Big Mess o' Wires

I just have to say when I saw BMOW 1 I was delighted. Also Magic-1, another homebrew CPU, also made out of 74LS TTL chips from the 1970s. Fantastic trend, really. https://www.bigmessowires.com/bmow1/ https://homebrewcpu.com (Of course it's a lot easier [but still quite fun] to make your own homebrew CPU/system on an FPGA.)

Agree. Most computers that are a joy to learn have a handful of controllers that operate in parallel. That is, multiple cores The Apple II had a really cool disk drive because of how it did what it did with so little hardware. By relying on the single CPU for everything it was elegant, advanced, interesting... but perhaps not so easy to program. https://www.bigmessowires.com/2021/11/12/the-amazing-disk-ii-controlle…

Follow up with the real board: https://www.bigmessowires.com/68-katy/

> Monotech NuXT Hadn't heard of this before, but it's a great concept. I love the idea of modern takes on retro tech. Wish it were more practical to do something like this for 68k or PPC Macs… unfortunately I don't think there are any usable 68k or PPC derivatives currently in production which limits possibilities. The closest thing I've seen are FPGA-based setups like the Plus Too[0]. [0]: https://www.bigmessowires.com/plus-too/

You are thinking about USB-C Alt Mode, which is a way for displayport to go over USB-C. To get 4k60 + USB3.1, you either need USB-C Alt Mode with DP1.4+ (supported by almost zero monitors), or Thunderbolt-3 (supported by fantastically expensive monitors). It's much more economical to live with USB2.0 for your keyboards and mice, and get a separate USB3.1 hub if you need that. https://www.bigmessowires.com/2019/05/19/explaining-4k-60hz-video-thro…

A fantastic off-the-shelf solution is already available: https://www.bigmessowires.com/floppy-emu/ It can emulate a floppy or hard drive. I tend to use a 2GB hard drive image which makes hacking on classic Mac a delight.

I've tried several docks and cables with no success until I've found this article: https://www.bigmessowires.com/2019/05/19/explaining-4k-60hz-video-thro… The recommended CableMatters dock solved the 4k60Hz issue with USB2.0 pheripherals connected (mouse, kb).

Apple //c from 1984 (with the original receipt!) The composite video output means I can plug it right into my 50" tv without any special hardware and everything looks great. I removed the disk drive cable from the motherboard and plugged a floppy EMU in, and now my kids play Lemonade Stand, Dig Dug, Oregon Trail, Carmen San Diego, and dozens of other classic games. https://www.bigmessowires.com/floppy-emu/

4k60 + gigabit is not possible without going up to Thunderbolt 3 - there isn't enough bandwidth otherwise. The best you can do is 4k60 + USB 2.0 (so a gigabit Ethernet connection would cap out at ~300mbps in practice.) See https://www.bigmessowires.com/2019/05/19/explaining-4k-60hz-video-thro… DisplayPort 1.4 changes this, but everything seems to be stuck on 1.2 100W is, of course, possible. I use a CalDigit USB-C Pro Dock with my MBP: https://www.amazon.com/gp/aw/d/B07VL675DT - it's TB3, but it can fall back to USC-C (with reduced capabilities, of course). It uses Intel's newer Titan Ridge chipset. The older and more common Alpine Ridge chipset is TB3 only.

This is probably the best explanation available of this: https://www.bigmessowires.com/2019/05/19/explaining-4k-60hz-video-thro…

I have a CFFA3000 and an SDFloppy II. Both are great, but I prefer the CFFA3000 and use it regularly. CFFA3000: http://dreher.net/?s=projects/CFforAppleII&c=projects/CFforAppleII… SDFloppy II: http://www.a2heaven.com/webshop/index.php?rt=product/product&produ… Another good option, the Floppy Emu: https://www.bigmessowires.com/floppy-emu/

> I want to build a simple circuit with a few LEDs and understand completely how it works and why it was designed that way. Once you get bored by "battery plus LED" circuits, I recommend Nibbler 4 bit CPU [1] and transistor clock [2]. They are sufficiently complex to be impressive and hone your EE skills, yet simple enough to still finish even if you're not really an EE. They also can be understood completely, there are no secrets and all design decisions are explained in the documentation. [1] http://bigmessowires.com/nibbler [2] http://transistorclock.com

Probably the easiest way would be buying the floppy emu [1] - it allows to run the computer from an SD card. A bit pricey, though ($139). If booting from a floppy would be enough then Rescue My Classic Mac is a way to go. [1] http://www.bigmessowires.com/floppy-emu/ [2] http://rescuemyclassicmac.com/

Followups since this was posted in November: http://www.bigmessowires.com/category/68katy/

I had bought an inexpensive FPGA board to play around with programmable logic and then later learned about CPLDs (from a bigmessowires project report at http://www.bigmessowires.com/68-katy/), which seemed a better, cheaper fit for what I want to do. I wanted to know more about the background and history of these programmable logic technologies and this tutorial was fantastic, so I posted it here. Hackaday also has some great articles and tutorials on this topic: http://hackaday.com/2008/12/11/how-to-programmable-logic-devices-cpld/… http://hackaday.com/2014/04/06/cpld-tutorial-learn-programmable-logic-…

If you're interested, check out http://www.bigmessowires.com/ This is actually a bit closer to hardware archaeology, i.e. reverse engineering the decade's old HD20 hard drive. But of course hardware has tons of software built into it, and even more so these days.

Ha! Okay, ya got meh! But! IN THEORY You could still construct a processor out of electromagnetic relays (springs, contacts, leads and solenoids only), if perhaps your goal was to never exceed 100 Hz. (...at first I was going to point out http://www.bigmessowires.com but it turns out that beyond the wire wrap connections, he's still using modern semi-conductor packages)

> The big storage breakthrough came in 1977 when Apple introduced the Apple II, its first mass-produced computer. It came with two 5-¼ inch floppy drives. Not quite. The Disk II Interface Card wasn't available till 1978. It supported two drives. But the card and drives were options. A couple ads re-affirming my memory: https://brian.carnell.com/articles/2021/apple-ii-ad-1978/ https://i.pinimg.com/originals/d9/92/81/d99281c7517692b4809398ff3f4ce6… The second ad has this copy: > Apple II'™ is a completely self-contained computer system with BASIC in ROM, color graphics, ASCII key board, light-weight, efficient switching power supply and molded case. It is supplied with BASIC in ROM, up to 48K bytes of RAM, and with cassette tape, video and game I/O interfaces built-in. Also included are two game paddles and a demonstration cassette. I owned an Apple II fully loaded and upgraded to a II+. (I actually still have most of it in a closet and someday need to get it functional again.) The Disk II Interface Card was another one of Woz's legendary designs: https://www.bigmessowires.com/2021/11/12/the-amazing-disk-ii-controlle…

This is why I was so excited when I heard about this. I have a Mac Classic II in the role of "transfer station" - it has a SuperDrive (the floppy drive, not the CD/DVD drive), so can read both standard IBM 1.44MB disks as well as the Mac 800K ones. But it's been getting a bit temperamental recently, mainly due to failing capacitors and an old SCSI hard drive. FluxEngine completely eliminates the need for it - I can download a 800k system disk image, write it to a physical floppy disk, and use that. What's more, transferring individual files is easy now too: I can read back the physical disk to a DiskCopy image, and either mount that in an emulator such as Mini vMac, or convert[1] it to a raw disk image and mount it with hmount[2]. (The reverse process is similar). [1] https://www.bigmessowires.com/2013/12/16/macintosh-diskcopy-4-2-floppy… [2] https://linux.die.net/man/1/hfsutils

Reminds me of this compression project from a few years back from Steve Chamberlin at Big Mess O' Wires, FC8. FC8 is designed to be as fast as possible to decompress on "legacy" hardware, while still maintaining a decent compression ratio. Generic C code for compression and decompression is provided, as well as an optimized 68K decompressor for the 68020 or later CPUs. The main loop of the 68K decompressor is exactly 256 bytes, so it fits entirely within the instruction cache of the 68020/030. Decompression speed on a 68030 is about 25% as fast as an optimized memcpy of uncompressed data. The algorithm is based on the classic LZ77 compression scheme, with a sliding history window and duplicated data replaced by (distance,length) markers pointing to previous instances of the same data. No extra RAM is required during decompression, aside from the input and output buffers. The match-finding code and length lookup table were borrowed from liblzg by Marcus Geelnard. https://www.bigmessowires.com/2016/05/06/fc8-faster-68k-decompression/

That's how I wish it was for me but it's not. So far the largest charger I've been able to find only has 2 USB-C plugs. So, switch + pixel + pocket wifi + macbook air Then I have lots different computers. My Macbook Air has USB-C, my MacBook Pro has USB-A, My brand new desktop PC has USB-A, my Razer laptop has both USB-A and USB-C, my Playstation has USB-A. I have USB-A SD-Card readers and USB-A hubs. Then, when If first got the Macbook Air I ended up going through 3 different USB-C hubs until I finally figured out how to buy one that actually supported 4k-60hz (the first 2 only supported 4k-30hz). Then later, I tried to use the Razer on a USB-C monitor. It worked but at some point the keyboard and mouse were flaky. Turned out apparently I needed a Thunderbolt HUB, not a USB-C hub (plugs are the same) so now I've gone through 4 hubs. you can read about the 4 or 5 kinds of possible USB-C hubs you might end up with if you're not careful. I have no idea how a non-techie figures this out. https://www.bigmessowires.com/2019/05/19/explaining-4k-60hz-video-thro… And then, I still have 3 iPhones that all use lighting (USB-A to lighting) and a few other devices at are USB-Micro (Kindle for example) And several external hard-drives that are all that USB-3 wide plug to USB-A I'm sure by the time USB-D arrives USB-C will be great and all my cables will be USB-C on both ends and all my devices will only have USB-C sockets but right now it's a mess

> So yeah, if you want to help, that's where to contribute your effort. Gentoo and Arch are good options. However, in the long term classical Linux will likely only be able to run on retro systems and FREE HARDWARE! If Gentoo and Arch want to survive they should focus on free hardware pretty soon. I think so because upcoming mainstream hardware will likely all be based on UEFI/SB. SB is yet optional but I expect it to be mandatory soon. Only Linux with certified kernels -- likely systemd Linux -- will be supported on those systems. I don't like that because I want to be able to install up-to-date kernels and software at any time without messing around with proprietary certificates. The Monster 6502 [1] was an excellent starting point into a world of discrete SMD cpus. I hope there will also be a 16/32-bit cpu capable to run Linux (or its successor). At least 68katy [2] is capable. The most promising project however is RISC-V which will hopefully be available with non SB-mainboards. [1] http://monster6502.com [2] http://www.bigmessowires.com/category/68katy/ [3] https://riscv.org

There's at least one implementation, a Mac Plus: https://www.bigmessowires.com/plus-too/

And there's the infamous DB-19: https://www.bigmessowires.com/2025/06/30/bulk-lots-of-db-19s-for-sale/

Anyone unfamiliar with the story check these: https://www.bigmessowires.com/2016/06/04/db-19-resurrecting-an-obsolet… https://news.ycombinator.com/item?id=40397593

maybe this would work? https://www.bigmessowires.com/usb-wombat/

There's also a 1MB EEPROM mod you can do on a Mac Plus that gives you a built-in ramdisk: https://www.bigmessowires.com/mac-rom-inator/ I wonder if one could put this larger ROM, and the other files into a custom built image so no swaps are required.

I wonder why the author didn't go straight to the BMOW WOMBAT instead? https://www.bigmessowires.com/usb-wombat/

Note this is Open Source Hardware proper[0]. 0. https://www.bigmessowires.com/2019/01/28/yellowstone-goes-open-source/

I wondered if anyone had written an IWM simulator, and I didn't find one, but I did find this FPGA project: https://www.bigmessowires.com/2017/12/07/fpga-based-disk-controller-fo…