Re: [OT] SCSI Primer
On 00:58, Wed 09 Mar 05, Seeker5528 wrote:
> On Mon, 7 Mar 2005 16:58:14 -0600
> Jacob S <stormspotter@6Texans.net> wrote:
>
> > Does anyone know of a good tutorial with pictures and descriptions of
> > the different connectors, explaining what can inter-operate with what
> > advantages and disadvantages, etc? My googling has been fairly futile
> > so far.
>
> I don't know of any general documentation, and SCSI is not my specialty.
>
> Having said that I do have some limited experience.
>
> Microsoft has a document floating around on their site somewhere
> indicating that a chain of SCSI devices will operate at the speed of the
> slowest device in the chain. Whether that is a SCSI limitation or an MS
> limitation I don't know for sure.
>
> The best source for compatibility information will probably be the
> documentation for on board SCSI, the raid card, and the back plane. I am
> not familiar with back planes, but a quick google for information, the
> thing that jumps out is it looks like some support hot plugging while
> others don't.
>
> In general terms, there are efforts to maintain some backwards
> compatibility as new generations of stuff come out, so there are lots of
> different adapters to hook older devices to newer style connectors and
> newer devices to older style connectors, which takes you back the the
> slowest device on the chain question.
>
> What I personally have experience with is mostly adaptec cards with a
> variety of hard drives, the occasional scanner, cd-rom drive, burner or
> zip drive.
>
> Mostly I have had pretty good luck mixing and matching stuff with
> various combinations, drives with 50 and 68 pin connectors on a cable
> with 50 pin connectors, drives with 50 and 68 pin connectors on a cable
> with 68 pin connectors, and drives with 80 and 68 pin connectors on a
> cable with 68 pin connectors.
>
> I have not had a card with 80 pin connectors to play with.
>
> I don't have experience with raid, but the general wisdom I have read is
> to use drives that are exactly that same if you can, or if you can't
> then as closely matched as possible.
>
> Later, Seeker
This is a good article that goes into the basics and a
little back ground about SCSI.
http://www.storagereview.com/guide2000/ref/hdd/if/scsi/std/scsi3.html
This is the site responsible for the standard, and as such
has not so friendly of a layout.
http://www.t11.org/index.htm
Now as far as raid is concerned you might want to follow
some of the threads in here in the past. It seems that under
Linux software raid seems to be a good choice, as some
hardware raid lacks the proper drivers and does not seem to
work under all conditions.
I would not suggest you mix and match too much, it might
work, but if something goes wrong you might have a nightmare
trying to figure out what is wrong. I would sell old stuff
on Ebay, or build a system with only those parts, then build
another system with the newer parts. Also what exactly are
you going to use the system for, server, gaming, or other
needs. Are your other parts up to the task, for instance if
your a server and serving files over a network do you have
the proper nic's.
A lot of people think that scsi will answer all their
prayers, jump whole hog wanting the fastest speeds possible.
But in fact their are other bottlenecks that do not allow
them to take advantage of the speed. The network is a good
example, memory, bandwidth, you almost have to build the
infastructure to take advantage of what SCSI can bring.
Gnu-Raiz
Reply to: