Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!lll-lcc!rutgers!mit-eddie!husc6!panda!genrad!decvax!wanginst!ulowell!miner From: miner@ulowell.UUCP (Richard Miner) Newsgroups: comp.sys.amiga Subject: Re: Hard disk through parallel port Message-ID: <889@ulowell.UUCP> Date: Mon, 22-Dec-86 00:27:30 EST Article-I.D.: ulowell.889 Posted: Mon Dec 22 00:27:30 1986 Date-Received: Mon, 22-Dec-86 05:41:57 EST Reply-To: miner@ulowell.UUCP (Richard Miner) Organization: University of Lowell Lines: 27 In several articles lots of people write: ...a disk on the parallel port can be close to the speed of a board on the expansion bus... - They even mention DMA on the serial port. A board on the expansion bus can grab the Amiga's bus and blast data into memory as fast as it takes to light up the address and data buses and trip the read/write strobes. Once the board has the address of an internal data buffer the DMA cycle far surpasses an assembly loop reading the serial or parallel ports. When we speak about DMA for hardrives we mean direct access to the systems bus. The solution is a nice address generating chip and a little 680xx bus arbitration logic. Perhapse all on a single LSI chip like the hardware group at Commodore came up with. Why are'nt more people taking this aproach? The logic to interface with the Zorro bus is not that complex, are address generators that expensive? PS (to weschester support) Thanks for the response to manx multitasking question, and great suport in 86, happy holidays and new year. -- Rich Miner ...!wanginst!ulowell!miner Ulowell, Center for Productivity Enhancement (617) 452-5000 x2693 HAL hears the Amiga9000 series is not selling. "Please explain Dave. Why aren't Amiga9000's selling?" Bowman hesitates, "You aren't IBM compatible."