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Tube🍂Time

this simple program configures the parallel port for Type 3 operation, turns on DMA, and starts a single DMA send transfer.

45 comments
Tube🍂Time replied to Tube🍂Time

the operation won't start until the parallel port is ready--i had to pull the BUSY line low with a jumper, and now i instantly get this error! good luck figuring that one out
EDIT: i figured it out, 113 is a DMA arbitration error, presumably the "5" is the arbitration value. DMA controller going off into the weeds lol

Tube🍂Time replied to Tube🍂Time

ok, the machine crashed because we didn't set up the DMA controller, but that doesn't matter because the number '5' showed up on the arbitration bus! this experiment, along with a few others, let me confirm which arbitration pin is which.

Tube🍂Time replied to Tube🍂Time

i'm troubleshooting the weird DBA-ESDI drive (type DF9F) and it's very strange because it sets a bit indicating a power on self test failure, but when you try to retrieve the failure code (basic and advanced) it's all zeros.

Tube🍂Time replied to Tube🍂Time

here's the board. a bunch of proprietary IBM chips and an Intel 80C196 microcontroller running the show. maybe the problem is with the microcontroller.

Fritz Adalis replied to Tube🍂Time

@tubetime
I wonder if these have a serial diag port like newer drives do.

Tube🍂Time replied to Tube🍂Time

the microcontroller is the 80C196KW, which i can't find documented anywhere. but having the "80" prefix implies that it uses an external ROM, like the device nearby with the "4510" sticker. devices with ROM start with 83 and EPROM with 87.

Darryl Ramm replied to Tube🍂Time

@tubetime I'd really like the W variant to use external bubble memory just 'coz 1980s Intel. 🙂

But what the heck is it, only thing I can see is a Japan fab variant mentioned here: cpu-galaxy.at/cpu/Ram%20Rom%20 Even the 8XC196Lx Supplement PDF linked there does not mention it.

Tube🍂Time replied to Tube🍂Time

some parts arrived! this little adapter is supposed to break out the docking connector to a single Micro Channel slot.

Tube🍂Time replied to Tube🍂Time

lookie here! the MC Mechanic works! the two unlit green LEDs are because the adapter doesn't have the +/-12V DC-DC converters installed.

Tube🍂Time replied to Tube🍂Time

unfortunately the Snark Barker doesn't work. the card isn't detected by the BIOS, so that means it's not responding to the card setup signal. logic analyzer time!

Abe the Honest replied to Tube🍂Time

@tubetime *takes out a bucket of popcorn*
OH BOY this looks like my kind of movie!

Joe Pasqua replied to Tube🍂Time

@tubetime ok, now you’re just making up words ☺️

Tube🍂Time replied to Tube🍂Time

let's downgrade and try it out with my Micro Channel Ad Lib clone, the Plaid Bib.

Tube🍂Time replied to Tube🍂Time

oh this is exciting, the card has been detected!

Tube🍂Time replied to Tube🍂Time

and it plays music! i must be the first person to have built a 3rd party expansion for the 700/720 series Thinkpads in a very long time.

Tube🍂Time replied to Tube🍂Time

one major issue was that i got the polarity of the channel reset signal backwards.

Tube🍂Time replied to Tube🍂Time

I've instrumented the Snark Barker but somehow it boots without crashing and even plays back digital audio!

AMS replied to Tube🍂Time

@tubetime Some marginal timing that the added capacitance fixes?

Card wasn't seated last time?

Tube🍂Time replied to AMS

@AMS hard to say, but i suspect timing. the IBM expansion module had two 14-pin chips that were probably used to buffer certain signals.

Tube🍂Time replied to Tube🍂Time

now for something truly strange: the ESDI drive from my Model 50Z along with the riser card. will it work?

Tube🍂Time replied to Tube🍂Time

i mean just admire how ridiculous it looks. ESDI hard drive->riser card->docking adapter->Thinkpad

Tube🍂Time replied to Tube🍂Time

"Hello, IBM support? Can you help me with this weird error code?"

"IBM here, yes, we can help, what is the error code?"

"It is I̶9̷9̷9̴0̷0̵8̵̨̨̢̨̛͖̜̤̥̦̣͉̞͔̭͈̣̙̜̻̻̱̝̬̭͕̬͚̋̿͑̍̊̅̒͆͗3̶̛͇̰̬͚̬̫͕̼͈͕͖̗̟̯̥̝͖̳̥̻̘͖̻̟̪̗̦̣̤̪̩͈̝̖̐͑̋̍̾̅̈́̌̒̈́̀̏̀̈́͐͌̆͆̒̾͗̔͝ͅͅ"

"Say again?"

Tube🍂Time replied to Tube🍂Time

i mean what did i expect? cursed setup, cursed error codes.

Tube🍂Time replied to Tube🍂Time

so the first one is probably an Incompatible Diskette IML Record error, then what seems to be a Thinkpad system partition error, then a Set Configuration error, then a System Board error, then a System Partition boot error.

Tube🍂Time replied to Tube🍂Time

i found a really good quality of life improvement for working with this machine. as with any PS/2, you can "bless" any boot disk and the PS/2 will think it is a Reference Disk. see tavi.co.uk/ps2pages/ohland/ref

Tube🍂Time replied to Tube🍂Time

this is useful for accessing the IML partition, which is not a real partition! it is hidden by the BIOS and cannot be accessed using normal int13h routines. instead, boot with this "blessed" disk and the BIOS makes the IML partition show up as C:

Tube🍂Time replied to Tube🍂Time

since i'm booting from floppy all the time, using the "blessed" disk reduces the disk swapping i've had to do.

DrScriptt replied to Tube🍂Time

@tubetime please elaborate what the partition table looks like.

Does the partition table MS-DOS sees cover the size of the disk minus some amount for the convenience partition?

This if you move the drive to another machine does it look like inpartitioned space?

Is it before or after the otherwise standard partitioned space?

Tube🍂Time replied to DrScriptt

@drscriptt these drives are Micro Channel and only work with compatible BIOSes. the raw sectors that MS-DOS sees sum to 3MB smaller than the capacity of the drive. the 3MB "partition" is at the end of the disk.

DrScriptt replied to Tube🍂Time

@tubetime are these what I see referred to as Direct Buss Attached drives?

Attila Kinali replied to Tube🍂Time

@tubetime ESDI? That's a name I haven't heard in a very long time.

Tube🍂Time replied to Eric
Matt replied to Tube🍂Time

@tubetime extra impedance loading pulling the lines into compliance? Possibly dampening a ringing or or reflection.

Darryl Ramm replied to Tube🍂Time

@tubetime It's at this point that the reader realizes they have been trapped in a thread, snaking straight into a Micro Channel sound card. 🙂

Ian Scott :apple_inc: 🐙 replied to Tube🍂Time

@tubetime I don’t know why I’m surprised that IBM used MCA in ThinkPads, but it does make sense!

William D. Jones replied to Tube🍂Time

@tubetime Where's the code setting up the DMA channel so the parallel port doesn't read/send data from the weeds? :D

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