Northstar Horizon - test-drb@ccmp.vtda.org

25 Nov 2006

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Subject: Re: Northstar Horizon
   From: "Chuck Guzis" <cclist at sydex.com>
   Date: Sat, 25 Nov 2006 08:32:35 -0800
     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>

On 25 Nov 2006 at 3:27, jim stephens wrote:

  And my memory of 256 bytes may be off, I vaguly
recall maybe on 32 bytes 
 are visible and used by the processor at boot.  People had to use pretty small proms 
 in the early days of the hobby. 
I recall that the disk controller had a small bipolar prom and that 
it was indeed 32 bytes.  It was miles better than toggling the boot 
code by hand...  A 256-byte boot prom back then would have been an 
almost obscene luxury... ;) 
No, it was 256bytes for SD and 512bytes for DD.

FYI the e800h start address works for SD or DD as the SD rom appears twice
in the address space at both e800h and e900h.

Allison