I replied to the original author, but forgot to cc the mailing list... > There's plenty of literature with the Scsi Host Adaptor - little of > which I understand at the moment, but I live in hope. Will a Potato > installation recognize this board - I haven't yet recompiled the > 2.2.17 kernel for Scsi so don't know what will be involved. Well, you probably need to enable SCSI in the kernel, and tell it what SCSI card you have in there. I don't know whether yours will be supported.
> The harddrive although old seems in good condition. Again, a
> problem as I can find nothing on IBM's website which helps with
> the jumper settings. There are 12 of these:-
> 1. Spare(50pin)
> ID bit3
> (For Wide)
> 2. ID bit 2
> 3. ID bit 1
> 4. ID bit 0
ID bits ~= address bits. Bit 0 is the least significant, bit 3 the most
significant. With bit 3 being labelled as "Spare", i guess that you can only
use IDs 0 through 7.
> 5. Disable Auto Spin
A guess: Mosts disks can "shutdown" themselves after a while of inactivity.
This is handy for power consumption, but there are situations where you don't
want that, e.g. when burning CD's.
> 6. SCSI term on
A (confident) guess: The SCSI bus needs to be "terminated" at/after the last
device on the cable, furthest away from the controller. Some SCSI devices have
built-in termination resistors that can be enabled. This sounds like one of
them.
> 7. Disable unit attn
> 8. Spare
> 9. Auto start delay
> 10. Delay start 6/12
Another (good?) guess: On larger machines with dozens of disks, it can take
quite a strain on the power supplies when you power it on and all the disks
spin up at the same time. So by having some disks "delay" their spinup, you can
get away with a less beefy power supply.
> 11. Disable parity
A (not-very-confident) guess: (from ancient memory): Transfers on the SCSI bus
can be parity-checked to guard somewhat against noisy cables, etc. You probably
have a similar setting on the SCSI controller. I *guess* that as long as they
match you should be OK. I have no idea of the (if any) performance implications.
> 12. LED out
You can probably guess this one:-) But I wouldn't be surprised if your SCSI
card has a similar set of pins, which would "light up" when *any* device on the
SCSI bus is accessed.
> How many jumpers do I need to set? And do I use 4 or 3 if
> the drive initially will be the only device attached?
As long as you choose an ID that does not "collide" with the ID of the SCSI
controller. By convention, the SCSI controller takes the highest ID (probably 7
in your case), but many have BIOS'es that can change that.
> If I can get to understand Scsi and find it a viable alternative to
> IDE, it was my intention to attach a CD writer and some new
> harddrives externally (the board provides for this). Here again
> I'm lost - some people I've spoken to insist only one device can
> be attached externally whilst the literature clearly says up to 7.
SCSI takes at least 7. Later versions of SCSI (where the last address bit is
used) can take up to 15.
> Furthermore, here in the UK no-one appears to stock any 'boxes'
> or whatever for more than one device. A stock explanation seems
Why should they? If they can sell one controller per device? :-) They probably
would argue that it's "just overengineering to be safe" :-)
On a serious note though, some cheaper cards do take quite a bit of CPU
overhead, and I ended up with such a card when I bought by SCSI CD-Rewriter.
Although it *can* take 7 devices (I now have a 18Gb disk, a CD-RW and a tape
station running off it), it doesn't seem to have an impressive bandwith...
Something to do with PCI-busmastering I've been told...
> to be "haven't seen any for years - there's no call for them"
> (One 'charming' individual said he knows nothing technical
> about computer parts "I only sell them".
And it sounds like that's what he *wants* to do. Sounds sad...
>
> Please, can anyone give any initial insight into the points that
> are confusing me so far? Regards, John
Hopefully, you're a bit less confused now. Well... At least you should know
that little bit more. Confusion and knowledge are not mutually exclusive...
--
Karl E. Jørgensen
[EMAIL PROTECTED]
www.karl.jorgensen.com
==== Today's fortune:
Utility is when you have one telephone, luxury is when you have two,
opulence is when you have three -- and paradise is when you have none.
-- Doug Larson
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