Revisiting 1990’s Mac Games That Never Were

September 23, 2024 by Dave Rowntree 17 Comments

[John Calhoun] was digging around their old MAC hard drives, revisiting some abandoned shareware games they wrote over three decades ago, and has uploaded the recovered disk images to GitHub for everyone to take apart and play with. This repository has a few of the games complete with their development files and the compiler environment, a mixture of Think Pascal and C.

Back then, [John] had a solid mantra when creating projects, specifically prototyping fast and abandoning things quickly if they were not working out. The blog shows a list of twenty-eight projects, of which only five ever made it to release, with all the rest left to rot. This is reminiscent of the attitude around Silicon Valley of moving fast and breaking things. Anyway, reasons for ditching a project ranged from ‘too much sprite work’ for a D’n’D style game to simply ‘not fun’ for some with clunky control mechanisms. [John] even abandoned a neat-looking steampunk flight simulator due to the sheer amount of work needed. Of course, it’s not all lost effort. Much of the code written was reused across multiple projects; after all, there’s no point in re-writing a cosine lookup table if you’ve already got one kicking around in another project.

Still, it’s a fun trip down memory lane, looking deep into projects that never were and the development journey to becoming a successful programmer.

While it isn’t hard to find old Macintosh hardware, some are not in great shape. Here’s a fun Hackintosh project that uses retro parts. [John] was featured a while back, with his homage to his first mac, a sleek Rpi-powered eInk desk ornament. Finally, we can’t talk about recovering retro software without looking in detail at the floppy disk themselves.

FreeCAD Is Near 1.0

September 21, 2024 by Elliot Williams 48 Comments

The open-source parametric 3D modelling software, FreeCAD, is out in a release candidate for version 1.0. If you’ve tried FreeCAD before and found a few showstoppers, it might be a good time for you to test it out again because the two biggest of them have been solved in this latest version.

First, version 1.0 finally implements a solution to the “topological naming problem”. Imagine you want to put a hole into a surface. The program needs to know on which surface to put the hole, and so it refers to this surface by name / number. Now imagine you subdivide the surface, and both subsections get new names. Where does your hole go now? If you want to dig into the issue, the inimitable [MangoJelly] has a great video about the topo naming problem. Practically, there were workarounds, like only adding chamfers after the main design has stabilized, but frankly it was a hassle to remember all of the tricks. This is a huge fix.

The second big fix concerns assemblies. Older versions of FreeCAD were great for making single parts, but combining them all together inside the CAD program was always janky. Version 1.0 combines the previous two patchwork assembly workbenches into one, and it’s altogether more pleasant to use. The constraints of how two parts move when held together with an axle just works now, and this is a big deal for multi-part models.

If you’re coming from any other parametric CAD program, most of FreeCAD will seem familiar to you, but there will also be workflow differences that will take some getting used to. In trade, what do you get? Scriptability in Python, real open source software, and all of the bells and whistles for free. Now that its two biggest pain points have been addressed, FreeCAD has become a lot easier to love. We’re looking forward to some good V1.0 tutorials in the future, and we’ll keep you posted when we find them.

Get Your Lisp On With The Dune Shell

September 20, 2024 by Dave Rowntree 10 Comments

Lisp is one of those programming languages that seems to keep taunting us for not learning it properly. It is still used for teaching functional languages today. [Adam McDaniel] has an obvious fondness for this fifty-year-old language and has used it in several projects, including their own shell, Dune.

Dune is a shell designed for powerful scripting. Think of it as an unholy combination of bash and Lisp.

Dune is designed to be highly customisable, allowing you to create a super-optimised workstation for your admin and programming tasks. [Adam] describes the front end for Dune as having turned up the cosiness dial to eleven, and we can see that. A cosy home is personalised, and Dune lets you customise everything.

Dune is a useable functional programming environment with a reasonably complete standard library to back it up, which should simplify some of the more complicated sysadmin tasks. [Adam] says the language also supports a few metaprogramming concepts, such as a quote operator, operator overloading, and macro programming. It’s difficult to describe much more about what you can do with Dune, as it’s a general-purpose programming language wrapped in a shell. The possibilities are endless, and [Adam] is looking forward to seeing what you lot out there do with his project!

The shell can be personalised by editing the prelude file, which allows you to overload functions for the prompt text, the incomplete prompt text (so you can implement intelligent completion options), and a function that deals with the formatting of the command response text. [Adam] gives us his personal prelude file, which defines many helper functions displaying useful things such as the current weather, a calendar, and an ASCII art cat. You never know when that might come in handy. This file is written in Lisp, so we reckon that’s where many people will start as they come up the Lisp (re)learning curve before embarking on more involved automation. Dune was written in Rust, so you need that infrastructure to install it with Cargo.

As we said earlier, Lisp is not a new language. We found a hack for porting a Lisp interpreter to any old language and also running Lisp bare metal on a Lisp machine. Finally, [Al] takes a look at some alternative shells.

Blowing Up Shell Scripts

September 18, 2024 by Bryan Cockfield 24 Comments

One of the most universal experiences of any Linux or Unix user is working through a guide or handbook and coming across an almost unbelievably complex line of code meant to be executed with a shell. At the time of encountering a snippet like this it’s difficult to imagine any human ever having written it in the first place, but with some dedication it is possible to tease out what these small bits of code do when they’re typed into the terminal and run (unless it’s something like :(){ :|:& };: but that’s another story entirely). [noperator] recently built a tool which helps users in this predicament understand these shell scripts by expanding them into a more human-intelligible form.

The tool is named sol and does much more than expanding shell one-liners into a readable format. It also provides an interactive shell environment where the user can explore the exploded code in detail, modify it in any way they see fit, and collapse it back down to a single line so it can easily be sent to other users. It can be used with most of the major text editors as well as piped directly to standard input, and has a number of other options as well such as custom configurations and the ability to see non-standard bits of code that might not be compatible from one shell environment to another, as well as helping to translate those bits of code.

[noperator] has made the code available in the linked GitHub page for anyone curious about its use, and has a to-do list for future versions of the tool as well including adding support beyond bash. We’d definitely recommend a tool like this especially if you’re still relatively new to bash scripting (or shell scripting in general) and, as always, we’d just to remind everyone not to blindly copy and paste commands into their terminal windows. If you’re the type of person to go out on a limb and run crazy commands to see what they actually do, though, make sure you’re at least logged into the right computer first.

Archiving Data On Paper Using 2D Images

September 15, 2024 by Dave Rowntree 44 Comments

It seems like only yesterday we covered a project using QR codes to archive data on paper (OK, it was last Thursday), so here’s another way to do it, this time with a dedicated codec using the full page. Optar or OPTical ARchiver is a project capable of squeezing a whopping 200 Kb of data onto a single A4 sheet of paper, with writing and reading achieved with a standard laser printer and a scanner. It’s a bit harder than you might think to get that much data on the page, given that even a 600 DPI printer can’t reliably place every dot each time. Additionally, paper is rarely uniform at the microscopic scale, so Optar utilizes a forward error-correcting coding scheme to cater for a little irregularity in both printing and scanning.

The error-correcting scheme selected was an Extended Golay code (24, 12, 8), which, interestingly, was also used for image transmission by the NASA Voyager 1 and 2 missions. In information theory terms, this scheme has a minimum Hamming Distance of 8, giving detection of up to seven bit errors. This Golay code implementation is capable of correcting three-bit errors in each 24-bit block, with 12 bits available for payload. That’s what the numbers in those brackets mean.

Another interesting problem is paper stretch during printing. A laser printer works by feeding the paper around rollers, some of which are heated. As a printer wears or gets dirty, the friction coefficient along the rollers can vary, leading to twisting and stretching of the paper during the printing process. Water absorbed by the paper can also lead to distortion. To compensate for these effects, Optar regularly inserts calibration targets throughout the bit image, which are used to locally resynchronize the decoding process as the image is processed. This is roughly similar to how the alignment patterns work within larger QR codes. Finally, similar to the position detection targets (those square bits) in QR codes, Optar uses a two-pixel-wide border around the bit image. The border is used to align to the corners well enough to locate the rows of bits to be decoded.

In the distant past of last week, we covered a similar project that uses QR codes. This got us thinking about how QR codes work, and even if encoding capacity can be increased using more colors than just black and white?

Thanks to [Petr] for the tip!

Create Custom Gridfinity Boxes Using Images Of Tools

September 14, 2024 by Dave Rowntree 3 Comments

We love it when a community grabs hold of an idea and runs wild with it despite obvious practicality issues. Gridfinity by YouTuber [Zach Freedman] is one of those concepts. For the unaware, this is a simple storage system standard, defining boxes to hold your things. These boxes can be stacked and held in place in anything from a desk drawer to hanging off the side of a 3D printer. [Georgs Lazdāns] is one such Gridfinity user who wanted to create tool-specific holders without leaving the sofa. To do so, they made a web application using node.js and OpenCV to extract outlines for tools (or anything else) when photographed on a blank sheet of paper.

The OpenCV stack assumes that the object to be profiled will be placed on a uniformly colored paper with all parts of its outline visible. The first part of the stack uses a bilateral filter to denoise the image whilst keeping edge details.

Next, the image is converted to greyscale, blurred, and run through an adaptive threshold. This converts the image to monochrome, again preserving edge details. Finally, the Canny algorithm pulls out the paper contour. The object outline can be given an accurate scale with the paper contour and paper size specified. The second part of the process works similarly to extract the object outline. The second contour should follow the object pretty accurately. If it doesn’t, it can be manually tweaked in the editor. Once a contour is captured, it can be used to modify a blank Gridfinity base in the model editor.

Continue reading “Create Custom Gridfinity Boxes Using Images Of Tools” →

Back Up Your Data On Paper With Lots Of QR Codes

September 12, 2024 by Lewin Day 59 Comments

QR codes are used just about everywhere now, for checking into venues, ordering food, or just plain old advertising. But what about data storage? It’s hardly efficient, but if you want to store your files in a ridiculous paper format—there’s a way to do that, too!

QR-Backup was developed by [za3k], and is currently available as a command-line Linux tool only. It takes a file or files, and turns them into a “paper backup”—a black-and white PDF file full of QR codes that’s ready to print. That’s legitimately the whole deal—you run the code, generate the PDF, then print the file. That piece of paper is now your backup. Naturally, qr-backup works in reverse, too. You can use a scanner or webcam to recover your files from the printed page.

Currently, it achieves a storage density of 3KB/page, and [za3k] says backups of text in the single-digit megabyte range are “practical.” You can alternatively print smaller, denser codes for up to 130 KB/page.

Is it something you’ll ever likely need? No. Is it super neat and kind of funny? Yes, very much so.

We’ve seen some other neat uses for QR codes before, too—like this printer that turns digital menus into paper ones. If you’ve got your own nifty uses for these attractive squares, let us know!