Most of the code supporting ATS is embedded in A-Shell; it requires A-Shell build 787 or higher. The only essential external module is ATSD.EXE, which must be launched on the server machine. ATSD.EXE just waits for clients to initiate Telnet connections, and as they are accepted, it spins off a new A-Shell session for each client.
Although launching ATSD.EXE as an application on the server is easy enough, it suffers from the fact that you have to be logged in to do it (even via the Startup folder), and many installations prefer to leave the server machine logged out (presumably to discourage unauthorized use of the console.) In order to allow ATSD to be launched automatically even before a login is established on the server console, we provide a wrapper module, ATSDSRV.EXE, which runs as a standard system service and can be maintained from the Windows Services Applet. ATSDSRV.EXE is configured via a simple INI file, ATSDSRV.INI, which primarily just tells it how to launch ATSD.
To clarify the terminology, "ATS" (A-Shell Telnet Service) refers to the capability or service in general or as a whole. ATS encompasses code inside ASHW32.EXE as well as the external modules ATSD.EXE and ATSDSRV.EXE. "ATSD" refers to the executable program ATSD.EXE that accepts the Telnet connections. The "D" suffix was meant to stand for "daemon", which is what background service programs (such as telnetd, the Telnet daemon) are called in the UNIX world (even though ATSD.EXE provides the un-daemon-like option of a standard foreground user interface.) ATSD is sometimes used interchangeably with ATS. "ATSDSRV" refers to the program module ATSDSRV.EXE which provides the Services Applet interface.
The "Services Applet" is a utility built in to the Windows NT, and W2K+ operating systems which keeps track of all the available services and allows you to control which services are started automatically, as well as to manually stop or start a service. Under NT, you will find it in the Control Panel. Under later versions of Windows, you will find it in the Administrative Tools folder, which is itself in the Control Panel. Some people refer to this applet as the Service Manager.
