Vintage computing enthusiast Lee Hart has created an Altair 8800 replica with a difference: It fits entirely within the footprint of an Altoids tin, despite using nothing but vintage hardware and a complete ban on modern replacements.
"One thing that struck me about microcomputers back then was how big they were. Big impressive boxes (with big impressive marketing claims) seemed to be the norm — even when the boxes (and marketing claims) were mostly full of hot air," Hart recalls. "Conventional wisdom says that they had to be big, due to the limitations of the technology at the time. But, is that really true?"
Using pocket calculators of a similar vintage — including the Hewlett-Packard HP-75, a scientific pocket calculator which came out three years before the MITS Altair 8800 kit — as evidence that it should, in theory, be possible, alongside an earlier effort to create a compact COSMAC Elf clone, Hart set about using vintage tech to pack an Altair into an Altoids tin.
"I kept thinking and 'schematicizing.' I couldn't fit the 8080, its support circuitry, memory, and I/O onto one Altoid-sized board (like my 1802 and Z80 versions)," Hart explains. "It was Josh Bensadon that provided the 'Aha!' idea. He said, 'You'll need a second Front Panel board anyway. So put the CPU on the Front Panel, so everyone can see that it's a real 8080. It can be the 'CPU board' as well as the 'Front Panel board'. Put the memory and I/O on the second board.'"
Thus the Altaid 8800 was born: a Front Panel PCB, which hosts a vintage 8080 processor, 8224 clock, power supply, support circuitry, and the 28 LEDs and 12 push-buttons switches which make up an Altair's front-panel interface; and a Memory/Input/Output PCB, holding up to 512kB of RAM, a 2-64kB EPROM bank-selectable in 8k blocks, and a TTL serial port for connectivity to external hardware — plus, as an added bonus, a couple of audio pins designed to load and save data from cassette tape or a modern PC's soundcard.
"With a 32k ROM and 512k RAM, the Altaid 8800 runs the CP/M-80 operating system with a 61k TPA and 448k RAM-disk with battery backup," Hart writes. "Two standard CP/M transient programs, PIP.COM and XM.COM (XMODEM) are pre-loaded. XMODEM can be used to load or save files or entire disk images from a host computer."
Full details, including a work-in-progress manual, are available on Hart's website, along with bare-board-and-EPROM kits for $19.75 of a complete kit with all parts for $80.80.