HP 3000 Manuals

Information Access Server: Database Administration

Mapping at a Glance 

The situation for most western European customers is as follows:

   *   The HP Vectra and IBM PCs operate in IBM8.  Access PC uses ROMAN-8
       to communicate with Access Server on the host HP 3000.  We can
       therefore consider the PC a ROMAN-8 machine.

The following figure summarizes the situation:


          Figure D-1.  ROMAN-8 and ISO-7 Mapping at a Glance 

The arrows and the words Best Fit and Exact in the figure show that the
direction of the communication determines how accurately the characters
are mapped:

   *   Mapping ISO-7 to ROMAN-8 usually gives an exact mapping since all
       characters in the ISO-7 character set also exist in ROMAN-8.  The
       exception is discussed below.

   *   Mapping ROMAN-8 to ISO-7 gives an exact mapping for characters
       whose decimal representation is 127 or less and for characters
       which map back to the twelve special characters shown in Figure D-
       2.  For other characters whose decimal representation exceeds 127,
       the mapping is only approximate.

Data traveling "round trip," such as PC data uploaded to a saved table on
the host HP 3000 and later downloaded to the PC, may lose information.
This occurs because at least one part of a round trip involves a "Best
Fit" mapping.  (Round trips are discussed in more detail later in this
appendix.)

MPE/iX 5.0 Documentation