HP 3000 Manuals HP 3000 Manuals
System Differences There are several areas in which the basis for working with IMAGE is different on the HP 260 and the HP 3000. Some of these differences can affect programs directly, while others are simply worth noting before migration. Data Set Sizes IMAGE/3000 supports data sets of more than 65535 entries, which is larger than IMAGE/260 can support. This difference is generally invisible, except in the status array (described later). In addition, IMAGE/3000 supports sorted chains; as IMAGE/260 does not, sorting is often done in the application code. The use of sorted chains and larger data sets may improve performance and reduce the size of a compiled application. Deadlocks IMAGE/260 automatically avoids deadlocks when multiple databases are used. On the HP 3000, the user must have multiple RIN (MR) capability to perform locks on multiple databases. However, IMAGE/3000 will not prevent a deadlock in this case. If more than one database is required at once, the program should guard against deadlocks. Control Numbers IMAGE/260 allows control (or format) numbers to be assigned and defined programatically to data items in the root file. This feature does not exist in HP Business BASIC/XL or IMAGE/3000. Naturally, the DBINFO call which returns the format numbers has no corresponding DBINFO call in IMAGE/3000. X Type Data items of type "X" can be up to 1022 characters long in IMAGE/260. These items are limited to 254 characters in IMAGE/3000. READ Lock IMAGE/260 supports read locking; IMAGE/3000 does not. The migration aid does changes BASIC/260 programs so that they perform a write lock. This can degrade performance. Sub-Items IMAGE/260 allows 512 sub-items; TurboIMAGE only allows 255. Detail Length The minimum record length in a detail is 4 bytes in IMAGE/3000. The HP 260 has a minimum length of 2 bytes. Floating Point Decimal Support TurboIMAGE does not directly support the floating point decimal data types available in HP Business BASIC/XL. BASIC/260's REAL and SHORT types (which map to DECIMAL and SHORT DECIMAL in HP Business BASIC/XL) are repeated in the migrated schema as K2 and K4. HP Business BASIC/XL processes these numbers as floating point decimal numbers when accessing a TurboIMAGE database.