When last week I shared a tip on powering the Tandy TRS-80 Model 100/102 and its derivatives (here), Duncan commented that Bill Gates personally wrote some of the code for the Kyocera Kyotronic 85, which is the blueprint for many portable computers of the 80s’, including the NECs and Olivetti. I found a reference in David Allison’s interview of Bill Gates when he received the Price Waterhouse Leadership Award for Lifetime Achievement in 1993 (here). I copied and pasted the relevant extract of the transcript at the end of this post for your reference. The exact statement is: “Part of my nostalgia about this machine is this was the last machine where I wrote a very high percentage of the code in the product. I did all the design and debugging along with Jey.“



















In this interview, Bill Gates speaks highly of the Tandy TRS-80 Model 100 – but really the 102. “This is in a sense my favorite machine; I mean, by today’s standards, it is kind of a pathetic machine.” I’m afraid I certainly have to disagree with him about the pathetic. If I had to go to the field to collect data today, I would take one of these machines without hesitation. I would ditch a fancy modern laptop in a second. I have a desktop computer, a smartphone, and a calculator. No laptop needed 😊.



Unlike Bill, who jumped to the next shiny system, others continue developing for this unique platform. So, if you own one of these machines, you can seriously beef them up. Adding RAM when possible is an excellent first step. For example, since the NEC PC-8201a has bank switching, it is worth expanding its RAM above the 32KB max. With a simple key strike (<SHIFT>+<F5>), you can literally switch between two virtual machines. You can find the 32KB SRAM card for less than $50 (here), which is way cheaper than finding the original 8KB chips. As a side note, although the Tandy, NEC, and Olivetti – I don’t own a Kyocera – are similar, their slight differences can have significant impacts on the user experience / features. Like the 1% DNA difference between the chimpanzees and us. As in Danica Patrick‘s podcast, Neil deGrasse Tyson expressed this fear many times.
So, the Model 100 cannot bank switch as the NEC? No problem, we can make it the King of Switching using the REX# module (here). Once the module is installed into the Option ROM slot and its management software installed – via a simple call into a model-specific address – you have access to 1MB of SRAM! Who is pathetic, Bill? After all, that’s more than 640KB 😊.
It is also true that Gates denied having said no-one would need more than 640KB. In an email answering Tom Betz, he wrote: “I’ve said some stupid things and some wrong things, but not that. No one involved in computers would ever say that a certain amount of memory is enough for all time. The need for memory increases as computers get more potent and software gets more powerful. In fact, every couple of years the amount of memory address space needed to run whatever software is mainstream at the time just about doubles. This is well-known. When IBM introduced its PC in 1981, many people attacked Microsoft for its role. These critics said that 8-bit computers, which had 64K of address space, would last forever. They said we were wastefully throwing out great 8-bit programming by moving the world toward 16-bit computers. We at Microsoft disagreed. We knew that even 16-bit computers, which had 640K of available address space, would be adequate for only four or five years. (The IBM PC had 1 megabyte of logical address space. But 384K of this was assigned to special purposes, leaving 640K of memory available. That’s where the now-infamous ”640K barrier” came from.)
A few years later, Microsoft was a big fan of Intel’s 386 microprocessor chip, which gave computers a 32-bit address space. Modern operating systems can now take advantage of that seemingly vast potential memory. But even 32 bits of address space won’t prove adequate as time goes on. Meanwhile, I keep bumping into that silly quotation attributed to me that says 640K of memory is enough. There’s never a citation; the quotation just floats like a rumor, repeated again and again.”

Regardless, that’s also 32 banks of 32KB, that you can select almost instantaneously. You can back up/update the current bank, switch, delete or copy them. All this using the menu. I almost forgot; it comes with a fix for the Y2K bug.












In addition to seamlessly switching RAM banks, REX# can similarly handle ROM images! This way, you can load several option ROMs and switch between them with the same ease! This is remarkable, and you don’t have to choose which ROM to take on the road – or have to swap them. The module comes with TS-DOS (here). This ROM allows you to use a TPDD-compatible device. TPDD stands for Tandy Portable Disk Drive (a single-sided floppy drive) or a TPDD-compatible server running on another computer. The latter allows loading the ROM images mentioned earlier. I have a TPDD and a TPPD2, but I need to service them as the driver belt likely disintegrated. Note that the TPDDs use the same power adapter as the Model 100 – if you don’t use AA batteries –which allows me to power from the same USB power bank and a second Birdcord USB to 6V Converter Cable. And I can beat hands down the pathetic ~20h of battery life a modern laptop claims 😉.

DA: One of the most interesting machines that came out of this area was the TRS-80 Model 100. Do you want to say a few words about Microsoft’s role with that machine?
BG: Yes. This is in a sense my favorite machine; I mean by today’s standards it is kind of a pathetic machine. But what happened was Kazuhiko Nishi, my friend from Japan, came over and said that we could have an 8-line LCD with 40 characters. And up to then all we had was four lines by 20 characters. I didn’t think using 4 by 20 you could do much that was interesting. But, when he said we could go 8 by 40, then I got to be pretty fascinated with the idea of a portable machine. It wasn’t just taking your desktop machine and trying to shrink it down, because battery life would be a problem, and ease of use would be a problem. But just taking the things you want as you move around and making it pretty inexpensive. So, this machine came out for $500. Jey Suzuki, from Japan, and I, wrote the ROM in this machine. It is a 32K ROM.












Part of my nostalgia about this machine is this was the last machine where I wrote a very high percentage of the code in the product. I did all the design and debugging along with Jey. And it is a cool user interface, because although most of the code is a BASIC Interpreter, we did this little file system where you never had to think about saving anything. You just had this menu where you pointed to things. It was a great little editor and scheduler. We crammed it all into a 32K ROM. And really designed it in an easy-to-use way around these special keys up here. This machine was incredibly popular with journalists. Even though it came out over 11 years ago now, it was out by 1982. You still see some journalists using this, although the technology has gone way beyond it.




We had some great things here like we had a way that you could add a bar code reader to this. We thought maybe people would distribute software on bar codes. In fact, Byte Magazine got into that for a while. We had a lot of ways you could extend this by putting a new ROM in the bottom. And it was sold not only in the U.S. by Radio Shack, but NEC sold it in Japan, and Olivetti sold it in Europe. And the company who made it, Kyocera, became a good partner of ours for lots of future projects.











DA: You may actually want to turn it on so that we can show it.
BG: Let’s make sure that this machine is still running. My God, it’s a machine that works! I don’t know how LCDs work in a camera. What you had here is just your files. And you would just move the cursor to the one that you wanted and hit the Enter key. And then you’d be back editing that file. So, if we go into text, you can type in the name of the program and it would know that’s what you wanted. It is a nice screen editor. You can just move the cursor around. The only real problem with this product is that the keyboard was noisy enough that if you sat in a meeting with it, it was still considered anti-social because you’d just be tapping away during the meeting. So actually, we did a version, just a slight modification, soon after it came out that had a very silent keyboard so that people could sit in meetings and use it. It is really a nice machine. A great, great way that we use these function keys.



Regarding power, what is the current recommendation for replacing the Ni-Cd backup batteries? (Yuasa 3-51FT-A, 3V 50mAh)
I think, you can’t run these pretty machines without them.
Hi Norbert, this is what I plan to use once I finish procrastinating 🙂
https://jameltayeb.com/wp-content/uploads/2022/09/Accu-Model-100-1-scaled.jpg
I don’t know if they can run without the accumulator. I can experiment when I get to it.
Ah, what brand/vendor is this?
A no-name one I bought here: https://www.arcadeshopper.com/wp/store/#!/NI-MH-3-6v-80Mah-replacement-battery/p/109811157/category=32594049
You can have them from a brand like Varta or so as well. I ordered from Arcade Shopper as I had several items on my list.
Thanks!