HP-67/-97

The HP -67 was a programmable calculator from Hewlett -Packard. He appeared in 1976 simultaneously with the functionally identical desktop calculator HP- 97, which also had a built-in thermal printer. The models extended the manufacturer's product line up and targeted at experienced and demanding users in science and technology. Using the technology of the computer of the series " Twenties" they broke the HP- 65 from and expanded its capabilities significantly. The computer used as the input method, the Reverse Polish Notation (RPN ).

Functions

The two models possessed a complete set of technical- scientific, statistical and mathematical functions, indexed addressing, a built-in card reader, subprograms ( 3 levels ), 20 labels, improved editing of programs ( BST ), 8 comparison functions, 4 flags and extended index - and loop control statements. The keys are four-threaded, which, in contrast to most other models is the imprint of the second and third function before the button.

The HP-67/97 used 8 -bit wide instruction words for storing the program instructions (HP- 65: 6 -bit). This allowed the 256 possible combinations, also from multiple keystrokes existing commands to store in a single program step ( "fully merged keycodes "). A total of 224 program steps were available, compared to only 100 for the HP -65, which meant that three to four times the capacity in practice.

The data memory included next 26 registers, of which there were only 10 but always in full control. These are called primary register; a second block of ten stands as secondary registers are available, on which no direct access is possible. Between these two blocks can be switched back and forth, the data of the inactive register set are retained. Internally, this happens via two pointers to the register sets, while the user has the impression that the data would be exchanged between the registers. The remaining six registers (A ... E, STO and RCL possible) and the index register i stand for the statistical functions available. About the indexed addressing allows all 26 registers with memory arithmetic, respond without switching.

The memory is not permanent. All memory contents are lost when power off. Data and computer settings can be stored on magnetic cards, which can be combined when reading data or program elements from different cards. The format of the magnetic card has been retained for the HP -41C; 41 emulates the ROM located in the card reader the hardware of the HP -67, so that in most cases can be easily run programs HP-67/-97, although the machine is not binary compatible with each other.

The LED display is 15 digits, while a separate place for the decimal point will be used.

The power supply consists of a package of three nickel - cadmium batteries size AA, which are located in a compartment at the bottom and can be loaded in the computer.

HP developed a new combined ROM / RAM chip, which contained, besides 1024 10 bit wide instruction words ROM also includes 16 registers each 56 bit RAM for this computer. Each computer contained four of these chips, for a total of 4 Kiw ROM and 448 bytes of RAM.

Likewise, HP presented a comprehensive program library before, including for measuring, medical, electrical and engineering applications, and many more that have been customized and improved for later models.

The HP -67 cost on publication 450 U.S. dollars, according to today's purchasing power about 1,900 U.S. dollars. Production ended in 1982.

HP -97

The table model HP -97 had a significantly larger keyboard, therefore only a secondary function key was required to provide the same features as the HP -67. The computers are binary compatible, so programs can be read by the same magnetic cards; implementation at the different between models keyboard code is in the firmware of the computer. The print commands of the HP -97 was thereby converted into mutatis mutandis equivalent at the HP -67. The HP -97 has a much larger battery pack of four cells and a stronger charger.

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

The HP -97 cost in 1976 show around 750 U.S. dollars, according to today's purchasing power about 3,200 U.S. dollars. It was produced until 1984.

Comparison

The computers got their successors with the HP- 41C. Compared with the performance of the TI -59 represented the only competition, the published one year after the HP models TI -59 offered a separate printer, larger memory and faster processing speed. Ultimately, HP retained, however, because of the higher mathematical accuracy and the mechanical durability of the devices, especially among engineers its high acceptance.