The purpose of this document is to provide information pertaining to the release of the CEM Kernel and user interface. This document is divided into three sections:

Enhancements Describes changes that enhance the capability of the CEM Kernel.

Problem Reports Describes changes that correct errors reported in problem reports.

CEM Help Describes changes made to the user interface that will eventually be added to the CEM On-Line Help.

Prior to this release, the CEM Kernel acquired the Current Noun and Measured Characteristic only from the RTS-to-CEM FNC Message and retained it for subsequent use by a CEM Device Driver. However, RTS-to-CEM FNC Messages are not generated for several Single Action ATLAS Statements (e.g., CONNECT, REMOVE, etc.), which resulted, under certain conditions, in an incorrect Current Noun and/or Measured Characteristic being returned to the CEM Device Driver.

With this release, the CEM Kernel supports RTS-to-CEM Statement Information Messages containing the Current Noun and Measured Characteristic.

Note Although CEM Group Modifier capability is and will be available to all CEM Device Drivers, Group Modifiers themselves are "defined" by a particular ATLAS Compiler and are peculiar to a specific ATLAS Subset / Station. Therefore, this section provides only a general description of the CEM Group Modifier capability. For those Customers whose ATLAS Compiler "defines" Group Modifiers, a full description will be provided in a separate document. For all other Customers, this section contains no relevant information for CEM Device Drivers.

Prior to this release, the CEM Kernel did not support Group Modifiers.

With this release, the CEM Kernel supports Group Modifiers. This capability has been provided to allow ATLAS Compilers and CEM Device Drivers to more easily deal with ATLAS Statements that contain multiple references to the same Modifier within a single ATLAS Statement.

A Group Modifier is a Modifier that has one or more lists of other Modifiers attached to it. These lists are called Group Modifier Lists. In addition, Group Modifiers may be nested (i.e., a Group Modifier List may itself contain one or more Group Modifiers). As currently implemented:

• There is no limit on the number of Group Modifier Lists that a Group Modifier may have.

• The maximum level of Group Modifier nesting is three.

To support Group Modifiers:

• Modifier Data Structure MODDAT has been expanded to hold Group Modifier information.

• New CEM Macro Group (Group Modifiers) containing eight Group Modifier CEM Macros has been added to allow CEM Device Drivers to access Group Modifier data. Refer to the CEM Help section for a full description of these new CEM Macros.

• CEM User Stub Functions have been enhanced to print Group Modifier information.

None.

Usage: int nStatus;

Description: This Macro enables Group Modifiers processing at Group Level 1 for Group #1 of Group Modifier M_XXXX. If the operation is successfully completed (and until otherwise directed), all GetDatum() requests will search for Datums in the first Group Modifier List of Group Modifier M_XXXX at Group Level 1 (instead of searching the Modifier List associated with the Current Device / Channel). This Macro must be called before any of the other Group Modifiers Macros are called.

• M_XXXX not valid.
• No Current Device / Channel.
• Group Modifiers capability not available.
• No Group Modifiers defined.

• Group #1 at Group Level 1 for Modifier M_XXXX not found.

Usage: int nStatus;

Description: This Macro advances Group Modifiers processing to the next Group Level for Group #1 of Group Modifier M_XXXX. If the operation is successfully completed (and until otherwise directed), all GetDatum() requests will search for Datums in the first Group Modifier List of Group Modifier M_XXXX at the new Group Level.

• M_XXXX not valid.
• No Current Device / Channel.
• Group Modifiers capability not available.

• Group Modifiers processing not enabled.
• Group #1 at next Group Level for Modifier M_XXXX not found.

Usage: int nStatus;

Usage: int nStatus;

Usage: int nStatus;

Note that, if Macro SetGroupModsON() returned a Good Status, so will this Macro. As currently implemented, there is no need to check nStatus.

Usage: int nModCode;

Description: This Macro returns the Modifier Code (M_XXXX) of the Current Group Modifier.

Usage: int nGrpModLevel;

Usage: int nGrpModGroup;