Date: Thu, 01 Jan 1998 23:14:15 +1030 From: Mike Smith <mike@smith.net.au> To: Rudy Gireyev <rgireyev@yahoo.com> Cc: freebsd-hardware@FreeBSD.ORG Subject: Re: zip drive problems Message-ID: <199801011244.XAA01771@word.smith.net.au> In-Reply-To: Your message of "Thu, 01 Jan 1998 02:25:53 -0800." <19980101102553.12506.rocketmail@send1b.yahoomail.com>
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> > Tell him to take some of them apart and look at the boards. > > Yeah, breaking stuff is cool !!! :-) Breaking is for amateurs. I was referring to exploratory surgery. 8) > > > BTW, I don't suppose that anyone has any detailed white papers on > the > > > subject? > > > > What subject? > > Well my knoweledge is somewhat limited on this but I thought I'd share > what I know. I apologize in advance if this is common knoweledge and > I'm wasting bandwidth. I meant more "what subject for the white paper"? > From what I know the way SCSI world works is you usually have a SCSI > interface, which is also a SCSI bus (kinda like PCI), that controls > multiple SCSI devices into this bus one can plug in HDs, CD-ROMS, > scanners etc etc. Yecch. Stop here. You may be thinking straight, but your terminology is pretty broken. The bottom line here is that SCSI is a means for connecting devices together. You generally need a device to interface between a SCSI bus and the bus inside your system. > Popular examples of SCSI buses are Adaptec AHA > family and Symbios 8XX family These are interfaces; they provide translation services between the host bus (ISA for the 1542, PCI for the 8xx family) and a SCSI bus. > What makes SCSI devices different from IDE is that they ship with an > adapter/controller built into the device itself and that is what makes > the SCSI unit intelligent (The hard disk itself may actually be the > same as IDE). No. Both IDE and SCSI peripherals contain "intelligence" and interface logic; in this case the interface is between the IDE/SCSI bus and the local bus onboard the peripheral. Features of the SCSI interface make it possible for devices using that interface to do extra "clever" things that are only just becoming possible with ATA (nee IDE) devices. > So SCSI Jaz drive only has a SCSI adapter. > The SCSI Parallel has the adapter, the entire SCSI interface (or bus) > to control a single unit. And on top of that a custom converter that > allows a parallel port to talk to a SCSI interface (Wow that is a lot > of hardware) There is no parallel Jaz; you may mean the Zip. The only significant difference between the SCSI and Parallel Zip devices is the parallel-SCSI adapter (variously referred to as the ppa3, vp0, etc.) If you want to drive a Jaz off a parallel port, the Jaz Traveller should work with the vpo driver. As soon as I can lay my hands on one, I'll confirm that. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ Remember, the race is long, \\ msmith@freebsd.org \\ and in the end it's only with yourself. \\
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