Glitch Count

[John Dammeyer]

This is showing up periodically.  What is Glitch Count?  Should I care? 

Drive 0 Cyl 6->10 select 1, head 2 dirty 0

  Waiting, seek time 4.0 ms max 4.8 min free buffers 74
select 0 head 2
glitch count 30
select 1 head 2
select 0 head 3
glitch count 31
glitch value c00
select 1 head 3

[David Gesswein]

Some of the control line pins are set up to generate a sort of interrupt
when they change. Glitch is when the code went to handle the control line
change it didn't see the state as changed. It seems to be harmless. Large
increases in count between each print could indicate a signal problem.
When I looked at it a long time ago I did see some controllers generated
little glitches on the lines when they were changing things.

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[John Dammeyer]

OK.  Then I won't worry about it. 

I have several copies of the Rodime ro204 drive and from those I was able to extract one image that had the 'copy' command that wasn't corrupted. 

I then created an empty image after creating a floppy with basic commands including 'format' and setting the execution directory as /d0/cmds on boot.

./mfm_emu --drive 1 --file ../jenifer_1 --initialize --cylinders 320 --heads 8

From the floppy I then ran the OS9 format utility and it told me it was going to format 320 cylinders.

First time it failed and hung about 100 cylinders in.  Next time it worked.  Not sure why.  Both Beagle and M68K system hung waiting to go to the next track.

Now flipping back and forth between the 'analyzed' image and the 'initialized' image I copied files from one to the floppy and from there to the new image.

I'm almost at the point where I can rewrite the EPROM to try and boot from the 'hard' drive (MFM in this case).

Oh and I'm running the entire MFM code on a micro-sd card on a Rev B Beaglebone.  I'll set it to auto start the 'Jenifer_1' image once the boot code is finished.  There was a comment in the one of the documents about automatic backups of the disk image but I cannot find that again.  Is there a write-up on that?

The MFM is a great product.

[David Gesswein]

On Thu, Jun 02, 2022 at 03:22:11PM -0700, John Dammeyer wrote:
> Oh and I'm running the entire MFM code on a micro-sd card on a Rev B
> Beaglebone. I'll set it to auto start the 'Jenifer_1' image once the boot
> code is finished. There was a comment in the one of the documents about
> automatic backups of the disk image but I cannot find that again. Is there
> a write-up on that?
>

Somewhat sparce. Look at Starting Emulation on Power On section in
http://www.pdp8online.com/mfm/revb/revb_board_build.shtml

and see comments in /etc/mfm_emu.conf.

> The MFM is a great product.
>

Thanks