What is Extended Services?
Prior to Version 2.0, IBM offered two separate packages with each release of OS/2: Standard Edition and Extended Edition. Extended Edition included extra, bundled software products: the Communications Manager (for communication with IBM mainframes, minicomputers, and other hosts), Database Manager (a full, network aware, relational database), and LAN Requester.
Later, IBM unbundled the Extended Edition features, dropped LAN Requester from the package (now available separately, with IBM's LAN Server), updated it for OS/2 2.x, and renamed it Extended Services 1.0. ES, by itself, did not include the base operating system as Extended Edition once did.
Most recently, IBM has stopped selling Extended Services, splitting it up into DB2 for OS/2 (a full 32-bit relational database) and Communications Manager/2. With each component available "a la carte," you can configure your OS/2 Warp system to your exact specifications (almost always at a lower cost), and you are free to substitute similar products from other vendors (so you aren't locked into IBM's offerings).
To install the now obsolete Extended Services 1.0 under OS/2 2.1 or later, you must replace the ESSTART.CMD file on ES Diskette 1 with the ESSTART.BAK file found in the \OS2\INSTALL directory. Remember to keep a backup of the old file.
(1.2) Differences Between Versions (2.1) Hardware Requirements (3.8) Networking Products (4.6) Corrective Service Diskettes