On (29 Jan 95) [EMAIL PROTECTED] wrote... > From: Simon Cooke <[EMAIL PROTECTED]> > Date: Sun, 29 Jan 1995 14:25:19 +0000 (GMT)
> Evenin' all... Hi Si! > I've found a slight problem with Prodos (including Johnathan's version) > and external drives... Make that slow-starting external drives;-) > Basically, the seek command in Prodos doesn't hold the correct value -- > it disables the spin-up sequence. I'm not sure about the original 1.9 I *think* that disables it... I did run a version with the spinup sequence and found that it didn't improve anything on my system! In fact it made drive access slower as both my internal and external drives spin-up in much less time than the FDC delays the procedings Hence the version I supplied was also like that:-) > To get it to work, you should poke the bit which does: > LD A,31 > OUT (C),A > with > LD A,%10111 > .... > Hope that helps -- it got Prodos working nicely on our system anyway Note that is also the place to change the step-rate at bits 0 & 1 %00010100 does 6mS seeks with spin-up sequence %00010101 " 12mS " " " " %00010110 " 2mS " " " " The 2mS step-rate worked fine on my external Teac and the internal Citizen drives but Brian had problems at that rate so I returned back to 3mS. If you're lucky, the 12mS rate will allow it to work on 5.25" external drives. I was thinking of doing a little system utility that allows the end user to alter the exact step-rate and spin-up option after inital boot sequence... As my version's not quite finished I've not done the utility *yet*... Regards Johnathan. PS With a little bit of hacking the internal SAM-FDI pcb can accept a right-angle 34way plug! I did it earlier today:-) ... Just when you think it's hopelessly broken, it works. -- |Fidonet: Johnathan Taylor 2:2501/307.9 |Internet: [EMAIL PROTECTED] | | Standard disclaimer: The views of this user are strictly his own.
