iX V6.5 (30391-90011)

678 AppendixH

TurboIMAGE/XL versus TurboIMAGE/V

Control Blocks

stored in an unnamed/new mapped ﬁle. One DBUX is created per process. The database

ID number serves as an index into the DBUX and points to the virtual addresses of all

current DBU/DBRs belonging to that process. 127 entries are allowed, meaning that

each user (process) is allowed 127 DBOPENs (63 per database). Refer to the discussion of

DBOPEN in Chapter 5 for additional information. If the DBUX is full and the user

attempts to open another database, the following error is displayed for status code

−198:

TOTAL DBOPEN COUNT PER USER EXCEEDS LIMIT OF 127

• The Database Lock Table (TURBOLKT) contains information pertaining to locks on the

database and is used to avoid deadlocks.

• The Multi-Database Transactions (TURBOGTX) contains information pertaining to

dynamic transaction constituting multiple databases.

• The QOPEN Table (QOPEN) contains information about user logging process for active

DBOPENS of modes 1-4.

• The QLOCK Table (QLOCK) contains information about all writers to databases and a

pointer to QOPEN.