The Last Acorn BBC Computer Wasn’t A BBC Micro

December 17, 2024 by Jenny List 27 Comments

For home computer users, the end of the 1980s was the era of 16-bit computers. The challenge facing manufacturers of 8-bit machines through the middle of the decade was to transfer their range and customers to the new hardware, and the different brands each did this in their own way. Commodore and Atari had 68000-based powerhouses, and Apple had their 16-bit-upgraded IIGS for the middle ground below the Mac, but what about Acorn, makers of the BBC Micro? They had the Archimedes, and [RetroBytes] takes us through how they packaged their 32-bit ARM processor for consumers.

The A3000 was the computer you wanted if you were a geeky British kid at the end of that decade, even if an Amiga or an ST was what you got. Schools had bought a few of the desktop Archimedes’, so if you were lucky you’d got to know Arthur and then RiscOS, so you knew just how fast these things were compared to the competition. The video below the break takes a dive into the decisions behind the design of this first ARM consumer product, and along the way it explains a few things we didn’t know at the time. We all know what happened to Acorn through the 1990s and we all use ARM processors today, so it’s a fascinating watch. If only an extra two hundred quid had been in the kitty back then and we could have bought one ourselves.

If you have never used an Archimedes you can get pretty close today with another Cambridge-designed and ARM-powered computer. RiscOS never went away, and you can run it on a Raspberry Pi. As we found, it’s still pretty useful.

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Documented Source Code For Elite On The C64, BBC Micro And Others

December 15, 2024 by Maya Posch 12 Comments

If you ever wanted to dive into the source code for the 1980s space game Elite, but didn’t want to invest many hours reverse-engineering the 6502 assembly code, then [Mark Moxon]’s annotated code has you covered. The systems referenced range from the BBC Micro and Commodore 64 to the NES and Apple II, with some of these versions based on the officially released source code. For other systems the available source code was used together with decompiled game binaries to determine the changes and to produce functional, fully commented source code.

The cutting-edge gameplay of Elite on the 8502.

This particular game is fascinating for being one of the first to use wire-frame 3D graphics with hidden-line removal and a sprawling universe in which to trade and deal with less than friendly parties using a variety of weapons. After this initial entry it would go on to spawn many sequels and inspired countless games that’d follow a similar formula.

On the respective GitHub project page for each version, you can find instructions on how to build the code for yourself, such as for the Commodore 64. Of note here is the license, which precludes anyone from doing more than forking and reading the code. If this is no concern, then building the game is as simple as using the assembler (BeebAsm) and the c1541 disk image utility from the VICE project.

Apple Newton Gets Rebuilt Battery Pack

December 13, 2024 by Bryan Cockfield 14 Comments

We all carry touch screen computers around in our pockets these days, but before the smartphone revolution, there was the personal digital assistant (PDA). While it wasn’t a commercial success, one of the first devices in this category was the Apple Newton. Today they’re sought after by collectors, although most of the ones surviving to this day need a bit of rework to the battery pack. Luckily, as [Robert’s Retro] shows, it’s possible to rebuild the pack with modern cells.

By modern standards, the most surprising thing about these battery packs is both that they’re removable and that they’re a standard size, matching that of AA batteries. The Newton battery pack uses four cells, so replacing them with modern rechargeable AA batteries should be pretty straightforward, provided they can be accessed. This isn’t as easy, though. In true Apple fashion the case is glued shut, and prying it apart can damage it badly enough so it won’t fit back in the tablet after repair is complete. The current solution is to cut a hatch into the top instead and then slowly work on replacing the cells while being careful to preserve the electronics inside.

[Robert’s Retro] also demonstrates how to spot weld these new AA batteries together to prepare them for their new home in the Newton case. With the two rows fastened together with nickel strips they can be quickly attached to the existing electrical leads in the battery pack, and from there it’s just a matter of snapping the batteries into the case and sliding it back into the tablet. If you’re looking for something a bit more modern, though, we’d recommend this Apple tablet-laptop combo, but it’s not particularly easy on the wallet.

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Debugging The UE1 Paper Tape Reader And Amplification Circuit

December 9, 2024 by Maya Posch 2 Comments

The tape reader and amplifiers mounted with the other UE1 modules. (Credit: David Lovett, YouTube)

After recently putting together the paper tape reader for his custom tube-based UE1 computer, [David Lovett] did get squiggles on the outputs, but not quite the right ones. In the most recent video, these issues are addressed one by one, so that this part of the UE1 1-bit computer can be called ‘done’. Starting off the list of issues were the odd readings from the photodiodes, which turned out to be due to the diodes being misaligned and a dodgy solder joint. This allowed [David] to move on to building the (obviously 6AU6 tube-based) amplifier for the photodiode output signals.

Much like the Bendix G-15’s tape reader which served as inspiration, this also meant adding potentiometers to adjust the gain. For the clock signal on the tape, a clock recovery PCB was needed, which should provide the UE1 computer system with both the clocks and the input data.

Using the potentiometers on the amplification board, the output signals can be adjusted at will to give the cleanest possible signal to the rest of the system, which theoretically means that as soon as [David] adds the permanent wiring and a few utility boards to allow the code to manipulate the tape reader (e.g. halt) as well as manual inputs. The UE1 computer system is thus being pretty close to running off tape by itself for the first time and with it being ‘complete’.

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Microchess Remembered

December 7, 2024 by Al Williams 10 Comments

Playing chess has always been a bellwether for computers. The game isn’t trivial, but the rules are managably simple. However, the game is too complex to be easily solved entirely, so you have to use tricky software to play a credible game. Big computers do have an advantage, of course. But Microchess — arguably the first commercial game for home computers — was able to play on tiny machines like the Kim-1. [Joachim Froholt] interviewed [Peter Jennings] — the man behind Microchess to learn the whole story of its creation.

In 1960, [Jennings] was ten years old and had to persuade the local librarian to let him read adult books on electronics and computers. Five years later, a ham radio teletype and some circuitry helped him practice chess openings and was the first of many chess-playing machines he’d build or program.

Microchess itself took six months of painstaking programming, entering hex codes into the computer. Word leaked out from a user’s group meeting (where Microchess beat a human player), and [Jennings] was swamped with requests for the program. In late 1976, the program was offered for sale as a teletype listing or, for an extra $3, a cassette tape.

The program went on to be very successful and moved to other platforms. Commodore even made a special dedicated device based on the Kim-1 to play Microchess, a piece of hardware unique enough that [Michael Gardi] honored it with one of his phenomenal replicas.

Retro Computer Goes Back To The 1950s

December 6, 2024 by Bryan Cockfield 24 Comments

When thinking of retrocomputing, many of us will imagine machines such as the Commodore 64 or Apple II. These computers were very popular and have plenty of parts and documentation available. Fewer will go back to the Intel 8008 or even 4004 era which were the first integrated circuit chips commercially available. But before even those transistor-based computers is a retrocomputing era rarely touched on: the era of programmable vacuum tube machines. [Mike] has gone back to the 1950s with this computer which uses vacuum tubes instead of transistors.

The computer has an eight-bit architecture and features most of the components of any modern transistor-based computer of similar computational ability. Memory, I/O, an arithmetic logic unit including a carry bit that allows it to do 16-bit arithmetic, are all implemented using 6N3P dual triode tubes that date to the 50s and 60s and would have been used in similar computers like the IBM 700. All of this drives a flight simulator program or a Fibonacci number generator, demonstrating its general purpose computing capabilities.

Of course, tubes were generally phased out in favor of transistors largely due to their power and space requirements; [Mike] needs a stepladder to maintain this computer as well as around ten minutes each time he starts it up to allow the tubes to warm up, with each module needing over three amps of current each. It’s a hugely impressive build and we’d recommend checking out the video linked below to get more details on its operation. If you’re looking for something a little more accessible to get into the world of vacuum tubes, this single-board tube computer fits the bill.

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Ampere WS-1: The Other APL Portable Computer

December 6, 2024 by Maya Posch 10 Comments

When thinking of home computers and their portable kin it’s easy to assume that all of them provided BASIC as their interpreter, but for a while APL also played a role. The most quaint APL portable system here might be the Ampere WS-1, called the BIG.APL. Released in Japan in November of 1985, it was a very modern Motorola M68000-based portable with fascinating styling and many expansion options. Yet amidst an onslaught of BASIC-based microcomputers and IBM’s slow retreat out of the APL-based luggables market with its IBM 5110, an APL-only portable in 1985 was a daring choice.

Rather than offering both APL and BASIC as IBM’s offerings had, the WS-1 offered only APL, with a custom operating system (called Big.DOS) which also provided a limited a form of multi-tasking involving a back- and foreground task. Running off rechargeable NiCd batteries it could power the system for eight hours, including the 25 x 80 character LCD screen and the built-in microcassette storage.

Although never released in the US, it was sold in Japan, Australia and the UK, as can be seen from the advertisements on the above linked Computer Ads from the Past article. Clearly the WS-1 never made that much of a splash, but its manufacturer seems to be still around today, which implies that it wasn’t a total bust. You also got to admit that the design is very unique, which is one of the reasons why this system has become a collector’s item today.