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All models satisfy the performance requirements for real-time control of 
the Planicomp and the tracing table and in addition offer the possibility 
of background computation and of parallel program development.. Because of 
their performance variations, they differ considerably in the amount of 
work that can be done in parallel with real-time processing. While the 
A 900 is the top model of the A series, the A600+ is an extremely low-cost 
computer which enables a Planicomp system to be offered in the price. 
bracket of analog instruments. 
Among the associated real-time operating systems, the RTE II was a simple 
foreground/background system. The later RTE IVB operating system with its 
multi-partition, multi-user and timesharing modes has been the preferred 
choice for the Planicomp. The new RTE A operating system for the A series, 
which has been expanded again, offers further options such as "virtual 
memory", "virtual code" and "FORTRAN 77". With a view to program de- 
velopment and installation, it may be mentioned that program editing and 
loading, file management and operating system modification are now simpler 
and much faster. 
On the peripheral equipment side, the dual disc drives have been replaced 
by Winchester discs, i. e. maintenance-free fixed disc drives with a sto- 
rage capacity of 10 to 132 MB, Being sealed, they should offer higher data 
security than interchangeable discs. For data filing and data interchange 
between different systems there is an integrated tape drive whose cartrid- 
ges can store the whole disc content, or an intergated micro-floppy drive. 
The variety of I/0 devices has been reduced by the elimination of the ori- 
ginally favored paper tape and punched card equipment; magnetic tape equip- 
ment is now being used. On the other hand, computer interconnection is ra- 
pidly gaining in importance. The following hook-ups are currently being 
supported: 
- Connection of the HP 1000 to mainframe computers such as the IBM 370 
with the HP RJE 1000 product. 
- Interconnection of HP 1000 computers or with HP 3000 computers with the 
HP DS 1000 product. 
- Data transfer between HP 1000 and HP 85/86, HP 9834/45 or HP 20 series 
computers with the HP IB interface. 
- Data transfer between two HP 1000 computers via the HP IB interface and 
a coupler. 
- Connection of an HP 1000 computer with an INTERGRAPH IGDS workstation 
and thus with a DEC VAX 11 computer with a processor-controlled serial 
interface. 
Further interconnection options will be provided.