To say that Tandy’s TRS-80 Model 100 was an influential piece of computer hardware would be something of an understatement. While there’s some debate over which computer can historically be called the “first laptop”, the Model 100 was early enough that it helped influence our modern idea of portable computing. It was also one of the most successful of these early portables, due in part to how easy it was to write your own software for it using the built-in BASIC interpreter.

But as handy and capable as that integrated development environment might have been, it never produced anything as impressive as this Baldur’s Gate III “demake” created by [Alex Bowen]. Written in assembly, the game’s engine implements a subset of the Dungeons & Dragons Systems Reference Document (SRD), and is flexible enough that you could use it to produce your own ASCII art role-playing game that can run on either a Model 100 emulator like Virtual-T or on the real hardware.

Don’t worry about not having enough experience with the Model 100’s hardware to conjure up your own fantasy adventure. Assembly is done through zasm, and even though the code is intended for the 8085 CPU used in the Model 100, it’s actually written in Z80 syntax. The assembler’s support for mapping unicode characters also allows you to get a serviceable preview of what the levels will look like on the Model 100’s display right inside of your editor.

As you might imagine, getting such a complex game running on the meager hardware of the Model 100 took considerable trickery. [Alex] goes into plenty of detail in the project’s documentation and the video below, but perhaps our favorite optimization is the text compression routine. A Python script ran through all of the text strings used in the game to identify the most commonly used character sequences, and then mapped them to values which could be used to piece together words and sentences. This saved approximately 1500 bytes, which might not sound like a lot to a modern game developer, but it’s much appreciated on a machine that’s only got 24 kilobytes of RAM to begin with.

We’ve seen a number of projects featuring the TRS-80 Model 100, but most of them involve ripping out the original hardware and replacing it with something modern. That said, if you’ve got a stock Model 100 and give this technical masterpiece a shot, we’d love to hear about it in the comments.

How many lines do you need on a CP/M terminal? More is usually better, of course, but the MicroOffice RoadRunner managed with an 8-row, 80-column LCD screen. That may sound anemic, but in 1983, it was high-tech, as was the RoadRunner, and [Tech Time Traveller] tells us about them in a recent video you can see below.

The intro to the video shows some really strange old laptops before it gets to the RoadRunner. The machine used a Z80 work-alike CPU and a form of CP/M with some organizer functions. The machine didn’t have floppies or other disk storage, but did have four cartridge slots that could hold more memory, a spreadsheet, BASIC, or a text editor. The memory cartridges were static RAM with battery backup, so they retained data when you pulled them from the slot. Assuming the battery didn’t die.

Unfortunately, this particular machine suffered some shipping damage. In addition to the cartridges, it also had a removable battery and modem. At around the eight-minute mark, the case comes off, and inside are — surprise — more internal cartridges.

While MicroOffice isn’t a household name today, it was founded by a former Exxon executive and tapped a CEO and investor from Timex. It was funded by the likes of Olivetti. The computer rolled out in late 1983 and lived until Telxon bought MicroOffice in 1985.

Attempts to run Zork were not fruitful. There really wasn’t enough memory, and file transfer was a bit wonky. If you want a modern Z80 laptop, we know of one with 16 cores. As clunky as the RoadRunner looks, it still beats the old suitcase computers.

As curious people, we’re all incredibly fortunate to live in an age where information can so easily be obtained. If you want to learn how something works, from a cotton gin to an RBMK reactor, you’re just a few keystrokes away from articles, diagrams, and videos on the subject. But as helpful as all of that information can be, we also know that there’s no substitute for hands-on experience.

While we can’t recommend you try building a miniature graphite-moderated nuclear reactor, there’s plenty of other devices that you can study by constructing your own functioning model. For example, when [Jorisclayton] wanted to really know what was going on inside a computer, they decided to go back to basics and build their own Z80 machine. To maximize the experience, they skipped any of the existing kit designs and instead wired the whole thing up by hand across a few perfboards.

The main board contains a 4 MHz Z80 processor, paired with 32K ROM and 64K RAM. Here you’ll also find the clock generator, I/O decoder, serial port, voltage regulator, and a trio of expansion slots that use a long strip of 2.54 mm pin headers as the interface. In the first expansion slot you’ve got a primordial “graphics card” based around the TMS9918 video display controller (VDC) and 16K of additional RAM. The second expansion card has a CompactFlash reader and an LED array mapped to I/O address 0x00h so it can be used for various notifications.

[Jorisclayton] says the final expansion board is still being worked on, but the idea is for it to handle user input through a PS/2 keyboard connector, as well as provide ports for a pair of Super Nintendo (or compatible) controllers. Everything is held together with a minimalist 3D printed frame to show off all that careful soldering.

Obviously there’s no PCB design files to share for this one, but [Jorisclayton] has posted a schematic for wiring everything up if you’re looking for resources to build your own Z80 computer. Sure the chips themselves might no longer be in production, but that doesn’t mean this venerable CPU is going anywhere just yet.

It’s with a tinge of sadness that we and many others reported on the recent move by Zilog to end-of-life the original Z80 8-bit microprocessor. This was the part that gave so many engineers and programmers their first introduction to a computer of their own. Even though now outdated its presence has been a constant over the decades. Zilog will continue to sell a Z80 derivative in the form of their eZ80, but that’s not the only place the core can be found on silicon. [Rejunity] is bringing us an open-source z80 core on real hardware, thanks of course to the TinyTapeout ASIC project. The classic core will occupy two tiles on the upcoming TinyTapeout 7. While perhaps it’s not quite the same as a real 40-pin DIP in your hands, like all of the open-source custom silicon world, it’s as yet early days.

The core in question is derived from the TV80 open-source core, which we would be very interested to compare when fabricated at TinyTapeout’s 130nm process with an original chip from a much larger 1970s process. While It’s true that this project is more of an interesting demonstration of TinyTapeout than a practical everyday Z80, it does at least serve as a reminder that there may be a future point in which a run of open-source real Z80s or other chips might become possible.

This isn’t the first time we’ve featured a TinyTapeout project.