[Coco] Disk drive questions?

[jdaggett at gate.net]

Jim

If I remember correctly yes you can have two disk controllers in the MPI. Drive 0 
must be in the first slot. Also, if my memory serves me corrrectly, you can have four 
single sided drives or two double sided drives or two single sided and one double 
sided drive. So yes three physical drives are the max allowable if one is the double 
sided otherwise four.

The main controllers used by the Coco are the 1773 and the 1793 chips. The 1773 
and 1793 will handle both single and double density. These controllers only work 
with single sided drives only! Therefore the capcity for 35 tracks is 160K and 320K 
respectively. These two can be replaced with a 1777 or a 1797 respectively and 
access double sided disk drives. Warning the 1777 conroller is a rare as hen's teeth. 
The 1797 is available. 

RSDOS treats double sided drives as two single sided drives. This is because the 
1773/1793 controller chips do not have side select capabilities. Also the 177x series 
of controllers, FD501 and FD502, can only read and write a maximum of 360K per 
side. The 1793, FD500 will read and write 720K per side. 

Also the 1793 controller will work on the COco3 if and only if it is plugged into the 
MPI. 

james

On 2 Dec 2003 at 23:53, jimcox at miba51.com wrote:

> Hi All!
> 
> Spent some time re-reading the manuals and realize I 
> should have done a better job of reading them the first 
> time through, cause I think I would have stuck with the 
> CoCo longer instead of abandoning it for the Atari ST I 
> got long ago.
> 
> One thing I noticed while going through the exercises in 
> the manual, was once I wound down, and started powering 
> off everything, I noticed that the back of the drive, 
> where the power supply is, was warmer than what I would 
> have expected it to be.  Then again, this IS 20 year old 
> technology that hasn't been powered up for some time.  Any 
> thoughts?
> 
> I'd also like to ask again, how easy is it to drop a 3.5" 
> drive into a system.  I know I have the answer some where 
> in the thousands of emails I have saved, but I thought I'd 
> save time and ask here.  Any pointers?
> 
> I know that someone has said that the maximum number of 
> drives in a system is 3, though in the manual, it says the 
> maximum drive number is 3, so if you start with 0, my 
> logic says you can have 4 drives total.  Is it possible to 
> have two different drive controllers in an MPI and toggle 
> between them?
> 
> BTW, after all the typing, I now realize how good we got 
> it now on current systems.  Boy, do I sure miss the "up 
> arrow" key.  Cheers!
> 
> Jim
> 
> PS: Anyone heard from Carl Boll lately?
> 
> -- 
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco


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