The vast majority of CD/DVD reading and writing drives are offered in one of the following interfaces.

• SCSI Interface

SCSI (pronounced "skuh-zee") is an acronym for the Small Computer Systems Interface. This interface is an American National Standards Institute (ANSI) standard for high-speed parallel data communication between computers and their peripheral devices. SCSI is a complex and powerful standard which allows you to connect, using a technique known as "daisy chaining," up to seven (SCSI 1 & 2) or fifteen (SCSI 3) different SCSI-compliant devices to one SCSI connection in your computer. The SCSI connection is made via a SCSI host adapter. SCSI devices that are commonly used with computers include hard disk drives, tape drives, disc reading drives, removable cartridge drives, disc writing drives, jukeboxes, scanners, and printers. The disconnect option must be enabled for all system SCSI devices and cards.

Following are some general rules to help you avoid any problems with SCSI devices.

• Always make sure that power is off on your computer and on all SCSI devices when connecting or removing a SCSI device.

• When you install a new SCSI device, check its address (SCSI ID) to make sure another device in the same chain is not already using that address.

• Always use high quality cables and host adapters.

• Avoid individual SCSI cables longer than six feet, and try to keep the total length of cabling in every single SCSI chain below 15 feet. If you absolutely must have long cabling runs, use an active terminator to boost and clean up signals on the SCSI bus.

• Make sure all the SCSI buses in the system are properly terminated. Only the first and the last device in the chain must be terminated. If the SCSI host adapter is the last device on the chain, make sure it is terminated (most SCSI host adapters provide internal bus termination that can usually be enabled or disabled from the board BIOS). Terminators may be internal or external. External terminators are small plugs that attach to the rear-panel of a device. Internal terminators are usually installed on the main circuit board of the SCSI device. Some internally terminated devices provide switches that let you switch the internal terminators on or off. Having more than two terminators in a SCSI chain can cause start-up problems, data transmission errors, and possible hardware damage. Whenever possible, use external active termination blocks.

• If you mix and match narrow (8 bit) and wide (16 bit) SCSI devices on the same SCSI bus, move all the wide devices to the end of the chain and make sure the last device is terminated.

• If you have more than one SCSI bus, try to balance the SCSI load among all the buses and keep the writing drives separated from all the other SCSI devices attached to the system. Generally, you should not daisy chain more than four writing drives to the same SCSI bus.

• Periodically check the SCSI interface and drive manufacturers' web site to download the latest device driver and firmware upgrade.

• IDE Interface

IDE stands for Integrated Drive Electronics. Other standards like ATA, UDMA, or EIDE may have different performance details but are all inter-compatible. IDE is a parallel data interface that is normally provided by PC manufacturers and is generally included when you purchase a new computer. Most computer motherboards come with Primary and Secondary IDE channels. Up to two IDE devices, a master and a slave, can be connected to each channel.

Because this interface is less sophisticated than other interfaces, IDE devices are usually more affordable. Please note that there are trade-offs. IDE devices rely on the CPU for calculating operations, where other devices have their own controller for operations. In a lot of cases this can limit how IDE devices are used.

Following are some general rules to help you avoid any problems with IDE devices.

• Always make sure that power is off on your computer and on all IDE devices when connecting or removing an IDE device.

• If you are considering using DiscJuggler with multiple drives, FireWire or SCSI are the recommended interfaces.

• Any device that you are communicating to and from cannot be interrupted during the recording process, or buffer under-runs will occur. To limit this make sure any device you and sending data to and from is a Master device on the IDE channel.

• Serial ATA Interface

Serial ATA replaces the IDE interface. Serial ATA was introduced at speeds up to 150 megabytes per second and is moving forward with plans to support speeds up to 600 megabytes per second. This new interface is fully compliant with the ATA protocol, resulting in automatic support from operating systems and software supporting ATA devices. While IDE supports two devices each shared channel, Serial ATA uses a point-to-point connection for dedicated bandwidth to each device. Additional benefits of Serial ATA over IDE include smarter cabling, hot-swap support, and error checking.

Following are some general rules to help you avoid any problems with Serial ATA devices.

• If you are considering using DiscJuggler with multiple drives, FireWire or SCSI are the recommended interfaces. Writing to multiple drives through Serial ATA is feasible, but only likely with a completely native solution.

• Some Serial ATA controllers require that the device be removed from the Device Manager before being unplugged. Failing to do so can result in the controller hanging.

• DiscJuggler will not display changes to devices plugged in or unplugged while running and will need to be restarted.

• FireWire Interface

FireWire is a standard interface for connecting storage, digital video, and many other devices to your computer. Developed by Apple Computer, FireWire 400 (IEEE-1394a) offers data bandwidth up to 50 per second and FireWire 800 (IEEE-1394b) offers data bandwidth up to 100 megabytes per second. One FireWire controller can support up to 63 devices, with the assistance of one or more FireWire hubs. The FireWire standard has special modes for transferring video and other "synchronous" information, making it ideal for communicating with video cameras. The version of FireWire developed by Sony for its video equipment is called i.LINK.

Following are some general rules to help you avoid any problems with FireWire devices.

• Neither Windows NT nor Windows 95 support this interface.

• Windows XP Service Pack 2 was released with crippled support of FireWire 800. Check with Microsoft and the manufacturers of your FireWire 800 devices for solutions.

• The amount of devices that you can have daisy-chained to one FireWire host adapter depends on many factors. There should be no problems running 4 drives on one host adapter, or possibly even more than that. If you notice performance is lacking with the amount of drives you have on one host adapter, purchase an identical host adapter and split up the number of drives to both host adapters.

• Always use high quality cables and host adapters.

• Windows will assign drive letters randomly, as these are Plug-and-Play devices. Take note of what drives are assigned to what drive letters by using the Eject command in Explorer, if important to you and your use of these drives.

• DiscJuggler will not display changes to devices plugged in or unplugged while running and will need to be restarted.

• USB Interface

USB stands for Universal Serial Bus. USB 1.1 offers a data speed of up to 1.2 megabytes per second and was developed to connect a low bandwidth devices such as keyboards, mice, scanners, and printers. USB 2.0 offers a data bandwidth up to 60 megabytes per second and was developed to compete with FireWire, offering bandwidth needed for multimedia devices. USB is a low cost interface integrated with most modern PCs and offers many benefits over traditional connection methods including better cabling and greater expansibility. With the assistance of one or more USB hubs, a single USB controller can handle up to 125 devices.

Following are some general rules to help you avoid any problems with USB devices.

• Neither Windows NT nor Windows 95 support this interface.

• If you are considering using DiscJuggler with multiple drives, FireWire or SCSI are the recommended interfaces.

• Always use high quality cables and host adapters.

• Because of the low bandwidth found in USB 1.1, we recommend using that bus only when none of the above are available.

• Windows will assign drive letters randomly, as these are Plug-and-Play devices. Take note of what drives are assigned to what drive letters by using the Eject command in Explorer, if important to you and your use of these drives.

• DiscJuggler will not display changes to devices plugged in or unplugged while running and will need to be restarted.

Please visit the Writing to Multiple Drives section of the Advanced Concepts chapter for additional information on multiple drive interfaces.