HP-71B
The HP-71B is in BASIC programmable calculators from Hewlett-Packard , which was produced from 1984 to 1989. It replaced the HP-75 and was smaller and lighter than this. Four expansion bays allowed the expansion of the memory or the use of ROM modules, including an emulator for the HP-41 , which reached about five times the speed of the original with full functionality.
properties
The HP-71B has a single-line LC display of 22 characters, which could also be used in a graphics mode with 8 × 132 pixels. The keys were pre-assigned with frequently used commands, but could be freely defined by the user. The computer could be secured with a password and only used after entering the correct password. The lock could be bypassed by removing the batteries (four AAA batteries), but only by deleting all data in the computer's memory.
The HP-71B was the first computer to use the "Saturn" CPU, the further development of which was later used in the HP-28 and HP-48 . It was also the first model to use floating point numbers according to the IEEE standard instead of the BCD representation used in earlier models. It had a real-time clock that could be used to start programs in a time-controlled manner. The memory comprised 64 KiB ROM and 17.5 KiB RAM; the total memory could be expanded up to 512 KiB (the CPU could address 1 Mi Nybbles). The elongated magnetic cards adopted from the HP-75 with a capacity of 2 × 650 bytes per card could be used, but more popular were HP-IL devices such as the 82161A cassette drive and the 9114A floppy disk drive, which were also powered by batteries and therefore in the same way Way were transportable. Both devices, magnetic card readers and HP-IL modules, were extensions that were installed in two additional slots on the back of the computer. An optical reading pen ('wand'), which made it possible to read barcodes, was also adopted from the HP-41.
For use as a pocket calculator, the HP-71B had a special input mode that was more like AOS than the UPN used until then . The computer determined evaluable partial results during the input, but also allowed a correction after this operation. The internal processing still followed UPN, the stack could be used as usual.
