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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Finally had some luck with FPGA board

So I bought an FPGA eval board and a book on Verilog awhile back.  I made some progress learning things, and had some simple things like UARTs, writing to the LCD, and even some small VGA software(hrrrm, maybe I should...

video showing current progress

I posted a video to youtube a little while ago showing my progress. It’s a little long winded (surprise surprise for those who read my posts) but it shows basically the framebuffer portion of the hardware working...

finally got some work into the VSC

Ok, so I’ve finally got some work done on this tonight. I’ve decided to go to a 4-line buffer system because it’s a more round number than 3 — makes everything easier to deal with. I’ve...

feasability of writing disks

While there are some other bug fixes and documentation to be done on what’s already been implemented, I started thinking about writing ADF’s to disk over the last few days. While the hardware part of it is...

On speed optimization

The theoretical limit, assuming 300rpm drives, is 200ms per track. Or 400ms per cylinder, or 32 seconds per disk. Most attempts read slightly more than one track. I read 16,384 bytes, or 262ms worth. Right now, if I...

Minor problems on techtravels.org email

I recently discovered a problem where email directed to techtravels.org accounts was bouncing. It’s been fixed. If you’ve emailed something over the last couple months and didn’t get a reply, please...

minor success at 2:00am

well I’ve got MFM flowing from the PC drive now.  A couple of things: Pins 10 and 14, the pins I’ve been using since last night, appear to be correct. Pin 10 is the motor lead.  Dropping a corresponding SX...

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...

USB uart send and receive

Good news, good news. After banging my head on the same problem for the last three hours, I’ve finally made some more progress. Using option #2 from the previous post, I’ve written two non-isr based software...