Northstar Horizon

Allison ajp166 at bellatlantic.net
Sat Nov 25 14:44:36 CST 2006


>
>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


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