From: Bill Stewart <stewarts@ix.netcom.com>
Date: Sat, 13 Apr 1996 09:27:53 +0800
To: jim bell <jimbell@pacifier.com>
Subject: Re: questions about bits and bytes
Message-ID: <199604121934.MAA13397@toad.com>
MIME-Version: 1.0
Content-Type: text/plain


At 09:05 AM 4/11/96 -0800, jim bell <jimbell@pacifier.com> wrote:
>>- From a really quick web search, we find that the SGI Impact jams 9-bit
>>bytes [that's what it says] across the Rambus internally. I'm not sure
>>if the memory itself is 9-bit.
>
>Are you sure they're not referring to 8 bits of data and a parity bit?  In 
>any case, please give the address to the list so that it can be checked out.

www.altavista.digital.com, which is the address of almost everything :-)

If you don't count the parity bit as part of the byte here, you probably
shouldn't count it in a typical 7-bit-ASCII-plus-parity situation either.

As far as jamming 9-bit-bytes across a bus, that almost certainly _is_
8 bits of data and one parity bit; people have been agitating for
and debating parity on memory busses for a long time.

AT&T's Datakit switch (an ancestor of ATM) used 9-bit bytes on its data busses,
where 8 bits were data-from-outside and one bit was a control-vs-data indicator,
which let cards listening to the bus decide whether to think about the byte
with their control processors or just shove them onto an output wire.
#					Thanks;  Bill
# Bill Stewart, stewarts@ix.netcom.com, +1-415-442-2215