ChanServ changed the topic of ##yamahasynths to: Channel dedicated to questions and discussion of Yamaha FM Synthesizer internals and corresponding REing. Discussion of synthesis methods similar to the Yamaha line of chips, Sound Blasters + clones, PCM chips like RF5C68, and CD theory of operation are also on-topic. Channel logs: https://freenode.irclog.whitequark.org/~h~yamahasynths
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<Sarayan>
Foone, whitequark, do any of you two know if a 3.5 floppy drive gives an index pulse even if there's no floppy in the drive? On 5.25 obviously no, but on 3.5 I'm not sure and that would explain things
<whitequark>
it might I think
<whitequark>
iirc the index pulse is driven by a hall sensor actuated by the rotor
<whitequark>
it might just not be gated on media presence
<Sarayan>
I have a fdx that timeouts a read on 3 rotations and nothing else
<Sarayan>
fdc
<Sarayan>
and the firmware just freezes waiting for it
<Sarayan>
do you still have the hardware handy from your "dump fluxes with glascow" happy fun time to check?
<cr1901_modern>
I seem to recall that 3.5" controllers don't even bother syncronizing to the index pulse
<whitequark>
yes
<whitequark>
and yes
<whitequark>
I don't think they are synchronizing so much as just measuring one rotation or sth
<whitequark>
like for read track command
<Sarayan>
read track starts reading at the pulse, write track starts writing at the pulse too
<Sarayan>
read/write sectors cares less but still can be funky when a sector is partially "under" the pulse
<Sarayan>
wq: was the second "and yes" meaning "index is always there"?
<whitequark>
1st to you (I can check), 2nd to cr1901_modern
<Sarayan>
:-)
<Sarayan>
please check whenever you feel like it :-)
<cr1901_modern>
It's an alternate version of your 100,000 follower celebration
<ZrX_NoMs>
Don't copy that floppy.
<cr1901_modern>
You wouldn't download a car
<Foone>
cr1901_modern: nice! seems to be a little lower-pitched than mine, but I am too tone-deaf to tell which one is more correct
<cr1901_modern>
It sounds slightly off, but I can't tell if that's due to resolution problems with the dos.h delay() function for 120ms pauses or just an artifact of how the song was generated
<cr1901_modern>
I definitely used someone else's code to program the PC speaker tho... I was _not_ in the mood to refresh
<Foone>
don't you like writing music by programming one 555 in a weird backwards way?
<cr1901_modern>
There are worse things to program
<whitequark>
hm
<whitequark>
555?
<cr1901_modern>
I'm guessing what Foone meant is "The PIT is a glorified 555"
<Sarayan>
fuck, it's a 3" drive, not 3.5"
<Sarayan>
and 3" is a hole
<whitequark>
you have a 3" one you mean?
<Sarayan>
I mean the hitachi basic master level 3 with its annoying firmware on its mp-1805 controller uses a 3" drive
<Sarayan>
And I also have the old 3" drive of my oric 1 in there somewhere, but that's another story :-)
<Sarayan>
my problem is that the underlying fdc is a mc6843 which timeouts a read sector after three disk rotations, and that's the only way
<Sarayan>
and the damn firmware seems to do go to track 0, read sector 1 unconditionally
<Sarayan>
so if I start the system without a floppy it freezes forever
<cr1901_modern>
I never heard of this machine :o
<Sarayan>
Neither did I
<Sarayan>
Which makes finding pertinent information difficult
<balrog>
Sarayan: I'm trying to find the pertinent documentation
<balrog>
huh, the main manual talks about the MP-1800 floppy, there's another manual about the MP-1802...
<balrog>
there's also an MP-3630...
<balrog>
yeah, there's little documentation on this 3" drive and card
<ZrX_NoMs>
Hm, friend has this old oscilloscope which requires some manufacturer preformatted floppy to work. Naturally no way to find said floppies anywhere.
<balrog>
ZrX_NoMs: what scope?
<balrog>
and what form-factor disk?
<balrog>
hopefully it's not e.g. a Kodak/Drivetec 3.3 style disk
<ZrX_NoMs>
5.25
<balrog>
Kodak/Drivetec disks are 5.25" disks that are 3.3MB, 6.6MB, or 12MB. They have embedded servo tracks.
<ZrX_NoMs>
Nicolet 4094
<balrog>
is the service manual publicly available?
<Foone>
balrog: and I really want one! they are basically not possible to be found
<balrog>
Foone: I think I have 3 drives, currently at Lord_Nightmare's place
<balrog>
I dumped the firmware
<balrog>
Was planning to use them for microstepping recovery and dumping of Twiggy disks, but never got around do it
<ZrX_NoMs>
Oh wait, it works without a floppy but to use floppy it has to be manufacturer preformatted.
<balrog>
to it*
<balrog>
don't have a controller, don't have any disks
<Foone>
balrog: very cool. I have some servo drives here, that I need to do more research and post about
<balrog>
ZrX_NoMs: those look like ordinary drives; Kodak/Drivetec drives have a weird lever
<ZrX_NoMs>
Dumped the ROMs to see if the format could be backtracked from there but can't read TMS(?) CPU opcodes.
<balrog>
no access to a formatted disk?
<balrog>
(so you can flux dump and look at it)
<ZrX_NoMs>
As I said no disks to be found from anywhere.
<Sarayan>
.jmi
<Sarayan>
ZrX: Do you know if the data on the disk is needed for the oscilloscope to work?
<balrog>
Foone: I poked you in #discferret but is there anything you'd be interested in doing with a Drivetec drive?
<balrog>
also what servo drives do you have?
<ZrX_NoMs>
No. Disks are used for storing measurements.
<Foone>
balrog: I mean, I'd love to have one, but I don't currently have a plan to do something with it. Eventually I'd love to have them controllable so I can do things like high-res archival of bad discs, but that probably won't happen soon
<Foone>
I'm not sure what the servo drives I have are! I need to look at them. They appear to be standard drives that have been professionally modified into being servo drives
<balrog>
Foone: yeah. from all I can tell, the servo-following is done in their microcontroller and they present as a mostly-standard 34pin drive
<Sarayan>
ZrX: is there a "standard" fdc controller in there?
<Foone>
they came out of an AME floppy disk analyzer, which is a thing that doesn't really have any results on google. that's why I need to post about it
<balrog>
oooh
<balrog>
hm can I invite philpem here?
<balrog>
he's been discussing hypothetically writing catseye disks
<balrog>
(yeah this is a public channel)
<balrog>
Foone: do you have this AME device?
<Foone>
yep! I have had it for a couple years and only recently pulled it apart to take some pictures
<balrog>
I'd be very interested in pictures, documentation, software, anything!
<Foone>
I've got no documentation or software, but I'll post pictures soon, and dump any firmware I can find on it
<balrog>
does AME stand for anything?
<Foone>
not sure. American Magnetics something, maybe?
<Foone>
I basically do all my research while I'm posting the thread, and since I haven't done that yet, I know basically nothing
<balrog>
fair :)
<Foone>
I'll @ you here when I finally post it
<balrog>
please do
<balrog>
I don't think I have twitter notifications on for you heh
<Sarayan>
Ask Me Everything? ;-)
<ZrX_NoMs>
Sarayan: Can't remember what the bolx had inside.
<ZrX_NoMs>
box
<Foone>
balrog: It's a 1100 Diskette Analyzer from Applied Micro Electronics LTD, of Dublin Ireland
<ZrX_NoMs>
Oh great, RTFM does work. The oscilloscope manual has a note that to do initial formatting of a disk there's a hardware switch to preformat a floppy. After that it can be softformatter.
<ZrX_NoMs>
softformatted
<Sarayan>
nice
<Sarayan>
at one point we should add the 'copes, LAs and anything of the kind to Mame
<balrog>
Sarayan: there already are a few
<balrog>
so yeah, the time to add them is now
<Sarayan>
TODO list too high already, not gonna do it at this point :-)
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<cr1901_modern>
TODO list bankruptcy
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<balrog>
Sarayan: oh sorry, wasn't suggesting that *you* should be doing it
<balrog>
Foone: do you have any automated duplicators?
<Foone>
at least two! One is mostly rebuilt into an automatic imaging machine. I had to put it aside when the pandemic hit for space reasons, and haven't gotten it out yet
<Foone>
both are CopyPro 2000s. I've actually been to their offices... they don't have any extended hoppers anymore, so I had to build my own with 3d printing and laser cutting
<Foone>
the other remaining company affiliated with them is AWP, who make the Trace series. They apparently still have one 5.25" duplicator left, but they want 5000$ for it
<balrog>
the Trace is quite well known.
<balrog>
At this point probably easier to get a used one off eBay
<Foone>
I've been keeping an eye out for them for at least 4 years, none have shown up
<balrog>
Is the code/tools around the automatic imaging online?
<Foone>
not yet, no.
<Foone>
the plan is it for being open sourced but I was waiting until it had been more finished, a lot of it was in flux when I had to put it away
<Foone>
part of the issue is that I was really overcomplicating it. it doesn't just insert the disk, read it, and eject it, it also takes a picture for later indexing