The Museum of HP Calculators

This Hewlett-Packard advertisement, originally published in Scientific American, is used by permission. If errors crept in during the scanning process, please contact Dave Hicks

HP's 9825A: a powerful new desk-top computing system.

Through its novel architecture and speed, the 9825A runs programs, accepts keyboard operations, and controls instruments--with apparent simultaneity. This virtual "multiprocessing" capability comes in a 26-pound package that combines advanced computer technology with the directness of a programmable calculator.

To understand what the 9825 can do, you must resist thinking of it either as a programmable calculator or as a computer. Unlike any other desk-top system, the 9825 has a live keyboard and optional vectored priority interrupt. For example, while it is controlling several instruments, and acquiring data from them, you can perform calculations, print or plot data, review and list programs, and change variables within a program--all through simple keyboard commands. Although it does all these operations on a priority basis, so great is its speed it seems to be doing all of them at the same time, as a multiprocessor would.

The 9825's storage capacity includes 8K bytes of internal read/write memory, expandable to 32K bytes; in addition, each bidirectional tape cartridge can store 250K bytes. Its built-in tape cartridge drive can access data in an average of six seconds, and transfer data at 2750 bytes per second. At these speeds, and with memory load and recall capabilities not previously found in desk-top systems, it becomes entirely practical to interrupt a long program, transfer it to tape, run a short program, then reload and continue the first one.

As a controller, the 9825 can handle up to 45 measuring instruments simultaneously through its three I/O slots. Three optional interface cards are available: one for 16-bit parallel data, one for BCD devices, and a third-HP-Interface Bus-for instruments that conform to IEEE Standard 488-1975.

When it comes to programming, you can do it all yourself. The 9825's advanced language (HPL) offers you power and efficiency for handling complex formulas and equations, coupled with ease of use. This combination lets you solve tough problems that were formerly the exclusive province of big computers. HPL handles subroutine nesting and flags, and allows 26 simple and 26 array variables.

Peripheral options include a choice of printers, plotters, and tape and card readers. Four slots accept optional plug-in ROM's to further extend the 9825's versatility.

The 9825A represents a new genre of computing capability-in both its performance and its base price of $5900*. And at just 26 pounds, it could legitimately be considered a portable computer.

*Domestic USA prices only.

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