View Full Version : Drive Bays vs. PCI slots

02-24-2001, 01:22 PM
Excuse my ignorance (hell 1 week ago I didn't even know what SCSI was!) but is a PCI slot different than a drive bay? If I install a drive internally will that take one of the 3 slots I have in my computer (G4 PCI ?). I only have one slot left and I need it for an eventualy FCP upgrade (Matrox board).

02-24-2001, 01:43 PM
OK. Basics here. http://macgurus.com/infopop/emoticons/icon_biggrin.gif

A Mac has a few key parts. These things are all on the motherboard.

1) Processor - The machine's brain. Also, the speed you see when people write about a computer.

2) RAM - A place for the computer to do all the math required for an application. It is not the amount of drive space required, for that is merely how much information the program takes to ge installed. Think of it as the place where the computer "carries the ones" and "does the long division".

3) PCI/AGP slots - These are phsical, plastic slots (with metal conductors) where cards can be plugged in to add features to your Mac. Video cards, SCSI controllers, USB, FireWire, audio cards, capture cards...to name a few. These plug right into your motherboard and usually have a port on the card that will be accessible from the back of your Mac.

4) Ports - Power, audio in & out, SCSI, video in & out, monitor, serial ports, USB, FireWire to name a few. Some machines have some of these, some have others. Your owner's manual will list them for ya.

Then you have the things that you will find in the case, but are not on the motherboard. They are all connected somehow, but are not phyically ON the mobo.

1) Storage - CD, DVD, Floppy, Zip, MO, Hard Drive, etc. They are located in Bays. Think of them as vehicles that hold your data. Your vehicles need to get parked in a bay in your garage, or computer. Simple. Kinda.

2) Power supply - Feeds juice to the mobo and to all your drives.

So if you install a drive, it wil have no correlation to your PCI bus, unless it plugs into a SCSI card that is plugged into your PCI slot. The drive will need to have a home. And in a G4 there are a few bays in which to mount it.

This is all kinda fun, to me. Don't feel like an idiot. Years ago, we all had a learning curve that was staring FAR down at us. Now, some of us are farther up the hill. That's all.

Enjoy your weekend, and keep the questions coming.

[This message has been edited by Dogstarman (edited 24 February 2001).]

02-24-2001, 03:37 PM
Ok, So how do I tell If I have any bays left? I haven't added anything to the computer yet. I did have Apple put in a Narrow 50 pin (I think) SCSI card in one of my PCI slots. If I install am Ultra 160 SCSI Cheetah 36G in one of the open bays (if I have any) I will need an Ultra 160 card in one of my PCI slots, right? Should I take out the Narrow SCSI card to put in the Ultra since I dont use it?

PS- is your username a reference to the Stan Brakhage films?

02-24-2001, 07:19 PM
If you add a Cheetah you will need an appropriate LVD card in one of your PCI slots. You don't use the Narrow card? It doesn't necessarily have to come out unless it is a bus mastering card. If it is the Adaptec card that Apple used to sell, it may be a bus hog and have to go. I really don't know many empty bays your machine has; probably two more.

[This message has been edited by Louie (edited 24 February 2001).]

02-25-2001, 01:59 AM
Yikes. You really have to open up that machine and look inside. Your G4 should have at least 2 empty bays in the very bottom of the computer. Depending on your other storage facilities (Zip, DVD, etc) you may have one below the DVD/Zip. Use Apple System Profiler to see what cards you have installed. It will tell you slot-by-slot with the manufacturer's designations. If you don't use the SCSI card, I would remove it just to have one less thing using ROM and system overhead.

Any drive with any "Ultra" specs will need an Ultra card of the same or better specs to take full advantage of the drive. So your best bet for a PCI-based Ultra160 SCSI controller would be the ATTO card, in either the UL3S (single channel) or UL3D (dula channel). The dual is great if you plan on absolute performance and expansion. Otherwise, the $$ would be better off spent on the drive itself and some good cabling.

And no, my name is not a ref to the SB films, though I do so enjoy his work. It is more of a reference to the actual star, and to a lesser degree, a band called Meat Beat Manifesto. They actually have a song entitled Dog Star Man. I have been using the name since college. Seems to stick, for some reason.

02-26-2001, 03:01 PM
I opened it up (I expected more stuff in there) and I think I see three bays on the floor of the computer. One of them has my hard drive, right? So, I get a 36G Cheetah (10,000rpm) put it in one of the open drives with some sort of brackets and attach by a cable to the motherboard? How do I tell were to put the cable on the motherboard?

02-26-2001, 07:46 PM
You will need an Ultra SCSI host adapter card in one of the PCI slots. An LVD cable with terminator connects between the drive and the card.