Path: utzoo!attcan!uunet!mcsun!unido!mpirbn!p554mve
From: p554mve@mpirbn.mpifr-bonn.mpg.de (Michael van Elst)
Newsgroups: comp.sys.amiga.hardware
Subject: Re:  GVP Trade-in
Keywords: SCSI, GVP
Message-ID: <1164@mpirbn.mpifr-bonn.mpg.de>
Date: 6 Sep 90 11:47:21 GMT
References: <14069@cbmvax.commodore.com> <1990Aug30.121102.11096@hod.uit.no> <1151@mpirbn.mpifr-bonn.mpg.de> <1990Sep4.213845.2043@agora.uucp>
Reply-To: p554mve@mpirbn.UUCP (Michael van Elst)
Organization: Max-Planck-Institut fuer Radioastronomie, Bonn
Lines: 20

In article <1990Sep4.213845.2043@agora.uucp> billsey@agora.uucp (Bill Seymour) writes:
>In article <1151@mpirbn.mpifr-bonn.mpg.de> p554mve@mpirbn.UUCP (Michael van Elst) writes:
>>MFM data comes with 500Kbit/sec == 62.5KB/sec. Therefore the disk-DMA
>
>	Actually, with the current Paula chips, data transfer from the floppies
>	is done at 250Kbit/sec. Not the 500Kbit.sec that the HD type drives
>	do. That's why it's so much trouble to get the 1.76M floppies working
>	on the Amiga.

That's the user data rate. MFM cells are 2 microseconds short giving
500Kbit/sec. Since a user bit is encoded into two MFM cells (clock & data)
you'll get 250Kbit/sec for user data. Nevertheless, the disk DMA
has to work with the raw data rate of 500Kbit/sec.

Regards,
-- 
Michael van Elst
UUCP:     universe!local-cluster!milky-way!sol!earth!uunet!unido!mpirbn!p554mve
Internet: p554mve@mpirbn.mpifr-bonn.mpg.de
                                "A potential Snark may lurk in every tree."