O IDE Drives: Ultra Series Emulators can use an internal IDE hard disk. IDE drives have several advantages such as low cost, high capacity, low noise and they don’t use up a precious SCSI ID number.
• Order IDE installation kit number 6303. This kit includes everything necessary except the IDE drive.
SCSI
SCSI (pronounced skuzzy) stands for Small Computer System Interface. SCSI is an industry standard hardware and software specification that allows high-speed data transfers between different pieces of equipment. SCSI devices can include hard disks, tape drives, optical disks and other types of digital equipment.
Why Use SCSI?
•SCSI is fast! SCSI is a parallel interface which transmits eight bits of information at a time at high speed over the SCSI cable. MIDI, in comparison, is a serial interface which can only send one bit of information at a time over its line.
•Compatibility: Since SCSI is an industry standard, equipment from many different manufacturers can be linked to work together.
•Expandability: Up to eight SCSI devices can be linked together (the Emulator counts as one SCSI device on the chain).
The SCSI Bus
You may have noticed that the rear panel of most external storage devices have two SCSI connectors. This is because SCSI devices are connected together in a chain arrangement. The wires that connect the different pieces of equipment are called the SCSI bus.
ID Numbers
Each device on the SCSI bus has its own ID number so that it can distinguish its data from data meant for another device. For example, if data is being saved to a device with ID-2, all the other devices on the SCSI bus will ignore that data. If two devices have the same ID number, the system will not work. Each device must have its own unique ID number.
The SCSI ID number of a Macintosh computer is fixed at ID-7 and cannot be changed. The SCSI ID numbers of most other devices can be changed.
Many SCSI devices have hardware defined ID numbers, which means that they have a switch on the front or the back of the unit which allows the ID number to be easily identified and changed.