schlae / minnow-disk Goto Github PK
View Code? Open in Web Editor NEWReading and analyzing IBM 23FD Minnow floppy disks
Reading and analyzing IBM 23FD Minnow floppy disks
Hi Eric, what a cool project! I was messing around with the track 0 data, and I could not make it match with the 370/135 sector description int the IBM doc. If I read it correctly, each byte should immediately be followed by the next start bit (so startbit, 8xdatabit, parity bit, startbit) but the track data seems to have lots of extra 0 bits between bits. Also, lots and lots of parity errors.
Now, treating it as if it were 3830 format, so 1 sync bit at sector start, then a continuous stream of 258 bytes consisting of 8 x databit, + 1 paritybit, it all seems to line up, and no parity errors on track 0.
Having said that, all the other tracks do give lots of parity errors (though some of them are mostly error free). I find it hard to believe that track0 would have no parity errors by pure coincidence! So I am wondering, is there any chance the disk is actually 3830 format?
Peter
I had a look at the data and it seems the first track is definitely different than the others.
This visualization is based on the Model 145 format - black/white are bits of a byte with start bit + 8 data + parity, and the gray areas are zero fillers - in a place that waits for the next start bit. As one can see:
Was the data capture 100% good or could it be done better? (eg in analog way, at correct rpm, with more microsteps?) - only if one could tap the wire on a real machine while loading this.
The use of zero-filler bits to delay operations is possible, but rather unlikely, and imho the disc has a non-145 alike byte framing.
A declarative, efficient, and flexible JavaScript library for building user interfaces.
๐ Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
An Open Source Machine Learning Framework for Everyone
The Web framework for perfectionists with deadlines.
A PHP framework for web artisans
Bring data to life with SVG, Canvas and HTML. ๐๐๐
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
Some thing interesting about web. New door for the world.
A server is a program made to process requests and deliver data to clients.
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
Some thing interesting about visualization, use data art
Some thing interesting about game, make everyone happy.
We are working to build community through open source technology. NB: members must have two-factor auth.
Open source projects and samples from Microsoft.
Google โค๏ธ Open Source for everyone.
Alibaba Open Source for everyone
Data-Driven Documents codes.
China tencent open source team.