28 Oct
2024
28 Oct
'24
1:42 p.m.
That is because you are writing "320K" disk
in a 1.2M drive.
double step is to get 40 tracks instead of 80
Makes sense, thanks. I wasn't 100% sure if this was a 1.2M drive or not.
How difficult is it to change a drive? And could it go the other way,
upping a 360K stock drive to support 1.2M? I imagine it's not as easy as
jumper settings- but a matter of voltage divider maybe? I don't want to
void my warranty (joking!! :) ) I think I've heard of people altering
their drives, I just hadn't seen it done.
I guess another 5.25 related question comes to mind - when a new system was
delivered, they had (cardboard?) inserts into the drives. Was that more to
protect them during transport/delivery? Or a dust protection? or both? For
long term storage (maybe 6+ months?) should we put inserts back into our
5.25 drives?
-Steve
On Mon, Oct 28, 2024 at 12:30 AM Fred Cisin via cctalk <
cctalk(a)classiccmp.org> wrote:
> On Mon, 28 Oct 2024, Steve Lewis via cctalk wrote:
>
> > Thomas,
> > Those images for the SHARP PC-5000 boot disk of MS-DOS 2.00 have worked
> > splendidly (at least the .IMD files, DiskImage is all I tried). I did
> have
> > to change the IMD Settings to Sides Two, Double-step On, and the 250kps
> to
> > 300kps. I don't fully understand that last setting, but absolutely it
> was
> > necessary - the IMD image file wouldn't write to disk otherwise.
>
That is because you are writing "320K" disk
in a 1.2M drive.
double step is to get 40 tracks instead of 80
> a 160/180/320/360K drive spins at 300 RPM, and uses 250K data transfer
> rate.
> But, a 1.2M drive spins at 360 RPM, so you have to either change the drive
> to 300 RPM at 250k, OR use the 360RPM at 300K
>
> (some drives are dual speed; the FDC has a 300bps rate to compensatefor
> those that are not.)
>
> --
> Grumpy Ol' Fred cisin(a)xenosoft.com
>