Apply to the behavior of the server as a whole and include options such as a trace file name, the maximum number of dispatchers, and maximum number of ASO slave processes

Specify default options for all dispatchers and include options such as the number of slave processes to start, what machine to run them on, and the timeout interval

Override the dispatcher defaults and can be specified differently for each application image file name. All dispatchers whose signature includes the specified ImageFile name use the configuration options associated with the file name. Thus, the default may be to have one slave process per dispatcher, but a particular application can be configured to run with four slaves.

The signature of an OpenROAD Server application uniquely identifies an ASO configuration for the purposes of pooling shared ASO instances. The full signature is actually a concatenation of the ImgFile and Flags parameters that were passed to the Initiate method. For each unique signature that the SPO encounters, a separate dispatcher instance is created to manage the pool of (one or more) shared slaves assigned to that signature. All clients that call Initiate with the same signature are assigned to the same dispatcher and share the same pool of slaves.

The image name is used as a registry key to control dispatcher configuration options. The ASN concept just abstracts that one step further, taking full advantage of a level of indirection through the registry. When a client passes an application signature as the ImgFile parameter on the Initiate method, this application signature is interpreted as a unique key with which all the information needed to configure a dispatcher and configure the ASOs can be obtained from the registry. Moreover, this registry key provides a place to put new ASO configuration options, such as environment variables. This allows different ASO instances under a single SPO to have different environment settings.

To prevent any risk of changing behavior for existing installations, the application signature name feature will remain dormant unless the Server Manager adds a new registry value under the Server Config key. If the “UseSignatureGUIDs” registry exists and is a nonzero REG_DWORD, then the new behavior will be activated. This registry entry is set by the Server Manager by setting the Use Application Signature Names option.

After the feature is activated, if the ImgFile string passed on an Initiate call begins with a curly brace “{”, then that string is interpreted as an ASN and not a real image name. This ASN string is then used as a subkey of Dispatcher Config to obtain the “real” ImgFile and “real” CmdFlags strings. (Any CmdFlags passed on the Initiate by the client are ignored in this case.) Furthermore, if this ASN key has an “Environment” subkey, then all the environment variables specified there will be set before the Initiate call is passed to the OpenROAD runtime. The Server Manager can be used to set up this section.

This change is transparent to the SPO. The SPO treats an ASN ImgFile string just like any other ImgFile string. All the transformation happens inside the ASO, and applies the same way for private and shared ASOs.