Connecting Your Jaz® Drive to a SCSI Chain
The Small Computer System Interface (SCSI) is an industry standard for connecting peripherals, such as a CD-ROM, scanner, or your Jaz® drive, to most personal computers. SCSI guidelines define how to connect more than one SCSI device to the same SCSI connection (either built-in or from a SCSI card). A SCSI card is the device that plugs into your motherboard and to which the SCSI devices are connected.
SCSI Chain
A SCSI chain is a series of SCSI devices, both internal and external, cabled one to another on a single SCSI connection. You can add your Jaz® drive to a SCSI chain.
Ultra SCSI Chain
It is recommended that the combined chain length of all internal and external SCSI devices connected to one Ultra SCSI card not exceed 1.5 meters or about 5 feet. SCSI devices that are not Ultra SCSI should be connected at the end of the chain.
CAUTION! To avoid damage to your hardware, always turn off power to all devices in the SCSI chain before making any change to the SCSI configuration.
- Before installing your Jaz® drive, check the SCSI IDs of your existing SCSI devices.
The SCSI ID is an address number, ranging from 0 to 7, that is assigned to each SCSI device. Each device in a SCSI chain must have a different SCSI ID number and ID 7 should not be used for any device. It is usually reserved for use by the SCSI card.
The SCSI ID for internal SCSI devices is usually set with jumpers (a jumper is a small plastic block that fits over and connects a set of metal pins). Refer to the documentation that came with the drive for information on setting the SCSI ID. If you are not able to see the SCSI ID assigned to each of the devices in the chain externally, you may be able to use these steps to find them on your computer:
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Checking the SCSI IDs on a Mac
If you have Mac OS 7.6 or higher you can use the Apple System Profiler to check the IDs of the devices in the SCSI chain.
- Go to the Apple Menu and select the Apple System Profiler.
- Depending on your version of Apple System Profiler, you will need to either select Device Information under the Select menu or click on the Devices and Volumes tab.
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NOTE: If Apple System Profiler lists more than one SCSI bus, you will need to select the correct one for your Jaz® drive. SCSI bus 0 is generally the internal (hard drive's) SCSI bus, and SCSI bus 1 is for the external. If you are connecting to a SCSI card such as the Jaz Ultra SCSI PCI card, it may appear as a bus number other than 0 or 1.
- If there is another device on SCSI ID 4, you will need to change the SCSI ID of your Jaz® drive. For instructions on changing the SCSI ID of your Jaz drive see step 3 Set the SCSI ID on your Jaz drive. If you do not need to change the SCSI ID, go to step 3 Connect the SCSI cable from your existing SCSI chain to your Jaz drive".
CAUTION! Do not set the SCSI ID on the Jaz® drive to 0 or 7. These SCSI ID numbers are used by the SCSI controller card and the internal hard disk. The factory default setting of your Jaz® drive is SCSI ID 4.
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Checking the SCSI IDs on PCs running Windows 95/98
- Replace the computer's cover and start your computer.
- Go to the Start menu, select Settings.
- Select Control Panel.
- Double click on System, then click on Device Manager.
- Double click on Disk Drives in the list of devices shown.
- Click on the first drive shown under Disk Drives to highlight it, then select Properties.
- Select the Settings tab and note the Target ID. This Target ID is the SCSI ID that the device is using. If it doesn't show a Target ID, it isn't a SCSI device.
- Close the current window for the first drive and repeat steps 5 and 6 for the remaining drives under Disk Drives. Once you have completed this for all of the drives, you will have a list of all of the SCSI IDs that are currently in use.
- Shut down the computer and turn the power off before connecting or disconnecting any SCSI devices.
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- Set the SCSI ID on your Jaz®
If another device in the SCSI chain is using SCSI ID 4, you can change the ID on your Jaz® drive by setting the SCSI ID jumpers (the jumpers are the small plastic blocks that fit over and connect the sets of metal pins). Locate the jumpers on the bottom of the Jaz drive.
There is a transparent piece of tape covering the jumpers. Remove the tape to expose the jumpers.
Remove the jumper blocks from the jumpers and set them to the desired SCSI ID. Your Jaz® drive can be set to any SCSI ID as long as that ID is not being used by another SCSI device. Refer to the illustration below to configure the Jaz drive to an unused SCSI ID.
- Connect the SCSI cable from your existing SCSI chain to your Jaz®
NOTE: If there is more than two internal drives (including the Jaz drive) in the SCSI chain, you will need to use a different data cable in order to daisy-chain your internal devices. See the internet address or phone number below to order a Jaz® internal dual-drive cable from Iomega.
Find the existing SCSI cable in your computer and connect the Jaz® drive to the middle connector. If your existing SCSI cable doesn't have an open connector on it, you will need a different SCSI cable.To order from Iomega online, go to: http://www.iomega.com/direct/main/home.jsp. To order from Iomega by phone, call: 1-412-690-2100 or purchase one from your local computer dealer.
Connect the Jaz® drive with the middle connector of your existing SCSI cable. You may need to disconnect the cable from your existing SCSI drive to do this.
Making the Connection—If the connector on the existing SCSI cable is not keyed, make sure that the PIN 1 connections match. PIN 1 on the cable is usually indicated by a red stripe. PIN 1 on the Jaz® drive is toward the middle, next to the power connector.
- Set the SCSI Termination.
The data signal is constantly sent from one termination point in the SCSI chain to the other. If one side is not terminated properly, or too many devices are terminated, the SCSI chain may not work correctly.
NOTE: SCSI guidelines require that the two ends of the SCSI chain have termination on. Make sure that no devices in between the two ends are terminated. The SCSI card is also considered a device. Verify that the last device in your SCSI chain is terminated. This device may use a jumper to set the termination, or it may use a termination block similar to the one provided with your Jaz® drive. Refer to the documentation that came with that device for information on proper termination.
- Installing your drive.
SCSI Cards for Jaz® Drive
Your Jaz® drive is a high performance drive that will work with most PC/Mac SCSI cards. For maximum Jaz drive performance, use a card that supports Ultra SCSI data transfers (such as the Jaz® Jet® PCI Ultra SCSI card). Refer to the documentation that came with the SCSI card for information on enabling Ultra SCSI transfer speeds.
Non-Iomega SCSI Cards
If you are using a non-Iomega SCSI card to connect your Jaz® drive to a PC, it must have a compatible 32-bit miniport driver for Windows 95/98. If you are not sure that your SCSI card is 100 percent compatible, check with the dealer where you purchased the SCSI card or the SCSI card manufacturer. You can also check the Iomega web site for information on compatible adapters and/or cards for the Jaz drive at: http://www.iomega.com.
- Click Support.
- Go to the Find It section at the bottom of the page and type compatible SCSI adapters and click the Find It button.
- A query of questions will be loaded, next to the question for compatible SCSI adapters and/or cards. Click on Find It.
To take advantage of all the features of your Jaz® drive, make sure the necessary software for the SCSI card is correctly installed on your system before installing the Jaz drive.
NOTE: If your Ultra SCSI card has more than one internal connector, connect all devices to one or the other. If you have devices connected to both internal connectors, system lockups may result.
Ultra SCSI Performance
Your Jaz® drive is designed to use Ultra SCSI data transfers when it is connected to a PCI SCSI card that supports Ultra SCSI. (The Jaz 2GB drive will also work with Fast SCSI-2 cards, but not at Ultra SCSI speeds.) In order to get Ultra SCSI performance from the Jaz 2GB drive, you must enable Ultra SCSI transfer speeds on the card. Refer to the documentation that came with the SCSI card for information on Ultra SCSI performance.
When using Ultra SCSI performance with your Jaz® drive, observe the following recommendations:
- Use only shorter, premium quality data cables for any drives in the SCSI chain.
- It is recommended that the total of all cables in the Ultra SCSI chain not exceed 1.5 meters or about 5 feet. Note that the total cable length includes all internal and external connections to a single SCSI card or SCSI connection.
- Connect the Jaz® drive at the beginning of the SCSI chain, or closest to the SCSI card.
*1-412-690-2100 available in the U.S and Canada only.)
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