Interactive Debug facilit y, which provides windows that allow you to simultaneously see the environment of the program being tested. It supports breakpoin ts, single stepping, calculation of expressions, macros, and command ￿les.

Multiprogramming

MPE/iX supports m ultiprogramming, the concurren t execution of multiple programs. All system resources are a vailable to you as if you were the only user on the system. While one program is w aiting for input, the system shifts con trol of the CPU to the next highest program in the queue. In this w ay, activities suc h as transaction processing, on-line program development, interactive data entry, data communications, and batc h processing can be concurrently performed.

MPE/iX is a m ultiprogramming, m ultiuser system. On this kind of a system, m ultiple users can share code. For example, when m ultiple users access the BASIC/V in terpreter, a separate process is created for eac h one. They all use the same code (because there is only one BASIC interpreter on the system), but eac h user has a unique en vironment created by MPE/iX. MPE/iX completely protects one program execution from in terfering with another.

Interactive and Batch Processing

MPE/iX provides interactive and batch processing. An in teractive process is called a session. A batch process is called a job.

In a session, y ou enter commands and data at a terminal and receiv e an immediate response. This is especially useful for data en try and retriev al, program development, text editing, and any application that is expedited b y direct dialogue with the computer.

In batch processing, you submit a job to the computer. A job is a single unit composed of commands that request v arious operations, suc h as program compilation and execution, ￿le manipulation, or utilit y functions. While a job is processing, there is no user in teraction with the computer unless the job is set up to request information. Jobs can be sc heduled to run at lower priorities than in teractive sessions and at speci￿c times (for example, when system activities are lo w).

MPE/iX Information Management

Commercial applications primarily use database applications. The 900 Series pro vides ALLBASE/SQL, whic h includes TurboIMAGE/XL, a network database managemen t product, and HP SQL, whic h has a relational in terface to data. ALLBASE/SQL pro vides a TurboIMAGE/XL cross-dev elopment environment. The relational in terface, HP SQL, is fully compatible with the v ersion of SQL in most common use. It pro vides relational access for increased ￿exibilit y.

ALLBASE/SQL and other tools form Hewlett-P ackard's information managemen t framework. These include:

Programming languages and tools.

Reporting and presentation tools that allo w access to information without programming.

1-8 OVERVIEW