   the ibm 5100 portable computer was a portable computer introduced in september 1975, six years before the ibm pc. it was the evolution of a prototype called the scamp (special computer apl machine portable) that was developed at the ibm palo alto scientific center in 1973. in january 1978 ibm announced the ibm 5110, its larger cousin, and in february 1980 ibm announced the ibm 5120. the 5100 was withdrawn in march 1982. when the ibm pc was introduced in 1981, it was originally designated as the ibm 5150, putting it in the "5100" series, though its architecture was not directly descended from the ibm 5100. ==description== the ibm 5100 is based on a 16-bit processor module called palm (put all logic in microcode). the ibm 5100 maintenance information manual also referred to the palm module as the controller. the palm could directly address 64 kb of memory. some configurations of the ibm 5100 had executable ros (rom) and ram memory totalling more than 64 kb, so a simple bank switching scheme was used. the actual apl and basic interpreters were stored in a separate language ros address space which the palm treats as a peripheral device. prices ranged from $11,000 (16k model) to $20,000 (64k). ===the portable computer=== a single integrated unit provided the keyboard, five-inch crt display, tape drive, processor, several hundred kilobytes of read only memory containing system software, and up to 64 kb of random access memory. it was the size of a small suitcase, weighed about 55&nbsp;lb (25&nbsp;kg), and could be transported in an optional carrying case, hence the "portable" designation. while the ibm 5100 seems large today, in 1975 it was an amazing technical accomplishment to package a complete computer with a large amount of rom and ram, crt display, and a tape drive into a machine th
1975_introductions IBM_personal_computers Portable_computers