TRS-80 Model 100: Interview With John R. Hogerhuis


Last month, on something of a whim, I wrote up an introduction and guide to working with the TRS-80 Model 100, one of the first ever “notebook” computers, released in 1983. The Model 100 was something that had always interested me, and I thought I would share some of my experiences with getting software installed on it, and maybe introduce this nearly 30 year old piece of hardware to a new audience.

Much to our surprise, the Model 100 guide quickly became one of the most popular pieces the site has ever run, completely dominating the site traffic in March. Clearly there is a lot of interest in this device, but why? We’re talking about a machine that’s older than many of this sites readers (and indeed, a few of the writers).

To try and get to the bottom of the Model 100’s continuing popularity almost three decades after its release, we spent some time talking to John R. Hogerhuis, a key player in the Model 100 community. John’s unique perspective gives us an inside look at this extremely dedicated and knowledgeable community.

Getting Involved

John Hogerhuis

The Powerbase: John, thanks for taking the time to answer a few questions for us. Why don’t you start by telling our readers a little bit about yourself?

John: First of all Tom, thank you for your initial introduction to the Model 100.

I’m happy to answer your questions, and gratified at the interest in the Model T and our community.

I grew up fascinated by computers. I had a TRS-80 Color Computer, and later a Tandy Coco 3 (still have the Coco 3). I learned to program by reading books and typing in BASIC program listings which, once upon a time, appeared in hobbyist computer magazines. I went on to get a degree in computer science from Cal State Fullerton. After working as a programmer I went back to school and got my MBA with a focus on entrepreneurship. I make my living by doing contract software development.

I’m married and have three kids which get most of my free time. What is left goes to reading and my retrocomputing hobby, primarily Model T discussions and projects.

The Powerbase: How are you involved with the Model 100 community?

John:  I run the mailing list and the web site and wiki. I write and maintain software for the machine and share it with my friends in the community. I try to maintain the friendly list culture that has developed over the years on the mailing list. Via the list and private email, I work with other folks across the globe to encourage new projects and assist with testing and development when I have spare cycles.

“Fun and Useful Stuff”

I am the author of DLPilot, LaddieCon, HTERM, and TBACK.

DLPilot and LaddieCon are “external storage” services that simulate a Tandy Portable Disk Drive.

HTERM is a terminal program that implements hardware flow control, UTF-8 character set mapping, and baud rates up to 76800bps. It is my first major bit of 8085 assembly, with some of the code (a perfect hash function for the UTF-8 mapper) generated by a Perl script. My current goal is to add Zmodem support to it.

TBACK is a command line swiss army to manage a Model T’s RAM file system without having to install a disk service on it. Very much a work-in-progress.

HTERM and LaddieCon are available in source form via Git repositories hosted at TBACK is not currently shared other than with those who have asked to see it.

The Powerbase: Between the mailing list, Wiki, and your Model 100 software projects, it seems pretty safe to say you are a serious devotee to this nearly 30 year old computer. What’s kept you interested for so long?

John:  Well I didn’t actually own a Model 100 until about 2004. As a Coco kid, I salivated over Model 100 ads in the magazines and Tandy catalogs. I thought it would be great to use at school. But at several hundred dollars, it wasn’t affordable to me. But as an adult, via Ebay, I found I could get my dream machine for $50.

The Model T is a unique computer. It’s lightweight, rugged, and gets 20 hours of battery life on off-the-shelf AA’s. Think about that: what machine can claim that today? Drop an iPad from a few feet and it’s not likely to work well any more. Only recently are we seeing general computing devices like the iPad that are instant-on and come with built-in productivity applications.

That said, it’s got a sprinkler computer for a brain. It was underpowered when it was still being sold by Tandy. DOS machines with much more memory were widely available soon after the Model 100 was introduced. But I believe it’s the combination of a tight, well architected and integrated system that made it and make it so useful despite specs that today make it uncompetitive with scientific calculators on raw specifications. The whole is greater than the sum of its parts.

Type in a BASIC program, and EDIT the whole program or a line of code… it pops it open in the TEXT editor. Pop open the TEXT editor and select some text… you can then use the PASTE key to dump it into another file or into a terminal prompt. Create a list of phone numbers in the TEXT editor… you use the ADRS program to search for a given name and then have the modem dial the phone.

In addition to the excellent design of the machine, I am fascinated by the way that the Model T is a forerunner of other equipment. The next truly portable device in my mind was the Palm Pilot. That died out and now we are seeing new true portables in the form of the smart phones and tablets. But the Model T was the blockbuster product of its day, especially with journalists who depended on true portability, instant-on and appreciate its incredibly good keyboard.

Another big feature of the Model T for a hobbyist is its small footprint. I can put it away when I’m not using it, or carry it anywhere in the house if my workbench is cluttered with another project. My Coco is stuck on my rack, it really doesn’t get much use just because of the amount of gear you need in one spot to use it effectively. I can pull out the Model T, get my retrocomputing fix, and then put it away.

About Tom Nardi

Tom is a Network Engineer with focus on GNU/Linux and open source software. He is a frequent submitter to "2600", and maintains a personal site of his projects and areas of research at: .
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  • Howard

    Great article. I enjoy reading about vintage computers in general, and the Model 100 in particular.

    • Rf

      I always quit reading t the big big rollover whatever it was.

      • Dean Howell

        Even though it’s off to the right and doesn’t cover the content?

  • Josh

    My step father used to have a Tandy 100.

    It bothers me that there’s no typing appliance these days with its features:
    1) really great keyboard (deeper keys that you get these days)
    2) instant on, instantly usable
    3) you don’t have to open it up, it’s ready to use all the time
    4) it’s tough enough to drop on a hard floor, or maybe even sit on it without breaking it.

    Of course it has problems by our standards:
    1) small screen that can’t display more than a few lines of text (and not lines that are all that long)
    2) not enough memory for large files, not even large text files.
    3) no gui, no touch screen, limited features. You can type and edit but it’s not Microsoft Word.

    A modern version would be welcome to some people.

    I remember another early note-taking computer in the early 90’s that had a different useful feature – totally silent keys (they had motion but were under rubber – I suppose it was waterproof too). It was a sinclair, thinner than the Tandy 100 but otherwise similar. Those features would still be useful too. I was once hired to reprogram one to have a dvorak layout (I burned a rom).

    • Will

      This exists today, as a mostly dedicated word processor, focused on the K-12 education market. Known as the AlphaSmart and its descendant, the Neo 1/2. These are dedicate Word Processors with 40×4 LCD screen and stupid battery life (3xAA, 100’s of hours).

      There is also a version called the Dana which is basically a Palm Pilot with a built in keyboard. So, its programmable and can work with Palm OS packages. Really totally different, rechargeable battery (12 hrs) but will go an extra 30 with AA batteries.

      Probably the closest “modern” equivalent of a Model 100 today.

    • jhoger

      “I remember another early note-taking computer in the early 90’s that had a different useful feature – totally silent keys (they had motion but were under rubber – I suppose it was waterproof too). It was a sinclair, thinner than the Tandy 100 but otherwise similar.”

      You’re probably thinking of the Cambridge Z88 or possibly the Amstrad NC100 or NC200.

      • Mike hibbett

        No he is right, the sinclair had soft rubber keys. There were of course other pcs that had a similar format ( the linx, I think )

        • jhoger

          But the Sinclair wasn’t a note taking computer. But were kind of both right since the z88 was the creation of Sir Clive Sinclair.

  • Jeremy Hidy

    I saved up money and bought one in school, then someone stole it out of my desk. I had it for less than a week.
    I had dreams of writing assembly to make a horizontal shooter on the LCD display.

  • Tom Hunter

    The Model 100 was my first computer. I spent $1,000 on it. I have heard that it was the last software that Bill Gates himself wrote. The manual was famously bad, with references to non-existent sections. I still have my model 100 and a disk drive for it. Sure it would work fine today if I put in batteries.

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  • Snorvell

    I still have mine in a drawer in my house. Trash-80 we use to call it, lovingly.

    One of the great things about it that no one mentioned was that it ran on double-As, which were available anywhere. I carried it around Central America as a working journalist in the late 1980s and loved it because I could slice into any hotel’s phone system to send stuff or just use the acoustic couplers.

    Great fun to hear about about people still using them.

    One other true story … I dropped it (in its black faux-leather case) into the ocean getting out of a dugout in Venezuela. I grabbed it quickly so it didn’t get THAT wet, but it got a little wet. But fired right back up later and never looked back.

    Thanks for the memories.

  • Morseman5

    not sure if it was mentioned here, but the model 100 was one product that Bill Gates personally wrote the os for…..and yes, i own one too……a great machine if you need a remote terminal. I have a dozen or so of the the hand scanners that were sold for them as well. they are fun to play with…..mark z

  • Hag

    Very cool…made me think of these

  • Larry K

    Why do I still use my M-100? … because of the rich, but not cluttered, BASIC interpreter. This type of programming capability is not available now for any operating system (think Visual BASIC and the learning curve). Also is the instant on feature… no boot up time.. a biggy for me. I have written or downloaded so many useful routines for this computer. Yes, all programs (some complex), perform well in the 32K bytes limitation. No problem.

    Sure I use a modern computer for the Internet, but never will get rid of my Tandy M-100… (now empowered, storagewise) with the NADS box, available from Club 100.

    This thing was way ahead of its time….


  • JoetheFilmmaker

    Isn’t this hogerhuis guy an obama sycophant? The guy’s a joke.