDEV= statements are processed. If drive or path information is included there, an error is generated.)

Also, unlike the DEVICE= statement, the file-name extension of the file being loaded has a special meaning. BASEDEV= statements are not necessarily processed in the order in which they appear in your CONFIG.SYS file. The extension of each BASEDEV= file name is examined; then, BASEDEV= statements are processed in the order indicated by the following figure.

ÚÄÄÄBASEDEV= Load Ordering by File ExtensionÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
³  .SYS (processed first)                                  ³
³  .BID                                                    ³
³  .VSD         ³                                          ³
³  .TSD         ³                                          ³
³  .ADD         ³                                          ³
³  .I13                                                   ³
³  .FLT                                                    ³
³  .DMD  (processed last)                                  ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ

Files with other file-name extensions are not loaded.

If several BASEDEV= statements load file names with the same extension, those files are loaded in the order in which they are encountered in the CONFIG.SYS file.


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