Strange Teledisk question

[Adrian Graham]

> On 24 Jun 2018, at 03:03, Fred Cisin via cctalk <cctalk at classiccmp.org> wrote:
> 
> What kind of drives does the Waveterm use?

I mentioned that in the original message, YE-Data YD380 HD with Shugart interface

> What kind of disk controller?

WD FDC1793. The main board is an Eltec Eurocom II V7.

> For example:
> 96tpi (80 tracks per side) drives can read 48tpi (40 tracks per side) disks, and can write them to virgin disks, but, when RE-writing them, leave part of the old (wide) track alongside.  Those RE-written disks are readable by a 96tpi drive, but not necessarily by a 48tpi drive.

The PC’s drive is simply the IBM version of the same drive, it’s a YE-Data YD380B. We format a disk using the PPG utilitiy (PPGA.EXE) then write a disk image to it, reread that disk with Teledisk and re-rewrite it again with Teledisk back to the same disk.

> PC is NEC-style FDC.

The motherboard in the PC we’re using is an Abit board containing a Winbond SuperIO chip, I can’t remember which variant but it seems most Athlon-based boards have one of these chips on, my own imaging machine is an Abit KV8Pro with a Winbond W83627HF. What that is based on I have no idea.

> 
> WD-style disk controllers (such as 179x) can handle post index gap smaller than NEC-style can.  For reading with NEC controllers, that can often be handled by masking the index pulse.
> 
> WD-style controllers can read sectors that have a WRONG number in the side number field, but NEC can't ignore that field.  The good news there is on formats that use a wrong number in the side number field (such as Kaypro DS), the WD controller doesn't MIND if it encounters the correct number in that field.

So you’re saying that the WD controller is a lot more easy-going for slightly awry disks whereas the NEC one is more strict? That could make sense in this case were we going from WD to NEC but we’re going the other way around.

> The FDADAP adapter's primary difference between a simple cable is support of TG43, a signal to indicate that it is on an inner track, for write-precompensation, etc.

For 8” drives yes, which at some point I will be using assuming both my 8” drives work, but it should also let me connect up a non-IBM drive to my PC if I read the description correctly.

Cheers,

-- 
adrian/witchy
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