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Xref: sserve comp.periphs.scsi:15497 comp.os.386bsd.questions:7032 comp.unix.osf.osf1:1450 Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!elroy.jpl.nasa.gov!swrinde!emory!news-feed-2.peachnet.edu!umn.edu!msc.edu!mckinley.cit.macalstr.edu!sferris From: sferris@budapest.math.macalstr.edu (Scott Ferris) Newsgroups: comp.periphs.scsi,comp.os.386bsd.questions,comp.unix.osf.osf1 Subject: Re: Driver for Adaptec 274xT Followup-To: comp.periphs.scsi,comp.os.386bsd.questions,comp.unix.osf.osf1 Date: 19 Nov 1993 23:42:29 GMT Organization: Macalester College, St. Paul Mn Lines: 48 Distribution: world Message-ID: <2cjll5$lcm@mckinley.cit.macalstr.edu> References: <1993Nov9.163202.2387@chpc.org> <2ce69c53.jonas@jonas.ars.muc.de> <CGIqME.48K@rahul.net> <2ceaa12f.jonas@jonas.ars.muc.de> NNTP-Posting-Host: sydney.math.macalstr.edu X-Newsreader: TIN [version 1.2 PL0] Kai Uwe Rommel (rommel@ars.muc.de) wrote: > lps@rahul.net (Kevin Martinez) writes in article <CGIqME.48K@rahul.net>: > >In <2ce69c53.jonas@jonas.ars.muc.de> rommel@ars.muc.de (Kai Uwe Rommel) writes: > > > >>heas@chpc.org (Heas) writes in article <1993Nov9.163202.2387@chpc.org>: > >>>hi all, > >>>I am looking for a PD driver for an Adaptec 274x[T] EISA SCSI card. > >>>This is the new 2 channel + floppy SCSI card which replaces the 174x. It > >>>features a new 29 bit RISC based processor. > >> ^^^^^^ > >>Are you sure about this? :-) > > > >According to Adaptec docs, it is a 29 bit sequencer or state machine. > However, that's not a 29-bit processor, or am I wrong? The AIC-7770 chip has 448 29-bit words for the sequencer (RISC chip) program memory (effectively microcode). The rest of the chip is like a standard PC card. The sequencer is used to offload processing from the host CPU, speeding operation of the card by reducing the number of host interrupts that must be generated, as well as optimizing the instruction set for the operations most likely to be needed for controlling the card. I'm not sure why they went with 29-bit instructions. I guess they had all the opcodes they wanted and didn't want to cram more bits on the chip for the program memory. The register set of the card is *not* 29-bit, only the sequencer program RAM. In every other respect the card is like the a normal PC scsi controller. > Kai Uwe Rommel > -- > /* Kai Uwe Rommel Muenchen, Germany * > * rommel@ars.muc.de CompuServe 100265,2651 * > * rommel@informatik.tu-muenchen.de Fax +49 89 324 4524 */ > DOS ... is still a real mode only non-reentrant interrupt > handler, and always will be. -Russell Williams -- Scott Ferris, sferris@macalstr.edu LaserMaster Inc, Macalester College, and points in between.