The OpenTP1 file system is specific to OpenTP1 and is distinct from the OS file system. It can consist of character special files or regular files. User data files, journals needed for OpenTP1 system recovery, and files of critical information related to system reliability can be created in the OpenTP1 file system. They are referred to as OpenTP1 files.

OpenTP1 files are listed in Table 4-1.

Table 4-1 List of OpenTP1 files

File type	Purpose
Status files	Store information about system service activities and the system configuration. This information is used for OpenTP1 recovery when a failure occurs.
System journal files	Store history information about transaction processing. This information is used for OpenTP1 recovery when a failure occurs. Also store information about UAP processing.
Checkpoint dump file	Stores status-table information needed for recovery. This information is used for OpenTP1 recovery when a failure occurs.
Archive journal file	Stores collected node journals in a cluster system or parallel processing system configured using TP1/Multi.
Message queue file	Stores messages waiting to be sent or received using the message exchange facility. TP1/Message Control must be installed in the system.
MQA message queue file	Stores a waiting queue for messages used by MQA message queuing. TP1/Message Queue must be installed in the system.
DAM files	Used as user files. TP1/FS/Direct Access must be installed in the system.
TAM files	Used as user files. TP1/FS/Table Access must be installed in the system.

Note

The following files can also be created to assist in OpenTP1 file management:

• Transaction recovery journal file
  Used to reduce the size of journals for user-specified transactions.
  
• Server recovery journal file
  Stores information about services. This information reduces recovery time at a complete-recovery restart.
  

Figure 4-1 shows the relationship between the OpenTP1 file system and the OS file system. Table 4-2 describes the differences between the two file systems. Figure 4-2 shows how to select files to create an OpenTP1 file system.

Figure 4-1 Possible locations of an OpenTP1 file system

Table 4-2 Differences between the OpenTP1 file system and the OS file system

Comparison point	OpenTP1 file system		OS file system
	Character special file	Ordinary file
(Reliability) What happens to data specified by a write request that normally terminates immediately before OpenTP1 abnormally terminates?	The data is written.	Same.	Undefined.
(Reliability) What happens to data specified by a write request that normally terminates immediately before a process abnormally terminates?	The data is written.	Same.	Undefined.
(Reliability) Security of disk files in the event of system shutdown for a reason such as a power outage	Security is high in terms of maintaining file integrity because management information is not stored in a separate area on the disk.	Security is lower than for character special file because management information is stored in a separate area on the disk.	Security is low in terms of file integrity because management information is stored in a separate area on the disk.
(Reliability) How is a file area allocated?	A shortage of space never occurs during online operation because a file area is allocated beforehand when the file system is created.		A shortage of space might occur in an extension of write operation because a block is allocated when a file is added.
(Performance) How efficient is usage of disk area?	If an area has been allocated to a file, it cannot be allocated to another file even if there are no OpenTP1 file records written in the area.		Because the disk area is allocated dynamically block by block as the file size increases, the efficiency of disk area usage is higher than for an OpenTP1 file system.
(Performance) How fast is read time (time until the function is returned)?	There is no buffer cache advantage because buffer cache is not used.	Read time is generally fast because if the target data is found in the buffer cache, the system does not have to search the disk. However, if a process uses the buffer for control at a higher level, overhead might increase due to double buffering.	Read time is generally fast because if the target data is found in the buffer cache, the system does not have to search the disk.
(Performance) How fast is write time: the time until the function is returned?	Write time is generally slower than for an OS file system because I/O operations are performed synchronously, but the overhead for write processing is low because the buffer cache is not used.	Write time is generally slower than for an OS file system because I/O operations are performed synchronously.	Write time is generally fast because I/O operations are performed asynchronously.
(Performance) How even is access time?	Access time is close to even because a contiguous area is allocated.	Access time is uneven because areas are not always contiguous.	Access time is uneven.
(Operations) Does file size need to be estimated?	Size must be specified during file creation.		Size does not need to be specified when creating the file.
(Operations) Is a dynamic secondary allocation of file size possible?	Not possible.		Possible.
(Operations) Can files be sorted according to directory?	Not possible.		Possible.

Figure 4-2 Selection of files to create the OpenTP1 file system

The advantage of regular files is that they are flexible and efficient to use. This is why they are used for OpenTP1 definition files and so on.

Table 4-3 describes the regular files used in OpenTP1.

Table 4-3 Regular files used in OpenTP1

File type	Purpose	Remarks
User program file	Stores a UAP executable program.	Created by the user.
Definition file	Stores OpenTP1 system definitions. A definition file can be created as a text file, using a text editor provided by the OS.
Map file	Used by the mapping service. Stores physical maps and pre-loaded maps.
OpenTP1 program file	Store an OpenTP1 program, including the executable file and files used to create the UAP.	Created automatically when the program is installed.
Definition analysis file	Used internally in OpenTP1 to analyze definitions.
Message object file	Stores a message text.
Command log file	Stores an OpenTP1 command log.
Message log file	Stores system messages output by OpenTP1.	Created at OpenTP1 execution.
MCF trace file	Stores MCF trace information.
Schedule queue information file	Stores schedule queue information internally in OpenTP1.
RPC trace file	Stores an RPC trace.
Trace information dump file	Stores internal OpenTP1 trace information.
Shared memory dump file	Stores a shared memory dump output by OpenTP1.
Core file	Stores the core of an abnormally ended process.
Deadlock and timeout information file	Stores deadlock and timeout information.
MCF dump file	Stores a MCF dump.
MCF shared memory dump file	Stores dump information, output when an error occurs, about the shared memory area allocated to the MCF.
Undetermined-transaction information file	Stores information about an undetermined transaction, output when an error occurs.
Invalid journal information file	Stores invalid journal information detected when a journal is read.
Copy file of input/output queue contents	Stores the queue contents when the command to copy the contents of the input/output queue is executed.
Trace information collection file for verification	Stores trace information for performance verification.
XAR performance verification trace information file	Stores trace information for events generated during transactional linkage using the XA resource service.
JNL performance verification trace information file	Stores trace information for the journal service.
LCK performance verification trace information file	Stores trace information for events generated during locking using the lock service.
MCF performance verification trace information file	Stores trace information for events generated during message transmission using MCF.
TRN event trace information file	Stores trace information for events generated by the transaction service and the XA function called at a transaction branch.
NAM event trace information file	Stores trace information for events relating to the name service, including communication invoked by the name service and the registration and deletion of service information from the cache.
Process service event trace information file	Stores trace information for a process service.
FIL event trace information file	Stores event information if the time required to process an OpenTP1 file access request is equal to or greater than the value specified in the fil_prf_trace_delay_time operand in the system common definition.
RTS log file	Stores real-time statistics.
UAP trace edit/output file	Stores a UAP trace that is edited and output automatically when a UAP terminates abnormally.
OpenTP1 debugging information file	Stores OpenTP1 information when a UAP terminates abnormally.