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Tube🍂Time

oh this is exciting, the card has been detected!

24 comments
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.

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