- thank you for your kind words on my program i actually updated it today to V0.0.3 which cleans up the ui makes the app more responsive to disk activity and i added a bunch more Hard drive samples most being from the 1990's
- See also https://github.com/LenShustek/AnalyticalEngine . Len is the founder and former chairman of the Computer History Museum, and had participated in Plan 28 but is spinning off a separate project to be built in the US rather than the UK.
- Glad to read about mame internals
- These machines fascinate me. Very interesting user interface.
- It's set up for PCBWay already: https://www.pcbway.com/project/shareproject/SC64_an_open_sou...
- oh wow, this is very cool.
Is there a consensus on the best PCB manufacturer for a small build like this?
- Happy holidays! Thanks for this terrific site, I read it daily. Can't get enough of this retro goodness!
- I did also post (a version of) this on HackerNews.
I think the software decoding technique used here is incomplete.
Consider what would happen if a data sector contained 12 * 0x00, 3 * 0xA1, 0xFE, ... then this implementation could mis-sync. On real hardware you'd have to be even more unlucky to have the CRC match -- which also isn't checked in this implementation. Using this as-is on real floppies could result in reading corrupt data. It would be possible to construct a floppy that would read correctly on real hardware and sometimes mis-read data with the current SW implementation.
The problem is that the 0xA1 bytes on the disk are special. The 0xA1 bytes are MFM encoded with a missing clock pulse -- making them "0xA1 syncs" that don't match an 0xA1 data byte. Proper clock recovery is necessary in order to detect the missing clock pulses for correct sync detection.
Based on my understanding, how the writes are done isn't quite how real hardware does it -- real hardware reads the sector header, waits for a "header gap" which, is described as where the 22 * 0x4E bytes are (these byes can get partially overwritten) and then rewrites the whole data header and data portion. Depending on the precise timing there can be trash bytes in the sector gap. I am not sure all floppy drives can switch from reading to writing immediately (page 22 of the pointed to SFB-321B PDF suggests not).
The special sync encoding and this strategy of header, sector is also present for 5.25 and early hard drives using MFM encodings, but with different values, timings and gaps.
- A-Max for Amiga was earlier than this and worked in a similar way. It let you run System 6.
- I hope it won't be taken down by Nintendo...
- Compatibility was such big big deal in those days. 99% compatible? Could it run flight simulator?
- In Zwolle, the Netherlands they have a similar museum with (very) old computers and also game computers. There you can play with the computers because a lot of them are still operational. https://www.flickr.com/photos/146579790@N07/albums/721576809...
- There's a 32-bit build of Doom8088. It's twice as fast as the 16-bit build.
- I've made a quick hack that should work on a Tandy 1000 and it looks like this: https://www.youtube.com/watch?v=2RdrLXblnlU With CGA graphics it looks like this: https://www.youtube.com/watch?v=FUEcr7XnbuA And in monochrome: https://www.youtube.com/watch?v=5o3rYTZt6BM
Seriously, proper Tandy / CGA / EGA / Monochrome graphics is on the to-do list.
- This is excellent, thank you.
- Back around the turn of the century, when I still had an enormous CRT monitor at work, I found it handy that the residual charge on the face of the monitor was sufficient to hold onto a sheet of paper. Could stick a sheet of notes from the lab to the monitor and enter stuff into various programs right beside the paper. Can't do that with LCD displays. If course, the entire computer can just go where the data is these days.
- Hope you enjoy! If you spot any issues or have any feedback I'd love to hear it!
- Thanks jgrahamc. Love the site and the blog!
- I've been using llvm-mos for a NES game that you can find here. https://github.com/jroweboy/evolve-machine-game/
If anyone has any questions about using llvm-mos I'd be happy to explain! I'm not a core dev though, so I can't really say much about the llvm side of things.
- Very fascinating! I always loved how the Mac was designed with its ROM.
- That was very interesting! I had no idea this existed, much less there were other manufacturers of the Saturn.
- I got a XP laptop at a thrift store, it had everything including tax records and Social Security Numbers. I called the previous owner (easy to find), he seemed unconcerned and threw his wife under the bus, said she donated it.
I put a lot in the recycle bin & emptied it then found a utility to wipe the empty space. I wasn't going to format the drive since I'd have a hard time finding the drivers again.
- bugmenot (top entry) works
- Atari50 was an incredible collection of materials but its really unique and new contribution was the excellent Jaguar emulation. Existing emulators have been a little hit-or-miss with compatibility but this absolutely nailed it. Huge kudos both for the technical achievement and to Digital Eclipse for allowing the author to release it separately:
- I love Tempest 2000 on Jaguar, but I feel like I'm missing out on the tactile heft of the rotary controller and the visual impact of the original arcade machine.
- No worries. Really appreciate what you’ve done with the site. I also see that you added mobile styles recently, which is handy.
- when i first used pcs in the late 80s i hated edlin with a passion. i would go out of my way to avoid using it to modify config.sys or autoexec.bat. it was easier to just copy con config.sys and retype the whole config.sys with whatever additions than use edlin. i ended up putting ted.com a tiny text editor on most systems to have something friendlier to use.
- Double or High Density? As HD magnetic surface is too dense for use in SD/DD/QD drives reliably - it might be you are using the wrong type of disks in your drives?
A good giveaway that a disk is DD is they usually have a hub ring. Hub rings were necessary on DD disks because some drives (Apple II?) couldn't grip disk without one.
- What a fantastic example of what the web should be. This whole site is a treasure trove.
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