The Texas Instruments CC-40 invades Gopherspace (plus TI-74 BASICALC)

I've mentioned on the blog several times the continuum that exists between handheld computers and pocket computers, battery powered devices in rather small form factors that are nevertheless fully-fledged general purpose computers — arguably more so than the modern locked-down smartphone has become. Some of these diminutive systems are best considered "handhelds," with larger size, larger keyboards, more power and (often) less battery life, and some are definitely "pocket computers," with smaller size, smaller keys, less power and (usually) better battery life. For example, systems like the Tandy PC-4/Casio PB-100 or Tandy PC-3/Sharp PC-1250 would be considered "definitely a pocket computer," while the Epson HX-20 or Kyotronic 85 systems like the NEC PC-8201A or TRS-80 Model 100 would be considered "definitely a handheld computer," and you can probably think up some examples in between.

Well, here's a notable example of one single architecture that birthed both types of machine, and it came from a company not really noted for either one: Texas Instruments.

TI certainly made calculators and many of those were programmable by some means, but neither handheld computers nor pocket computers had categorically been in their repertoire to date. Nevertheless, here we have the 1983 Compact Computer 40 — using the AA battery for scale, at that size definitely a handheld — and above it the 1985 TI-74 BASICALC, notionally a "BASIC programmable calculator," but actually an evolved version of nearly the same hardware in less than half the size. Thanks to the ingenuity of the Hexbus interface, which due to TI's shortsightedness was never effectively exploited during that era, we can get a serial port running on both of these with hobbyist hardware. If we have a serial port, that means we can bring up a terminal program — which we'll write from scratch in assembly language for shell and Gopherspace access.

But how would a Unix shell work on a single line screen, or for that matter, a Gopher menu? We'll explore some concepts, but before we do that, for context and understanding of their capabilities we'll start with the history of these machines — and because their development is unavoidably tangled with TI's other consumer products and their home computer family, we'll necessarily rehash some of those highlights and nadirs as well.

The unreleased Commodore HHC-4's secret identity

Once upon a time (and that time was Winter CES 1983), Commodore announced what was to be their one and only handheld computer, the Commodore HHC-4. It was never released and never seen again, at least not in that form. But it turns out that not only did the HHC-4 actually exist, it also wasn't manufactured by Commodore — it was a Toshiba.

Like Superman had Clark Kent, the Commodore HHC-4 had a secret identity too: the Toshiba Pasopia Mini IHC-8000, the very first portable computer Toshiba ever made. And like Clark Kent was Superman with glasses, compare the real device to the Commodore marketing photo and you can see that it's the very same machine modulo a plastic palette swap. Of course there's more to the story than that.

Programming the Convergent WorkSlate's spreadsheet microcassette future

In this particular future, we will all use handheld spreadsheets stored on microcassettes, talking to each other via speakerphone, and probably listening to Devo and New Order a lot. (Though that part isn't too different from my actual present.)

It's been awhile since we've had an entry for reasons I'll talk about later, and this entry is a doozy. Since we recently just spent a couple articles on a computer whose manufacturer insisted it was mostly a word processor, it only seems fitting to spend some time with a computer whose very designer insisted it was mostly a spreadsheet.

That's the 1983 Convergent WorkSlate, a one-of-a-kind handheld system from some misty alternate history where VisiCalc ruled the earth. Indeed, even the "software" packages Convergent shipped for it — on microcassette, which could store voice memos and data — were nothing more than cells and formulas in a worksheet. The built-in modem let you exchange data with other Workslates (or even speak over the phone to their users), and it came with a calculator desk accessory and a rudimentary terminal program, but apart from those creature comforts its built-in spreadsheet was the sole centre of your universe. And, unlike IAI and the Canon Cat, I've yet to find any backdoor (secret or otherwise) to enable anything else.

That means anything you want to program has to be somehow encoded in a spreadsheet too. Unfortunately, when it comes to actually programming the device it turns out the worst thing a spreadsheet on an 8-bit CPU can be is Turing-complete (so it's not), and it has several obnoxious bugs to boot. But that doesn't mean we can't make it do more than balance an expense account. Along the way we'll examine the hardware, wire into its peripheral bus, figure out how to exchange data with today's future, create a simple game, draw rudimentary graphics and (with some help) even put it on the Internet with its very own Gopher client — after we tell of the WorkSlate's brief and sorrowful commercial existence, as this blog always must.

CAP-X and COMP-X: how the Tandy Pocket Computers got a sucky Japanese assembler

I grew up primarily with the Commodore 64, where if you wanted to do anything really cool and useful, you had to do it in 6502 assembly language. Today I still write 6502 assembly, plus some Power ISA and even a little TMS9900. I like assembly languages and how in control of the CPU you feel writing in one. But you know what would make me not like an assembly language? One that was contrived and not actually the CPU it was running on. And you know what would make me like it even less? If it were kneecapped, convoluted and limited without even proper I/O facilities.

But this particular odd little assembler dialect had the bureaucratic weight of the Japanese government behind it, because in 1969 what was then the Ministry of International Trade and Industry (MITI, 通商産業省) developed a completely artificial processor architecture to help ensure everyone taking the Information Technology Engineer Examination (情報処理技術者試験) would do so on an even keel. No one would have been an expert in this architecture or how to program it because we just made it up, reasoned the Ministry, so therefore no one will have an unfair advantage on the test.

Of course, that lasted only a few years before the specifications got out, and soon afterwards a handful of Japanese manufacturers had added it to their computers as a feature — including their pocket computer line. Through the magic of Tandy badge engineering, two of them made it to Radio Shack stores in the United States in the mid-1980s, perplexing a generation of larval nerds like me who couldn't understand what the heck it was doing there. While it was no secret the Tandy PC-5 and Tandy PC-6 Assembler feature was a fake, few people knew its history or ever did a detailed exploration. Let's dig into the dark and gloomy corners of this utterly bogus virtual CPU that a few real computers ran — sort of — and write our own cross-assembler and virtual machine so that future geeks can be just as befuddled.