Interest in Teac FD235J drives and FC-1 boards?

Glen Slick glen.slick at gmail.com
Wed Jan 24 16:35:25 CST 2018


On Wed, Jan 24, 2018 at 9:45 AM, Fred Cisin via cctalk
<cctalk at classiccmp.org> wrote:
>
> Does ImageDisk or Teledisk support it?
> If so, then with the ED controller and one of these drives from Chuck, you
> could image things such as the "4 Meg" floppies from NeXT. (4M is the
> UNFORMATTED capacity of the 2.8M disk, and NeXT marketing thought that "4M"
> sounded better than the "2.8M" formatted capacity)
>

The ImageDisk 1.18 source code is available to inspect to answer the question.

If there is something special that software needs to do to select a
1000K bps data rate I don't see anything in the ImageDisk code which
does that. What does software need to do to select the 1000K bps data
rate for 2.8M mode?


http://www.classiccmp.org/dunfield/img/index.htm

imd.c:

unsigned Mtext[] = { // Translate Mode%3 to actual data rate
500, 300, 250 };

/*
 * Initialize data transfer mode (rate and density)
 * and update status display.
 */
void initmode(void)
{
unsigned x;
Mfm = (Mode / 3) ? 0x40 : 0x00;
out(FDC+5, x = Mode % 3);
w_gotoxy(3, 0, swin);
w_printf(swin, "%3uk %cD", Mtext[x], Mfm ? 'D' : 'S');
}


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