Path: utzoo!attcan!uunet!lll-winken!ames!xanth!nic.MR.NET!umn-cs!bungia!meccts!mvs
From: mvs@meccts.MECC.MN.ORG (Michael V. Stein)
Newsgroups: comp.sys.apple
Subject: Re: Apple //gs access speed.
Message-ID: <3870@meccts.MECC.MN.ORG>
Date: 12 Jan 89 02:59:32 GMT
References: <8901060920.aa17994@SMOKE.BRL.MIL> <452@cs-spool.calgary.UUCP> <13328@cup.portal.com>
Reply-To: mvs@meccts.UUCP (Michael V. Stein)
Organization: MECC Technical Services, St. Paul, MN
Lines: 24

In article <13328@cup.portal.com> -Rich-@cup.portal.com (Richard Sherman Payne) writes:
>
>This may not exactly follow the provious post, but this question came up
>on a local board. Does the //gs, in GS/OS, access the 3.5" drives at 1MHZ
>or at 2.8 MHZ, through the smartport. My understanding was that all access
>to the lower 64K were at 1MHZ. And that the drives were accessed through the
>lower 64K. I thought that the increased speed of GS/OS was the result of
>the 16 bit processor working more efficiently than the 8 bit (P16 v1.3) at
>the same speed. Dave Lyons, are you listening?
>

The increaed speed of GS/OS is due to the fact that it can avoid some
extra buffering that old ProDOS 16 ended up doing.  

In terms of processor rate, all accesses to anything in banks $e0 and
$e1 occur at 1 Mhz, so all accesses to the actual sence switches 
controlling the drive are executed at 1 Mhz, but the rest of the code
can be executing at 2.8 Mhz.

-- 
Michael V. Stein
Minnesota Educational Computing Corporation - Technical Services

UUCP	ihnp4!!meccts!mvs