techtravels.org

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...

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even first or odd?

Despite having a couple different official sources, both AFR.c and floppy.c from the fellow amiga emulator says that the even bits come before the odd bits. This is true in the sector header decoding as well as in the...

Logicport screenshots and project file

I thought this might be neat to put up. Sorry about the high-res image but you lose too much when it compresses it. Click here for the screenshot. Also, I uploaded the .LPF project file which can be viewed for free with...

new book

I recently received “On the Edge: the Spectacular Rise and Fall of Commodore” and have read about half of the book so far.  Very interesting read.  It’s fun to read about how the various Commodores...

Creating more test disks

From both Tim’s suggestions and from a reinforcement from Agans’ Debugging book, Chapter 6, “Divide and Conquer”, they suggest to “Inject Easy-to-Spot Patterns”. And of course, I knew...

MFMSanityCheck

While I’m hesitant to post this at all, this is a quick and dirty application I threw together, and I do mean threw, that will check for valid MFM bytes. See the previous post for the link to the actual bytes. It...

not the PC again?

I was doing some more tests trying to get the PC to fail. It seems that the PC really likes EVEN delays between data, and it’s wierd because faster data that comes in evenly is better than slower data that comes...

java client preview

I’ve put up a preview of the java client in action. It’s a 2 minute video with narration. You’ll need a DivX codec installed in order to view it. I probably could have messed with compressing this...

PC might be the problem!

I think I’ve found at least one problem here. My PC is at least one problem. Even though I’ve done extensive tests with the PC in the past, including measuring a 9us total cycle time, it appears the PC must...

adding more commands

Now that I *think* I’ve got a handle on the reading portion, I’ve been adding a couple more commands. I added support so that the SX knows what cylinder number it is on.  The F and B commands increase and...

more testing

so I put the amiga floppy back on the amiga, and the amiga reads disks no problem.  Glad to see that my drive hadn’t fried through all my messing around. I haven’t seen valid MFM coming from the drive in so...