If you have a SCSI host adapter in your system, you'll find a subdirectory named after the driver for this adapter in /proc/scsi.
NOTE: The general rule is that the contents, or even the existence of the /proc/scsi directory, depends on your kernel configuration. If SCSI is not enabled, the /proc/scsi directory may not exist.
To see a list of all recognized SCSI devices in /proc/scsi:
cat /proc/scsi/scsi Attached devices: Host: scsi0 Channel: 00 Id: 00 Lun: 00 Vendor: IBM Model: DGHS09U Rev: 03E0 Type: Direct-Access ANSI SCSI revision: 03 Host: scsi0 Channel: 00 Id: 06 Lun: 00 Vendor: PIONEER Model: CD-ROM DR-U06S Rev: 1.04 Type: CD-ROM ANSI SCSI revision: 02
The directory named after the driver has one file for each adapter found in the system. These files contain information about the controller, including the used IRQ and the IO address range. The amount of information shown is dependent on the adapter you use. This example shows the output for an Adaptec AHA-2940 SCSI adapter:
cat /proc/scsi/aic7xxx/0 Adaptec AIC7xxx driver version: 5.1.19/3.2.4 Compile Options: TCQ Enabled By Default : Disabled AIC7XXX_PROC_STATS : Disabled AIC7XXX_RESET_DELAY : 5 Adapter Configuration: SCSI Adapter: Adaptec AHA-294X Ultra SCSI host adapter Ultra Wide Controller PCI MMAPed I/O Base: 0xeb001000 Adapter SEEPROM Config: SEEPROM found and used. Adaptec SCSI BIOS: Enabled IRQ: 10 SCBs: Active 0, Max Active 2, Allocated 15, HW 16, Page 255 Interrupts: 160328 BIOS Control Word: 0x18b6 Adapter Control Word: 0x005b Extended Translation: Enabled Disconnect Enable Flags: 0xffff Ultra Enable Flags: 0x0001 Tag Queue Enable Flags: 0x0000 Ordered Queue Tag Flags: 0x0000 Default Tag Queue Depth: 8 Tagged Queue By Device array for aic7xxx host instance 0: {255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255} Actual queue depth per device for aic7xxx host instance 0: {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1} Statistics: (scsi0:0:0:0) Device using Wide/Sync transfers at 40.0 MByte/sec, offset 8 Transinfo settings: current(12/8/1/0), goal(12/8/1/0), user(12/15/1/0) Total transfers 160151 (74577 reads and 85574 writes) (scsi0:0:6:0) Device using Narrow/Sync transfers at 5.0 MByte/sec, offset 15 Transinfo settings: current(50/15/0/0), goal(50/15/0/0), user(50/15/0/0) Total transfers 0 (0 reads and 0 writes)