29 Jan
2013
29 Jan
'13
8:41 p.m.
On Tue, 29 Jan 2013, John S wrote:
> To conclude, information such as the IDAM content won't be readable by a
> PC with a normal FDC, so this approach looks limited. I am in touch with
Yes. The 5.25" and 3.5W HP drive units use normal FDC ICs. I think
Western Digital ones. They are hard-wired in MFM-only mode.
Although the 3.5" disk rotates at 600rpm (twice the speed od a PC 3.5"
disk), the data rate is twice as high too. so the actual bit denstiy on
the floipy disk is unchanged. HP disks can be read/written in PC drives.
I don;t know what hte 9895 uses, I've never been insdie one. The older
9885 (custom 16 bit host interface) usesa coupel of boads of TTL and an
HP Nenocotroller chip. I suspect it does normal FM (single density) encoding.
-tony