Date: Fri, 23 Feb 2001 19:33:30 +0100 (CET) From: Torbjorn Kristoffersen <sgt@netcom.no> To: FreeBSD-Hackers <hackers@FreeBSD.org> Subject: Re: IOmega ZIP problem Message-ID: <Pine.BSF.4.30.0102231921220.825-100000@hal.netforce.no> In-Reply-To: <20010223093943.A1899@ringworld.oblivion.bg>
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On Fri, 23 Feb 2001, Peter Pentchev wrote: > On Thu, Feb 22, 2001 at 01:19:33PM -0600, Michael C . Wu wrote: > > On Thu, Feb 22, 2001 at 07:40:16PM +0100, Torbjorn Kristoffersen scribbled: > > | Hi I'm using 4.2-RELEASE, with a parallel port ZIP drive (100M). > > | Whenever I copy a large file from the zip drive (for example /dev/da0s1), > > | the "cp" process eats 98% of the system resources. What's behind all this? > > | Is there a way to fix it? > > | > > | 711 root 54 0 280K 168K RUN 0:45 93.87% 93.21% cp > > | > > | A 'renice' won't help. > > > > > > That's natural with "parallel". No way around it. > > To clarify a bit, parallel port hardware depends on the system processor > doing all the data transfers, every single byte, and spending even more > time checking if it's time for the next byte to go. There's no DMA, there's > not even a controller you can tell 'here's a 512-byte block, let it fly'. > > There's no way around it indeed. > > G'luck, > Peter So there doesn't exists any controllers (ISA/PCI) that can do the serialization of parallel data, and pass it to a serial interface (or UART), so we can use DMA and move Serial Data Units instead of single bytes? (Probably a feather-brained question..) Cheers, Torbjorn Kristoffersen sgt@netcom.no To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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