Path: utzoo!attcan!uunet!samsung!usc!elroy.jpl.nasa.gov!ames!claris!wombat From: wombat@claris.com (Scott Lindsey) Newsgroups: comp.sys.apple2 Subject: Fast SCSI Keywords: puffery, structural, chaw, Bridgeport Message-ID: Date: 21 Mar 90 21:14:21 GMT Sender: wombat@claris.com Distribution: comp Organization: Claris Corporation, Santa Clara, CA Lines: 36 Subversive: supercomputer Since Road Runner has been announced and the press release and subsequent conversation didn't discuss too much of the technical details, I thought I'd post the blurb sheet from the preliminary documentation. High speed SCSI card for the enhanced IIe or IIgs. Major elements: * 53C80 SCSI SCSI interface chip * Custom gate array chip * 8 KB of RAM (8 banks of 1Kbyte each) * 32 KB of ROM (32 banks) * Page latches for RAM and ROM * SCSI Address and DMA Enable/Disable switches * 1/4 second watchdog timer * Buffers, I/O decoders, and timing circuitry Features: * Programmed I/O, Pseudo DMA, and real DMA supported * DMA transfers up to 64K in length * DMA stops on interrupts, address rollover from $FFFF to $0000, and watchdog timeout * DMA speed is up to 1MB/sec * DMA speed can be limited to 500KB/sec, to work with 65C02 processors * Will suspend DMA activity if higher priority DMA device needs the bus (Apple II DMA priority chain) ** IMPORTANT: In order for DMA to work right, the system must be running at 1MHz. [This was from preliminary docs, so details may have changed] Scott Lindsey | I dig iguana in their outer space duds Claris Corp. | saying, "Aren't you glad we only eat bugs?" ames!claris!wombat| DISCLAIMER: These are not the opinions of Claris, Apple, wombat@claris.com | StyleWare, the author, or anyone else living or Dead.