BBS software for the PDP 11

allison allisonportable at
Thu May 18 14:36:46 CDT 2017

On 5/18/17 3:19 PM, geneb via cctalk wrote:
> On Thu, 18 May 2017, allison via cctalk wrote:
>> On 5/18/17 12:51 PM, Adrian Stoness via cctalk wrote:
>>> So a 11/03 aka a lsi11 would be to slow for such things? Such as those
>>> Heathkit h11 lsi11 macheans? Witch was a hobyist pdp11 for those 
>>> that are
>>> unfamiliar with the hearhkits
>> No,  BBSs were run with 4mhz Z80s...  compared to LSI-11 (H11 or 
>> PDP11/03)
>> The -11 is a bit faster.  The H11 was not slower, the ram used didn't 
>> inject
>> bus waits.
> ...and 2Mhz Z-80s.  The first Citadel appeared on a bone stock H-89 
> with a pair of hard-sectored floppy drives.  I think Ward's original 
> S-100 box was that clock or maybe slower, using an 8080.
Wards S100 crate started with a 2mhz 8080 and not a full rack of ram 
(64K for then was full rack.).
Most moved to Z80 at 4MHZ by 1979 as they were common by then.

The speed needed to handle one line at speeds below 2400 was not a 
stress, there were 6800
based boards.


> g.

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