The BombSquad

Due to popular demand, here is a demonstration video of how to make 3D printed PCBs using just vector drawing software, a 3D printed (PETG filament for mine) and self-adhesive copper tape. Any questions, let me know!

I hate the ones that are soldered directly to the motherboard for some reason even more

2024 09 10
Dorumon loves the FM Towns UX-20!

A die photo of the 8087 chip, with the main functional blocks labeled. The chip is a tan rectangle with complex patterns in dark brown. Many of the patterned regions are textured rectangles. One of the largest rectangles is the microcode ROM in the middle. The bottom half of the chip is the datapath, performing operations on floating-point numbers. The instruction decoding happens in the upper left. Around the edges of the chip, bond wires connect the chip to the 40 external pins, but the pins are not visible, just short segments of the bond wires.

In 1980, Intel released the 8087 floating-point chip, making math much faster. I'm reverse-engineering this chip, 46 years later. Most of its instructions are implemented in microcode, but some are implemented in hardware. Let's look at the circuitry that decodes instructions and decides what to do.

I wonder if the presence of the magneto-optical icon is related to that type of media being used on NeXT computers back in the day. No clue why there's a SuperDisk icon though!

That's a tiny 486 board, is that for a laptop?

Amber gas-plasma displays are such an incredible aesthetic, that display looks gorgeous

One mild annoyance is how getting interrupted by writing a swap file to floppy takes a few seconds. That's how I learned about the `updatetime` and `updatecount` variables, for determining after how many characters/seconds after inactivity to trigger saving. (200 chars or 4secs by default)

A photograph of Vim 4.6 running on MS-DOS, on a 8088 computer. The 8088 computer has an amber CRT displaying the default .vimrc file.

Vim is actually quite a pleasant experience on an 8088 with 640k of RAM, especially with turbo enabled! The last version of Vim to support MS-DOS was 7.4, but an install of that version would take up nearly half of my 25 megabyte hard drive... so I'm using version 4.6 instead. #retrocomputing

This was a great and informative panel! I enjoyed it! Thanks!

Picture of an SNES with a Super Mario World cartridge inserted. The bottom half of the SNES has been replaced with an identical 3D printed version. Paint has been applied to the bottom half to match the color to the top half.

I printed a new bottom shell for my SNES. Early models seem fairly prone to plastic degradation, especially the bottom half of the enclosure. It can become so brittle that even manipulating the screws causes breakage. I think I did a pretty good job color matching with airbrushing. #3dprinting

I wonder if there have been any meaningful improvements in compiler optimizations for targeting the 8088 platform in the last few decades, too. I have a lot to learn about compiler design. Maybe I should read the compiler "dragon book" some day...

I wonder what the most recent C compiler that still runs on the 8086/8088 is. Apparently Open Watcom still exists and receives regular updates, but has a minimum requirement of an 80386, while capable of targetting the 8086/88. #retrocomputing #programming

Looks like a M1212 'Macintosh Color Display'. It probably would work with an adapter, though that monitor can only display at a resolution of 640x480 @ 67hz, and also the horizontal refresh frequency on that monitor is weird so you'd need to specifically configure that as well

A black book cover. Top right, an 'IP' logo, intended to mimic the Usborne logo but not sueably so. Top, the title "Creating Adventures on your Commodore 64," in white sans-serif angular block font. Center, a black dragon hoists a sparking blue ball in its clutches. At bottom, in the same font but in yellow and smaller, are the authors: Clive Gifford and Robert Young.

I could make a whole sub-bot based just on programming books with dragons on the cover. (Source.)

That's so cool! I've heard of Macintosh clones before but I never knew they existed in this form factor. I wonder what the battery life was like. Does 'Plus ROMs' in the manual mean that this behaves like a Macintosh Plus?

The $5 Computer Software Store is selling software for $6?? Damn, inflation is really hitting everything...

Image of a beige enclosure containing two floppy disk drives. The top drive is a 3.5 inch floppy disk drive. To the right of that drive is a label with an arrow pointing to it, reading 'DRIVE B'. To the left of the 3.5 inch floppy drive is a label with an arrow pointing downwards, also reading 'DRIVE A'. The bottom drive is a 5.25 inch floppy drive. Both of the drives are on carriages so that they can be swapped. The top of the enclosure has a small panel with the Greaseweazle logo on it, consisting of a weasle, and the text 'Greaseweazle v4.1 / Keir Fraser'. The bottom text on the small panel on the top reads 'Case: The BombSquad'.

I've been teaching myself CAD lately, so I designed and 3D printed a proper enclosure for my Greaseweazle floppy disk archiving setup! #retrocomputing

Looks great! That display looks incredibly sharp, love to see it. My brain keeps trying to see some of those icons as having color for some reason

The original keyboard for this luggable seems to have met an unfortunate end before I took ownership of it - I found the severed remains of the XT cable connected to the motherboard when I first disassembled it. I'd love to design and make a custom new keyboard for this that fits the case!

The most peculiar thing about it to me is how the internal CRT is connected to the video card - the CRT has a DB-9 connector that runs through the case and out through a hole on the side, connecting to the video card output. The mono/RGB switch also has leads hackily soldered to the motherboard!

This luggable XT clone is a restoration project I've been working on. Still needs some retrobriting as the top of the case is heavily yellowed. My best guess is that this is DTK branded based on the BIOS & RTC card, but it lacks any brand markings on the case at all. #retrocomputer #retrocomputing

What kind of oscilloscope do you have? Apparently there are USB to floppy adapters for some types of Tektronix scopes out there, but they're not particularly cheap. You might also have some luck looking for laptop floppy drive adapters as those are also slimmer than full height ones

Oh cool I didn't know there were 3D printed parts available for these, I have a couple of similar Powerbooks lying around that also have broken hinges and such everywhere. I swear the plastic on those PowerBooks shatters just by looking at it

Apparently the specific parameters of the design were chosen by Steve Jobs himself, I wonder if that's why it wasn't really changed at all.

There's a story about its development here:
www.folklore.org/Calculator_C...

I wonder what this would look like on a compact Mac modified with an amber display.

'Reverse Screen' by Darin Adler from 1986 is an early example of what we call 'dark mode' today, inverting the entire screen - even the mouse. It really takes the eye strain out of working with a compact Mac in the dark! #retrocomputing #VintageApple

An invoice dated 01/02/1987. The only line item present is a 20 megabyte Hardcard, which is a hard drive expansion card. The line item cost is $698.10, and the total cost with sales tax is $745.22. Some personal information of the original owner was edited out of this.

A few months later, the original owner purchased a 20 megabyte hard drive for a total of $745.22, or approximately $2,120 USD accounting for inflation. Despite the reputation of Hardcards as unreliable, this one is still working to this day.

The memory upgrade alone costs $400 USD, which would have expanded the memory from 256KB to 640KB. 16GB of system memory purchased at the same rate would cost approximately $17,000,000.

An invoice for a Compaq Portable. The invoice is dated May 1st, 1986. The unit cost of the Compaq Portable was $1,693.23, with the memory upgrade costing $138.24. The total cost with sales tax was $1,945.94. The personal information of the original owner and signatures were edited out of this image.

While I'm not the original owner of my Compaq Portable, I do happen to have the original invoices. It was purchased from ComputerLand in 1986, an Illinois computer retailer franchise, for use in a grocery store's back office. Adjusted for inflation, it cost approximately $5,600! #retrocomputing