HP-67 / -97

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A computer of the type HP-67 with second and third functions in front of the keys, on the right side of the slot of the magnetic card reader
HP-67 in programming mode, the command displayed is
STO + 6
An HP-97 with the end of the anti-theft tab on the back

The HP-67 was a programmable calculator from Hewlett-Packard . It appeared in 1976 at the same time as the functionally identical desktop calculator HP-97 , which also had an integrated thermal printer . The models expanded the manufacturer's product range upwards and were aimed at experienced and demanding users from science and technology. Using the technology of the computers of the "twenties" series , they replaced the HP-65 and expanded its range of functions considerably. The computers used reverse Polish notation (UPN) as the input method .

Functions

The two models had a complete set of technical-scientific, statistical and mathematical functions, indexed addressing, a built-in card reader , sub- programs (3 levels), 20 labels, improved processing of programs (through BST), 8 comparison functions, 4 flags and an extended index - and loop control commands. The keys have four functions, and unlike most other models, the second and third functions are printed in front of the key.

The HP-67/97 used 8 bit wide command words to store the program instructions (HP-65: 6 bit). Thanks to the 256 possible combinations, this made it possible to save commands consisting of several key presses in a single program step (“fully merged keycodes”). A total of 224 program steps were available, compared to only 100 with the HP-65, which in practice meant three to four times the capacity.

The data memory also comprised 26 registers, of which only 16 were ever fully accessible. The first 10 data memories (number 0… 9) are called primary registers; a second block of ten (numbers 10 ... 19) is available as a secondary register, which can only be accessed via indirect addressing. The two blocks can be swapped, the data of the inactive register set are retained. This is done internally via two pointers to the register records. The remaining six registers A… E and the index register I correspond to the numbers 20… 25. All 26 registers, also with memory arithmetic, can be addressed via the indexed addressing without switching. The secondary registers were also used for the data accumulation of the statistical functions.

The memory is volatile, so that all memory contents are lost when the device is switched off. Data and computer settings can be saved on magnetic cards , whereby data or program parts of different cards can be combined when reading them. The MERGE function can also be used to automatically reload new program parts, so programs that are larger than the memory of the computer can be executed. The format of the magnetic cards was retained for the HP-41C ; the 41 emulates the hardware of the HP-67 with the ROM in the card reader, so that programs of the HP-67 / -97 can usually be executed without any problems, although the machines are not binary compatible with each other.

The LED display has 15 digits, and a separate digit is used for the decimal point.

Power is supplied by the HP-67 by a (welded) package of three nickel-cadmium accumulators of size AA , which are located in a compartment at the bottom and loaded in the computer.

For these computers, HP developed a new, combined ROM / RAM chip which, in addition to 1024 10-bit wide ROM command words, also contained 16 registers, each with 56 bit RAM. Each computer contained four of these chips, a total of 4 KiW ROM and 448 bytes of RAM.

HP also introduced a comprehensive library of programs, including those for surveying, medical, electrical, and engineering applications, and many others that have been adapted and improved for later models.

The HP-67 cost 450 US dollars when it was released , or around 2,000 US dollars based on today's purchasing power . Production ended in 1982.

HP-97

The HP-97 desktop model had a significantly larger keyboard, so only a secondary function key was required to provide the same functions as the HP-67. The computers are binary compatible so that programs can be read from the same magnetic cards; the conversion to the different keyboard codes between the models takes place in the firmware of the computer. The print commands of the HP-97 were converted into correspondingly equivalent displays of the HP-67. The HP-97 has a significantly larger battery pack of four size C cells (900 mAh) in a compartment on the underside and an 8 V ~, 3 VA power supply unit.

An extended model, the HP-97S, had a parallel interface for controlling external hardware.

The HP-97 cost around US $ 750 when it appeared in 1976, and around US $ 3,400 based on today's purchasing power . It was produced until 1984.
The similar table model HP-91 lacked programmability.

HP-95C

In terms of housing and electronics, the HP-95C corresponded to the HP-97. However, it was equipped with a permanent memory and lost the card reader in return. After HP had made prototypes and planned the launch in 1977, it was later decided not to bring the model onto the market, as the price of the HP-95 would have been too close to the HP-97 (there was never an official price). Only a few photos and the manual have been preserved of the prototypes of the HP-95C that were produced. As a special technical feature, the HP-95C offered a different division of the program memory, as was later implemented in the HP-41C. With the labels AD the code was executed in separate memory, the line numbering of which began with 1. With 200 program lines and 17 data registers, it was somewhat less extensively equipped than the HP-97.

comparison

The computers received their successor in 1979 with the HP-41C with an LC display. In terms of performance, the TI-59 was the only competitor, with the TI-59 , which appeared a year after the HP models, with a larger memory and higher processing speed, a separate printer and small removable ROM modules with software could be purchased. Ultimately, however, HP retained its high level of acceptance, especially among engineers, due to the higher mathematical accuracy and mechanical durability of the devices.

simulation

Simulations of these two computers (and many others) are available for iPhone and iPad. With the exception of the HP-97, these simulators are free from the App Store. The HP-67/97 were u. a. the program steps to max. 999 extended. (For details see web link below)

Individual evidence

  1. ↑ The " HP-95C Owner's Handbook and Programming Guide " with picture can be found in the collection of the HP Museum

Web links