The most recent revision of this page is June 17 2023 updated July 9 2023 To email me, see see my ordering Web page for my email addresses.

short story

[Herb with namebadge 2014]

retrotechnology: repair, restoration and/or reuse of old technology, particularly but not limited to 1970's and 80's digital computers. Why bother? History of old technology reveals and reappears in, represent trends, or may be essential for, new technologies. Preservation and description of past methods, for future use in similar situations. And, preservation for its own sake, of items for use as produced.

Thanks for visiting my site. My name is Herb Johnson. I'm based in New Jersey, USA. My interests are in "vintage" personal and (not-so-)industrial computers of the 1970's; some minicomputers and graphics computers from DEC, SGI and Sun; some early Macintosh computers; and some bits of older technology. Links below are to pages which show those systems and parts. Some items and services are for sale. The photo on the left is me.

My biggest computing collection and core interest, is my S-100 personal computing equipment, documentation, history and commentry about those products of the 1970's and 80's, for you to look at and/or purchase. Closely related is my on-line history and early products of Digital Research Inc and Dr. Gary Kildall, who developed CP/M in the 1970's and beyond. And, his colleages.

In 2009 I started a new series of Web pages on restoration, repair and preservation of 1970's and 80's vintage computers. I show my work, other's work, and collaborative work. One of my collaberations, was to enourage and support Lee Hart's 1802 COSMAC Membership Card - a 1976 computer in an Altoids can! As a kit! That you can buy NOW! ;)

To keep this site and activity going, I sell stuff. See what I offer, below on this Web page.

I sell some classic Apple Mac equipment and parts; some Multibus, STDbus and VME cards and manuals; and some old SGI and Sun computers, also some DEC equipment. I offer and document 8-inch and 5.25-inch floppy disk drives. I have some electronic test equipment that you may be interested in purchasing. Also some odds and ends bits of equipment and books that I've found while obtaining all those other items.

Recent events

reoccuring problem: spoofing spam

Emails that claim to be from which either beg or threaten you, are "spoofed" - faked with my email address. They are not from me. When some sites "block" emails with my domain name, that may block my actual emails to you. These blocks only last for several days. My apologies.

So on occasion, your email service may block all emails with my domain name for a time. If you don't get a reply to an email you sent to me recently, use the alternative email address I provide. Check my contact-me Web page for current email issues. - regards, Herb Johnson

Earthday April 2023, 2022, 2021, 2020

[Earthday 2020]

April 22 2020 was the 50th anniversary of Earth Day, I celebrate it annually now by displaying "The Flag of Earth". In April 2020 it seemed appropriate to consider the state of the Earth and our common connections on this planet, during the Covid crisis, and on that day in particular. In 2023, global warming is even more apparent to those who follow facts.

James W. Cadle created the Flag of Earth after the first Earth Day, a year after the Apollo 11 lunar landing; as a reminder and symbol of our planetary connections. Things looked grim in April 2020. A year later on Earth Day 2021, the Pandemic in the USA is starting to receed, and the US government is conferencing with world leaders about re-engaging with them about climate change. There was grounds for optimism again. But in April 2022, there's war in Europe. In April 2023, local wars have grown, the Earth is hotter, fire and drought and more-powerful storms are more common. Covid has subsided in the Western world (rising in the Eastern) as people argue about masks and boosters. Politics struggles between facist neodictators and common democracy, and social-media has is politically weaponized, including disinformation on climate change. The planet is still burning. - Herb Johnson

Contacts, ordering, navigating my site, references

Contacts?My email address is on my ordering Web page. Brief questions get brief answers; give me some detail so I know what you are talking about. But don't be long-winded either. Please read my site's pages before asking questions, and see if what you want or want to ask is already on my site.

Navigating my Web site?This Web site is updated often by the page. So some pages may be years old. Check the top of each page for revision dates. I can't link every page to every other. If you want some magic "show me" index, use a Web search engine: search "(keywords)" will provide an "index". Most of my pages are text - facts, data, experiences. Many of my images can be "clicked" to provide a larger image. Many of my descriptions include links to more detailed information. And, some items are for sale.

Ordering?. Ordering is generally 1) see what I have, 2) deciding what you want, and 3) sending an email message listing your requests and (please, please) your city/state/ZIP code or city/country so I can figure shipping costs. Follow this link for contact and ordering information.

References? This Web site is about two decades old. I have references from many people. Here are references from my Apple Macintosh sales; from my S-100 sales; from my SGI system sales.

[Mac Plus]

Mac Stuff

Since 1997, I've provided vintage Apple Macintosh systems and their parts and accessories. . This is mostly 68K and Power PC Macs, before Intel, before OS X. I provide power supplies, motherboards or CPU boards, Nubus and PCI cards, SCSI drives, ZIP drives, and Mac parts of all kinds. Follow this link to my Mac home page which has pointers to all my Mac pages, features and categories. Follow this link to my Mac frequently asked questions. A lot of vintage Mac owners were happy to find me, see what my Mac clients said.

[IMSAI 8800]

S-100 Stuff

S-100 systems are computers, designed between about 1975 and the mid-1980's, with a specific kind of 100-pin computer "bus". For decades, I've provided assistance, hardware, and documentation for S-100 computer systems, and for the 8-inch floppy disk drives often associated with them. I wrote a series of articles about these computers for The Computer Journal in the 1990's as "Dr." S-100. Most of these systems ran CP/M, which I explore on my Web site as noted below.

I have S-100 documentation, ask about specific brand and card. I also have some S-100 equipment and cards. Be specific about your needs if you want something. Follow this link to see a list of my S-100 stuff, including cards and documentation. Follow this link to my S-100 FAQ's, or frequently asked questions.

[SWTPC 6800]

SS-50 Stuff

Of the same era as S-100, is the SS-50 bus architecture created by SouthWest Technical Products Corp (SWTPC). Their SWTPC 6800 system began a legacy of SS-50 systems that expanded to the 6809 and 68000 over a decade's production by several companies. After years of being out-of-favor, these systems regained interest. In part, due to Bob Applegate and his Corsham Technology production of new SS-50 boards. After Bob's passing in June 2023, I consolidated my pages on SS-50 and Motorola systems, as linked from this SS-50 Web page. Over recent decades, I've worked with a few of these, as helped by Bob.

Repair, Restoration, Preservation

I have another set of Web pages about repairing and restoring computers of the 1970's and earlier; and why people should bother to do so. That is a valuable activity. I show how restoration can be organized and supported. I list various organizations, Web sites, events, and individuals who actively support repair, diagnosis, restoration of these early computers. Check my repair and restoration home page for details.

The COSMAC 1802 Membership Card

[IMSAI 8800]

Some old computers are worth a redo. See how Lee Hart and his COSMAC friends re-developed the classic Cosmac ELF design into an Altoids-can-size 1802 Membership Card COSMAC computer.

My old friend and electronic designer, Lee Hart, was discussing a 30-year-old microprocessor design a few years ago. I bugged him into making his ideas into a kit. In 2009 he created the COSMAC 1802 Membership Card; it's still in producion today (2017). I've sponsored and written Web pages on how I and others built it and run it. It runs the RCA 1802 processor, developed in 1975 and used extensively in space and on Earth. Yet you can run simple toggle-in programs, and it runs on sunlight! Check it out.

Digital Research, Gary Kildall, and CP/M

Dr. Gary Kildall's operating system called CP/M is well over 40 years old. The IEEE and Computer History Museum has recognized Kildall for his CP/M work. CP/M was the leading operating system for Intel 8-bit computers of the 1970's and 80's. Its functionality was replicated in what became MS-DOS. Dr. Kildall's company, Digital Research Inc., sold CP/M and subsequent operating systems and development tools into the 1990's, until the company was acquired by a series of other companies, who also sold DRI OS's into the 21st century. DRI intellectual property is still liscensed today. but CP/M is free for personal use. CP/M, S-100 and other microcomputer systems of the 1970's laid the foundations of personal computing, that others built upon. See my Digital Research & CP/M Web page index, which has links to my many pages about early Digital Research and its early developers. I produced most of those pages in 2004 to 2008, but I update it as other early DRI developers contact me.

[Zenith floppy drive]

Floppy Diskette and Drive Stuff

Closely related to the S-100 and CP/M world is the world of floppy diskette drives and media. That linked Web page has become a technical reference used by many for years. If you would like to buy a drive, media, or manuals for vintage floppy drives, Here's the link to my page of docs, media, cabinets, drives, and manuals for 8-inch, 5.25-inch, 3.0 and 3.5-inch floppy drives. I have on-line some detailed discussion and 8080 AND Z80 code for operating floppy disk controller chips, using an S-100 floppy disk controller which I STILL stock and sell. Also, check my restoration Web pages about work on floppy drives and controllers.

DEC stuff

[PDP 8/f]

For more on my DEC PDP-8 and PDP-11 systems, check this Web page. I have a few other old DEC systems. In 2007-2008, I developed a museum display of a DEC PDP-11/20 from a national laboratory. A few years later, I have a PDP-8/F which I restored to operation in 2012.

[STD bus]

Multibus, STDbus, VMEbus, Sun/SGI Stuff

Intel's Multibus and Motorola VME bus are closely related to S-100, by history and design. STDbusis another, older bus design. We offer some docs and cards for all these bus architectures. Check out our computer cards Web page for specific links to Web pages about cards and cardcages and backplanes for each bus, many available for sale.

VMEbus VME cards;
STDbus cards;
a few bits of Multibus cards.

In 2008-09 I restored an Intel System 320, a 386 and Multibus based system running Xenix. Since about 2016, there's been signifigant hobby activity on Intel Multibus systems. Check my Multibus pages. [SGI Indy]

Follow this link to my SGI and Sun equipment. I had accumulated for sale, a variety of SGI's from Indy to 320's. I have a few older Sun systems. Since 2012, I don't have much left.

[power supply]

Test equipment, odds and ends

Follow this link to my electronic test equipment. Mostly old stuff, but in good condition or useful for parts. There is a demand for analog oscilloscopes and basic test gear.

Follow this link to my list of odds and ends. These items include DDS and 8MM and other magnetic tape cartridges and tape drives; old terminals; high current or semiconductor fuses; and other "odd" electronic items or items of the 1970's.

[GEM mount]

Astronomy Stuff

I was an amateur astronomer in New Jersey, from 1990, for several years. Check this page for a summary of my astronomical activities. I have links to some local (to New Jersey USA) amateur astronomy sites, some of my work, and a few items of interest. In 2004-05, I've worked on my own telescope mirror and telescope: check the details of how I made a new one.

Herb's Personal Stuff


I live in New Jersey in the United States with my wife, somtimes cats, annoying deer, and various bits of old technology. For my biography, follow this link. Your good comments, descriptions of your work which I can reference and publish here, and your purchases of items from me, allow me to continue the old-tech work I do on this site. Thank you. Also thanks to my wife, Lois Frankel, who is a fabric artist and sewing machine restorer and collector.

Herb Johnson
New Jersey, USA

If you are looking for my postal or shipping mailing address: you have to contact me first. My email address is on one of my ordering pages.

Copyright © 2023 Herb Johnson