techtravels.org
Amiga Floppy

inital results on error correction

While I have yet to actually implement the full-scale error correction as I want to, I did some manual tests today. I basically took a track that I was erroring out on, and swapped in 1-bit away values for the bad bytes.  In some cases, it appeared...

keith
4 comments

Latest articles

Amiga Floppy

my checksum algorithm

So I’m using an XOR checksum to detect errors in the transfer between the SX and the PC.  I always thought it was a reasonably strong checksum, even though it’s still an 8 bit checksum. I found a neat...

67 views
Amiga Floppy

proof of concept works

Today is the first day in months that I’ve made what I consider good progress. I am now able to read any track(so far) off of any disk with 100% success including checking and relying on the checksums. I read...

67 views
Amiga Floppy

further development on the AFP

I’m about to bring a new member of my family into this world.  As a new proud parent, I’m completely unsure about what this means in terms of time, dedication, and so on.  I’m sure I’ll have less...

67 views
Amiga Floppy

good data vs bad

So you’ve seen me talk about good data and bad data.  But what’s the difference? Good data looks like the picture I posted awhile back here. Note the very even spread of 4—4—8.  Every pattern is...

67 views
Amiga Floppy

first two bytes of checksum bad

Despite the data being received 100% correct, the data checksum fails in certain cases. It’s always the first two bytes of the 4-byte, 32-bit checksum that are wrong.  The last two are always right.  What does...

66 views
Amiga Floppy

more updates

I know I’ve been bad keeping you guys updated….. This doesn’t mean I haven’t been working on it, however. I recoded the ISR completely in assembly because I was just plain sick of the damn...

66 views
Amiga Floppy

Am I reading MFM wrong?

I’m beginning to think that I don’t fully understand the signalling coming out of the drive. I understand the concepts behind MFM (I think), but the actual application to this project, I’m not so sure...

66 views
Amiga Floppy

Canada Post sucks

So I made the mistake of having an Amiga book shipped from Canada using Canada Post Expedited USA shipping.  It was dropped off at a post office on Nov. 17th in Mississauga, Ontario.  Now Mississauga is about 300 miles...

66 views
Amiga Floppy

March 21st Status

Well, here’s where I’m at: The external amiga floppy drive is now hooked directly to my SX microcontroller.  The code within the microcontroller waits for a command.  If it get’s a “B”...

65 views