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Magazines, Patents & Schematics

HP Journal

The HP Journal was published from 1949 to 1998 and documented all major technical developments of HP. If was much more a showcase than a marketing medium. Developers, project managers and designers presented their new concepts, sometimes with surprising depth, but always comprehensible.

Several articles deal with the 9800 series or with one of their components. As with most new systems, first the systems are introduced as a whole, than special concepts or components are described in detail. The most complete descriptions of 9845 technology are in the April 1977 issue (where the 9845A is introduced) and in the December 1980 issue (where the 9845C is announced).

Issue	9800 Series Related Content
June 1976	Cover: 9825A Calculator with its high-performance NMOS LSI processor and the powerful system-controller capabilities Third Generation Programmable Calculator Has Computer-Like Capabilities...a new programming language, HPL, helps the user apply the many technological advances in this personal computing machine to a wide variety of computation and control problems, by Donald E. Morris, Chris J. Christopher, Geoffrey W. Chance, Dick B. Barney, pg 2-14 High-Performance NMOS LSI Processor, by William Eads, David S. Maitland, pg 15-18 Character Impact Printer Offers Maximum Printing Flexibility...this new printer is fast and reliable, and has features previously unavailable in a calculator peripheral, including programmable horizontal and vertical tabulation, variable character spacing, and plotting ability, by Robert B. Bump, Gary R. Paulson, pg 19-23 Mid-Range Calculator Delivers More Power at Lower Cost...its design takes advantage of the latest technology, principally a single-chip microprocessor, by Douglas Clifford, F. Timothy Hickenlooper, A. Craig Mortensen, pg 24-32
November 1977	An NMOS Process for High-Performance LSI Circuits...fast 16-bit microprocessors, 16K read-only memories and a variety of special-purpose random-logic chips are the result of an NMOS process that produces high-performance large-scale integrated circuits, by Joseph E. Deweese, Thomas R. Ligon, pg 26-32
April 1978	Cover: Model 9845A Desktop Computer, also called, System 45 A Highly Integrated Desktop Computer System...System 45, the new flagship of the HP 9800 Series, gives the user unprecedented power in a single compact unit while offering advanced capabilities in program documentation, string and matrix operations, subprograms, program linking, tracing, formatted output, mass storage and graphics, by Jack M. Walden, William D. Eads, pg 2-11 System 45 Hardware Design, by Louis T. Schulte, John C. Keith, Ansel K. Vogen, pg 11-21 System 45 Product Design, by Ray J. Cozzens, pg 14-15 System 45 Tape Control System, by Richard Kochis, pg 20 Advanced Thermal Page Printer Has High-Resolution Graphics Capability...this optional System 45 built-in peripheral quietly outputs program listings or hard copies of anything on the CRT display, by Ray J. Cozzens, pg 22-28 New Printhead Technology Developed for System 45, by Eugene R. Zeller, pg 25-26 Personal Calculator Algorithms IV: Logarithmic Functions...a detailed description of the algorithms used in HP's hand-held calculators to computer logarithms, by William E. Egbert, pg 29-32
May 1979	Cover: Model 9835A Desktop Computer aka System 35 Extending Possibilities in Desktop Computing...this midrange computer's large memory capacity, two languages (enhanced BASIC and assembly language), low radiated interference, and powerful input/output facilities suit it especially well for computation, control, and data acquisition applications, by Sandy L. Chumbley, pg 11-13 Processor Enchancements Expand Memory...a new NMOS LSI chip and larger memory chips extend memory capacity, by Damon R. Ujvarosy, Dyke T. Shaffer, pg 13-15 Designing to Meet Electromagnetic Interference Requirements...eliminating electromagnetic pollution is assuming increasing importance around the world, by John C. Becker, pg 16-17 Assembly Programming Capability in a Desktop Computer...although efficient, assembly languages aren't usually easy to use but this one is, by Robert M. Hallissy, pg 18-20
December 1980	Cover: System 45C desktop computer Color Enhances Computer Graphics System...the addition of a color CRT, extensive graphics control statements and faster vector generation to a desktop computer provides a comprehensive graphics system for the display and interpretation of complex data, by John B. Frost, William L. Hale, pg 3-5 The System 45C User's Firmware Interface...new language statements provide easy input of graphical data and control of color parameters for generation of curves, shapes and shaded areas, by Robert W. Fredrickson, Robert A. Jewett, pg 6-9 Light Pen Aids User Interaction with Display...getting a light pen to work with a raster-scan display is not easy, first several physical limitations had to be overcome, by Frederick J. Porter, pg 10-19 A Precision Color Raster-Scan Display for Graphics Applications...these scanning circuit designs provide a color display free from distracting anomalies, by Warren C. Pratt, pg 19-24 Display System Designed for Color Graphics...System 45C's graphics architecture yields high-speed color picture generation with area shading, by Harold L. Baeverstad, Jr., Clark C. Bruderer, pg 25-32 System 45C Power Supply Considerations...a separate power supply for the color display provides for easy upgrading of earlier System 45 Computers, by J. Steven Becker, pg 28

All copies are provided by permission of HP for non-commercial use only and copyrighted by Hewlett-Packard Company. Look here for other online issues of the HP Journal.

Keyboard Magazine

The Keyboard Magazine was published from 1969 to the early 80's. In contrast to the HP Journal, which was targeted more towards engineers, the Keyboard Magazine was an end-user publication. As such it provided information on different product applications, peripherals, software, user stories and programming tips.

There were no special issues for the 9800 Series calculators, however there are a lot of articles telling about certain applications or providing programming hints for the 9845 during the late 70's.

Many Keyboard Magazine issues are available for download from hpmuseum.net (look here for the Keyboard Magazine section).

Patents

Patents can be an invaluable source for technical data on vintage computer systems. There have been several patents around the HP 9800 series, which provide more or less technical details. Remarkable were especially the US patents no. 4075679, which included a full commented assembler OS source code listing for the HP 9825, and no. 4180854, which was the original patent for the 9845A and provides much internal data about the basic implementation concepts behind the System 45 series, although the 9845A differs from the later System 45 calculators in some implementation details.

Generally, patents describe innovations rather than complete systems. This is due to the fact, that in general some concepts have been covered already by earlier inventions (documented or undocumented). So, for a nearly complete description, several sources should be combined.

Technical Patents

Patent No.	System	Description	# Pages	D/L
US3692255	DC100	"Belt driven tape cartridge"	9
US3971925	HP9805	"Adaptable programmed calculator having provision for plug-in keyboard and memory modules" (includes firmware listing)	164
US4089059	HP9815	"Programmable calculator employing a read-write memory having a movable boundary between program and data storage sections thereof" (includes firmware listing)	381
US4012725	HP9830	"Programmable calculator" (includes firmware listing)	590
US4075679	HP9825	"Programmable calculator" (includes firmware listing)	606
GB1568094	HP9825	"Programmable calculator" (same as above, but British patent document, includes firmware listing)	871
DE2655241	HP9825	"Programmierbarer Rechner" (same as above, but German patent document, includes firmware listing)	1014
US4180854	HP9845A	"Programmable calculator having string variable editing capability"	584
US4330839	HP9815	"Programmable calculator including means for automatically processing imformation stored on a magnetic record member"	8
US4367465	HP9845	"Graphics lightpen and method for raster scan CRT"	29
US4437156	HP9825	"Programmable calculator"	341
US4455618	HP9845A	"Programmable calculator"	11
US4566072	HP9815	"Programmable calculator including means for digitizing the position of an X-Y plotter pen"	12

Design Patents

Patent No.	System	Description	# Pages	D/L
D244862	HP9815	"Casing for an electronic calculator"	2
D245107	HP9815	"Electronic calculator"	2
D245810	HP9825	"Casing for an electronic calculator"	2
D249090	HP9825	"Casing for an electronic calculator"	2
D256133	HP9845	"Casing for an electronic calculator"	3

Look also at this site for an overview of HP calculator patents.

Schematics

The 9845 systems have been technically documented with manually drawn schematics. Please download the blueprints for the various 9845A and 9845B assemblies here. Due to multiple copy processes and age, some of the schematics have limited quality.

Now also the schematics for the 98770A color monitor, 98775A light pen and 98776A RGB interface are available. Many thanks to François Lanciault for providing the scans!

Original blueprints for 9845A and 9845B mainframe assemblies
Original blueprints for 98750A standard monochrome monitor (including graphics option)
Original blueprints for 98770A color monitor
Original blueprints for 98775A light pen
Original blueprints for 98776A RGB interface

Also recommended is to examine the schematics created by Tony Duell. He did the amazing task to re-engineer a complete 9845B with fast LPU option, enhanced monochrome graphics and 512K-RAM-board (before the original blueprints had been available). It is worth using it for a better understanding of the 9845 digital circuit design. Tony also produced schematics for ancestors and successors of the 9845 (starting with the 9100, ending with the 9836) and a large number of peripherals. See hpmuseum for downloading his work.

Reference	Download
William D Eads, Jack M Walden, and Edward L Miller, “A Dual-Processor Desk-Top Computer: The HP 9845A”, Chapter 31, Computer Structures: Principles and Examples, edited by Daniel P Siewiorek, C Gordon Bell, and Allen Newell, McGraw-Hill Book Company, 1982, p 508-532.
“Bit-Sliced Microprocessor of the Am2900 Family: The Am2901/2909”, Chapter 13-15, Computer Structures: Principles and Examples, edited by Daniel P Siewiorek, C Gordon Bell, and Allen Newell, McGraw-Hill Book Company, 1982.