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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

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Latest articles

Amiga Floppy Inactive

Histogram of one track

Here’s a histogram of one track off an amiga floppy disk. Notice the peaks near 4us, 6us, and 8us. I’ve got this data from my logic analyzer, crunched through my little C proggie, and then graphed with...

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A501 Replacement Inactive

Found potential race condition on writes

After looking at datasheets for the 273 latches used and 74act74 flipflop used, the worst case propagation delay is something like 12.3ns. But my NAND gate ACT00 logic which is triggered by the same CAS signals has a...

127 views

Amiga Floppy

sleep inversely proportional to the AFP and no more tokens

So I have figured one thing out. The more I work on the AFP, the less I sleep. At least that’s how it’s been over the last two nights. Two nights ago it was 3am, last night it was after 2am. Ideas come and...

127 views

Amiga Floppy

RXTX and Java

As I mentioned before, I’m using RXTX to do serial communication in Java since Sun has dropped support for serial communication under the Windows platform. I want to revamp my read routines on the java side...

125 views

Amiga Floppy

Flow control

I’ve gotten away thus far without any flow control. I just started noticing that my software was locking up occasionally when reading a disk. It was locking up in the “read” portion of the code because...

124 views

Amiga Floppy

HD media, low-density format disks now readable by Amiga Floppy Project

Good news. Got my Teac FD235HFC291/s which is now discontinued. Just as Jens suggested, it works perfectly to read HD media that is formatted low-density. No need to cover the hole, etc, it just works. I read two...

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Amiga-VSC Inactive

switching design from DRAM to ALTRAMs

So as my last couple posts alluded to, I’ve been having problems with my DRAM-based design. My controller isn’t dual-port. And I’ve been trying to wrap my head around a time-slot method for arbitration...

121 views

Uncategorized

Kickstarter: Commodore, The Amiga Years Book

I just wanted to mention that I’m a backer on this kickstarter, and I just wanted to get the word out. I’ve read On the Edge: the Spectacular Rise and Fall of Commodore and I’d love to read this...

121 views

Amiga Floppy

Interesting article and comments

Someone on sci.electronics.design mentioned the following article: This is a Floppy Disk Data Separator Design Guide for DP8473 which is a floppy disk controller like the infamous NEC 765 controller. It’s a...

119 views

Amiga Floppy

pullups

These are all 2us per division on the scope. Top trace is the actual MFM, bottom trace is the entering and exiting of my ISR. You should see an entry into the ISR for every falling edge, and every ~2us afterwards. 1k...

119 views