V4 Design: Database Initialization - Revision history

MartyKraimer at 15:52, 27 May 2005

2005-05-27T15:52:32Z

← Older revision		Revision as of 15:52, 27 May 2005
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	== EPICS: IOC Database Initialization ==		== EPICS: IOC Database Initialization ==
	May 26 2005		May 27 2005
	<center>		<center>

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	<b>QUESTION?</b> Should iocRecord.dbd define a field		<b>QUESTION?</b> Should iocRecord.dbd define a field
	field(pDbdRecord,private("DbdRecord *")		field(pDbdRecord,private("DbdRecord *")
			I think yes becaise given the address of an iocRecord instance
	~~Perhaps not since DbdRecordInstance~~ is ~~passed to DbdRecordSupport~~		it's description is available.
	----		----
	<center>		<center>
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	Not yet defined. Some Questions		Not yet defined. Some Questions

	# What is done ~~by loading~~ an executable that includes support code?		# What is done when an executable that includes support code is loaded?
	# What must be done by iocInit?		# What must be done by iocInit?
	# How is on-line add/delete of new support code handled?		# How is on-line add/delete of new support code handled?


	~~----~~
	~~<center>~~

	~~== DbdRecordEpicsFieldPutString ==~~
	~~</center>~~


	~~This is an interface that is implemented by iocCore. It is responsible for~~
	~~taking a string and converting to an epicsType.~~
	~~It is defined as an interface instead of a class with static methods for consistency.~~

	~~For all methods if <tt>pfrom.pbuffer</tt> is null an exception is raised.~~

	~~=== epicsPrimitive ===~~
	~~This implements:~~
	~~epicsPrimitive(EpicsString pfrom,epicsType type,void pstorage) = 0;~~

	~~<tt>type</tt> must be one of epicsBooleanT, ..., epicsFloat64T.~~

	~~The string in <tt>pfrom</tt> is converted to <tt>type</tt>.~~

	~~=== epicsString ===~~

	~~This implements~~
	~~epicsString(EpicsString pfrom,EpicsString pEpicsString)~~

	~~It copies pfrom to pEpicsString.~~

	~~=== epicsArray ===~~

	~~This implements~~
	~~epicsArray(EpicsString pfrom, EpicsArray pEpicsArray)~~

	~~The array type must be one of epicsBooleanT, ..., epicsStringT.~~
	~~<tt>pfrom</tt> must be DBD array syntax .~~

	~~For each array element epicsArray calls either epicsPrimitive or epicsString to do the conversion.~~

	~~=== epicsStruct ===~~

	~~This implements~~
	~~epicsStruct(EpicsString pfrom, EpicsStruct pEpicsStruct)~~

	~~<tt>pfrom</tt> must be DBD struct syntax .~~

	~~For each struct field epicsStruct calls either epicsPrimitive or epicsString~~
	~~or epicsArray to do the conversion.~~


	~~=== epicsMDArray ===~~

	~~This implements~~
	~~epicsMDArray(EpicsString pfrom,EpicsMDArray pEpicsMDArray)~~

	~~The array type must be one of epicsBooleanT, ..., epicsStringT.~~
	~~<tt>pfrom</tt> must be DBD array syntax .~~

	~~For each array element epicsMDArray calls either epicsPrimitive or epicsString to do the conversion.~~

	----		----
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	=== Allocate Storage ===		=== Allocate Storage ===
	Storage is allocated for each record and for any structures that are		Storage is allocated for each record and for any structures that are
	~~part of~~ the record. Note that buffer storage for strings and arrays		within the record. Note that buffer storage for strings and arrays
	are not allocated during this phase.		are not allocated during this phase.

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	pDbdRecord is set to record type		pDbdRecord is set to record type
	pDbdRecordInstance = ~~alloc~~		pDbdRecordInstance = // just allocate it
	pDbdRecordInstance->pDbdRecord = pDbdRecord;		pDbdRecordInstance->pDbdRecord = pDbdRecord;
	pDbdRecordInstance->precord = pDbdRecord->plifetime->allocate		pDbdRecordInstance->precord = pDbdRecord->plifetime->allocate
Line 169:		Line 110:
	not for any arrays or structures that are part of the record.		not for any arrays or structures that are part of the record.

	EpicsStructDef.plifetime.allocate must allocate storage for an instance		EpicsStructDef.plifetime.allocate must allocate storage for a
	~~of itself~~ and if any of its fields are of type epicsStructT it must		structure instance and if any of its fields are of type epicsStructT it must

	initialize pEpicsStruct->pstructDef by locating the fields EpicsStructDef		initialize pEpicsStruct->pstructDef by locating the fields EpicsStructDef
	pEpicsStruct->pstorage = pEpicsStruct->pstructDef->plifetime->allocate		pEpicsStruct->pstorage = pEpicsStruct->pstructDef->plifetime->allocate

	DbdStruct.plifetime.allocate must allocate storage for an instance		DbdStruct.plifetime.allocate must allocate storage for
	~~of itself~~ and also allocate storage associated with fields		structure instance and also allocate storage associated with fields
	of type epicsStructT or dbfStructT.		of type epicsStructT or dbfStructT.

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	case dbfDeviceT		case dbfDeviceT
	dataStruct = DbdRecordEpicsFieldPutString:epicsStruct		dataStruct = DbdRecordEpicsFieldPutString:epicsStruct
			DbdRecord.psupport->initBuffers

			Record support is expected to create buffers for all strings or arrays
			in the record. It may call associated support to create the buffers for
			structure fields managed by the support.


	=== Initialize connections ===		=== Initialize connections ===
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	pDbdRecord->psupport->initConnections		pDbdRecord->psupport->initConnections

			=== prepare the record for processing ===

			TBD

			Amoung the things to do are:

			# compute or recompute lock sets
			# Add record instance to a scan list

MartyKraimer at 19:40, 26 May 2005

2005-05-26T19:40:13Z

New page

== EPICS: IOC Database Initialization ==
May 26 2005
<center>

== Overview ==

</center>

This document gives a summary of actions required to initialize an IOC database.
This includes actions that must be taken when an IOC is booted and also
during on-line add/delete of record intances, link support, and device
support.

<b>QUESTION?</b> Should iocRecord.dbd define a field
field(pDbdRecord,private("DbdRecord *")

Perhaps not since DbdRecordInstance is passed to DbdRecordSupport
----
<center>

== IOC Initialization ==
</center>

What must be done to prepare an IOC?
This should include everything so that an IOC is prepared to
handle everything connected with an IOC database.
This includes things like:

* error logging system
* scan threads
* ???

== record types, etc ==

This section describes how the following are created.

* DbdStructList - The list of the description of each structure type.
* DbdRecordList - The list of the description of each record type.
* DbdLinkList - The list of the description of each DBD link definition
* DbdDeviceList - The list of the description of each DBD device definition.

Not yet defined. Some Questions

# What is done by loading an executable that includes support code?
# What must be done by iocInit?
# How is on-line add/delete of new support code handled?

----
<center>

== DbdRecordEpicsFieldPutString ==
</center>

This is an interface that is implemented by iocCore. It is responsible for
taking a string and converting to an epicsType.
It is defined as an interface instead of a class with static methods for consistency.

For all methods if <tt>pfrom.pbuffer</tt> is null an exception is raised.

=== epicsPrimitive ===
This implements:
epicsPrimitive(EpicsString *pfrom,epicsType type,void *pstorage) = 0;

<tt>type</tt> must be one of epicsBooleanT, ..., epicsFloat64T.

The string in <tt>pfrom</tt> is converted to <tt>type</tt>.

=== epicsString ===

This implements
epicsString(EpicsString *pfrom,EpicsString *pEpicsString)

It copies pfrom to pEpicsString.

=== epicsArray ===

This implements
epicsArray(EpicsString *pfrom, EpicsArray *pEpicsArray)

The array type must be one of epicsBooleanT, ..., epicsStringT.
<tt>pfrom</tt> must be DBD array syntax .

For each array element epicsArray calls either epicsPrimitive or epicsString to do the conversion.

=== epicsStruct ===

This implements
epicsStruct(EpicsString *pfrom, EpicsStruct *pEpicsStruct)

<tt>pfrom</tt> must be DBD struct syntax .

For each struct field epicsStruct calls either epicsPrimitive or epicsString
or epicsArray to do the conversion.

=== epicsMDArray ===

This implements
epicsMDArray(EpicsString *pfrom,EpicsMDArray *pEpicsMDArray)

The array type must be one of epicsBooleanT, ..., epicsStringT.
<tt>pfrom</tt> must be DBD array syntax .

For each array element epicsMDArray calls either epicsPrimitive or epicsString to do the conversion.

----
<center>

== iocLoadRecords ==
</center>

iocLoadRecords loads and initializes new record instances.
This can be done during IOC initialization or on-line.

Initialization consists of the following phases:
* Allocate storage
* Allocate buffer managers
* Initialize storage
* Initialize external connections
* Enable record processing

=== Allocate Storage ===
Storage is allocated for each record and for any structures that are
part of the record. Note that buffer storage for strings and arrays
are not allocated during this phase.

For each instance of the set of records being loaded do the following:

pDbdRecord is set to record type
pDbdRecordInstance = alloc
pDbdRecordInstance->pDbdRecord = pDbdRecord;
pDbdRecordInstance->precord = pDbdRecord->plifetime->allocate

for each pDbdStructField in pDbdRecord->pfield[]
get address of field via pDbdRecord->plifetime->expose
switch pDbdStructField->type
case dbfEpicsT
if(pDbdStructField->basic==epicsStructT)
pEpicsStruct = pDbdRecord->plifetime=>expose
initialize pEpicsStruct->pstructDef
pEpicsStruct->pstorage =
pEpicsStruct->pstructDef->plifetime->allocate
default:
nothing to do for other basic types
case dbfStructT
pDbfStruct = pDbdRecord->plifetime=>expose
initialize pDbfStruct->pDbdStruct;
pDbfStruct->pstorage = pDbfStruct->pDbdStruct->plifetime->allocate
case dbfMenuT
initialize pDbfMenu->pmenuDef
case dbfEnumT
initialize pDbfEnum->pchoiceArray
case dbfLinkT
initialize pDbfLink->dir
initialize pDbfLink->plinkDef
initialize pDbfLink->dataStruct.pstructDef
pDbfLink->dataStruct.pstorage =
pDbfLink->dataStruct.pstructDef->plifetime->allocate
case dbfDeviceT
initialize pDbfDevice->dir
initialize pDbfDevice->pDbdDevice
initialize pDbfDevice->dataStruct.pstructDef
pDbfDevice->dataStruct.pstorage =
pDbfDevice->dataStruct.pstructDef->plifetime->allocate

DbdRecordLifetime.allocate just allocates storage for the record instance
not for any arrays or structures that are part of the record.

EpicsStructDef.plifetime.allocate must allocate storage for an instance
of itself and if any of its fields are of type epicsStructT it must

initialize pEpicsStruct->pstructDef by locating the fields EpicsStructDef
pEpicsStruct->pstorage = pEpicsStruct->pstructDef->plifetime->allocate

DbdStruct.plifetime.allocate must allocate storage for an instance
of itself and also allocate storage associated with fields
of type epicsStructT or dbfStructT.

For epicsStructT fields it must

initialize pEpicsStruct->pstructDef by locating the fields EpicsStructDef
pEpicsStruct->pstorage = pEpicsStruct->pstructDef->plifetime->allocate

For dbfStructT fields it must

initialize pDbfStruct->pDbdStruct by locating the fields DbdStruct
pDbfStruct->pstorage = pDbfStruct->pDbdStruct->plifetime->allocate

=== Allocate Buffer Managers ===

The buffer managers associated with epicsStringT, epicsArrayT, epicsStructT,
epicsMDArrayT, dbfArrayT, and dbfStructT are allocated during this phase.
Allocating the buffer managers is the responsibility of record support.
Record support may call interfaces associated with epicsStructT or dbfStructT
so that aother support can decide the type of buffer manager.

Thus for each record instance the following is called

pDbdRecord->psupport->initBuffers

=== Initialize storage ===

The allocated storage is initialized. This does NOT include initializing
connections outside the record.

For each instance of the set of records being loaded do the following:

for each DbdStructField in DbdRecord.pfield
EpicsString *pfrom = DbdStructField.pattribute.default
if(pfrom->pbuffer==null) next // no default defined
get address of field via DbdRecordLifetime.expose
switch DbdStructField.type
case: epicsBooleanT, ..., epicsFloat64T
DbdRecordEpicsFieldPutString:epicsPrimitive
break;
case: epicsStringT
DbdRecordEpicsFieldPutString:epicsString
break;
case: epicsArrayT
DbdRecordEpicsFieldPutString:epicsArray
break;
case: epicsStructT
DbdRecordEpicsFieldPutString:epicsStruct
break;
case: epicsMDArrayT
DbdRecordEpicsFieldPutString:epicsMDArray
break;
case: dbfArrayT
case: dbfStructT
do nothing. Let record support handle it
case: dbfMenuT
index = DbdRecordEpicsFieldPutString:epicsPrimitive
case dbfEnumT
index = DbdRecordEpicsFieldPutString:epicsPrimitive
case dbfLinkT
dataStruct = DbdRecordEpicsFieldPutString:epicsStruct
case dbfDeviceT
dataStruct = DbdRecordEpicsFieldPutString:epicsStruct

=== Initialize connections ===

The next step is to make external connections from record instances.
This is the responsibility of record support.
Record support may call interfaces associated with link and/or device
support.

Thus for each record instance the following is called

pDbdRecord->psupport->initConnections