Keyboard Builders' Digest
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IBM 5100

The IBM 5100 is one of the many "first" portable computers (1975). Shared by u/Crul_.
Published May 15, 2022

The IBM 5100 Portable Computer is one of the many "first" portable computers, introduced in September 1975.

(In fact, the truck-based IBM 1401 from 1960 for military use was a "portable computer" too.)

The IBM 5100 was the evolution of the SCAMP prototype (Special Computer APL Machine Portable) that was developed at the IBM Palo Alto Scientific Center in 1973.

The unit included an integrated keyboard, five-inch CRT display, tape drive, processor, several hundred KiB of read-only memory containing system software, and up to 64 KiB of RAM. "It was the size of a small suitcase, weighed about 55 lb (25 kg), and could be transported in an optional carrying case, hence the "portable" designation."

As you can see in the picture above, mass storage was provided by quarter-inch cartridge (QIC) magnetic tape drives.

As vulkman points out:

Fun fact if you're a programmer: This thing has a hardware switch to switch from BASIC to APL! Crazy times...

APL was generally available only on mainframe computers, and most desktop sized computers offered only BASIC.

Machines that supported both languages provided a toggle switch on the front panel to select the language. On the 5100's front panel, it was the third toggle from the right: down for APL, up for BASIC. (At least with the model in the photo. Other specimen may have the button in a different place and also the function may be reversed.)

The 5100 was also available with only APL or BASIC. These configurations had no such hardware switch.


Published on Sun 15th May 2022. Featured in KBD #78 (source).

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