This is topic SCSI installation in forum Film-Yak at Film-Tech Forum ARCHIVE.
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Posted by Josh Jones (Member # 447) on 02-14-2001, 02:11 PM:
I want to put a scsi 40GB hard drive in my little HP. I want it to be removable so I can swap drives while the machine is running. What would be involved in such a project?
Perhaps Mr. Chriswell knows...Josh
Posted by Paul G. Thompson (Member # 655) on 02-15-2001, 12:11 AM:
Josh, I don't think it can be done without major problems. Pulling a hard drive (either IDE or SCSI) out of a computer while it is running is like disconnecting your drive shaft at 70MPH! You may not only damage the drive and/or its programs, but it could toast the controllers or main board.(My opinion - do as you wish. Eventually, when things are just right, you'll say OOPS!). Even if someone says "sure", no problem I would never do it.
Kind of reminds me of a friend of mine who always switched around his keyboard from one operating computer to another. I said to him not to do it, and he laughs, said he never had any problem doing it.
Well, a week later, he blew the mainboard and the keyboard fuse on the main board. Murphy's Law strikes again! Naturally, the main board protects a small-specialized cheap fuse (which is a pain in the butt to change) by blowing first.
It is never a good idea to disconnect any component from any electronic device without removing the power first. I don't even trust Microsoft when it says "It is now safe to plug in your...."
Also reminds me of a person who did not unplug the ATX power supply before she pulled out a modem. It ruined the main board and modem because there was still contact potential on those components.
Even main board manufacturers will warn you to make sure you disconnect the power from the computer before you yank any component out of it.
Posted by Mark Lensenmayer (Member # 134) on 02-15-2001, 07:57 AM:
I'm not sure SCSI is very forgiving of removable media. SCSI was primarily a Mac medium for many years, and it was bad news to connect or disconnect ANY SCSI device while things were running. It almost always led to a crash.It might be possible to do such a thing in the USB world, but you would probably be taking a big performance hit.
Mark Lensenmayer
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"As a moral to young men who come down to the city, don't go round breaking people's tambourines."
Posted by Scott Norwood (Member # 30) on 02-15-2001, 09:00 AM:
There are some pieces of hardware which use SCSI drives which are designed to be hot-swappable. More specifically, the drives themselves are standard, but the hardware/software itself is designed to allow the drives to be removed and replaced while the system is running.
Network Appliance file servers allow this, as do Sun A1000 disk arrays. The purpose is to allow swapping a replacement drive for one that is going bad. You give a software command to spin down the bad drive, then you swap the drives and give another software command to make the new drive part of the RAID array. In Netapp boxes, this requires that you have at least one drive configured as a hot spare.
Some server-type PC hardware allows this as well, but I'm not terribly familiar with it. I doubt that you could do this with a garden-variety PC...even the enclosures which allow easily swapping drives among machines aren't usually supposed to be removed without powering down the machine.
Most external SCSI items can be connected while the machine is running, but (with NT and Solaris, at least), you still will need to reboot the machine to get it to recognize the existance of the newly added (disk, tape drive, etc.).
Posted by Mark Gulbrandsen (Member # 72) on 02-15-2001, 07:56 PM:
Josh,
Personally I'd stay away from SCSI drives for use in a home computer. There is very little to gain but a lot of frustration if you hvae little experience with them. Of course it is a good way to learn about them too.
I'd go with an add on ATA100 PCI card and an ATA100 IDE drive of your choice of size....up to 85GB now. These drives are now within a fraction of the speed of SCSI and alot cheaper. You can get a 20GB drive for a tad over a hunderd bucks and the card is only about 40.00. This will make such a huge difference in the speed that your CPU may not be able to deal with the incomming data. Also consider building a new computer with an ASUS RAID type motherboard. These also use standard ATA 100 drives and you can stack many drives in there on the RAID. Just be sure to get all the same size drives!! If you have a drive smaller than say a 20Gb drive the RAID will make all the drives the same size as the small one. Also you can get ATA100 IDE drives up to 85GB now for less money than a 20GB SCSI!
My system running a P3 at 900 meg speed can defrag a 20gb drive in about 6 min.
Mark @ GTS
Posted by Jason Burroughs (Member # 68) on 02-15-2001, 09:09 PM:
I agree with Scott. Doing so without the solutions that he mentioned would result in Serious Damage to related components.USB would possibly be a choice, but FireWire would probably be a better solution, as they have better performace, the drives aren't TERRIBLY expensive, but still a little steep, and the controllers are usually fairly inexpensive.
Posted by Tim Reed (Member # 137) on 02-15-2001, 11:53 PM:
If I had my system to build again, I would get an add-on SCSI port adapter and not one built into the motherboard. I've had trouble with throughput, and no way to upgrade it.FYI, Seagate drives with a "C" suffix, have 80-pin SCA connectors, and are "hot-swappable". They are designed for this.
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Better Projection Pays!
Posted by Josh Jones (Member # 447) on 02-17-2001, 09:43 AM:
Perhaps I should clarify a weeee bit(I have a problem with that dont I? 
) I want the removable to be a slave or second drive, not the system drive. The system disk is going to be fixed(non removable). see if that helps....Josh
Posted by Jason Burroughs (Member # 68) on 02-17-2001, 03:52 PM:
Josh,It dosen't matter wether it is a primary or slave drive, without the proper hardware, you will toast your controller (on motherboard etc) and the hard drive. You can only do this with hardware designed to do so, and it is usually a bit pricy as it is designed for server applications. Now if you don't mind shutting the computer down to remove the drive, that's a whole different story. But to keep everything on and running during the removal you absolutly need hardware capable of this.
Posted by Mark Gulbrandsen (Member # 72) on 02-18-2001, 04:52 AM:
So whats so good about SCSI drives anyway? I can't justify using them. They are not that much faster than ATA100 drives,they cost at least double to triple the price of an equivelent size ATA100 drive, and can be a pain to deal with in arrays. ATA 100's can run great in RAID arrays and are about to get even faster and pass up SCSI speedwise all together. They are also available in larger size drives.
Since I'm not a specialist in server type frames whats so special about them?
Mark
Posted by Scott Norwood (Member # 30) on 02-18-2001, 07:07 AM:
Overall throughput is higher with SCSI, even though ATA drives "appear" to be almost as fast (in bursts, but not continuously). SCSI also takes some of the load off of the CPU, which can significantly increase performance on a system with lots of disk activity (news server, file server, etc.).
Note, too, that there are many other SCSI devices besides disks; scanners, CD-R drives, tape drives, etc. all require SCSI for top performance.
I don't trust IDE RAID...
For desktop PC use, I agree that SCSI is probably overkill, but I've been using it for years for all different purposes and have had far fewer problems with SCSI than with IDE. It's actually really simple to set up a SCSI chain as long as you remember that each device needs a unique ID number and that each chain must be terminated.
Posted by Jason Burroughs (Member # 68) on 02-18-2001, 09:50 PM:
Particulary with severs, IDE just wouldn't be able to handle the bandwidth needed, even ATA-100, especially when you consider the availability of Ultra3 devices capable of 160 Mbp/s continous, vs ATA 100Mbp/s PEAK. About the only thing IDE is used for on a server is for the CD-ROMs (at least in the Compaq and Dell servers I've been working with) however even then there are pure SCSI machines. Like Scott stated, to me SCSI is easier than IDE, and some adapter cards are self terminating eliminating that a terminator be used. Also spindle speeds are higher in SCSI devices currently, 10K RPM is pretty much standard now, with the 15K RPMs becomming more and more common. This is vs the 7.5K RPM that is currently the max on an IDE drive. IDE's a great for PC's where price is a major considering factor, but when performace is, SCSI is king.
Posted by Paul G. Thompson (Member # 655) on 02-18-2001, 10:34 PM:
I still would not remove a drive, even if the software/hardware says it is ok. Too risky. Nature sides with the hidden flaw. The only thing that is a positive without question is Death and Taxes. 
Posted by Mark Gulbrandsen (Member # 72) on 02-19-2001, 05:45 PM:
It seems to me that ATA 100 also works similar to scsi. Either card feeds the PCI bus just as a scsi card would. I can't see how it would load down the cpu at all. The ATA cards all have their own bios as well.
Mark
Posted by Paul G. Thompson (Member # 655) on 02-19-2001, 11:56 PM:
Here's one for Scott, or anyone else that knows the answer. My Winblows 2000 professional looks for a graphics card in an ISA slot that does not exist. I have an ATI AGP card in that machine. I have the BIOS set for AGP. Does Winblows need a dose of Ginko Viagra to remember what the **** it is doing?I don't understand this one, unless it is a normal thing for Winblows 2000.
Posted by Josh Jones (Member # 447) on 02-20-2001, 09:39 AM:
I am going to use drive pulls that when the drive is unlocked, it removes power from the drive, so why would that blow a controller card?Josh
Posted by Scott Norwood (Member # 30) on 02-20-2001, 09:44 AM:
I don't know much about graphics stuff, as it happens. I assume that W2k defaults to look for an ISA graphics card, but I don't really know.The hot-swap stuff really does work with Network Appliance and Sun disk arrays. It's much better than taking down systems that an entire company depends on just to replace a bad drive.
My only concern here would be about swapping drives on a regular basis, which sounds like a bad idea. Drives need to be kept spinning over time and will tend to go bad rather quickly if they are repeatedly stopped and re-started by being removed and re-inserted.
Posted by Paul G. Thompson (Member # 655) on 02-20-2001, 11:36 AM:
Josh, I do not know what causes the drive to return to the "park" position. If you just turn off the power to the drive, the heads might not park properly. Then, the drive could be damaged by bumping or jarring it and screw up the disk. Maybe Scott knows.
Posted by Jason Burroughs (Member # 68) on 02-20-2001, 12:40 PM:
Even when the power is disconnected from the power, there is still current in the connection between the drive and the controller. As far as CPU utilization, there is not much difference between SCSI and IDE (ATA) per a given drive throughput, however SCSI can out perform IDE any day of the week in both burst and constant data throughput. Annother factor, I don't see any 64bit IDE controllers!
On the subject of the video card, Windows will initally detect the video card as a standard ISA VGA Adapter, untill you load the drivers for the video card, and ATI requires this for the drivers to load properly, what type of motherboard and chipset do you have (ie Intel BX, LX, AMD, VIA etc...) that plays a part as well as the proper AGP drivers have to be loaded as well.
Posted by Paul G. Thompson (Member # 655) on 02-20-2001, 09:58 PM:
Jason, as far as I can determine, the ATI drivers may have been a bum load. Reason why is sometimes Windows sees them correctly, and sometimes it does not. I'll try re-loading the drivers to see if it will correct what Bill Gates cannot.
Posted by Mark Lensenmayer (Member # 134) on 02-21-2001, 11:18 AM:
On the subject of hot-swapping drives, I just received a catalog from a drive company that shows many different kinds of drives. Their suggestion for hot swappable drives are Firewire/USB combo drives. Both of these technologies are designed for swapability. They have hard drives as big as 75 gig, CD-RW and DVD-RAM drives in this configuration. None of the SCSI drives are hot swappable EXCEPT for drives in the big RAID units, which are somewhat pricy.BTW, the company here is APS, who have been making drives for many years.
Mark Lensenmayer
Posted by Jason Burroughs (Member # 68) on 02-21-2001, 10:17 PM:
I have not installed an ATI card in a 2000 system, only 98, and ME. Unless the card is imbedded in the mobo. For 2000 which I use Matrox cards when I build a system typically, as I have never had a customer request anything otherwise.To reinstall the ATI drivers you have to make sure that the previous load is throughly removed. One thing you may try, is checking both ATI's website as well as Microsoft's Updates site for updated drivers. Which ATI card are you using? Also what type of motherboard do you have?
Between a USB and a Firewire drive I would recommend the Firewire, as Firewire has a much higher bandwitdth. Don't remember Firewire's thoughput off hand, but USB's is only approx. 12MBp/s.
Posted by Paul G. Thompson (Member # 655) on 02-22-2001, 01:22 AM:
Thanks, Jason. I didn't get a chance to fiddle with it yet, But I plan to uninstall the drivers and re-install. It could be I don't have the updated drivers that run under 2000. Had lots of problems with that. The more I fool around with 2000, the less I like it.
Posted by Jason Burroughs (Member # 68) on 02-22-2001, 10:06 AM:
Hopefully it will work.2000 is acutally very stable, and easier to work with, trick is making sure everything is up to snuff, resources, drivers, etc...
95, and 98 drivers will not work with 2000 as it is a totally different operating system, just has a similar skin. But once you get everything up and running, its pretty smooth.... and FAR more stable than any other version of Windows and even most versions of the MAC OS. (IMO)