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Miscellaneous Configuration Info
LVD drives do *not* come with (any) terminators. Therefore, make sure you get one with your card, if you buy an LVD-capable adapter
(which you should). Terminators are not
cheap when purchased separately.
Most/all current LVD-capable SCSI adapters come with auto-termination, which means the card sees what devices are
installed/connected, and terminates (or unterminates) automatically. This is a nice feature, and you should look for it in a card. If not, you will have to
manually set the card's termination (with jumpers), and this is one more place where you can screw up.
Naturally, the less places where you can screw up, the better.
The LVD terminator goes on the very last connector of the twisted-pair LVD cable. If you put the terminator on any connector (also called a
position) other than the very last one, you will have what it
called a dangling cable, which can generate signal interference,
reflectivity, and other bad things. Before learning this, I have run my system
with a 'dangling cable' and it seemed to run well. But everyone I consulted
insisted that I place the terminator on the very last position.
None of my IBM Ultrastar SCSI hard drives came with the Write Cache Enabled (WCE). Enabling the write cache provides significantly better performance. I use Adaptec's EZSCSI 5 to enable the write cache on my IBM drives. (Thx to Joshua for that tip.) Apparently, the SCSI standards are tight enough that the Adaptec utility will work fine on a Tekram card. IBM also has a utility, but it is a POS (piece of cow manure), and will make your head hurt trying to use it.
Seagate also makes a
similar utility - far better than IBM's, but not nearly as
easy as EZSCSI 5. For those with Win2000, you can go to the Disk Properties tab
for the hard drive in the Device Manger, and put a check in the Write cache
box. That will enable your write cache, too (very easy - and will stay for stay
for Win98/ME, too).
Some people have problems with the write cache reverting back to its original
disabled status after a reboot. I've gotten quite a few emails about this, and
frankly, have no solution, other than use a utility made the the drive's
manufacturer. I've never had this problem.
Enabling the
write cache on
the HDD allows the system to move on to the next task/function/operation, as soon as data is in
the cache. If the write cache is disabled, the system must wait until the data
is (actually) on the disk itself before it recognizes the write as complete. Because RAM/cache is
several orders of magnitude (1 million times) faster than HDD disks, writing will take significantly longer.
My system ran noticeably slower at times with the write cache disabled. Here's what Adaptec EZSCSI has to say about it, and here is discussion from the Adaptec website. Microsoft has this to say about the subject.
There is a
risk
involved with enabling the write cache. If you have critical (system) data being written
to the drive, and your system loses power after the data arrives in the
cache, but before the data (actually) makes it to the
disk, you could have serious problems. The chances for this happening are small,
depending where you live, and the reliability of your local power company, time
of year (summers are worst, due to high demand for electricity to run air
conditioners, and therefore, even dependant on the weather.
Worst case scenario
= you could have to reformat & re-install your OS & apps. For this reason, it's a good idea to run
a UPS (uninterruptible power supply). I use the BackUPS 650 by APC.
Heard
that some drives won't keep/hold the write-cache enable setting, using either
the W2K check box or EZSCSI5. But I don't think this applies to IBM drives, cuz
I have no prob with either method.
None of my IBM Ultrastars (9LZX & 18LZX) came with Autostart enabled by (factory) default. You have to manually set this jumper (jumper config is spelled out on the IBM web site, and on a sticker attached to the drive itself). If you don't set the Autostart jumper, the drive will not power up when you press the start button on your PC.
This can be a source of
angst, especially if you just paid a good chunk of cash for it. Alternately, you
can enable Send Start Unit in the (Tekram's) SCSI card's bios. This will spin up the
drive when the SCSI bus starts its scan. But this will take a few more secs than
setting the Autostart jumper. You want to set the Autostart jumper - at
least on IBM Ultrastars.
Update: just got a 36LZX (Jan, 2001) which
had the Autostart jumper set by default. Also the SCSI ID was set to 6
by default. Usually you'll want that to be set to SCSI ID 0. You do
this with jumpers.
Be extra careful when setting SCSI ID jumpers, especially if when selecting an
ID other than 0, and especially with IBM Ultrastars. (I have no
experience with drives made by any other manufacturer.) It seems that IBM made
the selection of SCSI ID's as confusing as possible. The numbers are backwards,
right-to-left. Anyway, you'll see what I mean. SCSI ID 0 is easy, cuz you simply
remove all the jumpers used to set SCSI IDs. But for any other ID, it can get
confusing. Triple check your jumper settings with those for your drive at the
manufacturers web site.
I disable the start-up bus scan for all SCSI IDs except ones I'm actually using. This shaves a few secs from your start-up time, which can add up, over the months & years. But you have to remember to re-enable the bus scan for the ID of any new devices you add to the chain. Nothing like adding a new hard drive, or CDROM, & not having it show up, cuz you forgot to enable the bus scan. Doh!
For maximum compatibility, use Microsoft's FDISK to both partition & format both your SCSI and IDE
drives. Forgetting to partition & format is one of the big Doh!s that people
make with SCSI hard drives. They install it, see it in the BIOS scan, Windows
sees it, but they can't access it. Still have to partition & format the
drive. I use Microsoft's FDISK to partition, and have used Partition Magic a few
times to modify things, to make room for Linux (ext2) partitions, and Linux
swap(s).
Use Partition Magic to partition & format EXT2 partitions for Linux. Many
use PM to partition SCSI & ATA drives. Nothing wrong with that, but I think
MS FDISK has better compatibility, as more (that I know) use it. If you're not
handy with FDISK, see Doc's Guide
to Partitioning a Hard Drive with FDISK.
For SCSI
CD-ROMs & burners, for W98/SE/ME, you want to look in the device manager and
enable Sync data transfer and Disconnect. I disable auto-insert
notification, as it bothers CDRWin (burning app), but this is more pers pref If
you want to disable AutoInsert notification in W2K, you need to use TweakUI,
or at least I did. There is also a registry edit that will do this, but I can't
seem to find it right now.
I use 4GB for each of my Windows partitions (WinME & Win2000), and 1.8GB for each of my Linux partitions (Linux swap = 128MB). This is plenty (for me). I have each OS on a separate (physical) hard drive, but this is not necessary.
In order
to run LVD devices in/with LVD mode/protocol, you need *every* part of your
hardware config (to be) LVD-rated. In other words, to run your LVD/Ultra160 hard
drive(s) in/with LVD mode/protocol, you need an LVD-rated adapter/controller, an
LVD-rated cable (68-pin), an LVD terminator, and of course, and
LVD/Ultra160-rated hard drive. So far, hard drives are the only storage devices
capable of operating in LVD/Ultra160 mode.
If any one of the previous components is not LVD-rated, then everything on the bus default to Single-Ended (SE) mode. Max SE transfer rate = 40MB/s. LVD/Ultra2Wide = 80MB/s. Ultra160 = 160MB/s, but this tends to be a misnomer, cuz the PCI bus can only handle max 133MB/s. I think I've already discussed this elsewhere, so will not beat a dead horse. Consider too, that the fastest drive out right now, the Cheetah X15-36LP, can only sustain a maximum transfer rate of about 60MB/s.
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