1. SCSI (pronounced scuzzy) stands for Small Computer System Interface. SCSI is a ribbon, a specification, and an electronic protocol for communication between devices and computers. Like your IDE ribbons, SCSI ribbons can connect to their own SCSI hard disks. SCSI ribbons have gone through some versions to make SCSI faster, the latest ``Ultra-Wide'' SCSI ribbons are thin, with a dense array of pins. Unlike your IDE, SCSI can also connect tape drives, scanners, and many other types of peripherals. SCSI theoretically allows multiple computers to share the same device, although I have not seen this implemented in practice. Because many UNIX hardware platforms only support SCSI, it has become an integral part of UNIX operating systems. SCSIs also introduce the concept of LUNs (which stands for Logical Unit Number), Buses, and ID. These are just numbers given to each device in order of the SCSI cards you are using (if more than one), the SCSI cables on those cards, and the SCSI devices on those cables--the SCSI standard was designed to support a great many of these. The kernel assigns each SCSI drive in sequence as it finds them: /dev/sda, /dev/sdb, and so on, so these details are usually irrelevant. An enormous amount should be said on SCSI, but the bare bones is that for 90% of situations, insmod <pci-scsi-driver> is all you are going to need. You can then immediately begin accessing the device through /dev/sd? for disks, /dev/st? for tapes, /dev/scd? for CD-ROMs, or /dev/sg? for scanners. [Scanner user programs will have docs on what devices they access.] SCSIs often also come with their own BIOS that you can enter on startup (like your CMOS). This will enable you to set certain things. In some cases, where your distribution compiles-out certain modules, you may have to load one of sd_mod.o, st.o, sr_mod.o, or sg.o, respectively. The core scsi_mod.o module may also need loading, and /dev/ devices may need to be created. From Rute-Users-Guide