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 Atom-8 and Easy-4, published in Japanese magazines. 
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Joined: Tue Dec 18, 2018 11:25 am
Posts: 21
Location: Hampshire, UK.
ATOM-8 was a minimal 8 bit CPU, designed by Mr. Tomisaki.Arata(富崎新) and published in a Japanese magazine; "トランジスタ技術"(Transistor Technology) in issue #5 of 1973. Issue #6 was general software and issue #7 was on peripheral and supplementary, and was re-published in "つくるコンピュータ" (Homebrew Computer) 1976 issue.

It was similar to the Kenbak-1 in that it was a bit serial design, but with a much smaller program space of only 32 words.
Each 8 bit word had 3 bits for the instruction, and thus only 8 instructions, and 5 bits for an address.
It used 25 TTL MSI,SSI chips and an Intel 1101A 256 bit memory chip.

In 1974 a Mr. Nehi completed his construction of an Atom-8, but soon outgrew the limited memory.
In October 1975 he designed a 16 bit (parallel) CPU, the Easy-4, using 100 TTL chips, and had it working by December 1975. He soon expanded it with more memory and created a Very Tiny FORTRAN (VTF) language interpreter, and had his design published in Japan in 1977 in Radio-Science magazine.

Details and pictures here:-
https://easy-4netobi.jimdofree.com/5-atom-8-cpu/
Videos here:-
https://m.youtube.com/watch?v=PNtf-lDKbVM
https://m.youtube.com/watch?reload=9&v=_RGeBdVPvmo

And his Very Tiny FORTRAN interpreter:-
[url]https://easy-4netobi.jimdofree.com/4-very-tiny-fortran-10パズル/[/url]

P.S. It has an nusual construction technique of ‘dead bug’ wire-wrapping.


Last edited by B.Bibby on Wed Jan 29, 2020 7:52 pm, edited 2 times in total.



Tue Jan 28, 2020 11:22 pm
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Joined: Tue Dec 18, 2018 11:25 am
Posts: 21
Location: Hampshire, UK.
The Easy-4 above, inspired Tanaka to create his Tanacom-1 in 1978, also a 16 bit machine.
https://translate.google.com/translate?sl=ja&tl=en&u=http%3A%2F%2Ftanacom.jpn.org%2Findex.php%3FOverview

Videos here:-
https://m.youtube.com/watch?v=3Cs8Thddy7U
https://m.youtube.com/watch?v=XsN_QOo4goo


Tue Jan 28, 2020 11:35 pm
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Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1384
Great finds! Homebrew machines calculating pi, that's always a good milestone. And a Space Invaders for light relief.


Wed Jan 29, 2020 9:18 am
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Joined: Tue Dec 18, 2018 11:25 am
Posts: 21
Location: Hampshire, UK.
Although the Elektuur 74 came before the Mark-8 and Educ-8 by a few months:-
https://anycpu.org/forum/viewtopic.php?f=15&t=53
https://en.m.wikipedia.org/wiki/Mark-8
https://en.m.wikipedia.org/wiki/EDUC-8 (Another bit serial machine.)

The Atom-8 predates the Elektuur 74 article by ten months, and may be able to claim the title of “the first DIY computer project from a magazine”.


Last edited by BigEd on Wed Jan 29, 2020 10:57 am, edited 1 time in total.

fix link



Wed Jan 29, 2020 10:27 am
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Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1384
I'd be happy to post these findings over on retrocomputingforum.com - unless you'd prefer to?


Wed Jan 29, 2020 1:56 pm
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Joined: Tue Dec 18, 2018 11:25 am
Posts: 21
Location: Hampshire, UK.
@BigEd; go ahead and cross-post.

More detail on the unusual construction technique of the Tanacom-1 (and Easy-4).
No printed circuit board involved!
The top of each IC is coated with silicon grease, flipped over and clamped upside down on an aluminium plate that then acts as a large heat sink. Then the connections are made by wire wrapping each pin of each IC using urethane coated wire, where the urethane coating melts away when soldering the wire to a pin. IC pins on a common signal line are linked via a single continuous strand of urethane wire between the pins.
https://translate.google.com/translate?sl=ja&tl=en&u=http%3A%2F%2Ftanacom.jpn.org%2Findex.php%3FOverview

Image

Though it would make replacing a defective IC difficult.


Wed Jan 29, 2020 3:32 pm
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Joined: Tue Dec 18, 2018 11:25 am
Posts: 21
Location: Hampshire, UK.
Another Japanese DIY computer from 1973, the HITOM-8.
Although It’s not clear from the (Google) translation I think it is based on the published Atom-8 design of the same year.

https://translate.google.com/translate?sl=ja&tl=en&u=http%3A%2F%2Fwww.dokidoki.ne.jp%2Fhome2%2Fhisa%2Fhitom8.htm


Wed Jan 29, 2020 8:04 pm
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